Commit Graph

86 Commits

Author SHA1 Message Date
Eric W. Biederman
ee17e5d620 signal: Make siginmask safe when passed a signal of 0
Eric Biggers reported:
> The following commit, which went into v4.20, introduced undefined behavior when
> sys_rt_sigqueueinfo() is called with sig=0:
>
> commit 4ce5f9c9e7
> Author: Eric W. Biederman <ebiederm@xmission.com>
> Date:   Tue Sep 25 12:59:31 2018 +0200
>
>     signal: Use a smaller struct siginfo in the kernel
>
> In sig_specific_sicodes(), used from known_siginfo_layout(), the expression
> '1ULL << ((sig)-1)' is undefined as it evaluates to 1ULL << 4294967295.
>
> Reproducer:
>
> #include <signal.h>
> #include <sys/syscall.h>
> #include <unistd.h>
>
> int main(void)
> {
> 	siginfo_t si = { .si_code = 1 };
> 	syscall(__NR_rt_sigqueueinfo, 0, 0, &si);
> }
>
> UBSAN report for v5.0-rc1:
>
> UBSAN: Undefined behaviour in kernel/signal.c:2946:7
> shift exponent 4294967295 is too large for 64-bit type 'long unsigned int'
> CPU: 2 PID: 346 Comm: syz_signal Not tainted 5.0.0-rc1 #25
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
> Call Trace:
>  __dump_stack lib/dump_stack.c:77 [inline]
>  dump_stack+0x70/0xa5 lib/dump_stack.c:113
>  ubsan_epilogue+0xd/0x40 lib/ubsan.c:159
>  __ubsan_handle_shift_out_of_bounds+0x12c/0x170 lib/ubsan.c:425
>  known_siginfo_layout+0xae/0xe0 kernel/signal.c:2946
>  post_copy_siginfo_from_user kernel/signal.c:3009 [inline]
>  __copy_siginfo_from_user+0x35/0x60 kernel/signal.c:3035
>  __do_sys_rt_sigqueueinfo kernel/signal.c:3553 [inline]
>  __se_sys_rt_sigqueueinfo kernel/signal.c:3549 [inline]
>  __x64_sys_rt_sigqueueinfo+0x31/0x70 kernel/signal.c:3549
>  do_syscall_64+0x4c/0x1b0 arch/x86/entry/common.c:290
>  entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x433639
> Code: c4 18 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b 27 00 00 c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007fffcb289fc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000081
> RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000433639
> RDX: 00007fffcb289fd0 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: 00000000006b2018 R08: 000000000000004d R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401560
> R13: 00000000004015f0 R14: 0000000000000000 R15: 0000000000000000

I have looked at the other callers of siginmask and they all appear to
in locations where sig can not be zero.

I have looked at the code generation of adding an extra test against
zero and gcc was able with a simple decrement instruction to combine
the two tests together. So the at most adding this test cost a single
cpu cycle.  In practice that decrement instruction was already present
as part of the mask comparison, so the only change was when the
instruction was executed.

So given that it is cheap, and obviously correct to update siginmask
to verify the signal is not zero.  Fix this issue there to avoid any
future problems.

Reported-by: Eric Biggers <ebiggers@kernel.org>
Fixes: 4ce5f9c9e7 ("signal: Use a smaller struct siginfo in the kernel")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2019-01-12 11:48:20 -06:00
Deepa Dinamani
854a6ed568 signal: Add restore_user_sigmask()
Refactor the logic to restore the sigmask before the syscall
returns into an api.
This is useful for versions of syscalls that pass in the
sigmask and expect the current->sigmask to be changed during
the execution and restored after the execution of the syscall.

With the advent of new y2038 syscalls in the subsequent patches,
we add two more new versions of the syscalls (for pselect, ppoll
and io_pgetevents) in addition to the existing native and compat
versions. Adding such an api reduces the logic that would need to
be replicated otherwise.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2018-12-06 17:22:53 +01:00
Deepa Dinamani
ded653ccbe signal: Add set_user_sigmask()
Refactor reading sigset from userspace and updating sigmask
into an api.

This is useful for versions of syscalls that pass in the
sigmask and expect the current->sigmask to be changed during,
and restored after, the execution of the syscall.

With the advent of new y2038 syscalls in the subsequent patches,
we add two more new versions of the syscalls (for pselect, ppoll,
and io_pgetevents) in addition to the existing native and compat
versions. Adding such an api reduces the logic that would need to
be replicated otherwise.

Note that the calls to sigprocmask() ignored the return value
from the api as the function only returns an error on an invalid
first argument that is hardcoded at these call sites.
The updated logic uses set_current_blocked() instead.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2018-12-06 17:22:38 +01:00
Gustavo A. R. Silva
3819ddec1f include/linux/signal.h: mark expected switch fall-throughs
In preparation to enabling -Wimplicit-fallthrough, mark switch cases where
we are expecting to fall through.

Link: http://lkml.kernel.org/r/20181013114847.GA3160@embeddedor.com
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-31 08:54:14 -07:00
Eric W. Biederman
a36700589b signal: Guard against negative signal numbers in copy_siginfo_from_user32
While fixing an out of bounds array access in known_siginfo_layout
reported by the kernel test robot it became apparent that the same bug
exists in siginfo_layout and affects copy_siginfo_from_user32.

The straight forward fix that makes guards against making this mistake
in the future and should keep the code size small is to just take an
unsigned signal number instead of a signed signal number, as I did to
fix known_siginfo_layout.

Cc: stable@vger.kernel.org
Fixes: cc731525f2 ("signal: Remove kernel interal si_code magic")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-10-10 20:34:14 -05:00
Eric W. Biederman
4ce5f9c9e7 signal: Use a smaller struct siginfo in the kernel
We reserve 128 bytes for struct siginfo but only use about 48 bytes on
64bit and 32 bytes on 32bit.  Someday we might use more but it is unlikely
to be anytime soon.

Userspace seems content with just enough bytes of siginfo to implement
sigqueue.  Or in the case of checkpoint/restart reinjecting signals
the kernel has sent.

Reducing the stack footprint and the work to copy siginfo around from
2 cachelines to 1 cachelines seems worth doing even if I don't have
benchmarks to show a performance difference.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-10-03 16:50:39 +02:00
Eric W. Biederman
ae7795bc61 signal: Distinguish between kernel_siginfo and siginfo
Linus recently observed that if we did not worry about the padding
member in struct siginfo it is only about 48 bytes, and 48 bytes is
much nicer than 128 bytes for allocating on the stack and copying
around in the kernel.

The obvious thing of only adding the padding when userspace is
including siginfo.h won't work as there are sigframe definitions in
the kernel that embed struct siginfo.

So split siginfo in two; kernel_siginfo and siginfo.  Keeping the
traditional name for the userspace definition.  While the version that
is used internally to the kernel and ultimately will not be padded to
128 bytes is called kernel_siginfo.

The definition of struct kernel_siginfo I have put in include/signal_types.h

A set of buildtime checks has been added to verify the two structures have
the same field offsets.

To make it easy to verify the change kernel_siginfo retains the same
size as siginfo.  The reduction in size comes in a following change.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-10-03 16:47:43 +02:00
Eric W. Biederman
4cd2e0e70a signal: Introduce copy_siginfo_from_user and use it's return value
In preparation for using a smaller version of siginfo in the kernel
introduce copy_siginfo_from_user and use it when siginfo is copied from
userspace.

Make the pattern for using copy_siginfo_from_user and
copy_siginfo_from_user32 to capture the return value and return that
value on error.

This is a necessary prerequisite for using a smaller siginfo
in the kernel than the kernel exports to userspace.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-10-03 16:47:15 +02:00
Linus Torvalds
cd9b44f907 Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton:

 - the rest of MM

 - procfs updates

 - various misc things

 - more y2038 fixes

 - get_maintainer updates

 - lib/ updates

 - checkpatch updates

 - various epoll updates

 - autofs updates

 - hfsplus

 - some reiserfs work

 - fatfs updates

 - signal.c cleanups

 - ipc/ updates

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (166 commits)
  ipc/util.c: update return value of ipc_getref from int to bool
  ipc/util.c: further variable name cleanups
  ipc: simplify ipc initialization
  ipc: get rid of ids->tables_initialized hack
  lib/rhashtable: guarantee initial hashtable allocation
  lib/rhashtable: simplify bucket_table_alloc()
  ipc: drop ipc_lock()
  ipc/util.c: correct comment in ipc_obtain_object_check
  ipc: rename ipcctl_pre_down_nolock()
  ipc/util.c: use ipc_rcu_putref() for failues in ipc_addid()
  ipc: reorganize initialization of kern_ipc_perm.seq
  ipc: compute kern_ipc_perm.id under the ipc lock
  init/Kconfig: remove EXPERT from CHECKPOINT_RESTORE
  fs/sysv/inode.c: use ktime_get_real_seconds() for superblock stamp
  adfs: use timespec64 for time conversion
  kernel/sysctl.c: fix typos in comments
  drivers/rapidio/devices/rio_mport_cdev.c: remove redundant pointer md
  fork: don't copy inconsistent signal handler state to child
  signal: make get_signal() return bool
  signal: make sigkill_pending() return bool
  ...
2018-08-22 12:34:08 -07:00
Christian Brauner
20ab7218d2 signal: make get_signal() return bool
make get_signal() already behaves like a boolean function.  Let's actually
declare it as such too.

Link: http://lkml.kernel.org/r/20180602103653.18181-18-christian@brauner.io
Signed-off-by: Christian Brauner <christian@brauner.io>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: James Morris <james.morris@microsoft.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 10:52:51 -07:00
Christian Brauner
67a48a2447 signal: make unhandled_signal() return bool
unhandled_signal() already behaves like a boolean function.  Let's
actually declare it as such too.  All callers treat it as such too.

Link: http://lkml.kernel.org/r/20180602103653.18181-13-christian@brauner.io
Signed-off-by: Christian Brauner <christian@brauner.io>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: James Morris <james.morris@microsoft.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 10:52:51 -07:00
Eric W. Biederman
40b3b02535 signal: Pass pid type into do_send_sig_info
This passes the information we already have at the call sight into
do_send_sig_info.  Ultimately allowing for better handling of signals
sent to a group of processes during fork.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-07-21 12:57:35 -05:00
Eric W. Biederman
0102498083 signal: Pass pid type into group_send_sig_info
This passes the information we already have at the call sight
into group_send_sig_info.  Ultimatelly allowing for to better handle
signals sent to a group of processes.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-07-21 12:57:35 -05:00
Eric W. Biederman
31931c93df signal: Extend siginfo_layout with SIL_FAULT_{MCEERR|BNDERR|PKUERR}
Update the siginfo_layout function and enum siginfo_layout to represent
all of the possible field layouts of struct siginfo.

This allows the uses of siginfo_layout in um and arm64 where they are testing
for SIL_FAULT to be more accurate as this rules out the other cases.

Further this allows the switch statements on siginfo_layout to be simpler
if perhaps a little more wordy.  Making it easier to understand what is
actually going on.

As SIL_FAULT_BNDERR and SIL_FAULT_PKUERR are never expected to appear
in signalfd just treat them as SIL_FAULT.  To include them would take
20 extra bytes an pretty much fill up what is left of
signalfd_siginfo.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-04-26 19:51:14 -05:00
Eric W. Biederman
0326e7ef05 signal: Remove unnecessary ifdefs now that there is only one struct siginfo
Remove HAVE_ARCH_SIGINFO_T
Remove __ARCH_SIGSYS

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-01-12 14:34:49 -06:00
Eric W. Biederman
8c5dbf2ae0 signal: Introduce clear_siginfo
Unfortunately struct siginfo has holes both in the common part of the
structure, in the union members, and in the lack of padding of the
union members.  The result of those wholes is that the C standard does
not guarantee those bits will be initialized.  As struct siginfo is
for communication between the kernel and userspace that is a problem.

Add the helper function clear_siginfo that is guaranteed to clear all of
the bits in struct siginfo so when the structure is copied there is no danger
of copying old kernel data and causing a leak of information from kernel
space to userspace.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-01-12 14:21:06 -06:00
Eric W. Biederman
8c36fdf5ed signal: Reduce copy_siginfo to just a memcpy
The savings for copying just part of struct siginfo appears to be in the
noise on modern machines.  So remove this ``optimization'' and simplify the code.

At the same time mark the second parameter as constant so there is no confusion
as to which direction the copy will go.

This ensures that a fully initialized siginfo that is sent ends up as
a fully initialized siginfo on the signal queue.  This full initialization
ensures even confused code won't copy unitialized data to userspace, and
it prepares for turning copy_siginfo_to_user into a simple copy_to_user.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-01-12 14:21:06 -06:00
Greg Kroah-Hartman
b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Eric W. Biederman
cc731525f2 signal: Remove kernel interal si_code magic
struct siginfo is a union and the kernel since 2.4 has been hiding a union
tag in the high 16bits of si_code using the values:
__SI_KILL
__SI_TIMER
__SI_POLL
__SI_FAULT
__SI_CHLD
__SI_RT
__SI_MESGQ
__SI_SYS

While this looks plausible on the surface, in practice this situation has
not worked well.

- Injected positive signals are not copied to user space properly
  unless they have these magic high bits set.

- Injected positive signals are not reported properly by signalfd
  unless they have these magic high bits set.

- These kernel internal values leaked to userspace via ptrace_peek_siginfo

- It was possible to inject these kernel internal values and cause the
  the kernel to misbehave.

- Kernel developers got confused and expected these kernel internal values
  in userspace in kernel self tests.

- Kernel developers got confused and set si_code to __SI_FAULT which
  is SI_USER in userspace which causes userspace to think an ordinary user
  sent the signal and that it was not kernel generated.

- The values make it impossible to reorganize the code to transform
  siginfo_copy_to_user into a plain copy_to_user.  As si_code must
  be massaged before being passed to userspace.

So remove these kernel internal si codes and make the kernel code simpler
and more maintainable.

To replace these kernel internal magic si_codes introduce the helper
function siginfo_layout, that takes a signal number and an si_code and
computes which union member of siginfo is being used.  Have
siginfo_layout return an enumeration so that gcc will have enough
information to warn if a switch statement does not handle all of union
members.

A couple of architectures have a messed up ABI that defines signal
specific duplications of SI_USER which causes more special cases in
siginfo_layout than I would like.  The good news is only problem
architectures pay the cost.

Update all of the code that used the previous magic __SI_ values to
use the new SIL_ values and to call siginfo_layout to get those
values.  Escept where not all of the cases are handled remove the
defaults in the switch statements so that if a new case is missed in
the future the lack will show up at compile time.

Modify the code that copies siginfo si_code to userspace to just copy
the value and not cast si_code to a short first.  The high bits are no
longer used to hold a magic union member.

Fixup the siginfo header files to stop including the __SI_ values in
their constants and for the headers that were missing it to properly
update the number of si_codes for each signal type.

The fixes to copy_siginfo_from_user32 implementations has the
interesting property that several of them perviously should never have
worked as the __SI_ values they depended up where kernel internal.
With that dependency gone those implementations should work much
better.

The idea of not passing the __SI_ values out to userspace and then
not reinserting them has been tested with criu and criu worked without
changes.

Ref: 2.4.0-test1
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2017-07-24 14:30:28 -05:00
Eric W. Biederman
d08477aa97 fcntl: Don't use ambiguous SIG_POLL si_codes
We have a weird and problematic intersection of features that when
they all come together result in ambiguous siginfo values, that
we can not support properly.

- Supporting fcntl(F_SETSIG,...) with arbitrary valid signals.

- Using positive values for POLL_IN, POLL_OUT, POLL_MSG, ..., etc
  that imply they are signal specific si_codes and using the
  aforementioned arbitrary signal to deliver them.

- Supporting injection of arbitrary siginfo values for debugging and
  checkpoint/restore.

The result is that just looking at siginfo si_codes of 1 to 6 are
ambigious.  It could either be a signal specific si_code or it could
be a generic si_code.

For most of the kernel this is a non-issue but for sending signals
with siginfo it is impossible to play back the kernel signals and
get the same result.

Strictly speaking when the si_code was changed from SI_SIGIO to
POLL_IN and friends between 2.2 and 2.4 this functionality was not
ambiguous, as only real time signals were supported.  Before 2.4 was
released the kernel began supporting siginfo with non realtime signals
so they could give details of why the signal was sent.

The result is that if F_SETSIG is set to one of the signals with signal
specific si_codes then user space can not know why the signal was sent.

I grepped through a bunch of userspace programs using debian code
search to get a feel for how often people choose a signal that results
in an ambiguous si_code.  I only found one program doing so and it was
using SIGCHLD to test the F_SETSIG functionality, and did not appear
to be a real world usage.

Therefore the ambiguity does not appears to be a real world problem in
practice.  Remove the ambiguity while introducing the smallest chance
of breakage by changing the si_code to SI_SIGIO when signals with
signal specific si_codes are targeted.

Fixes: v2.3.40 -- Added support for queueing non-rt signals
Fixes: v2.3.21 -- Changed the si_code from SI_SIGIO
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2017-07-24 14:29:23 -05:00
Linus Torvalds
c856863988 Merge branch 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc compat stuff updates from Al Viro:
 "This part is basically untangling various compat stuff. Compat
  syscalls moved to their native counterparts, getting rid of quite a
  bit of double-copying and/or set_fs() uses. A lot of field-by-field
  copyin/copyout killed off.

   - kernel/compat.c is much closer to containing just the
     copyin/copyout of compat structs. Not all compat syscalls are gone
     from it yet, but it's getting there.

   - ipc/compat_mq.c killed off completely.

   - block/compat_ioctl.c cleaned up; floppy compat ioctls moved to
     drivers/block/floppy.c where they belong. Yes, there are several
     drivers that implement some of the same ioctls. Some are m68k and
     one is 32bit-only pmac. drivers/block/floppy.c is the only one in
     that bunch that can be built on biarch"

* 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  mqueue: move compat syscalls to native ones
  usbdevfs: get rid of field-by-field copyin
  compat_hdio_ioctl: get rid of set_fs()
  take floppy compat ioctls to sodding floppy.c
  ipmi: get rid of field-by-field __get_user()
  ipmi: get COMPAT_IPMICTL_RECEIVE_MSG in sync with the native one
  rt_sigtimedwait(): move compat to native
  select: switch compat_{get,put}_fd_set() to compat_{get,put}_bitmap()
  put_compat_rusage(): switch to copy_to_user()
  sigpending(): move compat to native
  getrlimit()/setrlimit(): move compat to native
  times(2): move compat to native
  compat_{get,put}_bitmap(): use unsafe_{get,put}_user()
  fb_get_fscreeninfo(): don't bother with do_fb_ioctl()
  do_sigaltstack(): lift copying to/from userland into callers
  take compat_sys_old_getrlimit() to native syscall
  trim __ARCH_WANT_SYS_OLD_GETRLIMIT
2017-07-06 20:57:13 -07:00
Al Viro
1b3c872c83 rt_sigtimedwait(): move compat to native
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-09 23:57:12 -04:00
Christoph Hellwig
b9253a4337 signal: Move copy_siginfo_to_user to <linux/signal.h>
Having it in asm-generic/siginfo.h doesn't make any sense as it is in no way
architecture specific.  Move it to signal.h instead where several related
functions already reside.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-ia64@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: sparclinux@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20170603190102.28866-5-hch@lst.de
2017-06-04 15:11:46 +02:00
Christoph Hellwig
7994200ce6 ia64: Remove HAVE_ARCH_COPY_SIGINFO
Since ia64 defines __ARCH_SI_PREAMBLE_SIZE it can just use the generic
copy_siginfo implementation, which is identical to the architecture
specific one.

With that support for HAVE_ARCH_COPY_SIGINFO can go away entirely.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-ia64@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: sparclinux@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20170603190102.28866-3-hch@lst.de
2017-06-04 15:11:46 +02:00
Eric W. Biederman
d27158c0cf signal: Remove unused definition of sig_user_definied
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2017-04-17 21:53:19 -05:00
Ingo Molnar
76960dbf9b signals: Move signal data types from <linux/signal.h> to <linux/signal_types.h>
Separate out just the pure data types - sched.h will be able to use
this reduced size header.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-03 01:43:48 +01:00
Ingo Molnar
e6d930b4e0 signals: Prepare to split out <linux/signal_types.h> from <linux/signal.h>
Introduce dummy header and add dependencies to places that will depend on it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:37 +01:00
Waiman Long
c7be96af89 signals: avoid unnecessary taking of sighand->siglock
When running certain database workload on a high-end system with many
CPUs, it was found that spinlock contention in the sigprocmask syscalls
became a significant portion of the overall CPU cycles as shown below.

  9.30%  9.30%  905387  dataserver  /proc/kcore 0x7fff8163f4d2
  [k] _raw_spin_lock_irq
            |
            ---_raw_spin_lock_irq
               |
               |--99.34%-- __set_current_blocked
               |          sigprocmask
               |          sys_rt_sigprocmask
               |          system_call_fastpath
               |          |
               |          |--50.63%-- __swapcontext
               |          |          |
               |          |          |--99.91%-- upsleepgeneric
               |          |
               |          |--49.36%-- __setcontext
               |          |          ktskRun

Looking further into the swapcontext function in glibc, it was found that
the function always call sigprocmask() without checking if there are
changes in the signal mask.

A check was added to the __set_current_blocked() function to avoid taking
the sighand->siglock spinlock if there is no change in the signal mask.
This will prevent unneeded spinlock contention when many threads are
trying to call sigprocmask().

With this patch applied, the spinlock contention in sigprocmask() was
gone.

Link: http://lkml.kernel.org/r/1474979209-11867-1-git-send-email-Waiman.Long@hpe.com
Signed-off-by: Waiman Long <Waiman.Long@hpe.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stas Sergeev <stsp@list.ru>
Cc: Scott J Norton <scott.norton@hpe.com>
Cc: Douglas Hatch <doug.hatch@hpe.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14 16:04:07 -08:00
Oleg Nesterov
5c8ccefdf4 signal: move the "sig < SIGRTMIN" check into siginmask(sig)
All the users of siginmask() must ensure that sig < SIGRTMIN.  sig_fatal()
doesn't and this is wrong:

	UBSAN: Undefined behaviour in kernel/signal.c:911:6
	shift exponent 32 is too large for 32-bit type 'long unsigned int'

the patch doesn't add the neccesary check to sig_fatal(), it moves the
check into siginmask() and updates other callers.

Link: http://lkml.kernel.org/r/20160517195052.GA15187@redhat.com
Reported-by: Meelis Roos <mroos@linux.ee>
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>
2016-05-23 17:04:14 -07:00
Linus Torvalds
07b75260eb Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus
Pull MIPS updates from Ralf Baechle:
 "This is the main pull request for MIPS for 4.7.  Here's the summary of
  the changes:

   - ATH79: Support for DTB passuing using the UHI boot protocol
   - ATH79: Remove support for builtin DTB.
   - ATH79: Add zboot debug serial support.
   - ATH79: Add initial support for Dragino MS14 (Dragine 2), Onion Omega
            and DPT-Module.
   - ATH79: Update devicetree clock support for AR9132 and AR9331.
   - ATH79: Cleanup the DT code.
   - ATH79: Support newer SOCs in ath79_ddr_ctrl_init.
   - ATH79: Fix regression in PCI window initialization.
   - BCM47xx: Move SPROM driver to drivers/firmware/
   - BCM63xx: Enable partition parser in defconfig.
   - BMIPS: BMIPS5000 has I cache filing from D cache
   - BMIPS: BMIPS: Add cpu-feature-overrides.h
   - BMIPS: Add Whirlwind support
   - BMIPS: Adjust mips-hpt-frequency for BCM7435
   - BMIPS: Remove maxcpus from BCM97435SVMB DTS
   - BMIPS: Add missing 7038 L1 register cells to BCM7435
   - BMIPS: Various tweaks to initialization code.
   - BMIPS: Enable partition parser in defconfig.
   - BMIPS: Cache tweaks.
   - BMIPS: Add UART, I2C and SATA devices to DT.
   - BMIPS: Add BCM6358 and BCM63268support
   - BMIPS: Add device tree example for BCM6358.
   - BMIPS: Improve Improve BCM6328 and BCM6368 device trees
   - Lantiq: Add support for device tree file from boot loader
   - Lantiq: Allow build with no built-in DT.
   - Loongson 3: Reserve 32MB for RS780E integrated GPU.
   - Loongson 3: Fix build error after ld-version.sh modification
   - Loongson 3: Move chipset ACPI code from drivers to arch.
   - Loongson 3: Speedup irq processing.
   - Loongson 3: Add basic Loongson 3A support.
   - Loongson 3: Set cache flush handlers to nop.
   - Loongson 3: Invalidate special TLBs when needed.
   - Loongson 3: Fast TLB refill handler.
   - MT7620: Fallback strategy for invalid syscfg0.
   - Netlogic: Fix CP0_EBASE redefinition warnings
   - Octeon: Initialization fixes
   - Octeon: Add DTS files for the D-Link DSR-1000N and EdgeRouter Lite
   - Octeon: Enable add Octeon-drivers in cavium_octeon_defconfig
   - Octeon: Correctly handle endian-swapped initramfs images.
   - Octeon: Support CN73xx, CN75xx and CN78xx.
   - Octeon: Remove dead code from cvmx-sysinfo.
   - Octeon: Extend number of supported CPUs past 32.
   - Octeon: Remove some code limiting NR_IRQS to 255.
   - Octeon: Simplify octeon_irq_ciu_gpio_set_type.
   - Octeon: Mark some functions __init in smp.c
   - Octeon: Octeon: Add Octeon III CN7xxx interface detection
   - PIC32: Add serial driver and bindings for it.
   - PIC32: Add PIC32 deadman timer driver and bindings.
   - PIC32: Add PIC32 clock timer driver and bindings.
   - Pistachio: Determine SoC revision during boot
   - Sibyte: Fix Kconfig dependencies of SIBYTE_BUS_WATCHER.
   - Sibyte: Strip redundant comments from bcm1480_regs.h.
   - Panic immediately if panic_on_oops is set.
   - module: fix incorrect IS_ERR_VALUE macro usage.
   - module: Make consistent use of pr_*
   - Remove no longer needed work_on_cpu() call.
   - Remove CONFIG_IPV6_PRIVACY from defconfigs.
   - Fix registers of non-crashing CPUs in dumps.
   - Handle MIPSisms in new vmcore_elf32_check_arch.
   - Select CONFIG_HANDLE_DOMAIN_IRQ and make it work.
   - Allow RIXI to be used on non-R2 or R6 cores.
   - Reserve nosave data for hibernation
   - Fix siginfo.h to use strict POSIX types.
   - Don't unwind user mode with EVA.
   - Fix watchpoint restoration
   - Ptrace watchpoints for R6.
   - Sync icache when it fills from dcache
   - I6400 I-cache fills from dcache.
   - Various MSA fixes.
   - Cleanup MIPS_CPU_* definitions.
   - Signal: Move generic copy_siginfo to signal.h
   - Signal: Fix uapi include in exported asm/siginfo.h
   - Timer fixes for sake of KVM.
   - XPA TLB refill fixes.
   - Treat perf counter feature
   - Update John Crispin's email address
   - Add PIC32 watchdog and bindings.
   - Handle R10000 LL/SC bug in set_pte()
   - cpufreq: Various fixes for Longson1.
   - R6: Fix R2 emulation.
   - mathemu: Cosmetic fix to ADDIUPC emulation, plenty of other small fixes
   - ELF: ABI and FP fixes.
   - Allow for relocatable kernel and use that to support KASLR.
   - Fix CPC_BASE_ADDR mask
   - Plenty fo smp-cps, CM, R6 and M6250 fixes.
   - Make reset_control_ops const.
   - Fix kernel command line handling of leading whitespace.
   - Cleanups to cache handling.
   - Add brcm, bcm6345-l1-intc device tree bindings.
   - Use generic clkdev.h header
   - Remove CLK_IS_ROOT usage.
   - Misc small cleanups.
   - CM: Fix compilation error when !MIPS_CM
   - oprofile: Fix a preemption issue
   - Detect DSP ASE v3 support:1"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (275 commits)
  MIPS: pic32mzda: fix getting timer clock rate.
  MIPS: ath79: fix regression in PCI window initialization
  MIPS: ath79: make ath79_ddr_ctrl_init() compatible for newer SoCs
  MIPS: Fix VZ probe gas errors with binutils <2.24
  MIPS: perf: Fix I6400 event numbers
  MIPS: DEC: Export `ioasic_ssr_lock' to modules
  MIPS: MSA: Fix a link error on `_init_msa_upper' with older GCC
  MIPS: CM: Fix compilation error when !MIPS_CM
  MIPS: Fix genvdso error on rebuild
  USB: ohci-jz4740: Remove obsolete driver
  MIPS: JZ4740: Probe OHCI platform device via DT
  MIPS: JZ4740: Qi LB60: Remove support for AVT2 variant
  MIPS: pistachio: Determine SoC revision during boot
  MIPS: BMIPS: Adjust mips-hpt-frequency for BCM7435
  mips: mt7620: fallback to SDRAM when syscfg0 does not have a valid value for the memory type
  MIPS: Prevent "restoration" of MSA context in non-MSA kernels
  MIPS: cevt-r4k: Dynamically calculate min_delta_ns
  MIPS: malta-time: Take seconds into account
  MIPS: malta-time: Start GIC count before syncing to RTC
  MIPS: Force CPUs to lose FP context during mode switches
  ...
2016-05-19 10:02:26 -07:00
James Hogan
ca9eb49aa9 SIGNAL: Move generic copy_siginfo() to signal.h
The generic copy_siginfo() is currently defined in
asm-generic/siginfo.h, after including uapi/asm-generic/siginfo.h which
defines the generic struct siginfo. However this makes it awkward for an
architecture to use it if it has to define its own struct siginfo (e.g.
MIPS and potentially IA64), since it means that asm-generic/siginfo.h
can only be included after defining the arch-specific siginfo, which may
be problematic if the arch-specific definition needs definitions from
uapi/asm-generic/siginfo.h.

It is possible to work around this by first including
uapi/asm-generic/siginfo.h to get the constants before defining the
arch-specific siginfo, and include asm-generic/siginfo.h after. However
uapi headers can't be included by other uapi headers, so that first
include has to be in an ifdef __kernel__, with the non __kernel__ case
including the non-UAPI header instead.

Instead of that mess, move the generic copy_siginfo() definition into
linux/signal.h, which allows an arch-specific uapi/asm/siginfo.h to
include asm-generic/siginfo.h and define the arch-specific siginfo, and
for the generic copy_siginfo() to see that arch-specific definition.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Petr Malat <oss@malat.biz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Christopher Ferris <cferris@google.com>
Cc: linux-arch@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: <stable@vger.kernel.org> # 4.0-
Patchwork: https://patchwork.linux-mips.org/patch/12478/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13 14:02:10 +02:00
Stas Sergeev
2a74213838 signals/sigaltstack: Implement SS_AUTODISARM flag
This patch implements the SS_AUTODISARM flag that can be OR-ed with
SS_ONSTACK when forming ss_flags.

When this flag is set, sigaltstack will be disabled when entering
the signal handler; more precisely, after saving sas to uc_stack.
When leaving the signal handler, the sigaltstack is restored by
uc_stack.

When this flag is used, it is safe to switch from sighandler with
swapcontext(). Without this flag, the subsequent signal will corrupt
the state of the switched-away sighandler.

To detect the support of this functionality, one can do:

  err = sigaltstack(SS_DISABLE | SS_AUTODISARM);
  if (err && errno == EINVAL)
	unsupported();

Signed-off-by: Stas Sergeev <stsp@list.ru>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Amanieu d'Antras <amanieu@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Jason Low <jason.low2@hp.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Moore <pmoore@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: linux-api@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1460665206-13646-4-git-send-email-stsp@list.ru
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-03 08:37:59 +02:00
Richard Weinberger
9d8a765211 kernel/signal.c: unexport sigsuspend()
sigsuspend() is nowhere used except in signal.c itself, so we can mark it
static do not pollute the global namespace.

But this patch is more than a boring cleanup patch, it fixes a real issue
on UserModeLinux.  UML has a special console driver to display ttys using
xterm, or other terminal emulators, on the host side.  Vegard reported
that sometimes UML is unable to spawn a xterm and he's facing the
following warning:

  WARNING: CPU: 0 PID: 908 at include/linux/thread_info.h:128 sigsuspend+0xab/0xc0()

It turned out that this warning makes absolutely no sense as the UML
xterm code calls sigsuspend() on the host side, at least it tries.  But
as the kernel itself offers a sigsuspend() symbol the linker choose this
one instead of the glibc wrapper.  Interestingly this code used to work
since ever but always blocked signals on the wrong side.  Some recent
kernel change made the WARN_ON() trigger and uncovered the bug.

It is a wonderful example of how much works by chance on computers. :-)

Fixes: 68f3f16d9a ("new helper: sigsuspend()")
Signed-off-by: Richard Weinberger <richard@nod.at>
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Tested-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>	[3.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-20 16:17:32 -08:00
Oleg Nesterov
1c3bea0e71 signal: use BUILD_BUG() instead of _NSIG_WORDS_is_unsupported_size()
Kill _NSIG_WORDS_is_unsupported_size(), use BUILD_BUG() instead.  This
simplifies the code, avoids the nested-externs warnings, and this way we
do not defer the problem to linker.

Also, fix the indentation in _SIG_SET_BINOP() and _SIG_SET_OP().

Note: this patch assumes that the code like "if (0) BUILD_BUG();" is
valid.  If not (say __compiletime_error() is not defined and thus
__compiletime_error_fallback() uses a negative array) we should fix
BUILD_BUG() and/or BUILD_BUG_ON_MSG().  This code should be fine by
definition, this is the documented purpose of BUILD_BUG().

[sfr@canb.auug.org.au: fix powerpc build failures]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:18:20 +02:00
Richard Weinberger
828b1f65d2 Rip out get_signal_to_deliver()
Now we can turn get_signal() to the main function.

Signed-off-by: Richard Weinberger <richard@nod.at>
2014-08-06 13:03:44 +02:00
Richard Weinberger
10b1c7ac8b Clean up signal_delivered()
- Pass a ksignal struct to it
 - Remove unused regs parameter
 - Make it private as it's nowhere outside of kernel/signal.c is used

Signed-off-by: Richard Weinberger <richard@nod.at>
2014-08-06 13:03:43 +02:00
Oleg Nesterov
b4e74264eb signals: introduce kernel_sigaction()
Now that allow_signal() is really trivial we can unify it with
disallow_signal().  Add the new helper, kernel_sigaction(), and
reimplement allow_signal/disallow_signal as a trivial wrappers.

This saves one EXPORT_SYMBOL() and the new helper can have more users.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06 16:08:12 -07:00
Oleg Nesterov
0341729b4b signals: mv {dis,}allow_signal() from sched.h/exit.c to signal.[ch]
Move the declaration/definition of allow_signal/disallow_signal to
signal.h/signal.c.  The new place is more logical and allows to use the
static helpers in signal.c (see the next changes).

While at it, make them return void and remove the valid_signal() check.
Nobody checks the returned value, and in-kernel users must not pass the
wrong signal number.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06 16:08:11 -07:00
Oleg Nesterov
36fac0a214 signals: kill sigfindinword()
It has no users and it doesn't look useful.  I do not know why/when it was
introduced, I can't even find any user in the git history.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06 16:08:11 -07:00
Al Viro
bd1c149aa9 Introduce [compat_]save_altstack_ex() to unbreak x86 SMAP
For performance reasons, when SMAP is in use, SMAP is left open for an
entire put_user_try { ... } put_user_catch(); block, however, calling
__put_user() in the middle of that block will close SMAP as the
STAC..CLAC constructs intentionally do not nest.

Furthermore, using __put_user() rather than put_user_ex() here is bad
for performance.

Thus, introduce new [compat_]save_altstack_ex() helpers that replace
__[compat_]save_altstack() for x86, being currently the only
architecture which supports put_user_try { ... } put_user_catch().

Reported-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org> # v3.8+
Link: http://lkml.kernel.org/n/tip-es5p6y64if71k8p5u08agv9n@git.kernel.org
2013-09-01 14:16:33 -07:00
Linus Torvalds
20b4fb4852 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
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
  ...
2013-05-01 17:51:54 -07:00
David Howells
34db8aaf0f proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h}
Move some bits from linux/proc_fs.h to linux/of.h, signal.h and tty.h.

Also move proc_tty_init() and proc_device_tree_init() to fs/proc/internal.h as
they're internal to procfs.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
cc: devicetree-discuss@lists.ozlabs.org
cc: linux-arch@vger.kernel.org
cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cc: Jri Slaby <jslaby@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-05-01 17:29:40 -04:00
David Howells
2a1486981c Fix breakage in MIPS siginfo handling
MIPS's siginfo handling has been broken since this commit:

	commit 574c4866e3
	Author: Al Viro <viro@zeniv.linux.org.uk>
	Date:   Sun Nov 25 22:24:19 2012 -0500
	consolidate kernel-side struct sigaction declarations

for 64-bit BE MIPS CPUs.

The UAPI variant looks like this:

	struct sigaction {
		unsigned int	sa_flags;
		__sighandler_t	sa_handler;
		sigset_t	sa_mask;
	};

but the core kernel's variant looks like this:

	struct sigaction {
	#ifndef __ARCH_HAS_ODD_SIGACTION
		__sighandler_t	sa_handler;
		unsigned long	sa_flags;
	#else
		unsigned long	sa_flags;
		__sighandler_t	sa_handler;
	#endif
	#ifdef __ARCH_HAS_SA_RESTORER
		__sigrestore_t sa_restorer;
	#endif
		sigset_t	sa_mask;
	};

The problem is that sa_flags has been changed from an unsigned int to an
unsigned long.

Fix this by making sa_flags unsigned int if __ARCH_HAS_ODD_SIGACTION is
defined.

Whilst we're at it, rename __ARCH_HAS_ODD_SIGACTION to
__ARCH_HAS_IRIX_SIGACTION.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-03-19 19:15:52 +01:00
Al Viro
2ce5da1757 new helper: signal_setup_done()
usual "call force_sigsegv or signal_delivered" logics.  Takes
ksignal instead of separate siginfo/k_sigaction.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-03 15:09:26 -05:00
Al Viro
ca86b5dce2 new helper: get_signal()
On success get_signal_to_deliver() fills k_sigaction and siginfo.
_All_ users pass it addresses of the local variables sitting in
the same function.  Then they proceed to pass those addresses
pretty much in tandem to a bunch of helper functions; again, all
callers of those helpers are passing them such a pair, and one that
had been through get_signal_to_deliver() at that.

The obvious cleanup: introduce a new type that would contain a
<k_sigaction,siginfo> pair (struct ksignal) and begin switching to
using it.  Turns out that it's convenient to store the signal number
in the same object.

New helper, taking that sucker is a wrapper for get_signal_to_deliver();
takes struct ksignal * and returns bool.  On success fills ksignal
with the information for signal handler to be invoked.

For now it's a macro (to avoid header ordering headache), but eventually
it'll be a function in kernel/signal.c, with get_signal_to_deliver()
folded into it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-03 15:09:25 -05:00
Al Viro
495dfbf767 generic sys_sigaction() and compat_sys_sigaction()
conditional on OLD_SIGACTION/COMPAT_OLD_SIGACTION

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-03 15:09:23 -05:00
Al Viro
574c4866e3 consolidate kernel-side struct sigaction declarations
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-03 15:09:22 -05:00
Al Viro
92a3ce4a1e consolidate declarations of k_sigaction
Only alpha and sparc are unusual - they have ka_restorer in it.
And nobody needs that exposed to userland.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-03 15:09:22 -05:00
Al Viro
9aae8fc05d switch rt_tgsigqueueinfo to COMPAT_SYSCALL_DEFINE
C ABI violations on sparc, ppc and mips

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-03 15:09:21 -05:00
Al Viro
fe9c1db2cf generic compat_sys_rt_sigpending()
conditional on GENERIC_COMPAT_RT_SIGPENDING; by the end of that series
it will become the same thing as COMPAT and conditional will die out.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-03 15:09:19 -05:00