Merge first patch-bomb from Andrew Morton:
"Quite a lot of other stuff is banked up awaiting further
next->mainline merging, but this batch contains:
- Lots of random misc patches
- OCFS2
- Most of MM
- backlight updates
- lib/ updates
- printk updates
- checkpatch updates
- epoll tweaking
- rtc updates
- hfs
- hfsplus
- documentation
- procfs
- update gcov to gcc-4.7 format
- IPC"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (269 commits)
ipc, msg: fix message length check for negative values
ipc/util.c: remove unnecessary work pending test
devpts: plug the memory leak in kill_sb
./Makefile: export initial ramdisk compression config option
init/Kconfig: add option to disable kernel compression
drivers: w1: make w1_slave::flags long to avoid memory corruption
drivers/w1/masters/ds1wm.cuse dev_get_platdata()
drivers/memstick/core/ms_block.c: fix unreachable state in h_msb_read_page()
drivers/memstick/core/mspro_block.c: fix attributes array allocation
drivers/pps/clients/pps-gpio.c: remove redundant of_match_ptr
kernel/panic.c: reduce 1 byte usage for print tainted buffer
gcov: reuse kbasename helper
kernel/gcov/fs.c: use pr_warn()
kernel/module.c: use pr_foo()
gcov: compile specific gcov implementation based on gcc version
gcov: add support for gcc 4.7 gcov format
gcov: move gcov structs definitions to a gcc version specific file
kernel/taskstats.c: return -ENOMEM when alloc memory fails in add_del_listener()
kernel/taskstats.c: add nla_nest_cancel() for failure processing between nla_nest_start() and nla_nest_end()
kernel/sysctl_binary.c: use scnprintf() instead of snprintf()
...
Pull vfs updates from Al Viro:
"All kinds of stuff this time around; some more notable parts:
- RCU'd vfsmounts handling
- new primitives for coredump handling
- files_lock is gone
- Bruce's delegations handling series
- exportfs fixes
plus misc stuff all over the place"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (101 commits)
ecryptfs: ->f_op is never NULL
locks: break delegations on any attribute modification
locks: break delegations on link
locks: break delegations on rename
locks: helper functions for delegation breaking
locks: break delegations on unlink
namei: minor vfs_unlink cleanup
locks: implement delegations
locks: introduce new FL_DELEG lock flag
vfs: take i_mutex on renamed file
vfs: rename I_MUTEX_QUOTA now that it's not used for quotas
vfs: don't use PARENT/CHILD lock classes for non-directories
vfs: pull ext4's double-i_mutex-locking into common code
exportfs: fix quadratic behavior in filehandle lookup
exportfs: better variable name
exportfs: move most of reconnect_path to helper function
exportfs: eliminate unused "noprogress" counter
exportfs: stop retrying once we race with rename/remove
exportfs: clear DISCONNECTED on all parents sooner
exportfs: more detailed comment for path_reconnect
...
The get_dumpable() return value is not boolean. Most users of the
function actually want to be testing for non-SUID_DUMP_USER(1) rather than
SUID_DUMP_DISABLE(0). The SUID_DUMP_ROOT(2) is also considered a
protected state. Almost all places did this correctly, excepting the two
places fixed in this patch.
Wrong logic:
if (dumpable == SUID_DUMP_DISABLE) { /* be protective */ }
or
if (dumpable == 0) { /* be protective */ }
or
if (!dumpable) { /* be protective */ }
Correct logic:
if (dumpable != SUID_DUMP_USER) { /* be protective */ }
or
if (dumpable != 1) { /* be protective */ }
Without this patch, if the system had set the sysctl fs/suid_dumpable=2, a
user was able to ptrace attach to processes that had dropped privileges to
that user. (This may have been partially mitigated if Yama was enabled.)
The macros have been moved into the file that declares get/set_dumpable(),
which means things like the ia64 code can see them too.
CVE-2013-2929
Reported-by: Vasily Kulikov <segoon@openwall.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the audit_bprm() call from search_binary_handler() to exec_binprm(). This
allows us to get rid of the mm member of struct audit_aux_data_execve since
bprm->mm will equal current->mm.
This also mitigates the issue that ->argc could be modified by the
load_binary() call in search_binary_handler().
audit_bprm() was being called to add an AUDIT_EXECVE record to the audit
context every time search_binary_handler() was recursively called. Only one
reference is necessary.
Reported-by: Oleg Nesterov <onestero@redhat.com>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
---
This patch is against 3.11, but was developed on Oleg's post-3.11 patches that
introduce exec_binprm().
It is possible for a task in a numa group to call exec, and
have the new (unrelated) executable inherit the numa group
association from its former self.
This has the potential to break numa grouping, and is trivial
to fix.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1381141781-10992-51-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The error hanling and ret-from-loop look confusing and inconsistent.
- "retval >= 0" simply returns
- "!bprm->file" returns too but with read_unlock() because
binfmt_lock was already re-acquired
- "retval != -ENOEXEC || bprm->mm == NULL" does "break" and
relies on the same check after the main loop
Consolidate these checks into a single if/return statement.
need_retry still checks "retval == -ENOEXEC", but this and -ENOENT before
the main loop are not needed. This is only for pathological and
impossible list_empty(&formats) case.
It is not clear why do we check "bprm->mm == NULL", probably this
should be removed.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Zach Levis <zml@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A separate one-liner for better documentation.
It doesn't make sense to retry if request_module() fails to exec
/sbin/modprobe, add the additional "request_module() < 0" check.
However, this logic still doesn't look exactly right:
1. It would be better to check "request_module() != 0", the user
space modprobe process should report the correct exit code.
But I didn't dare to add the user-visible change.
2. The whole ENOEXEC logic looks suboptimal. Suppose that we try
to exec a "#!path-to-unsupported-binary" script. In this case
request_module() + "retry" will be done twice: first by the
"depth == 1" code, and then again by the "depth == 0" caller
which doesn't make sense.
3. And note that in the case above bprm->buf was already changed
by load_script()->prepare_binprm(), so this looks even more
ugly.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Zach Levis <zml@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
search_binary_handler() uses "for (try=0; try<2; try++)" to avoid "goto"
but the code looks too complicated and horrible imho. We still need to
check "try == 0" before request_module() and add the additional "break"
for !CONFIG_MODULES case.
Kill this loop and use a simple "bool need_retry" + "goto retry". The
code looks much simpler and we do not even need ifdef's, gcc can optimize
out the "if (need_retry)" block if !IS_ENABLED().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Zach Levis <zml@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
search_binary_handler() checks ->load_binary != NULL for no reason, this
method should be always defined. Turn this check into WARN_ON() and move
it into __register_binfmt().
Also, kill the function pointer. The current code looks confusing, as if
->load_binary can go away after read_unlock(&binfmt_lock). But we rely on
module_get(fmt->module), this fmt can't be changed or unregistered,
otherwise this code is buggy anyway.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Zach Levis <zml@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When search_binary_handler() succeeds it does allow_write_access() and
fput(), then it clears bprm->file to ensure the caller will not do the
same.
We can simply move this code to exec_binprm() which is called only once.
In fact we could move this to free_bprm() and remove the same code in
do_execve_common's error path.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Zach Levis <zml@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A separate one-liner with the minor fix.
PROC_EVENT_EXEC reports the "exec" event, but this message is sent at
least twice if search_binary_handler() is called by ->load_binary()
recursively, say, load_script().
Move it to exec_binprm(), this is "depth == 0" code too.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Zach Levis <zml@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nobody except search_binary_handler() should touch ->recursion_depth, "int
depth" buys nothing but complicates the code, kill it.
Probably we should also kill "fn" and the !NULL check, ->load_binary
should be always defined. And it can not go away after read_unlock() or
this code is buggy anyway.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Zach Levis <zml@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
task_pid_nr_ns() and trace/ptrace code in the middle of the recursive
search_binary_handler() looks confusing and imho annoying. We only need
this code if "depth == 0", lets add a simple helper which calls
search_binary_handler() and does trace_sched_process_exec() +
ptrace_event().
The patch also moves the setting of task->did_exec, we need to do this
only once.
Note: we can kill either task->did_exec or PF_FORKNOEXEC.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Zach Levis <zml@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pavel reported that in case if vma area get unmapped and then mapped (or
expanded) in-place, the soft dirty tracker won't be able to recognize this
situation since it works on pte level and ptes are get zapped on unmap,
loosing soft dirty bit of course.
So to resolve this situation we need to track actions on vma level, there
VM_SOFTDIRTY flag comes in. When new vma area created (or old expanded)
we set this bit, and keep it here until application calls for clearing
soft dirty bit.
Thus when user space application track memory changes now it can detect if
vma area is renewed.
Reported-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Rob Landley <rob@landley.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ben Tebulin reported:
"Since v3.7.2 on two independent machines a very specific Git
repository fails in 9/10 cases on git-fsck due to an SHA1/memory
failures. This only occurs on a very specific repository and can be
reproduced stably on two independent laptops. Git mailing list ran
out of ideas and for me this looks like some very exotic kernel issue"
and bisected the failure to the backport of commit 53a59fc67f ("mm:
limit mmu_gather batching to fix soft lockups on !CONFIG_PREEMPT").
That commit itself is not actually buggy, but what it does is to make it
much more likely to hit the partial TLB invalidation case, since it
introduces a new case in tlb_next_batch() that previously only ever
happened when running out of memory.
The real bug is that the TLB gather virtual memory range setup is subtly
buggered. It was introduced in commit 597e1c3580 ("mm/mmu_gather:
enable tlb flush range in generic mmu_gather"), and the range handling
was already fixed at least once in commit e6c495a96c ("mm: fix the TLB
range flushed when __tlb_remove_page() runs out of slots"), but that fix
was not complete.
The problem with the TLB gather virtual address range is that it isn't
set up by the initial tlb_gather_mmu() initialization (which didn't get
the TLB range information), but it is set up ad-hoc later by the
functions that actually flush the TLB. And so any such case that forgot
to update the TLB range entries would potentially miss TLB invalidates.
Rather than try to figure out exactly which particular ad-hoc range
setup was missing (I personally suspect it's the hugetlb case in
zap_huge_pmd(), which didn't have the same logic as zap_pte_range()
did), this patch just gets rid of the problem at the source: make the
TLB range information available to tlb_gather_mmu(), and initialize it
when initializing all the other tlb gather fields.
This makes the patch larger, but conceptually much simpler. And the end
result is much more understandable; even if you want to play games with
partial ranges when invalidating the TLB contents in chunks, now the
range information is always there, and anybody who doesn't want to
bother with it won't introduce subtle bugs.
Ben verified that this fixes his problem.
Reported-bisected-and-tested-by: Ben Tebulin <tebulin@googlemail.com>
Build-testing-by: Stephen Rothwell <sfr@canb.auug.org.au>
Build-testing-by: Richard Weinberger <richard.weinberger@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
924b42d5 ("Use boot based time for process start time and boot time in
/proc") updated copy_process/do_task_stat but forgot about de_thread().
This breaks "ps axOT" if a sub-thread execs.
Note: I think that task->start_time should die.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: John Stultz <johnstul@us.ibm.com>
Cc: Tomas Janousek <tjanouse@redhat.com>
Cc: Tomas Smetana <tsmetana@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Trivial cleanup. do_execve_common() can use current_user() and avoid the
unnecessary "struct cred *cred" var.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
de_thread() can use change_pid() instead of detach + attach. This looks
better and this ensures that, say, next_thread() can never see a task with
->pid == NULL.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Sergey Dyasly <dserrg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull second set of VFS changes from Al Viro:
"Assorted f_pos race fixes, making do_splice_direct() safe to call with
i_mutex on parent, O_TMPFILE support, Jeff's locks.c series,
->d_hash/->d_compare calling conventions changes from Linus, misc
stuff all over the place."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
Document ->tmpfile()
ext4: ->tmpfile() support
vfs: export lseek_execute() to modules
lseek_execute() doesn't need an inode passed to it
block_dev: switch to fixed_size_llseek()
cpqphp_sysfs: switch to fixed_size_llseek()
tile-srom: switch to fixed_size_llseek()
proc_powerpc: switch to fixed_size_llseek()
ubi/cdev: switch to fixed_size_llseek()
pci/proc: switch to fixed_size_llseek()
isapnp: switch to fixed_size_llseek()
lpfc: switch to fixed_size_llseek()
locks: give the blocked_hash its own spinlock
locks: add a new "lm_owner_key" lock operation
locks: turn the blocked_list into a hashtable
locks: convert fl_link to a hlist_node
locks: avoid taking global lock if possible when waking up blocked waiters
locks: protect most of the file_lock handling with i_lock
locks: encapsulate the fl_link list handling
locks: make "added" in __posix_lock_file a bool
...
There was a a bug in setup_new_exec(), whereby
the test to disabled perf monitoring was not
correct because the new credentials for the
process were not yet committed and therefore
the get_dumpable() test was never firing.
The patch fixes the problem by moving the
perf_event test until after the credentials
are committed.
Signed-off-by: Stephane Eranian <eranian@google.com>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull VFS updates from Al Viro,
Misc cleanups all over the place, mainly wrt /proc interfaces (switch
create_proc_entry to proc_create(), get rid of the deprecated
create_proc_read_entry() in favor of using proc_create_data() and
seq_file etc).
7kloc removed.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits)
don't bother with deferred freeing of fdtables
proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h
proc: Make the PROC_I() and PDE() macros internal to procfs
proc: Supply a function to remove a proc entry by PDE
take cgroup_open() and cpuset_open() to fs/proc/base.c
ppc: Clean up scanlog
ppc: Clean up rtas_flash driver somewhat
hostap: proc: Use remove_proc_subtree()
drm: proc: Use remove_proc_subtree()
drm: proc: Use minor->index to label things, not PDE->name
drm: Constify drm_proc_list[]
zoran: Don't print proc_dir_entry data in debug
reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show()
proc: Supply an accessor for getting the data from a PDE's parent
airo: Use remove_proc_subtree()
rtl8192u: Don't need to save device proc dir PDE
rtl8187se: Use a dir under /proc/net/r8180/
proc: Add proc_mkdir_data()
proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h}
proc: Move PDE_NET() to fs/proc/proc_net.c
...
threadgroup_lock() takes signal->cred_guard_mutex to ensure that
thread_group_leader() is stable. This doesn't look nice, the scope of
this lock in do_execve() is huge.
And as Dave pointed out this can lead to deadlock, we have the
following dependencies:
do_execve: cred_guard_mutex -> i_mutex
cgroup_mount: i_mutex -> cgroup_mutex
attach_task_by_pid: cgroup_mutex -> cred_guard_mutex
Change de_thread() to take threadgroup_change_begin() around the
switch-the-leader code and change threadgroup_lock() to avoid
->cred_guard_mutex.
Note that de_thread() can't sleep with ->group_rwsem held, this can
obviously deadlock with the exiting leader if the writer is active, so it
does threadgroup_change_end() before schedule().
Reported-by: Dave Jones <davej@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
set_task_comm() does memset() + wmb() before strlcpy(). This buys
nothing and to add to the confusion, the comment is wrong.
- We do not need memset() to be "safe from non-terminating string
reads", the final char is always zero and we never change it.
- wmb() is paired with nothing, it cannot prevent from printing
the mixture of the old/new data unless the reader takes the lock.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On architectures where a pgd entry may be shared between user and kernel
(e.g. ARM+LPAE), freeing page tables needs a ceiling other than 0.
This patch introduces a generic USER_PGTABLES_CEILING that arch code can
override. It is the responsibility of the arch code setting the ceiling
to ensure the complete freeing of the page tables (usually in
pgd_free()).
[catalin.marinas@arm.com: commit log; shift_arg_pages(), asm-generic/pgtables.h changes]
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: <stable@vger.kernel.org> [3.3+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
switch binfmts that use ->read() to that (and to kernel_read()
in several cases in binfmt_flat - sure, it's nommu, but still,
doing ->read() into kmalloc'ed buffer...)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The existing SUID_DUMP_* defines duplicate the newer SUID_DUMPABLE_*
defines introduced in 54b501992d ("coredump: warn about unsafe
suid_dumpable / core_pattern combo"). Remove the new ones, and use the
prior values instead.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Chen Gang <gang.chen@asianux.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alan Cox <alan@linux.intel.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: James Morris <james.l.morris@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is only one user of bprm_mm_init, and it's inside the same file.
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The tricky problem is this check:
if (i++ >= max)
icc (mis)optimizes this check as:
if (++i > max)
The check now becomes a no-op since max is MAX_ARG_STRINGS (0x7FFFFFFF).
This is "allowed" by the C standard, assuming i++ never overflows,
because signed integer overflow is undefined behavior. This
optimization effectively reverts the previous commit 362e6663ef
("exec.c, compat.c: fix count(), compat_count() bounds checking") that
tries to fix the check.
This patch simply moves ++ after the check.
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge the rest of Andrew's patches for -rc1:
"A bunch of fixes and misc missed-out-on things.
That'll do for -rc1. I still have a batch of IPC patches which still
have a possible bug report which I'm chasing down."
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (25 commits)
keys: use keyring_alloc() to create module signing keyring
keys: fix unreachable code
sendfile: allows bypassing of notifier events
SGI-XP: handle non-fatal traps
fat: fix incorrect function comment
Documentation: ABI: remove testing/sysfs-devices-node
proc: fix inconsistent lock state
linux/kernel.h: fix DIV_ROUND_CLOSEST with unsigned divisors
memcg: don't register hotcpu notifier from ->css_alloc()
checkpatch: warn on uapi #includes that #include <uapi/...
revert "rtc: recycle id when unloading a rtc driver"
mm: clean up transparent hugepage sysfs error messages
hfsplus: add error message for the case of failure of sync fs in delayed_sync_fs() method
hfsplus: rework processing of hfs_btree_write() returned error
hfsplus: rework processing errors in hfsplus_free_extents()
hfsplus: avoid crash on failed block map free
kcmp: include linux/ptrace.h
drivers/rtc/rtc-imxdi.c: must include <linux/spinlock.h>
mm: cma: WARN if freed memory is still in use
exec: do not leave bprm->interp on stack
...
Pull signal handling cleanups from Al Viro:
"sigaltstack infrastructure + conversion for x86, alpha and um,
COMPAT_SYSCALL_DEFINE infrastructure.
Note that there are several conflicts between "unify
SS_ONSTACK/SS_DISABLE definitions" and UAPI patches in mainline;
resolution is trivial - just remove definitions of SS_ONSTACK and
SS_DISABLED from arch/*/uapi/asm/signal.h; they are all identical and
include/uapi/linux/signal.h contains the unified variant."
Fixed up conflicts as per Al.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
alpha: switch to generic sigaltstack
new helpers: __save_altstack/__compat_save_altstack, switch x86 and um to those
generic compat_sys_sigaltstack()
introduce generic sys_sigaltstack(), switch x86 and um to it
new helper: compat_user_stack_pointer()
new helper: restore_altstack()
unify SS_ONSTACK/SS_DISABLE definitions
new helper: current_user_stack_pointer()
missing user_stack_pointer() instances
Bury the conditionals from kernel_thread/kernel_execve series
COMPAT_SYSCALL_DEFINE: infrastructure
If a series of scripts are executed, each triggering module loading via
unprintable bytes in the script header, kernel stack contents can leak
into the command line.
Normally execution of binfmt_script and binfmt_misc happens recursively.
However, when modules are enabled, and unprintable bytes exist in the
bprm->buf, execution will restart after attempting to load matching
binfmt modules. Unfortunately, the logic in binfmt_script and
binfmt_misc does not expect to get restarted. They leave bprm->interp
pointing to their local stack. This means on restart bprm->interp is
left pointing into unused stack memory which can then be copied into the
userspace argv areas.
After additional study, it seems that both recursion and restart remains
the desirable way to handle exec with scripts, misc, and modules. As
such, we need to protect the changes to interp.
This changes the logic to require allocation for any changes to the
bprm->interp. To avoid adding a new kmalloc to every exec, the default
value is left as-is. Only when passing through binfmt_script or
binfmt_misc does an allocation take place.
For a proof of concept, see DoTest.sh from:
http://www.halfdog.net/Security/2012/LinuxKernelBinfmtScriptStackDataDisclosure/
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: halfdog <me@halfdog.net>
Cc: P J P <ppandit@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All architectures have
CONFIG_GENERIC_KERNEL_THREAD
CONFIG_GENERIC_KERNEL_EXECVE
__ARCH_WANT_SYS_EXECVE
None of them have __ARCH_WANT_KERNEL_EXECVE and there are only two callers
of kernel_execve() (which is a trivial wrapper for do_execve() now) left.
Kill the conditionals and make both callers use do_execve().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Merge misc patches from Andrew Morton:
"Incoming:
- lots of misc stuff
- backlight tree updates
- lib/ updates
- Oleg's percpu-rwsem changes
- checkpatch
- rtc
- aoe
- more checkpoint/restart support
I still have a pile of MM stuff pending - Pekka should be merging
later today after which that is good to go. A number of other things
are twiddling thumbs awaiting maintainer merges."
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (180 commits)
scatterlist: don't BUG when we can trivially return a proper error.
docs: update documentation about /proc/<pid>/fdinfo/<fd> fanotify output
fs, fanotify: add @mflags field to fanotify output
docs: add documentation about /proc/<pid>/fdinfo/<fd> output
fs, notify: add procfs fdinfo helper
fs, exportfs: add exportfs_encode_inode_fh() helper
fs, exportfs: escape nil dereference if no s_export_op present
fs, epoll: add procfs fdinfo helper
fs, eventfd: add procfs fdinfo helper
procfs: add ability to plug in auxiliary fdinfo providers
tools/testing/selftests/kcmp/kcmp_test.c: print reason for failure in kcmp_test
breakpoint selftests: print failure status instead of cause make error
kcmp selftests: print fail status instead of cause make error
kcmp selftests: make run_tests fix
mem-hotplug selftests: print failure status instead of cause make error
cpu-hotplug selftests: print failure status instead of cause make error
mqueue selftests: print failure status instead of cause make error
vm selftests: print failure status instead of cause make error
ubifs: use prandom_bytes
mtd: nandsim: use prandom_bytes
...
To avoid an explosion of request_module calls on a chain of abusive
scripts, fail maximum recursion with -ELOOP instead of -ENOEXEC. As soon
as maximum recursion depth is hit, the error will fail all the way back
up the chain, aborting immediately.
This also has the side-effect of stopping the user's shell from attempting
to reexecute the top-level file as a shell script. As seen in the
dash source:
if (cmd != path_bshell && errno == ENOEXEC) {
*argv-- = cmd;
*argv = cmd = path_bshell;
goto repeat;
}
The above logic was designed for running scripts automatically that lacked
the "#!" header, not to re-try failed recursion. On a legitimate -ENOEXEC,
things continue to behave as the shell expects.
Additionally, when tracking recursion, the binfmt handlers should not be
involved. The recursion being tracked is the depth of calls through
search_binary_handler(), so that function should be exclusively responsible
for tracking the depth.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: halfdog <me@halfdog.net>
Cc: P J P <ppandit@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull user namespace changes from Eric Biederman:
"While small this set of changes is very significant with respect to
containers in general and user namespaces in particular. The user
space interface is now complete.
This set of changes adds support for unprivileged users to create user
namespaces and as a user namespace root to create other namespaces.
The tyranny of supporting suid root preventing unprivileged users from
using cool new kernel features is broken.
This set of changes completes the work on setns, adding support for
the pid, user, mount namespaces.
This set of changes includes a bunch of basic pid namespace
cleanups/simplifications. Of particular significance is the rework of
the pid namespace cleanup so it no longer requires sending out
tendrils into all kinds of unexpected cleanup paths for operation. At
least one case of broken error handling is fixed by this cleanup.
The files under /proc/<pid>/ns/ have been converted from regular files
to magic symlinks which prevents incorrect caching by the VFS,
ensuring the files always refer to the namespace the process is
currently using and ensuring that the ptrace_mayaccess permission
checks are always applied.
The files under /proc/<pid>/ns/ have been given stable inode numbers
so it is now possible to see if different processes share the same
namespaces.
Through the David Miller's net tree are changes to relax many of the
permission checks in the networking stack to allowing the user
namespace root to usefully use the networking stack. Similar changes
for the mount namespace and the pid namespace are coming through my
tree.
Two small changes to add user namespace support were commited here adn
in David Miller's -net tree so that I could complete the work on the
/proc/<pid>/ns/ files in this tree.
Work remains to make it safe to build user namespaces and 9p, afs,
ceph, cifs, coda, gfs2, ncpfs, nfs, nfsd, ocfs2, and xfs so the
Kconfig guard remains in place preventing that user namespaces from
being built when any of those filesystems are enabled.
Future design work remains to allow root users outside of the initial
user namespace to mount more than just /proc and /sys."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (38 commits)
proc: Usable inode numbers for the namespace file descriptors.
proc: Fix the namespace inode permission checks.
proc: Generalize proc inode allocation
userns: Allow unprivilged mounts of proc and sysfs
userns: For /proc/self/{uid,gid}_map derive the lower userns from the struct file
procfs: Print task uids and gids in the userns that opened the proc file
userns: Implement unshare of the user namespace
userns: Implent proc namespace operations
userns: Kill task_user_ns
userns: Make create_new_namespaces take a user_ns parameter
userns: Allow unprivileged use of setns.
userns: Allow unprivileged users to create new namespaces
userns: Allow setting a userns mapping to your current uid.
userns: Allow chown and setgid preservation
userns: Allow unprivileged users to create user namespaces.
userns: Ignore suid and sgid on binaries if the uid or gid can not be mapped
userns: fix return value on mntns_install() failure
vfs: Allow unprivileged manipulation of the mount namespace.
vfs: Only support slave subtrees across different user namespaces
vfs: Add a user namespace reference from struct mnt_namespace
...
When performing an exec where the binary lives in one user namespace and
the execing process lives in another usre namespace there is the possibility
that the target uids can not be represented.
Instead of failing the exec simply ignore the suid/sgid bits and run
the binary with lower privileges. We already do this in the case
of MNT_NOSUID so this should be a well tested code path.
As the user and group are not changed this should not introduce any
security issues.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
...and fix up the callers. For do_file_open_root, just declare a
struct filename on the stack and fill out the .name field. For
do_filp_open, make it also take a struct filename pointer, and fix up its
callers to call it appropriately.
For filp_open, add a variant that takes a struct filename pointer and turn
filp_open into a wrapper around it.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
getname() is intended to copy pathname strings from userspace into a
kernel buffer. The result is just a string in kernel space. It would
however be quite helpful to be able to attach some ancillary info to
the string.
For instance, we could attach some audit-related info to reduce the
amount of audit-related processing needed. When auditing is enabled,
we could also call getname() on the string more than once and not
need to recopy it from userspace.
This patchset converts the getname()/putname() interfaces to return
a struct instead of a string. For now, the struct just tracks the
string in kernel space and the original userland pointer for it.
Later, we'll add other information to the struct as it becomes
convenient.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull generic execve() changes from Al Viro:
"This introduces the generic kernel_thread() and kernel_execve()
functions, and switches x86, arm, alpha, um and s390 over to them."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (26 commits)
s390: convert to generic kernel_execve()
s390: switch to generic kernel_thread()
s390: fold kernel_thread_helper() into ret_from_fork()
s390: fold execve_tail() into start_thread(), convert to generic sys_execve()
um: switch to generic kernel_thread()
x86, um/x86: switch to generic sys_execve and kernel_execve
x86: split ret_from_fork
alpha: introduce ret_from_kernel_execve(), switch to generic kernel_execve()
alpha: switch to generic kernel_thread()
alpha: switch to generic sys_execve()
arm: get rid of execve wrapper, switch to generic execve() implementation
arm: optimized current_pt_regs()
arm: introduce ret_from_kernel_execve(), switch to generic kernel_execve()
arm: split ret_from_fork, simplify kernel_thread() [based on patch by rmk]
generic sys_execve()
generic kernel_execve()
new helper: current_pt_regs()
preparation for generic kernel_thread()
um: kill thread->forking
um: let signal_delivered() do SIGTRAP on singlestepping into handler
...
During mremap(), the destination VMA is generally placed after the
original vma in rmap traversal order: in move_vma(), we always have
new_pgoff >= vma->vm_pgoff, and as a result new_vma->vm_pgoff >=
vma->vm_pgoff unless vma_merge() merged the new vma with an adjacent one.
When the destination VMA is placed after the original in rmap traversal
order, we can avoid taking the rmap locks in move_ptes().
Essentially, this reintroduces the optimization that had been disabled in
"mm anon rmap: remove anon_vma_moveto_tail". The difference is that we
don't try to impose the rmap traversal order; instead we just rely on
things being in the desired order in the common case and fall back to
taking locks in the uncommon case. Also we skip the i_mmap_mutex in
addition to the anon_vma lock: in both cases, the vmas are traversed in
increasing vm_pgoff order with ties resolved in tree insertion order.
Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Daniel Santos <daniel.santos@pobox.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change de_thread() to use KILLABLE rather than UNINTERRUPTIBLE while
waiting for other threads. The only complication is that we should
clear ->group_exit_task and ->notify_count before we return, and we
should do this under tasklist_lock. -EAGAIN is used to match the
initial signal_group_exit() check/return, it doesn't really matter.
This fixes the (unlikely) race with coredump. de_thread() checks
signal_group_exit() before it starts to kill the subthreads, but this
can't help if another CLONE_VM (but non CLONE_THREAD) task starts the
coredumping after de_thread() unlocks ->siglock. In this case the
killed sub-thread can block in exit_mm() waiting for coredump_finish(),
execing thread waits for that sub-thead, and the coredumping thread
waits for execing thread. Deadlock.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cosmetic. Change setup_new_exec() and task_dumpable() to use
SUID_DUMPABLE_ENABLED for /bin/grep.
[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Create a new header file, fs/coredump.h, which contains functions only
used by the new coredump.c. It also moves do_coredump to the
include/linux/coredump.h header file, for consistency.
Signed-off-by: Alex Kelly <alex.page.kelly@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This prepares for making core dump functionality optional.
The variable "suid_dumpable" and associated functions are left in fs/exec.c
because they're used elsewhere, such as in ptrace.
Signed-off-by: Alex Kelly <alex.page.kelly@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Selected by __ARCH_WANT_SYS_EXECVE in unistd.h. Requires
* working current_pt_regs()
* *NOT* doing a syscall-in-kernel kind of kernel_execve()
implementation. Using generic kernel_execve() is fine.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
based mostly on arm and alpha versions. Architectures can define
__ARCH_WANT_KERNEL_EXECVE and use it, provided that
* they have working current_pt_regs(), even for kernel threads.
* kernel_thread-spawned threads do have space for pt_regs
in the normal location. Normally that's as simple as switching to
generic kernel_thread() and making sure that kernel threads do *not*
go through return from syscall path; call the payload from equivalent
of ret_from_fork if we are in a kernel thread (or just have separate
ret_from_kernel_thread and make copy_thread() use it instead of
ret_from_fork in kernel thread case).
* they have ret_from_kernel_execve(); it is called after
successful do_execve() done by kernel_execve() and gets normal
pt_regs location passed to it as argument. It's essentially
a longjmp() analog - it should set sp, etc. to the situation
expected at the return for syscall and go there. Eventually
the need for that sucker will disappear, but that'll take some
surgery on kernel_thread() payloads.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull second vfs pile from Al Viro:
"The stuff in there: fsfreeze deadlock fixes by Jan (essentially, the
deadlock reproduced by xfstests 068), symlink and hardlink restriction
patches, plus assorted cleanups and fixes.
Note that another fsfreeze deadlock (emergency thaw one) is *not*
dealt with - the series by Fernando conflicts a lot with Jan's, breaks
userland ABI (FIFREEZE semantics gets changed) and trades the deadlock
for massive vfsmount leak; this is going to be handled next cycle.
There probably will be another pull request, but that stuff won't be
in it."
Fix up trivial conflicts due to unrelated changes next to each other in
drivers/{staging/gdm72xx/usb_boot.c, usb/gadget/storage_common.c}
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits)
delousing target_core_file a bit
Documentation: Correct s_umount state for freeze_fs/unfreeze_fs
fs: Remove old freezing mechanism
ext2: Implement freezing
btrfs: Convert to new freezing mechanism
nilfs2: Convert to new freezing mechanism
ntfs: Convert to new freezing mechanism
fuse: Convert to new freezing mechanism
gfs2: Convert to new freezing mechanism
ocfs2: Convert to new freezing mechanism
xfs: Convert to new freezing code
ext4: Convert to new freezing mechanism
fs: Protect write paths by sb_start_write - sb_end_write
fs: Skip atime update on frozen filesystem
fs: Add freezing handling to mnt_want_write() / mnt_drop_write()
fs: Improve filesystem freezing handling
switch the protection of percpu_counter list to spinlock
nfsd: Push mnt_want_write() outside of i_mutex
btrfs: Push mnt_want_write() outside of i_mutex
fat: Push mnt_want_write() outside of i_mutex
...
In commit 898b374af6 ("exec: replace call_usermodehelper_pipe with use
of umh init function and resolve limit"), the core limits recursive
check value was changed from 0 to 1, but the corresponding comments were
not updated.
Signed-off-by: Jovi Zhang <bookjovi@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When suid_dumpable=2, detect unsafe core_pattern settings and warn when
they are seen.
Signed-off-by: Kees Cook <keescook@chromium.org>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alan Cox <alan@linux.intel.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: James Morris <james.l.morris@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the suid_dumpable sysctl is set to "2", and there is no core dump
pipe defined in the core_pattern sysctl, a local user can cause core files
to be written to root-writable directories, potentially with
user-controlled content.
This means an admin can unknowningly reintroduce a variation of
CVE-2006-2451, allowing local users to gain root privileges.
$ cat /proc/sys/fs/suid_dumpable
2
$ cat /proc/sys/kernel/core_pattern
core
$ ulimit -c unlimited
$ cd /
$ ls -l core
ls: cannot access core: No such file or directory
$ touch core
touch: cannot touch `core': Permission denied
$ OHAI="evil-string-here" ping localhost >/dev/null 2>&1 &
$ pid=$!
$ sleep 1
$ kill -SEGV $pid
$ ls -l core
-rw------- 1 root kees 458752 Jun 21 11:35 core
$ sudo strings core | grep evil
OHAI=evil-string-here
While cron has been fixed to abort reading a file when there is any
parse error, there are still other sensitive directories that will read
any file present and skip unparsable lines.
Instead of introducing a suid_dumpable=3 mode and breaking all users of
mode 2, this only disables the unsafe portion of mode 2 (writing to disk
via relative path). Most users of mode 2 (e.g. Chrome OS) already use
a core dump pipe handler, so this change will not break them. For the
situations where a pipe handler is not defined but mode 2 is still
active, crash dumps will only be written to fully qualified paths. If a
relative path is defined (e.g. the default "core" pattern), dump
attempts will trigger a printk yelling about the lack of a fully
qualified path.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alan Cox <alan@linux.intel.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: James Morris <james.l.morris@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Recently, glibc made a change to suppress sign-conversion warnings in
FD_SET (glibc commit ceb9e56b3d1). This uncovered an issue with the
kernel's definition of __NFDBITS if applications #include
<linux/types.h> after including <sys/select.h>. A build failure would
be seen when passing the -Werror=sign-compare and -D_FORTIFY_SOURCE=2
flags to gcc.
It was suggested that the kernel should either match the glibc
definition of __NFDBITS or remove that entirely. The current in-kernel
uses of __NFDBITS can be replaced with BITS_PER_LONG, and there are no
uses of the related __FDELT and __FDMASK defines. Given that, we'll
continue the cleanup that was started with commit 8b3d1cda4f
("posix_types: Remove fd_set macros") and drop the remaining unused
macros.
Additionally, linux/time.h has similar macros defined that expand to
nothing so we'll remove those at the same time.
Reported-by: Jeff Law <law@redhat.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
CC: <stable@vger.kernel.org>
Signed-off-by: Josh Boyer <jwboyer@redhat.com>
[ .. and fix up whitespace as per akpm ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
do_exit() and exec_mmap() call sync_mm_rss() before mm_release() does
put_user(clear_child_tid) which can update task->rss_stat and thus make
mm->rss_stat inconsistent. This triggers the "BUG:" printk in check_mm().
Let's fix this bug in the safest way, and optimize/cleanup this later.
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit 40af1bbdca.
It's horribly and utterly broken for at least the following reasons:
- calling sync_mm_rss() from mmput() is fundamentally wrong, because
there's absolutely no reason to believe that the task that does the
mmput() always does it on its own VM. Example: fork, ptrace, /proc -
you name it.
- calling it *after* having done mmdrop() on it is doubly insane, since
the mm struct may well be gone now.
- testing mm against NULL before you call it is insane too, since a
NULL mm there would have caused oopses long before.
.. and those are just the three bugs I found before I decided to give up
looking for me and revert it asap. I should have caught it before I
even took it, but I trusted Andrew too much.
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm->rss_stat counters have per-task delta: task->rss_stat. Before
changing task->mm pointer the kernel must flush this delta with
sync_mm_rss().
do_exit() already calls sync_mm_rss() to flush the rss-counters before
committing the rss statistics into task->signal->maxrss, taskstats,
audit and other stuff. Unfortunately the kernel does this before
calling mm_release(), which can call put_user() for processing
task->clear_child_tid. So at this point we can trigger page-faults and
task->rss_stat becomes non-zero again. As a result mm->rss_stat becomes
inconsistent and check_mm() will print something like this:
| BUG: Bad rss-counter state mm:ffff88020813c380 idx:1 val:-1
| BUG: Bad rss-counter state mm:ffff88020813c380 idx:2 val:1
This patch moves sync_mm_rss() into mm_release(), and moves mm_release()
out of do_exit() and calls it earlier. After mm_release() there should
be no pagefaults.
[akpm@linux-foundation.org: tweak comment]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org> [3.4.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull user namespace enhancements from Eric Biederman:
"This is a course correction for the user namespace, so that we can
reach an inexpensive, maintainable, and reasonably complete
implementation.
Highlights:
- Config guards make it impossible to enable the user namespace and
code that has not been converted to be user namespace safe.
- Use of the new kuid_t type ensures the if you somehow get past the
config guards the kernel will encounter type errors if you enable
user namespaces and attempt to compile in code whose permission
checks have not been updated to be user namespace safe.
- All uids from child user namespaces are mapped into the initial
user namespace before they are processed. Removing the need to add
an additional check to see if the user namespace of the compared
uids remains the same.
- With the user namespaces compiled out the performance is as good or
better than it is today.
- For most operations absolutely nothing changes performance or
operationally with the user namespace enabled.
- The worst case performance I could come up with was timing 1
billion cache cold stat operations with the user namespace code
enabled. This went from 156s to 164s on my laptop (or 156ns to
164ns per stat operation).
- (uid_t)-1 and (gid_t)-1 are reserved as an internal error value.
Most uid/gid setting system calls treat these value specially
anyway so attempting to use -1 as a uid would likely cause
entertaining failures in userspace.
- If setuid is called with a uid that can not be mapped setuid fails.
I have looked at sendmail, login, ssh and every other program I
could think of that would call setuid and they all check for and
handle the case where setuid fails.
- If stat or a similar system call is called from a context in which
we can not map a uid we lie and return overflowuid. The LFS
experience suggests not lying and returning an error code might be
better, but the historical precedent with uids is different and I
can not think of anything that would break by lying about a uid we
can't map.
- Capabilities are localized to the current user namespace making it
safe to give the initial user in a user namespace all capabilities.
My git tree covers all of the modifications needed to convert the core
kernel and enough changes to make a system bootable to runlevel 1."
Fix up trivial conflicts due to nearby independent changes in fs/stat.c
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (46 commits)
userns: Silence silly gcc warning.
cred: use correct cred accessor with regards to rcu read lock
userns: Convert the move_pages, and migrate_pages permission checks to use uid_eq
userns: Convert cgroup permission checks to use uid_eq
userns: Convert tmpfs to use kuid and kgid where appropriate
userns: Convert sysfs to use kgid/kuid where appropriate
userns: Convert sysctl permission checks to use kuid and kgids.
userns: Convert proc to use kuid/kgid where appropriate
userns: Convert ext4 to user kuid/kgid where appropriate
userns: Convert ext3 to use kuid/kgid where appropriate
userns: Convert ext2 to use kuid/kgid where appropriate.
userns: Convert devpts to use kuid/kgid where appropriate
userns: Convert binary formats to use kuid/kgid where appropriate
userns: Add negative depends on entries to avoid building code that is userns unsafe
userns: signal remove unnecessary map_cred_ns
userns: Teach inode_capable to understand inodes whose uids map to other namespaces.
userns: Fail exec for suid and sgid binaries with ids outside our user namespace.
userns: Convert stat to return values mapped from kuids and kgids
userns: Convert user specfied uids and gids in chown into kuids and kgid
userns: Use uid_eq gid_eq helpers when comparing kuids and kgids in the vfs
...
Pull fpu state cleanups from Ingo Molnar:
"This tree streamlines further aspects of FPU handling by eliminating
the prepare_to_copy() complication and moving that logic to
arch_dup_task_struct().
It also fixes the FPU dumps in threaded core dumps, removes and old
(and now invalid) assumption plus micro-optimizes the exit path by
avoiding an FPU save for dead tasks."
Fixed up trivial add-add conflict in arch/sh/kernel/process.c that came
in because we now do the FPU handling in arch_dup_task_struct() rather
than the legacy (and now gone) prepare_to_copy().
* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, fpu: drop the fpu state during thread exit
x86, xsave: remove thread_has_fpu() bug check in __sanitize_i387_state()
coredump: ensure the fpu state is flushed for proper multi-threaded core dump
fork: move the real prepare_to_copy() users to arch_dup_task_struct()
Nalluru reported hitting the BUG_ON(__thread_has_fpu(tsk)) in
arch/x86/kernel/xsave.c:__sanitize_i387_state() during the coredump
of a multi-threaded application.
A look at the exit seqeuence shows that other threads can still be on the
runqueue potentially at the below shown exit_mm() code snippet:
if (atomic_dec_and_test(&core_state->nr_threads))
complete(&core_state->startup);
===> other threads can still be active here, but we notify the thread
===> dumping core to wakeup from the coredump_wait() after the last thread
===> joins this point. Core dumping thread will continue dumping
===> all the threads state to the core file.
for (;;) {
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
if (!self.task) /* see coredump_finish() */
break;
schedule();
}
As some of those threads are on the runqueue and didn't call schedule() yet,
their fpu state is still active in the live registers and the thread
proceeding with the coredump will hit the above mentioned BUG_ON while
trying to dump other threads fpustate to the coredump file.
BUG_ON() in arch/x86/kernel/xsave.c:__sanitize_i387_state() is
in the code paths for processors supporting xsaveopt. With or without
xsaveopt, multi-threaded coredump is broken and maynot contain
the correct fpustate at the time of exit.
In coredump_wait(), wait for all the threads to be come inactive, so
that we are sure all the extended register state is flushed to
the memory, so that it can be reliably copied to the core file.
Reported-by: Suresh Nalluru <suresh@aristanetworks.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1336692811-30576-2-git-send-email-suresh.b.siddha@intel.com
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
With this change, calling
prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)
disables privilege granting operations at execve-time. For example, a
process will not be able to execute a setuid binary to change their uid
or gid if this bit is set. The same is true for file capabilities.
Additionally, LSM_UNSAFE_NO_NEW_PRIVS is defined to ensure that
LSMs respect the requested behavior.
To determine if the NO_NEW_PRIVS bit is set, a task may call
prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
It returns 1 if set and 0 if it is not set. If any of the arguments are
non-zero, it will return -1 and set errno to -EINVAL.
(PR_SET_NO_NEW_PRIVS behaves similarly.)
This functionality is desired for the proposed seccomp filter patch
series. By using PR_SET_NO_NEW_PRIVS, it allows a task to modify the
system call behavior for itself and its child tasks without being
able to impact the behavior of a more privileged task.
Another potential use is making certain privileged operations
unprivileged. For example, chroot may be considered "safe" if it cannot
affect privileged tasks.
Note, this patch causes execve to fail when PR_SET_NO_NEW_PRIVS is
set and AppArmor is in use. It is fixed in a subsequent patch.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Will Drewry <wad@chromium.org>
Acked-by: Eric Paris <eparis@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
v18: updated change desc
v17: using new define values as per 3.4
Signed-off-by: James Morris <james.l.morris@oracle.com>
1. TRACE_EVENT(sched_process_exec) forgets to actually use the
old pid argument, it sets ->old_pid = p->pid.
2. search_binary_handler() uses the wrong pid number. tracepoint
needs the global pid_t from the root namespace, while old_pid
is the virtual pid number as it seen by the tracer/parent.
With this patch we have two pid_t's in search_binary_handler(),
not really nice. Perhaps we should switch to "struct pid*", but
in this case it would be better to cleanup the current code
first and move the "depth == 0" code outside.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: David Smith <dsmith@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Link: http://lkml.kernel.org/r/20120330162636.GA4857@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x32 support for x86-64 from Ingo Molnar:
"This tree introduces the X32 binary format and execution mode for x86:
32-bit data space binaries using 64-bit instructions and 64-bit kernel
syscalls.
This allows applications whose working set fits into a 32 bits address
space to make use of 64-bit instructions while using a 32-bit address
space with shorter pointers, more compressed data structures, etc."
Fix up trivial context conflicts in arch/x86/{Kconfig,vdso/vma.c}
* 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (71 commits)
x32: Fix alignment fail in struct compat_siginfo
x32: Fix stupid ia32/x32 inversion in the siginfo format
x32: Add ptrace for x32
x32: Switch to a 64-bit clock_t
x32: Provide separate is_ia32_task() and is_x32_task() predicates
x86, mtrr: Use explicit sizing and padding for the 64-bit ioctls
x86/x32: Fix the binutils auto-detect
x32: Warn and disable rather than error if binutils too old
x32: Only clear TIF_X32 flag once
x32: Make sure TS_COMPAT is cleared for x32 tasks
fs: Remove missed ->fds_bits from cessation use of fd_set structs internally
fs: Fix close_on_exec pointer in alloc_fdtable
x32: Drop non-__vdso weak symbols from the x32 VDSO
x32: Fix coding style violations in the x32 VDSO code
x32: Add x32 VDSO support
x32: Allow x32 to be configured
x32: If configured, add x32 system calls to system call tables
x32: Handle process creation
x32: Signal-related system calls
x86: Add #ifdef CONFIG_COMPAT to <asm/sys_ia32.h>
...
asm/system.h is a cause of circular dependency problems because it contains
commonly used primitive stuff like barrier definitions and uncommonly used
stuff like switch_to() that might require MMU definitions.
asm/system.h has been disintegrated by this point on all arches into the
following common segments:
(1) asm/barrier.h
Moved memory barrier definitions here.
(2) asm/cmpxchg.h
Moved xchg() and cmpxchg() here. #included in asm/atomic.h.
(3) asm/bug.h
Moved die() and similar here.
(4) asm/exec.h
Moved arch_align_stack() here.
(5) asm/elf.h
Moved AT_VECTOR_SIZE_ARCH here.
(6) asm/switch_to.h
Moved switch_to() here.
Signed-off-by: David Howells <dhowells@redhat.com>
Merge first batch of patches from Andrew Morton:
"A few misc things and all the MM queue"
* emailed from Andrew Morton <akpm@linux-foundation.org>: (92 commits)
memcg: avoid THP split in task migration
thp: add HPAGE_PMD_* definitions for !CONFIG_TRANSPARENT_HUGEPAGE
memcg: clean up existing move charge code
mm/memcontrol.c: remove unnecessary 'break' in mem_cgroup_read()
mm/memcontrol.c: remove redundant BUG_ON() in mem_cgroup_usage_unregister_event()
mm/memcontrol.c: s/stealed/stolen/
memcg: fix performance of mem_cgroup_begin_update_page_stat()
memcg: remove PCG_FILE_MAPPED
memcg: use new logic for page stat accounting
memcg: remove PCG_MOVE_LOCK flag from page_cgroup
memcg: simplify move_account() check
memcg: remove EXPORT_SYMBOL(mem_cgroup_update_page_stat)
memcg: kill dead prev_priority stubs
memcg: remove PCG_CACHE page_cgroup flag
memcg: let css_get_next() rely upon rcu_read_lock()
cgroup: revert ss_id_lock to spinlock
idr: make idr_get_next() good for rcu_read_lock()
memcg: remove unnecessary thp check in page stat accounting
memcg: remove redundant returns
memcg: enum lru_list lru
...
sync_mm_rss() can only be used for current to avoid race conditions in
iterating and clearing its per-task counters. Remove the task argument
for it and its helper function, __sync_task_rss_stat(), to avoid thinking
it can be used safely for anything other than current.
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull vfs pile 1 from Al Viro:
"This is _not_ all; in particular, Miklos' and Jan's stuff is not there
yet."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (64 commits)
ext4: initialization of ext4_li_mtx needs to be done earlier
debugfs-related mode_t whack-a-mole
hfsplus: add an ioctl to bless files
hfsplus: change finder_info to u32
hfsplus: initialise userflags
qnx4: new helper - try_extent()
qnx4: get rid of qnx4_bread/qnx4_getblk
take removal of PF_FORKNOEXEC to flush_old_exec()
trim includes in inode.c
um: uml_dup_mmap() relies on ->mmap_sem being held, but activate_mm() doesn't hold it
um: embed ->stub_pages[] into mmu_context
gadgetfs: list_for_each_safe() misuse
ocfs2: fix leaks on failure exits in module_init
ecryptfs: make register_filesystem() the last potential failure exit
ntfs: forgets to unregister sysctls on register_filesystem() failure
logfs: missing cleanup on register_filesystem() failure
jfs: mising cleanup on register_filesystem() failure
make configfs_pin_fs() return root dentry on success
configfs: configfs_create_dir() has parent dentry in dentry->d_parent
configfs: sanitize configfs_create()
...
Pull kmap_atomic cleanup from Cong Wang.
It's been in -next for a long time, and it gets rid of the (no longer
used) second argument to k[un]map_atomic().
Fix up a few trivial conflicts in various drivers, and do an "evil
merge" to catch some new uses that have come in since Cong's tree.
* 'kmap_atomic' of git://github.com/congwang/linux: (59 commits)
feature-removal-schedule.txt: schedule the deprecated form of kmap_atomic() for removal
highmem: kill all __kmap_atomic() [swarren@nvidia.com: highmem: Fix ARM build break due to __kmap_atomic rename]
drbd: remove the second argument of k[un]map_atomic()
zcache: remove the second argument of k[un]map_atomic()
gma500: remove the second argument of k[un]map_atomic()
dm: remove the second argument of k[un]map_atomic()
tomoyo: remove the second argument of k[un]map_atomic()
sunrpc: remove the second argument of k[un]map_atomic()
rds: remove the second argument of k[un]map_atomic()
net: remove the second argument of k[un]map_atomic()
mm: remove the second argument of k[un]map_atomic()
lib: remove the second argument of k[un]map_atomic()
power: remove the second argument of k[un]map_atomic()
kdb: remove the second argument of k[un]map_atomic()
udf: remove the second argument of k[un]map_atomic()
ubifs: remove the second argument of k[un]map_atomic()
squashfs: remove the second argument of k[un]map_atomic()
reiserfs: remove the second argument of k[un]map_atomic()
ocfs2: remove the second argument of k[un]map_atomic()
ntfs: remove the second argument of k[un]map_atomic()
...
Minor cleanup. de_thread()->setmax_mm_hiwater_rss() looks a bit
strange, move it into exec_mmap() which plays with old_mm.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
exit_notify() checks "tsk->self_exec_id != tsk->parent_exec_id"
to handle the "we have changed execution domain" case.
We can change do_thread() to always set ->exit_signal = SIGCHLD
and remove this check to simplify the code.
We could change setup_new_exec() instead, this looks more logical
because it increments ->self_exec_id. But note that de_thread()
already resets ->exit_signal if it changes the leader, let's keep
both changes close to each other.
Note that we change ->exit_signal lockless, this changes the rules.
Thereafter ->exit_signal is not stable under tasklist but this is
fine, the only possible change is OLDSIG -> SIGCHLD. This can race
with eligible_child() but the race is harmless. We can race with
reparent_leader() which changes our ->exit_signal in parallel, but
it does the same change to SIGCHLD.
The noticeable user-visible change is that the execing task is not
"visible" to do_wait()->eligible_child(__WCLONE) right after exec.
To me this looks more logical, and this is consistent with mt case.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that CLONE_VFORK is killable, coredump_wait() no longer needs
complete_vfork_done(). zap_threads() should find and kill all tasks with
the same ->mm, this includes our parent if ->vfork_done is set.
mm_release() becomes the only caller, unexport complete_vfork_done().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
No functional changes.
Move the clear-and-complete-vfork_done code into the new trivial helper,
complete_vfork_done().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Added a minimal exec tracepoint. Exec is an important major event
in the life of a task, like fork(), clone() or exit(), all of
which we already trace.
[ We also do scheduling re-balancing during exec() - so it's useful
from a scheduler instrumentation POV as well. ]
If you want to watch a task start up, when it gets exec'ed is a good place
to start. With the addition of this tracepoint, exec's can be monitored
and better picture of general system activity can be obtained. This
tracepoint will also enable better process life tracking, allowing you to
answer questions like "what process keeps starting up binary X?".
This tracepoint can also be useful in ftrace filtering and trigger
conditions: i.e. starting or stopping filtering when exec is called.
Signed-off-by: David Smith <dsmith@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/4F314D19.7030504@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Replace the fd_sets in struct fdtable with an array of unsigned longs and then
use the standard non-atomic bit operations rather than the FD_* macros.
This:
(1) Removes the abuses of struct fd_set:
(a) Since we don't want to allocate a full fd_set the vast majority of the
time, we actually, in effect, just allocate a just-big-enough array of
unsigned longs and cast it to an fd_set type - so why bother with the
fd_set at all?
(b) Some places outside of the core fdtable handling code (such as
SELinux) want to look inside the array of unsigned longs hidden inside
the fd_set struct for more efficient iteration over the entire set.
(2) Eliminates the use of FD_*() macros in the kernel completely.
(3) Permits the __FD_*() macros to be deleted entirely where not exposed to
userspace.
Signed-off-by: David Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20120216174954.23314.48147.stgit@warthog.procyon.org.uk
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Wrap accesses to the fd_sets in struct fdtable (for recording open files and
close-on-exec flags) so that we can move away from using fd_sets since we
abuse the fd_set structs by not allocating the full-sized structure under
normal circumstances and by non-core code looking at the internals of the
fd_sets.
The first abuse means that use of FD_ZERO() on these fd_sets is not permitted,
since that cannot be told about their abnormal lengths.
This introduces six wrapper functions for setting, clearing and testing
close-on-exec flags and fd-is-open flags:
void __set_close_on_exec(int fd, struct fdtable *fdt);
void __clear_close_on_exec(int fd, struct fdtable *fdt);
bool close_on_exec(int fd, const struct fdtable *fdt);
void __set_open_fd(int fd, struct fdtable *fdt);
void __clear_open_fd(int fd, struct fdtable *fdt);
bool fd_is_open(int fd, const struct fdtable *fdt);
Note that I've prepended '__' to the names of the set/clear functions because
they require the caller to hold a lock to use them.
Note also that I haven't added wrappers for looking behind the scenes at the
the array. Possibly that should exist too.
Signed-off-by: David Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20120216174942.23314.1364.stgit@warthog.procyon.org.uk
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Setting the task name is done within setup_new_exec() by accessing
bprm->filename. However this happens after flush_old_exec().
This may result in a use after free bug, flush_old_exec() may
"complete" vfork_done, which will wake up the parent which in turn
may free the passed in filename.
To fix this add a new tcomm field in struct linux_binprm which
contains the now early generated task name until it is used.
Fixes this bug on s390:
Unable to handle kernel pointer dereference at virtual kernel address 0000000039768000
Process kworker/u:3 (pid: 245, task: 000000003a3dc840, ksp: 0000000039453818)
Krnl PSW : 0704000180000000 0000000000282e94 (setup_new_exec+0xa0/0x374)
Call Trace:
([<0000000000282e2c>] setup_new_exec+0x38/0x374)
[<00000000002dd12e>] load_elf_binary+0x402/0x1bf4
[<0000000000280a42>] search_binary_handler+0x38e/0x5bc
[<0000000000282b6c>] do_execve_common+0x410/0x514
[<0000000000282cb6>] do_execve+0x46/0x58
[<00000000005bce58>] kernel_execve+0x28/0x70
[<000000000014ba2e>] ____call_usermodehelper+0x102/0x140
[<00000000005bc8da>] kernel_thread_starter+0x6/0xc
[<00000000005bc8d4>] kernel_thread_starter+0x0/0xc
Last Breaking-Event-Address:
[<00000000002830f0>] setup_new_exec+0x2fc/0x374
Kernel panic - not syncing: Fatal exception: panic_on_oops
Reported-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
oom_score_adj is used for guarding processes from OOM-Killer. One of
problem is that it's inherited at fork(). When a daemon set oom_score_adj
and make children, it's hard to know where the value is set.
This patch adds some tracepoints useful for debugging. This patch adds
3 trace points.
- creating new task
- renaming a task (exec)
- set oom_score_adj
To debug, users need to enable some trace pointer. Maybe filtering is useful as
# EVENT=/sys/kernel/debug/tracing/events/task/
# echo "oom_score_adj != 0" > $EVENT/task_newtask/filter
# echo "oom_score_adj != 0" > $EVENT/task_rename/filter
# echo 1 > $EVENT/enable
# EVENT=/sys/kernel/debug/tracing/events/oom/
# echo 1 > $EVENT/enable
output will be like this.
# grep oom /sys/kernel/debug/tracing/trace
bash-7699 [007] d..3 5140.744510: oom_score_adj_update: pid=7699 comm=bash oom_score_adj=-1000
bash-7699 [007] ...1 5151.818022: task_newtask: pid=7729 comm=bash clone_flags=1200011 oom_score_adj=-1000
ls-7729 [003] ...2 5151.818504: task_rename: pid=7729 oldcomm=bash newcomm=ls oom_score_adj=-1000
bash-7699 [002] ...1 5175.701468: task_newtask: pid=7730 comm=bash clone_flags=1200011 oom_score_adj=-1000
grep-7730 [007] ...2 5175.701993: task_rename: pid=7730 oldcomm=bash newcomm=grep oom_score_adj=-1000
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
some stuff in there can actually become static; some belongs to pnode.h
as it's a private interface between namespace.c and pnode.c...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This removes mm->oom_disable_count entirely since it's unnecessary and
currently buggy. The counter was intended to be per-process but it's
currently decremented in the exit path for each thread that exits, causing
it to underflow.
The count was originally intended to prevent oom killing threads that
share memory with threads that cannot be killed since it doesn't lead to
future memory freeing. The counter could be fixed to represent all
threads sharing the same mm, but it's better to remove the count since:
- it is possible that the OOM_DISABLE thread sharing memory with the
victim is waiting on that thread to exit and will actually cause
future memory freeing, and
- there is no guarantee that a thread is disabled from oom killing just
because another thread sharing its mm is oom disabled.
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ying Han <yinghan@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The patch http://lkml.org/lkml/2003/7/13/226 introduced an RLIMIT_NPROC
check in set_user() to check for NPROC exceeding via setuid() and
similar functions.
Before the check there was a possibility to greatly exceed the allowed
number of processes by an unprivileged user if the program relied on
rlimit only. But the check created new security threat: many poorly
written programs simply don't check setuid() return code and believe it
cannot fail if executed with root privileges. So, the check is removed
in this patch because of too often privilege escalations related to
buggy programs.
The NPROC can still be enforced in the common code flow of daemons
spawning user processes. Most of daemons do fork()+setuid()+execve().
The check introduced in execve() (1) enforces the same limit as in
setuid() and (2) doesn't create similar security issues.
Neil Brown suggested to track what specific process has exceeded the
limit by setting PF_NPROC_EXCEEDED process flag. With the change only
this process would fail on execve(), and other processes' execve()
behaviour is not changed.
Solar Designer suggested to re-check whether NPROC limit is still
exceeded at the moment of execve(). If the process was sleeping for
days between set*uid() and execve(), and the NPROC counter step down
under the limit, the defered execve() failure because NPROC limit was
exceeded days ago would be unexpected. If the limit is not exceeded
anymore, we clear the flag on successful calls to execve() and fork().
The flag is also cleared on successful calls to set_user() as the limit
was exceeded for the previous user, not the current one.
Similar check was introduced in -ow patches (without the process flag).
v3 - clear PF_NPROC_EXCEEDED on successful calls to set_user().
Reviewed-by: James Morris <jmorris@namei.org>
Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
acct_arg_size() takes ->page_table_lock around add_mm_counter() if
!SPLIT_RSS_COUNTING. This is not needed after commit 172703b08c ("mm:
delete non-atomic mm counter implementation").
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If CONFIG_MODULES=n, it makes no sense to retry the list of binary formats
handler because the list will not be modified by request_module().
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Richard Weinberger <richard@nod.at>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, search_binary_handler() tries to load binary loader module
using request_module() if a loader for the requested program is not yet
loaded. But second attempt of request_module() does not affect the result
of search_binary_handler().
If request_module() triggered recursion, calling request_module() twice
causes 2 to the power of MAX_KMOD_CONCURRENT (= 50) repetitions. It is
not an infinite loop but is sufficient for users to consider as a hang up.
Therefore, this patch changes not to call request_module() twice, making 1
to the power of MAX_KMOD_CONCURRENT repetitions in case of recursion.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: Richard Weinberger <richard@nod.at>
Tested-by: Richard Weinberger <richard@nod.at>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit a8bef8ff6e ("mm: migration: avoid race between
shift_arg_pages() and rmap_walk() during migration by not migrating
temporary stacks") introduced a BUG_ON() to ensure that VM_STACK_FLAGS
and VM_STACK_INCOMPLETE_SETUP do not overlap. The check is a compile
time one, so BUILD_BUG_ON is more appropriate.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
do_coredump() assumes that if format_corename() fails it should return
-ENOMEM. This is not true, for example cn_print_exe_file() can propagate
the error from d_path. Even if it was true, this is too fragile. Change
the code to check "ispipe < 0".
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reviewed-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change every occurence of / in comm and hostname to !. If the process
changes its name to contain /, the core is not dumped (if the directory
tree doesn't exist like that). The same with hostname being something
like myhost/3. Fix this behaviour by using the escape loop used in %E.
(We extract it to a separate function.)
Now both with comm == myprocess/1 and hostname == myhost/1, the core is
dumped like (kernel.core_pattern='core.%p.%e.%h):
core.2349.myprocess!1.myhost!1
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If we don't know the file corresponding to the binary (i.e. exe_file is
unknown), use "task->comm (path unknown)" instead of simple "(unknown)"
as suggested by ak.
The fallback is the same as %e except it will append "(path unknown)".
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (107 commits)
vfs: use ERR_CAST for err-ptr tossing in lookup_instantiate_filp
isofs: Remove global fs lock
jffs2: fix IN_DELETE_SELF on overwriting rename() killing a directory
fix IN_DELETE_SELF on overwriting rename() on ramfs et.al.
mm/truncate.c: fix build for CONFIG_BLOCK not enabled
fs:update the NOTE of the file_operations structure
Remove dead code in dget_parent()
AFS: Fix silly characters in a comment
switch d_add_ci() to d_splice_alias() in "found negative" case as well
simplify gfs2_lookup()
jfs_lookup(): don't bother with . or ..
get rid of useless dget_parent() in btrfs rename() and link()
get rid of useless dget_parent() in fs/btrfs/ioctl.c
fs: push i_mutex and filemap_write_and_wait down into ->fsync() handlers
drivers: fix up various ->llseek() implementations
fs: handle SEEK_HOLE/SEEK_DATA properly in all fs's that define their own llseek
Ext4: handle SEEK_HOLE/SEEK_DATA generically
Btrfs: implement our own ->llseek
fs: add SEEK_HOLE and SEEK_DATA flags
reiserfs: make reiserfs default to barrier=flush
...
Fix up trivial conflicts in fs/xfs/linux-2.6/xfs_super.c due to the new
shrinker callout for the inode cache, that clashed with the xfs code to
start the periodic workers later.
* 'ptrace' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc: (39 commits)
ptrace: do_wait(traced_leader_killed_by_mt_exec) can block forever
ptrace: fix ptrace_signal() && STOP_DEQUEUED interaction
connector: add an event for monitoring process tracers
ptrace: dont send SIGSTOP on auto-attach if PT_SEIZED
ptrace: mv send-SIGSTOP from do_fork() to ptrace_init_task()
ptrace_init_task: initialize child->jobctl explicitly
has_stopped_jobs: s/task_is_stopped/SIGNAL_STOP_STOPPED/
ptrace: make former thread ID available via PTRACE_GETEVENTMSG after PTRACE_EVENT_EXEC stop
ptrace: wait_consider_task: s/same_thread_group/ptrace_reparented/
ptrace: kill real_parent_is_ptracer() in in favor of ptrace_reparented()
ptrace: ptrace_reparented() should check same_thread_group()
redefine thread_group_leader() as exit_signal >= 0
do not change dead_task->exit_signal
kill task_detached()
reparent_leader: check EXIT_DEAD instead of task_detached()
make do_notify_parent() __must_check, update the callers
__ptrace_detach: avoid task_detached(), check do_notify_parent()
kill tracehook_notify_death()
make do_notify_parent() return bool
ptrace: s/tracehook_tracer_task()/ptrace_parent()/
...
Test-case:
void *tfunc(void *arg)
{
execvp("true", NULL);
return NULL;
}
int main(void)
{
int pid;
if (fork()) {
pthread_t t;
kill(getpid(), SIGSTOP);
pthread_create(&t, NULL, tfunc, NULL);
for (;;)
pause();
}
pid = getppid();
assert(ptrace(PTRACE_ATTACH, pid, 0,0) == 0);
while (wait(NULL) > 0)
ptrace(PTRACE_CONT, pid, 0,0);
return 0;
}
It is racy, exit_notify() does __wake_up_parent() too. But in the
likely case it triggers the problem: de_thread() does release_task()
and the old leader goes away without the notification, the tracer
sleeps in do_wait() without children/tracees.
Change de_thread() to do __wake_up_parent(traced_leader->parent).
Since it is already EXIT_DEAD we can do this without ptrace_unlink(),
EXIT_DEAD threads do not exist from do_wait's pov.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
new helper: would_dump(bprm, file). Checks if we are allowed to
read the file and if we are not - sets ENFORCE_NODUMP. Exported,
used in places that previously open-coded the same logics.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When multithreaded program execs under ptrace,
all traced threads report WIFEXITED status, except for
thread group leader and the thread which execs.
Unless tracer tracks thread group relationship between tracees,
which is a nontrivial task, it will not detect that
execed thread no longer exists.
This patch allows tracer to figure out which thread
performed this exec, by requesting PTRACE_GETEVENTMSG
in PTRACE_EVENT_EXEC stop.
Another, samller problem which is solved by this patch
is that tracer now can figure out which of the several
concurrent execs in multithreaded program succeeded.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Change de_thread() to set old_leader->exit_signal = -1. This is
good for the consistency, it is no longer the leader and all
sub-threads have exit_signal = -1 set by copy_process(CLONE_THREAD).
And this allows us to micro-optimize thread_group_leader(), it can
simply check exit_signal >= 0. This also makes sense because we
should move ->group_leader from task_struct to signal_struct.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
At this point, tracehooks aren't useful to mainline kernel and mostly
just add an extra layer of obfuscation. Although they have comments,
without actual in-kernel users, it is difficult to tell what are their
assumptions and they're actually trying to achieve. To mainline
kernel, they just aren't worth keeping around.
This patch kills the following clone and exec related tracehooks.
tracehook_prepare_clone()
tracehook_finish_clone()
tracehook_report_clone()
tracehook_report_clone_complete()
tracehook_unsafe_exec()
The changes are mostly trivial - logic is moved to the caller and
comments are merged and adjusted appropriately.
The only exception is in check_unsafe_exec() where LSM_UNSAFE_PTRACE*
are OR'd to bprm->unsafe instead of setting it, which produces the
same result as the field is always zero on entry. It also tests
p->ptrace instead of (p->ptrace & PT_PTRACED) for consistency, which
also gives the same result.
This doesn't introduce any behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
At this point, tracehooks aren't useful to mainline kernel and mostly
just add an extra layer of obfuscation. Although they have comments,
without actual in-kernel users, it is difficult to tell what are their
assumptions and they're actually trying to achieve. To mainline
kernel, they just aren't worth keeping around.
This patch kills the following trivial tracehooks.
* Ones testing whether task is ptraced. Replace with ->ptrace test.
tracehook_expect_breakpoints()
tracehook_consider_ignored_signal()
tracehook_consider_fatal_signal()
* ptrace_event() wrappers. Call directly.
tracehook_report_exec()
tracehook_report_exit()
tracehook_report_vfork_done()
* ptrace_release_task() wrapper. Call directly.
tracehook_finish_release_task()
* noop
tracehook_prepare_release_task()
tracehook_report_death()
This doesn't introduce any behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
____call_usermodehelper() now erases any credentials set by the
subprocess_inf::init() function. The problem is that commit
17f60a7da1 ("capabilites: allow the application of capability limits
to usermode helpers") creates and commits new credentials with
prepare_kernel_cred() after the call to the init() function. This wipes
all keyrings after umh_keys_init() is called.
The best way to deal with this is to put the init() call just prior to
the commit_creds() call, and pass the cred pointer to init(). That
means that umh_keys_init() and suchlike can modify the credentials
_before_ they are published and potentially in use by the rest of the
system.
This prevents request_key() from working as it is prevented from passing
the session keyring it set up with the authorisation token to
/sbin/request-key, and so the latter can't assume the authority to
instantiate the key. This causes the in-kernel DNS resolver to fail
with ENOKEY unconditionally.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Tested-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit 7f81c8890c.
It turns out that it's not actually a build-time check on x86-64 UML,
which does some seriously crazy stuff with VM_STACK_FLAGS.
The VM_STACK_FLAGS define depends on the arch-supplied
VM_STACK_DEFAULT_FLAGS value, and on x86-64 UML we have
arch/um/sys-x86_64/shared/sysdep/vm-flags.h:
#define VM_STACK_DEFAULT_FLAGS \
(test_thread_flag(TIF_IA32) ? vm_stack_flags32 : vm_stack_flags)
#define VM_STACK_DEFAULT_FLAGS vm_stack_flags
(yes, seriously: two different #define's for that thing, with the first
one being inside an "#ifdef TIF_IA32")
It's possible that it is UML that should just be fixed in this area, but
for now let's just undo the (very small) optimization.
Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit a8bef8ff6e ("mm: migration: avoid race between shift_arg_pages()
and rmap_walk() during migration by not migrating temporary stacks")
introduced a BUG_ON() to ensure that VM_STACK_FLAGS and
VM_STACK_INCOMPLETE_SETUP do not overlap. The check is a compile time
one, so BUILD_BUG_ON is more appropriate.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Unconditionally changing the address limit to USER_DS and not restoring
it to its old value in the error path is wrong because it prevents us
using kernel memory on repeated calls to this function. This, in fact,
breaks the fallback of hard coded paths to the init program from being
ever successful if the first candidate fails to load.
With this patch applied switching to USER_DS is delayed until the point
of no return is reached which makes it possible to have a multi-arch
rootfs with one arch specific init binary for each of the (hard coded)
probed paths.
Since the address limit is already set to USER_DS when start_thread()
will be invoked, this redundancy can be safely removed.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
JOBCTL_TRAPPING indicates that ptracer is waiting for tracee to
(re)transit into TRACED. task_clear_jobctl_pending() must be called
when either tracee enters TRACED or the transition is cancelled for
some reason. The former is achieved by explicitly calling
task_clear_jobctl_pending() in ptrace_stop() and the latter by calling
it at the end of do_signal_stop().
Calling task_clear_jobctl_trapping() at the end of do_signal_stop()
limits the scope TRAPPING can be used and is fragile in that seemingly
unrelated changes to tracee's control flow can lead to stuck TRAPPING.
We already have task_clear_jobctl_pending() calls on those cancelling
events to clear JOBCTL_STOP_PENDING. Cancellations can be handled by
making those call sites use JOBCTL_PENDING_MASK instead and updating
task_clear_jobctl_pending() such that task_clear_jobctl_trapping() is
called automatically if no stop/trap is pending.
This patch makes the above changes and removes the fallback
task_clear_jobctl_trapping() call from do_signal_stop().
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
This patch introduces JOBCTL_PENDING_MASK and replaces
task_clear_jobctl_stop_pending() with task_clear_jobctl_pending()
which takes an extra @mask argument.
JOBCTL_PENDING_MASK is currently equal to JOBCTL_STOP_PENDING but
future patches will add more bits. recalc_sigpending_tsk() is updated
to use JOBCTL_PENDING_MASK instead.
task_clear_jobctl_pending() takes @mask which in subset of
JOBCTL_PENDING_MASK and clears the relevant jobctl bits. If
JOBCTL_STOP_PENDING is set, other STOP bits are cleared together. All
task_clear_jobctl_stop_pending() users are updated to call
task_clear_jobctl_pending() with JOBCTL_STOP_PENDING which is
functionally identical to task_clear_jobctl_stop_pending().
This patch doesn't cause any functional change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
signal->group_stop currently hosts mostly group stop related flags;
however, it's gonna be used for wider purposes and the GROUP_STOP_
flag prefix becomes confusing. Rename signal->group_stop to
signal->jobctl and rename all GROUP_STOP_* flags to JOBCTL_*.
Bit position macros JOBCTL_*_BIT are defined and JOBCTL_* flags are
defined in terms of them to allow using bitops later.
While at it, reassign JOBCTL_TRAPPING to bit 22 to better accomodate
future additions.
This doesn't cause any functional change.
-v2: JOBCTL_*_BIT macros added as suggested by Linus.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Now, exe_file is not proc FS dependent, so we can use it to name core
file. So we add %E pattern for core file name cration which extract path
from mm_struct->exe_file. Then it converts slashes to exclamation marks
and pastes the result to the core file name itself.
This is useful for environments where binary names are longer than 16
character (the current->comm limitation). Also where there are binaries
with same name but in a different path. Further in case the binery itself
changes its current->comm after exec.
So by doing (s/$/#/ -- # is treated as git comment):
$ sysctl kernel.core_pattern='core.%p.%e.%E'
$ ln /bin/cat cat45678901234567890
$ ./cat45678901234567890
^Z
$ rm cat45678901234567890
$ fg
^\Quit (core dumped)
$ ls core*
we now get:
core.2434.cat456789012345.!root!cat45678901234567890 (deleted)
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Reviewed-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Setup and cleanup of mm_struct->exe_file is currently done in fs/proc/.
This was because exe_file was needed only for /proc/<pid>/exe. Since we
will need the exe_file functionality also for core dumps (so core name can
contain full binary path), built this functionality always into the
kernel.
To achieve that move that out of proc FS to the kernel/ where in fact it
should belong. By doing that we can make dup_mm_exe_file static. Also we
can drop linux/proc_fs.h inclusion in fs/exec.c and kernel/fork.c.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rework the existing mmu_gather infrastructure.
The direct purpose of these patches was to allow preemptible mmu_gather,
but even without that I think these patches provide an improvement to the
status quo.
The first 9 patches rework the mmu_gather infrastructure. For review
purpose I've split them into generic and per-arch patches with the last of
those a generic cleanup.
The next patch provides generic RCU page-table freeing, and the followup
is a patch converting s390 to use this. I've also got 4 patches from
DaveM lined up (not included in this series) that uses this to implement
gup_fast() for sparc64.
Then there is one patch that extends the generic mmu_gather batching.
After that follow the mm preemptibility patches, these make part of the mm
a lot more preemptible. It converts i_mmap_lock and anon_vma->lock to
mutexes which together with the mmu_gather rework makes mmu_gather
preemptible as well.
Making i_mmap_lock a mutex also enables a clean-up of the truncate code.
This also allows for preemptible mmu_notifiers, something that XPMEM I
think wants.
Furthermore, it removes the new and universially detested unmap_mutex.
This patch:
Remove the first obstacle towards a fully preemptible mmu_gather.
The current scheme assumes mmu_gather is always done with preemption
disabled and uses per-cpu storage for the page batches. Change this to
try and allocate a page for batching and in case of failure, use a small
on-stack array to make some progress.
Preemptible mmu_gather is desired in general and usable once i_mmap_lock
becomes a mutex. Doing it before the mutex conversion saves us from
having to rework the code by moving the mmu_gather bits inside the
pte_lock.
Also avoid flushing the tlb batches from under the pte lock, this is
useful even without the i_mmap_lock conversion as it significantly reduces
pte lock hold times.
[akpm@linux-foundation.org: fix comment tpyo]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Tony Luck <tony.luck@intel.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently we have expand_upwards exported while expand_downwards is
accessible only via expand_stack or expand_stack_downwards.
check_stack_guard_page is a nice example of the asymmetry. It uses
expand_stack for VM_GROWSDOWN while expand_upwards is called for
VM_GROWSUP case.
Let's clean this up by exporting both functions and make those names
consistent. Let's use expand_{upwards,downwards} because expanding
doesn't always involve stack manipulation (an example is
ia64_do_page_fault which uses expand_upwards for registers backing store
expansion). expand_downwards has to be defined for both
CONFIG_STACK_GROWS{UP,DOWN} because get_arg_page calls the downwards
version in the early process initialization phase for growsup
configuration.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6: (48 commits)
serial: 8250_pci: add support for Cronyx Omega PCI multiserial board.
tty/serial: Fix break handling for PORT_TEGRA
tty/serial: Add explicit PORT_TEGRA type
n_tracerouter and n_tracesink ldisc additions.
Intel PTI implementaiton of MIPI 1149.7.
Kernel documentation for the PTI feature.
export kernel call get_task_comm().
tty: Remove to support serial for S5P6442
pch_phub: Support new device ML7223
8250_pci: Add support for the Digi/IBM PCIe 2-port Adapter
ASoC: Update cx20442 for TTY API change
pch_uart: Support new device ML7223 IOH
parport: Use request_muxed_region for IT87 probe and lock
tty/serial: add support for Xilinx PS UART
n_gsm: Use print_hex_dump_bytes
drivers/tty/moxa.c: Put correct tty value
TTY: tty_io, annotate locking functions
TTY: serial_core, remove superfluous set_task_state
TTY: serial_core, remove invalid test
Char: moxa, fix locking in moxa_write
...
Fix up trivial conflicts in drivers/bluetooth/hci_ldisc.c and
drivers/tty/serial/Makefile.
I did the hci_ldisc thing as an evil merge, cleaning things up.
This allows drivers who call this function to be compiled modularly.
Otherwise, a driver who is interested in this type of functionality
has to implement their own get_task_comm() call, causing code
duplication in the Linux source tree.
Signed-off-by: J Freyensee <james_p_freyensee@linux.intel.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Add the appropriate members into struct user_arg_ptr and teach
get_user_arg_ptr() to handle is_compat = T case correctly.
This allows us to remove the compat_do_execve() code from fs/compat.c
and reimplement compat_do_execve() as the trivial wrapper on top of
do_execve_common(is_compat => true).
In fact, this fixes another (minor) bug. "compat_uptr_t str" can
overflow after "str += len" in compat_copy_strings() if a 64bit
application execs via sys32_execve().
Unexport acct_arg_size() and get_arg_page(), fs/compat.c doesn't
need them any longer.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
No functional changes, preparation.
Introduce struct user_arg_ptr, change do_execve() paths to use it
instead of "char __user * const __user *argv".
This makes the argv/envp arguments opaque, we are ready to handle the
compat case which needs argv pointing to compat_uptr_t.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Introduce get_user_arg_ptr() helper, convert count() and copy_strings()
to use it.
No functional changes, preparation. This helper is trivial, it just
reads the pointer from argv/envp user-space array.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Currently task->signal->group_stop_count is used to decide whether to
stop for group stop. However, if there is a task in the group which
is taking a long time to stop, other tasks which are continued by
ptrace would repeatedly stop for the same group stop until the group
stop is complete.
Conversely, if a ptraced task is in TASK_TRACED state, the debugger
won't get notified of group stops which is inconsistent compared to
the ptraced task in any other state.
This patch introduces GROUP_STOP_PENDING which tracks whether a task
is yet to stop for the group stop in progress. The flag is set when a
group stop starts and cleared when the task stops the first time for
the group stop, and consulted whenever whether the task should
participate in a group stop needs to be determined. Note that now
tasks in TASK_TRACED also participate in group stop.
This results in the following behavior changes.
* For a single group stop, a ptracer would see at most one stop
reported.
* A ptracee in TASK_TRACED now also participates in group stop and the
tracer would get the notification. However, as a ptraced task could
be in TASK_STOPPED state or any ptrace trap could consume group
stop, the notification may still be missing. These will be
addressed with further patches.
* A ptracee may start a group stop while one is still in progress if
the tracer let it continue with stop signal delivery. Group stop
code handles this correctly.
Oleg:
* Spotted that a task might skip signal check even when its
GROUP_STOP_PENDING is set. Fixed by updating
recalc_sigpending_tsk() to check GROUP_STOP_PENDING instead of
group_stop_count.
* Pointed out that task->group_stop should be cleared whenever
task->signal->group_stop_count is cleared. Fixed accordingly.
* Pointed out the behavior inconsistency between TASK_TRACED and
RUNNING and the last behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Hi,
I was backporting the coredump over pipe feature and noticed this small typo,
I wish I would have something bigger to contribute...
>From 15d6080e0ed4267da103c706917a33b1015e8804 Mon Sep 17 00:00:00 2001
From: Holger Hans Peter Freyther <holger@moiji-mobile.com>
Date: Thu, 24 Feb 2011 17:42:50 +0100
Subject: [PATCH] fs: Fix a small typo in the comment
The function is called umh_pipe_setup not uhm_pipe_setup.
Signed-off-by: Holger Hans Peter Freyther <holger@moiji-mobile.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
take calculation of open_flags by open(2) arguments into new helper
in fs/open.c, move filp_open() over there, have it and do_sys_open()
use that helper, switch exec.c callers of do_filp_open() to explicit
(and constant) struct open_flags.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
FMODE_EXEC is a constant type of fmode_t but was used with normal integer
constants. This results in following warnings from sparse. Fix it using
new macro __FMODE_EXEC.
fs/exec.c:116:58: warning: restricted fmode_t degrades to integer
fs/exec.c:689:58: warning: restricted fmode_t degrades to integer
fs/fcntl.c:777:9: warning: restricted fmode_t degrades to integer
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The install_special_mapping routine (used, for example, to setup the
vdso) skips the security check before insert_vm_struct, allowing a local
attacker to bypass the mmap_min_addr security restriction by limiting
the available pages for special mappings.
bprm_mm_init() also skips the check, and although I don't think this can
be used to bypass any restrictions, I don't see any reason not to have
the security check.
$ uname -m
x86_64
$ cat /proc/sys/vm/mmap_min_addr
65536
$ cat install_special_mapping.s
section .bss
resb BSS_SIZE
section .text
global _start
_start:
mov eax, __NR_pause
int 0x80
$ nasm -D__NR_pause=29 -DBSS_SIZE=0xfffed000 -f elf -o install_special_mapping.o install_special_mapping.s
$ ld -m elf_i386 -Ttext=0x10000 -Tbss=0x11000 -o install_special_mapping install_special_mapping.o
$ ./install_special_mapping &
[1] 14303
$ cat /proc/14303/maps
0000f000-00010000 r-xp 00000000 00:00 0 [vdso]
00010000-00011000 r-xp 00001000 00:19 2453665 /home/taviso/install_special_mapping
00011000-ffffe000 rwxp 00000000 00:00 0 [stack]
It's worth noting that Red Hat are shipping with mmap_min_addr set to
4096.
Signed-off-by: Tavis Ormandy <taviso@google.com>
Acked-by: Kees Cook <kees@ubuntu.com>
Acked-by: Robert Swiecki <swiecki@google.com>
[ Changed to not drop the error code - akpm ]
Reviewed-by: James Morris <jmorris@namei.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Note: this patch targets 2.6.37 and tries to be as simple as possible.
That is why it adds more copy-and-paste horror into fs/compat.c and
uglifies fs/exec.c, this will be cleanuped later.
compat_copy_strings() plays with bprm->vma/mm directly and thus has
two problems: it lacks the RLIMIT_STACK check and argv/envp memory
is not visible to oom killer.
Export acct_arg_size() and get_arg_page(), change compat_copy_strings()
to use get_arg_page(), change compat_do_execve() to do acct_arg_size(0)
as do_execve() does.
Add the fatal_signal_pending/cond_resched checks into compat_count() and
compat_copy_strings(), this matches the code in fs/exec.c and certainly
makes sense.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Brad Spengler published a local memory-allocation DoS that
evades the OOM-killer (though not the virtual memory RLIMIT):
http://www.grsecurity.net/~spender/64bit_dos.c
execve()->copy_strings() can allocate a lot of memory, but
this is not visible to oom-killer, nobody can see the nascent
bprm->mm and take it into account.
With this patch get_arg_page() increments current's MM_ANONPAGES
counter every time we allocate the new page for argv/envp. When
do_execve() succeds or fails, we change this counter back.
Technically this is not 100% correct, we can't know if the new
page is swapped out and turn MM_ANONPAGES into MM_SWAPENTS, but
I don't think this really matters and everything becomes correct
once exec changes ->mm or fails.
Reported-by: Brad Spengler <spender@grsecurity.net>
Reviewed-and-discussed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Presently do_execve() turns PF_KTHREAD off before search_binary_handler().
THis has a theorical risk of PF_KTHREAD getting lost. We don't have to
turn PF_KTHREAD off in the ENOEXEC case.
This patch moves this flag modification to after the finding of the
executable file.
This is only a theorical issue because kthreads do not call do_execve()
directly. But fixing would be better.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Roland McGrath <roland@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We met a parameter truncated issue, consider following:
> echo "|/root/core_pattern_pipe_test %p /usr/libexec/blah-blah-blah \
%s %c %p %u %g 11 12345678901234567890123456789012345678 %t" > \
/proc/sys/kernel/core_pattern
This is okay because the strings is less than CORENAME_MAX_SIZE. "cat
/proc/sys/kernel/core_pattern" shows the whole string. but after we run
core_pattern_pipe_test in man page, we found last parameter was truncated
like below:
argc[10]=<12807486>
The root cause is core_pattern allows % specifiers, which need to be
replaced during parse time, but the replace may expand the strings to
larger than CORENAME_MAX_SIZE. So if the last parameter is % specifiers,
the replace code is using snprintf(out_ptr, out_end - out_ptr, ...), this
will write out of corename array.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Neil Horman <nhorman@tuxdriver.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Oleg Nesterov pointed out we have to prevent multiple-threads-inside-exec
itself and we can reuse ->cred_guard_mutex for it. Yes, concurrent
execve() has no worth.
Let's move ->cred_guard_mutex from task_struct to signal_struct. It
naturally prevent multiple-threads-inside-exec.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's pointless to kill a task if another thread sharing its mm cannot be
killed to allow future memory freeing. A subsequent patch will prevent
kills in such cases, but first it's necessary to have a way to flag a task
that shares memory with an OOM_DISABLE task that doesn't incur an
additional tasklist scan, which would make select_bad_process() an O(n^2)
function.
This patch adds an atomic counter to struct mm_struct that follows how
many threads attached to it have an oom_score_adj of OOM_SCORE_ADJ_MIN.
They cannot be killed by the kernel, so their memory cannot be freed in
oom conditions.
This only requires task_lock() on the task that we're operating on, it
does not require mm->mmap_sem since task_lock() pins the mm and the
operation is atomic.
[rientjes@google.com: changelog and sys_unshare() code]
[rientjes@google.com: protect oom_disable_count with task_lock in fork]
[rientjes@google.com: use old_mm for oom_disable_count in exec]
Signed-off-by: Ying Han <yinghan@google.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If you build aout support as a module, you'll want these exported.
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Tony Luck reports that the addition of the access_ok() check in commit
0eead9ab41 ("Don't dump task struct in a.out core-dumps") broke the
ia64 compile due to missing the necessary header file includes.
Rather than add yet another include (<asm/unistd.h>) to make everything
happy, just uninline the silly core dump helper functions and move the
bodies to fs/exec.c where they make a lot more sense.
dump_seek() in particular was too big to be an inline function anyway,
and none of them are in any way performance-critical. And we really
don't need to mess up our include file headers more than they already
are.
Reported-and-tested-by: Tony Luck <tony.luck@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
An execve with a very large total of argument/environment strings
can take a really long time in the execve system call. It runs
uninterruptibly to count and copy all the strings. This change
makes it abort the exec quickly if sent a SIGKILL.
Note that this is the conservative change, to interrupt only for
SIGKILL, by using fatal_signal_pending(). It would be perfectly
correct semantics to let any signal interrupt the string-copying in
execve, i.e. use signal_pending() instead of fatal_signal_pending().
We'll save that change for later, since it could have user-visible
consequences, such as having a timer set too quickly make it so that
an execve can never complete, though it always happened to work before.
Signed-off-by: Roland McGrath <roland@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This adds a preemption point during the copying of the argument and
environment strings for execve, in copy_strings(). There is already
a preemption point in the count() loop, so this doesn't add any new
points in the abstract sense.
When the total argument+environment strings are very large, the time
spent copying them can be much more than a normal user time slice.
So this change improves the interactivity of the rest of the system
when one process is doing an execve with very large arguments.
Signed-off-by: Roland McGrath <roland@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The CONFIG_STACK_GROWSDOWN variant of setup_arg_pages() does not
check the size of the argument/environment area on the stack.
When it is unworkably large, shift_arg_pages() hits its BUG_ON.
This is exploitable with a very large RLIMIT_STACK limit, to
create a crash pretty easily.
Check that the initial stack is not too large to make it possible
to map in any executable. We're not checking that the actual
executable (or intepreter, for binfmt_elf) will fit. So those
mappings might clobber part of the initial stack mapping. But
that is just userland lossage that userland made happen, not a
kernel problem.
Signed-off-by: Roland McGrath <roland@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
fs: brlock vfsmount_lock
fs: scale files_lock
lglock: introduce special lglock and brlock spin locks
tty: fix fu_list abuse
fs: cleanup files_lock locking
fs: remove extra lookup in __lookup_hash
fs: fs_struct rwlock to spinlock
apparmor: use task path helpers
fs: dentry allocation consolidation
fs: fix do_lookup false negative
mbcache: Limit the maximum number of cache entries
hostfs ->follow_link() braino
hostfs: dumb (and usually harmless) tpyo - strncpy instead of strlcpy
remove SWRITE* I/O types
kill BH_Ordered flag
vfs: update ctime when changing the file's permission by setfacl
cramfs: only unlock new inodes
fix reiserfs_evict_inode end_writeback second call
