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  1. 04 7月, 2013 2 次提交
  3. 29 6月, 2013 1 次提交
  5. 26 6月, 2013 1 次提交
  7. 01 5月, 2013 2 次提交
  9. 30 4月, 2013 2 次提交
  11. 25 4月, 2013 1 次提交
  13. 28 2月, 2013 1 次提交
  15. 26 2月, 2013 1 次提交
  17. 23 2月, 2013 1 次提交
  19. 12 1月, 2013 1 次提交
    • X
      fs/exec.c: work around icc miscompilation · 6d92d4f6
      由 Xi Wang 提交于 
      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 362e6663
("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: NXi Wang <xi.wang@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      6d92d4f6
  21. 21 12月, 2012 1 次提交
    • K
      exec: do not leave bprm->interp on stack · b66c5984
      由 Kees Cook 提交于 
      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: NKees 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      b66c5984
  23. 20 12月, 2012 1 次提交
  25. 18 12月, 2012 1 次提交
    • K
      exec: use -ELOOP for max recursion depth · d7402698
      由 Kees Cook 提交于 
      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: NKees 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      d7402698
  27. 29 11月, 2012 5 次提交
  29. 19 11月, 2012 1 次提交
  31. 26 10月, 2012 1 次提交
  33. 13 10月, 2012 2 次提交
    • J
      vfs: make path_openat take a struct filename pointer · 669abf4e
      由 Jeff Layton 提交于 
      ...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: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      669abf4e
    • J
      vfs: define struct filename and have getname() return it · 91a27b2a
      由 Jeff Layton 提交于 
      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: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      91a27b2a
  35. 09 10月, 2012 2 次提交
    • M
      mm: avoid taking rmap locks in move_ptes() · 38a76013
      由 Michel Lespinasse 提交于 
      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: NMichel 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      38a76013
    • O
      exec: make de_thread() killable · d5bbd43d
      由 Oleg Nesterov 提交于 
      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: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      d5bbd43d
  37. 06 10月, 2012 2 次提交
  39. 03 10月, 2012 1 次提交
  41. 01 10月, 2012 2 次提交
    • A
      generic sys_execve() · 38b983b3
      由 Al Viro 提交于 
      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: NAl Viro <viro@zeniv.linux.org.uk>
      38b983b3
    • A
      generic kernel_execve() · 282124d1
      由 Al Viro 提交于 
      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: NAl Viro <viro@zeniv.linux.org.uk>
      282124d1
  43. 27 9月, 2012 3 次提交
  45. 20 9月, 2012 1 次提交
  47. 31 7月, 2012 3 次提交
    • J
      coredump: fix wrong comments on core limits of pipe coredump case · 108ceeb0
      由 Jovi Zhang 提交于 
      In commit 898b374a ("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: NJovi Zhang <bookjovi@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      108ceeb0
    • K
      coredump: warn about unsafe suid_dumpable / core_pattern combo · 54b50199
      由 Kees Cook 提交于 
      When suid_dumpable=2, detect unsafe core_pattern settings and warn when
they are seen.
Signed-off-by: NKees Cook <keescook@chromium.org>
Suggested-by: NAndrew 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      54b50199
    • K
      fs: make dumpable=2 require fully qualified path · 9520628e
      由 Kees Cook 提交于 
      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: NKees 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      9520628e
  49. 30 7月, 2012 1 次提交