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  1. 10 8月, 2009 1 次提交
    • O
      mm_for_maps: simplify, use ptrace_may_access() · 13f0feaf
      由 Oleg Nesterov 提交于 
      It would be nice to kill __ptrace_may_access(). It requires task_lock(),
but this lock is only needed to read mm->flags in the middle.

Convert mm_for_maps() to use ptrace_may_access(), this also simplifies
the code a little bit.

Also, we do not need to take ->mmap_sem in advance. In fact I think
mm_for_maps() should not play with ->mmap_sem at all, the caller should
take this lock.

With or without this patch, without ->cred_guard_mutex held we can race
with exec() and get the new ->mm but check old creds.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Reviewed-by: NSerge Hallyn <serue@us.ibm.com>
Signed-off-by: NJames Morris <jmorris@namei.org>
      13f0feaf
  3. 17 6月, 2009 1 次提交
    • D
      oom: move oom_adj value from task_struct to mm_struct · 2ff05b2b
      由 David Rientjes 提交于 
      The per-task oom_adj value is a characteristic of its mm more than the
task itself since it's not possible to oom kill any thread that shares the
mm.  If a task were to be killed while attached to an mm that could not be
freed because another thread were set to OOM_DISABLE, it would have
needlessly been terminated since there is no potential for future memory
freeing.

This patch moves oomkilladj (now more appropriately named oom_adj) from
struct task_struct to struct mm_struct.  This requires task_lock() on a
task to check its oom_adj value to protect against exec, but it's already
necessary to take the lock when dereferencing the mm to find the total VM
size for the badness heuristic.

This fixes a livelock if the oom killer chooses a task and another thread
sharing the same memory has an oom_adj value of OOM_DISABLE.  This occurs
because oom_kill_task() repeatedly returns 1 and refuses to kill the
chosen task while select_bad_process() will repeatedly choose the same
task during the next retry.

Taking task_lock() in select_bad_process() to check for OOM_DISABLE and in
oom_kill_task() to check for threads sharing the same memory will be
removed in the next patch in this series where it will no longer be
necessary.

Writing to /proc/pid/oom_adj for a kthread will now return -EINVAL since
these threads are immune from oom killing already.  They simply report an
oom_adj value of OOM_DISABLE.

Cc: Nick Piggin <npiggin@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      2ff05b2b
  5. 29 5月, 2009 1 次提交
  7. 11 5月, 2009 1 次提交
  9. 05 5月, 2009 1 次提交
  11. 17 4月, 2009 1 次提交
  13. 01 4月, 2009 1 次提交
  15. 29 3月, 2009 1 次提交
    • H
      fix setuid sometimes wouldn't · 7c2c7d99
      由 Hugh Dickins 提交于 
      check_unsafe_exec() also notes whether the fs_struct is being
shared by more threads than will get killed by the exec, and if so
sets LSM_UNSAFE_SHARE to make bprm_set_creds() careful about euid.
But /proc/<pid>/cwd and /proc/<pid>/root lookups make transient
use of get_fs_struct(), which also raises that sharing count.

This might occasionally cause a setuid program not to change euid,
in the same way as happened with files->count (check_unsafe_exec
also looks at sighand->count, but /proc doesn't raise that one).

We'd prefer exec not to unshare fs_struct: so fix this in procfs,
replacing get_fs_struct() by get_fs_path(), which does path_get
while still holding task_lock, instead of raising fs->count.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Cc: stable@kernel.org
___

 fs/proc/base.c |   50 +++++++++++++++--------------------------------
 1 file changed, 16 insertions(+), 34 deletions(-)
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      7c2c7d99
  17. 28 3月, 2009 1 次提交
  19. 18 3月, 2009 1 次提交
    • L
      Avoid 64-bit "switch()" statements on 32-bit architectures · ee568b25
      由 Linus Torvalds 提交于 
      Commit ee6f779b ("filp->f_pos not
correctly updated in proc_task_readdir") changed the proc code to use
filp->f_pos directly, rather than through a temporary variable.  In the
process, that caused the operations to be done on the full 64 bits, even
though the offset is never that big.

That's all fine and dandy per se, but for some unfathomable reason gcc
generates absolutely horrid code when using 64-bit values in switch()
statements.  To the point of actually calling out to gcc helper
functions like __cmpdi2 rather than just doing the trivial comparisons
directly the way gcc does for normal compares.  At which point we get
link failures, because we really don't want to support that kind of
crazy code.

Fix this by just casting the f_pos value to "unsigned long", which
is plenty big enough for /proc, and avoids the gcc code generation issue.
Reported-by: NAlexey Dobriyan <adobriyan@gmail.com>
Cc: Zhang Le <r0bertz@gentoo.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      ee568b25
  21. 16 3月, 2009 1 次提交
    • Z
      filp->f_pos not correctly updated in proc_task_readdir · ee6f779b
      由 Zhang Le 提交于 
      filp->f_pos only get updated at the end of the function. Thus d_off of those
dirents who are in the middle will be 0, and this will cause a problem in
glibc's readdir implementation, specifically endless loop. Because when overflow
occurs, f_pos will be set to next dirent to read, however it will be 0, unless
the next one is the last one. So it will start over again and again.

There is a sample program in man 2 gendents. This is the output of the program
running on a multithread program's task dir before this patch is applied:

  $ ./a.out /proc/3807/task
  --------------- nread=128 ---------------
  i-node#  file type  d_reclen  d_off   d_name
    506442  directory    16          1  .
    506441  directory    16          0  ..
    506443  directory    16          0  3807
    506444  directory    16          0  3809
    506445  directory    16          0  3812
    506446  directory    16          0  3861
    506447  directory    16          0  3862
    506448  directory    16          8  3863

This is the output after this patch is applied

  $ ./a.out /proc/3807/task
  --------------- nread=128 ---------------
  i-node#  file type  d_reclen  d_off   d_name
    506442  directory    16          1  .
    506441  directory    16          2  ..
    506443  directory    16          3  3807
    506444  directory    16          4  3809
    506445  directory    16          5  3812
    506446  directory    16          6  3861
    506447  directory    16          7  3862
    506448  directory    16          8  3863
Signed-off-by: NZhang Le <r0bertz@gentoo.org>
Acked-by: NAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      ee6f779b
  23. 06 1月, 2009 1 次提交
  25. 05 1月, 2009 5 次提交
  27. 22 12月, 2008 1 次提交
    • I
      sched: fix warning in fs/proc/base.c · 826e08b0
      由 Ingo Molnar 提交于 
      Stephen Rothwell reported this new (harmless) build warning on platforms that
define u64 to long:

 fs/proc/base.c: In function 'proc_pid_schedstat':
 fs/proc/base.c:352: warning: format '%llu' expects type 'long long unsigned int', but argument 3 has type 'u64'

asm-generic/int-l64.h platforms strike again: that file should be eliminated.

Fix it by casting the parameters to long long.
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      826e08b0
  29. 18 12月, 2008 1 次提交
  31. 11 12月, 2008 1 次提交
  33. 14 11月, 2008 2 次提交
  35. 21 10月, 2008 1 次提交
  37. 10 10月, 2008 3 次提交
  39. 06 8月, 2008 1 次提交
    • A
      proc: fix warnings · 7c44319d
      由 Alexander Beregalov 提交于 
      proc: fix warnings

 fs/proc/base.c:2429: warning: format '%llu' expects type 'long long unsigned int', but argument 3 has type 'u64'
 fs/proc/base.c:2429: warning: format '%llu' expects type 'long long unsigned int', but argument 4 has type 'u64'
 fs/proc/base.c:2429: warning: format '%llu' expects type 'long long unsigned int', but argument 5 has type 'u64'
 fs/proc/base.c:2429: warning: format '%llu' expects type 'long long unsigned int', but argument 6 has type 'u64'
 fs/proc/base.c:2429: warning: format '%llu' expects type 'long long unsigned int', but argument 7 has type 'u64'
 fs/proc/base.c:2429: warning: format '%llu' expects type 'long long unsigned int', but argument 8 has type 'u64'
 fs/proc/base.c:2429: warning: format '%llu' expects type 'long long unsigned int', but argument 9 has type 'u64'
Signed-off-by: NAlexander Beregalov <a.beregalov@gmail.com>
Acked-by: NAndrea Righi <righi.andrea@gmail.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      7c44319d
  41. 28 7月, 2008 2 次提交
  43. 27 7月, 2008 4 次提交
  45. 26 7月, 2008 1 次提交
  47. 14 7月, 2008 1 次提交
    • S
      Security: split proc ptrace checking into read vs. attach · 006ebb40
      由 Stephen Smalley 提交于 
      Enable security modules to distinguish reading of process state via
proc from full ptrace access by renaming ptrace_may_attach to
ptrace_may_access and adding a mode argument indicating whether only
read access or full attach access is requested.  This allows security
modules to permit access to reading process state without granting
full ptrace access.  The base DAC/capability checking remains unchanged.

Read access to /proc/pid/mem continues to apply a full ptrace attach
check since check_mem_permission() already requires the current task
to already be ptracing the target.  The other ptrace checks within
proc for elements like environ, maps, and fds are changed to pass the
read mode instead of attach.

In the SELinux case, we model such reading of process state as a
reading of a proc file labeled with the target process' label.  This
enables SELinux policy to permit such reading of process state without
permitting control or manipulation of the target process, as there are
a number of cases where programs probe for such information via proc
but do not need to be able to control the target (e.g. procps,
lsof, PolicyKit, ConsoleKit).  At present we have to choose between
allowing full ptrace in policy (more permissive than required/desired)
or breaking functionality (or in some cases just silencing the denials
via dontaudit rules but this can hide genuine attacks).

This version of the patch incorporates comments from Casey Schaufler
(change/replace existing ptrace_may_attach interface, pass access
mode), and Chris Wright (provide greater consistency in the checking).

Note that like their predecessors __ptrace_may_attach and
ptrace_may_attach, the __ptrace_may_access and ptrace_may_access
interfaces use different return value conventions from each other (0
or -errno vs. 1 or 0).  I retained this difference to avoid any
changes to the caller logic but made the difference clearer by
changing the latter interface to return a bool rather than an int and
by adding a comment about it to ptrace.h for any future callers.
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Acked-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NJames Morris <jmorris@namei.org>
      006ebb40
  49. 07 6月, 2008 1 次提交
  51. 17 5月, 2008 1 次提交
  53. 02 5月, 2008 1 次提交
  55. 29 4月, 2008 2 次提交
    • R
      procfs: mem permission cleanup · 638fa202
      由 Roland McGrath 提交于 
      This cleans up the permission checks done for /proc/PID/mem i/o calls.  It
puts all the logic in a new function, check_mem_permission().

The old code repeated the (!MAY_PTRACE(task) || !ptrace_may_attach(task))
magical expression multiple times.  The new function does all that work in one
place, with clear comments.

The old code called security_ptrace() twice on successful checks, once in
MAY_PTRACE() and once in __ptrace_may_attach().  Now it's only called once,
and only if all other checks have succeeded.
Signed-off-by: NRoland McGrath <roland@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      638fa202
    • M
      procfs task exe symlink · 925d1c40
      由 Matt Helsley 提交于 
      The kernel implements readlink of /proc/pid/exe by getting the file from
the first executable VMA.  Then the path to the file is reconstructed and
reported as the result.

Because of the VMA walk the code is slightly different on nommu systems.
This patch avoids separate /proc/pid/exe code on nommu systems.  Instead of
walking the VMAs to find the first executable file-backed VMA we store a
reference to the exec'd file in the mm_struct.

That reference would prevent the filesystem holding the executable file
from being unmounted even after unmapping the VMAs.  So we track the number
of VM_EXECUTABLE VMAs and drop the new reference when the last one is
unmapped.  This avoids pinning the mounted filesystem.

[akpm@linux-foundation.org: improve comments]
[yamamoto@valinux.co.jp: fix dup_mmap]
Signed-off-by: NMatt Helsley <matthltc@us.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: David Howells <dhowells@redhat.com>
Cc:"Eric W. Biederman" <ebiederm@xmission.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: NYAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      925d1c40