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  1. 22 3月, 2011 1 次提交
    • J
      Prevent rt_sigqueueinfo and rt_tgsigqueueinfo from spoofing the signal code · da48524e
      由 Julien Tinnes 提交于 
      Userland should be able to trust the pid and uid of the sender of a
signal if the si_code is SI_TKILL.

Unfortunately, the kernel has historically allowed sigqueueinfo() to
send any si_code at all (as long as it was negative - to distinguish it
from kernel-generated signals like SIGILL etc), so it could spoof a
SI_TKILL with incorrect siginfo values.

Happily, it looks like glibc has always set si_code to the appropriate
SI_QUEUE, so there are probably no actual user code that ever uses
anything but the appropriate SI_QUEUE flag.

So just tighten the check for si_code (we used to allow any negative
value), and add a (one-time) warning in case there are binaries out
there that might depend on using other si_code values.
Signed-off-by: NJulien Tinnes <jln@google.com>
Acked-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      da48524e
  3. 28 10月, 2010 2 次提交
  5. 07 10月, 2010 1 次提交
    • A
      HWPOISON: Copy si_addr_lsb to user · a337fdac
      由 Andi Kleen 提交于 
      The original hwpoison code added a new siginfo field si_addr_lsb to
pass the granuality of the fault address to user space. Unfortunately
this field was never copied to user space. Fix this here.

I added explicit checks for the MCEERR codes to avoid having
to patch all potential callers to initialize the field.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
      a337fdac
  7. 05 8月, 2010 1 次提交
  9. 28 5月, 2010 2 次提交
  11. 21 5月, 2010 1 次提交
  13. 07 3月, 2010 1 次提交
  15. 04 3月, 2010 1 次提交
    • L
      Prioritize synchronous signals over 'normal' signals · a27341cd
      由 Linus Torvalds 提交于 
      This makes sure that we pick the synchronous signals caused by a
processor fault over any pending regular asynchronous signals sent to
use by [t]kill().

This is not strictly required semantics, but it makes it _much_ easier
for programs like Wine that expect to find the fault information in the
signal stack.

Without this, if a non-synchronous signal gets picked first, the delayed
asynchronous signal will have its signal context pointing to the new
signal invocation, rather than the instruction that caused the SIGSEGV
or SIGBUS in the first place.

This is not all that pretty, and we're discussing making the synchronous
signals more explicit rather than have these kinds of implicit
preferences of SIGSEGV and friends.  See for example

	http://bugzilla.kernel.org/show_bug.cgi?id=15395

for some of the discussion.  But in the meantime this is a simple and
fairly straightforward work-around, and the whole

	if (x & Y)
		x &= Y;

thing can be compiled into (and gcc does do it) just three instructions:

	movq    %rdx, %rax
	andl    $Y, %eax
	cmovne  %rax, %rdx

so it is at least a simple solution to a subtle issue.
Reported-and-tested-by: NPavel Vilim <wylda@volny.cz>
Acked-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a27341cd
  17. 12 1月, 2010 1 次提交
    • A
      kernel/signal.c: fix kernel information leak with print-fatal-signals=1 · b45c6e76
      由 Andi Kleen 提交于 
      When print-fatal-signals is enabled it's possible to dump any memory
reachable by the kernel to the log by simply jumping to that address from
user space.

Or crash the system if there's some hardware with read side effects.

The fatal signals handler will dump 16 bytes at the execution address,
which is fully controlled by ring 3.

In addition when something jumps to a unmapped address there will be up to
16 additional useless page faults, which might be potentially slow (and at
least is not very efficient)

Fortunately this option is off by default and only there on i386.

But fix it by checking for kernel addresses and also stopping when there's
a page fault.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      b45c6e76
  19. 16 12月, 2009 5 次提交
  21. 11 12月, 2009 2 次提交
  23. 26 11月, 2009 3 次提交
  25. 09 11月, 2009 1 次提交
    • N
      signal: Print warning message when dropping signals · f84d49b2
      由 Naohiro Ooiwa 提交于 
      When the system has too many timers or too many aggregate
queued signals, the EAGAIN error is returned to application
from kernel, including timer_create() [POSIX.1b].

It means that the app exceeded the limit of pending signals,
but in general application writers do not expect this
outcome and the current silent failure can cause rare app
failures under very high load.

This patch adds a new message when we reach the limit
and if print_fatal_signals is enabled:

    task/1234: reached RLIMIT_SIGPENDING, dropping signal

If you see this message and your system behaved unexpectedly,
you can run following command to lift the limit:

   # ulimit -i unlimited

With help from Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>.
Signed-off-by: NNaohiro Ooiwa <nooiwa@miraclelinux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: oleg@redhat.com
LKML-Reference: <4AF6E7E2.9080406@miraclelinux.com>
[ Modified a few small details, gave surrounding code some love. ]
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      f84d49b2
  27. 24 9月, 2009 4 次提交
  29. 02 8月, 2009 2 次提交
    • L
      do_sigaltstack: small cleanups · 0dd8486b
      由 Linus Torvalds 提交于 
      The previous commit ("do_sigaltstack: avoid copying 'stack_t' as a
structure to user space") fixed a real bug.  This one just cleans up the
copy from user space to that gcc can generate better code for it (and so
that it looks the same as the later copy back to user space).
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      0dd8486b
    • L
      do_sigaltstack: avoid copying 'stack_t' as a structure to user space · 0083fc2c
      由 Linus Torvalds 提交于 
      Ulrich Drepper correctly points out that there is generally padding in
the structure on 64-bit hosts, and that copying the structure from
kernel to user space can leak information from the kernel stack in those
padding bytes.

Avoid the whole issue by just copying the three members one by one
instead, which also means that the function also can avoid the need for
a stack frame.  This also happens to match how we copy the new structure
from user space, so it all even makes sense.

[ The obvious solution of adding a memset() generates horrid code, gcc
  does really stupid things. ]
Reported-by: NUlrich Drepper <drepper@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      0083fc2c
  31. 19 6月, 2009 2 次提交
  33. 15 6月, 2009 1 次提交
    • V
      signal: fix __send_signal() false positive kmemcheck warning · 7a0aeb14
      由 Vegard Nossum 提交于 
      This false positive is due to field padding in struct sigqueue. When
this dynamically allocated structure is copied to the stack (in arch-
specific delivery code), kmemcheck sees a read from the padding, which
is, naturally, uninitialized.

Hide the false positive using the __GFP_NOTRACK_FALSE_POSITIVE flag.
Also made the rlimit override code a bit clearer by introducing a new
variable.

Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NVegard Nossum <vegard.nossum@gmail.com>
      7a0aeb14
  35. 01 5月, 2009 2 次提交
  37. 30 4月, 2009 1 次提交
  39. 15 4月, 2009 2 次提交
    • S
      tracing/events: move trace point headers into include/trace/events · ad8d75ff
      由 Steven Rostedt 提交于 
      Impact: clean up

Create a sub directory in include/trace called events to keep the
trace point headers in their own separate directory. Only headers that
declare trace points should be defined in this directory.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
      ad8d75ff
    • S
      tracing: create automated trace defines · a8d154b0
      由 Steven Rostedt 提交于 
      This patch lowers the number of places a developer must modify to add
new tracepoints. The current method to add a new tracepoint
into an existing system is to write the trace point macro in the
trace header with one of the macros TRACE_EVENT, TRACE_FORMAT or
DECLARE_TRACE, then they must add the same named item into the C file
with the macro DEFINE_TRACE(name) and then add the trace point.

This change cuts out the needing to add the DEFINE_TRACE(name).
Every file that uses the tracepoint must still include the trace/<type>.h
file, but the one C file must also add a define before the including
of that file.

 #define CREATE_TRACE_POINTS
 #include <trace/mytrace.h>

This will cause the trace/mytrace.h file to also produce the C code
necessary to implement the trace point.

Note, if more than one trace/<type>.h is used to create the C code
it is best to list them all together.

 #define CREATE_TRACE_POINTS
 #include <trace/foo.h>
 #include <trace/bar.h>
 #include <trace/fido.h>

Thanks to Mathieu Desnoyers and Christoph Hellwig for coming up with
the cleaner solution of the define above the includes over my first
design to have the C code include a "special" header.

This patch converts sched, irq and lockdep and skb to use this new
method.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
      a8d154b0
  41. 03 4月, 2009 4 次提交
    • S
      signals: SI_USER: Masquerade si_pid when crossing pid ns boundary · 6588c1e3
      由 Sukadev Bhattiprolu 提交于 
      When sending a signal to a descendant namespace, set ->si_pid to 0 since
the sender does not have a pid in the receiver's namespace.

Note:
	- If rt_sigqueueinfo() sets si_code to SI_USER when sending a
	  signal across a pid namespace boundary, the value in ->si_pid
	  will be cleared to 0.
Signed-off-by: NSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      6588c1e3
    • S
      signals: protect cinit from blocked fatal signals · b3bfa0cb
      由 Sukadev Bhattiprolu 提交于 
      Normally SIG_DFL signals to global and container-init are dropped early.
But if a signal is blocked when it is posted, we cannot drop the signal
since the receiver may install a handler before unblocking the signal.
Once this signal is queued however, the receiver container-init has no way
of knowing if the signal was sent from an ancestor or descendant
namespace.  This patch ensures that contianer-init drops all SIG_DFL
signals in get_signal_to_deliver() except SIGKILL/SIGSTOP.

If SIGSTOP/SIGKILL originate from a descendant of container-init they are
never queued (i.e dropped in sig_ignored() in an earler patch).

If SIGSTOP/SIGKILL originate from parent namespace, the signal is queued
and container-init processes the signal.

IOW, if get_signal_to_deliver() sees a sig_kernel_only() signal for global
or container-init, the signal must have been generated internally or must
have come from an ancestor ns and we process the signal.

Further, the signal_group_exit() check was needed to cover the case of a
multi-threaded init sending SIGKILL to other threads when doing an exit()
or exec().  But since the new sig_kernel_only() check covers the SIGKILL,
the signal_group_exit() check is no longer needed and can be removed.

Finally, now that we have all pieces in place, set SIGNAL_UNKILLABLE for
container-inits.
Signed-off-by: NSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      b3bfa0cb
    • S
      signals: protect cinit from unblocked SIG_DFL signals · 921cf9f6
      由 Sukadev Bhattiprolu 提交于 
      Drop early any SIG_DFL or SIG_IGN signals to container-init from within
the same container.  But queue SIGSTOP and SIGKILL to the container-init
if they are from an ancestor container.

Blocked, fatal signals (i.e when SIG_DFL is to terminate) from within the
container can still terminate the container-init.  That will be addressed
in the next patch.

Note:	To be bisect-safe, SIGNAL_UNKILLABLE will be set for container-inits
   	in a follow-on patch. Until then, this patch is just a preparatory
	step.
Signed-off-by: NSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      921cf9f6
    • S
      signals: add from_ancestor_ns parameter to send_signal() · 7978b567
      由 Sukadev Bhattiprolu 提交于 
      send_signal() (or its helper) needs to determine the pid namespace of the
sender.  But a signal sent via kill_pid_info_as_uid() comes from within
the kernel and send_signal() does not need to determine the pid namespace
of the sender.  So define a helper for send_signal() which takes an
additional parameter, 'from_ancestor_ns' and have kill_pid_info_as_uid()
use that helper directly.

The 'from_ancestor_ns' parameter will be used in a follow-on patch.
Signed-off-by: NSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      7978b567