Leon Yu 06b2849d10 proc: fix NULL dereference when reading /proc/<pid>/auxv ... Reading auxv of any kernel thread results in NULL pointer dereferencing in auxv_read() where mm can be NULL. Fix that by checking for NULL mm and bailing out early. This is also the original behavior changed by recent commit c531716785 ("proc: switch auxv to use of __mem_open()"). # cat /proc/2/auxv Unable to handle kernel NULL pointer dereference at virtual address 000000a8 Internal error: Oops: 17 [#1] PREEMPT SMP ARM CPU: 3 PID: 113 Comm: cat Not tainted 4.9.0-rc1-ARCH+ #1 Hardware name: BCM2709 task: ea3b0b00 task.stack: e99b2000 PC is at auxv_read+0x24/0x4c LR is at do_readv_writev+0x2fc/0x37c Process cat (pid: 113, stack limit = 0xe99b2210) Call chain: auxv_read do_readv_writev vfs_readv default_file_splice_read splice_direct_to_actor do_splice_direct do_sendfile SyS_sendfile64 ret_fast_syscall Fixes: c531716785 ("proc: switch auxv to use of __mem_open()") Link: http://lkml.kernel.org/r/1476966200-14457-1-git-send-email-chianglungyu@gmail.com Signed-off-by: Leon Yu <chianglungyu@gmail.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Kees Cook <keescook@chromium.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Mateusz Guzik <mguzik@redhat.com> Cc: Janis Danisevskis <jdanis@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2016-10-27 18:43:43 -07:00
..
array.c	fs/proc: Stop reporting eip and esp in /proc/PID/stat	2016-10-20 09:21:41 +02:00
base.c	proc: fix NULL dereference when reading /proc/<pid>/auxv	2016-10-27 18:43:43 -07:00
cmdline.c
consoles.c
cpuinfo.c
devices.c
fd.c	proc: unsigned file descriptors	2016-09-27 18:47:38 -04:00
fd.h	proc: unsigned file descriptors	2016-09-27 18:47:38 -04:00
generic.c	Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2016-10-10 13:04:49 -07:00
inode.c	fs: Replace CURRENT_TIME with current_time() for inode timestamps	2016-09-27 21:06:21 -04:00
internal.h	proc: unsigned file descriptors	2016-09-27 18:47:38 -04:00
interrupts.c
Kconfig
kcore.c	fs/proc/kcore.c: Add bounce buffer for ktext data	2016-09-20 13:32:49 -07:00
kmsg.c
loadavg.c
Makefile
meminfo.c	meminfo: break apart a very long seq_printf with #ifdefs	2016-10-07 18:46:30 -07:00
namespaces.c
nommu.c
page.c
proc_net.c
proc_sysctl.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2016-10-10 20:16:43 -07:00
proc_tty.c
root.c
self.c	fs: Replace CURRENT_TIME with current_time() for inode timestamps	2016-09-27 21:06:21 -04:00
softirqs.c
stat.c	seq/proc: modify seq_put_decimal_[u]ll to take a const char *, not char	2016-10-07 18:46:30 -07:00
task_mmu.c	fs/proc: Stop trying to report thread stacks	2016-10-20 09:21:41 +02:00
task_nommu.c	fs/proc: Stop trying to report thread stacks	2016-10-20 09:21:41 +02:00
thread_self.c	fs: Replace CURRENT_TIME with current_time() for inode timestamps	2016-09-27 21:06:21 -04:00
uptime.c
version.c
vmcore.c