linux-stable.git/arch/arm/kernel/ptrace.c, branch linux-4.2.y

Merge git://git.infradead.org/users/eparis/audit

2014-10-19T23:25:56+00:00

Pull audit updates from Eric Paris:
 "So this change across a whole bunch of arches really solves one basic
  problem.  We want to audit when seccomp is killing a process.  seccomp
  hooks in before the audit syscall entry code.  audit_syscall_entry
  took as an argument the arch of the given syscall.  Since the arch is
  part of what makes a syscall number meaningful it's an important part
  of the record, but it isn't available when seccomp shoots the
  syscall...

  For most arch's we have a better way to get the arch (syscall_get_arch)
  So the solution was two fold: Implement syscall_get_arch() everywhere
  there is audit which didn't have it.  Use syscall_get_arch() in the
  seccomp audit code.  Having syscall_get_arch() everywhere meant it was
  a useless flag on the stack and we could get rid of it for the typical
  syscall entry.

  The other changes inside the audit system aren't grand, fixed some
  records that had invalid spaces.  Better locking around the task comm
  field.  Removing some dead functions and structs.  Make some things
  static.  Really minor stuff"

* git://git.infradead.org/users/eparis/audit: (31 commits)
  audit: rename audit_log_remove_rule to disambiguate for trees
  audit: cull redundancy in audit_rule_change
  audit: WARN if audit_rule_change called illegally
  audit: put rule existence check in canonical order
  next: openrisc: Fix build
  audit: get comm using lock to avoid race in string printing
  audit: remove open_arg() function that is never used
  audit: correct AUDIT_GET_FEATURE return message type
  audit: set nlmsg_len for multicast messages.
  audit: use union for audit_field values since they are mutually exclusive
  audit: invalid op= values for rules
  audit: use atomic_t to simplify audit_serial()
  kernel/audit.c: use ARRAY_SIZE instead of sizeof/sizeof[0]
  audit: reduce scope of audit_log_fcaps
  audit: reduce scope of audit_net_id
  audit: arm64: Remove the audit arch argument to audit_syscall_entry
  arm64: audit: Add audit hook in syscall_trace_enter/exit()
  audit: x86: drop arch from __audit_syscall_entry() interface
  sparc: implement is_32bit_task
  sparc: properly conditionalize use of TIF_32BIT
  ...

ARCH: AUDIT: audit_syscall_entry() should not require the arch

2014-09-23T20:21:26+00:00

We have a function where the arch can be queried, syscall_get_arch().
So rather than have every single piece of arch specific code use and/or
duplicate syscall_get_arch(), just have the audit code use the
syscall_get_arch() code.

Based-on-patch-by: Richard Briggs 
Signed-off-by: Eric Paris 
Cc: linux-alpha@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-ia64@vger.kernel.org
Cc: microblaze-uclinux@itee.uq.edu.au
Cc: linux-mips@linux-mips.org
Cc: linux@lists.openrisc.net
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: linux-xtensa@linux-xtensa.org
Cc: x86@kernel.org

seccomp,x86,arm,mips,s390: Remove nr parameter from secure_computing

2014-09-03T21:58:17+00:00

The secure_computing function took a syscall number parameter, but
it only paid any attention to that parameter if seccomp mode 1 was
enabled.  Rather than coming up with a kludge to get the parameter
to work in mode 2, just remove the parameter.

To avoid churn in arches that don't have seccomp filters (and may
not even support syscall_get_nr right now), this leaves the
parameter in secure_computing_strict, which is now a real function.

For ARM, this is a bit ugly due to the fact that ARM conditionally
supports seccomp filters.  Fixing that would probably only be a
couple of lines of code, but it should be coordinated with the audit
maintainers.

This will be a slight slowdown on some arches.  The right fix is to
pass in all of seccomp_data instead of trying to make just the
syscall nr part be fast.

This is a prerequisite for making two-phase seccomp work cleanly.

Cc: Russell King 
Cc: linux-arm-kernel@lists.infradead.org
Cc: Ralf Baechle 
Cc: linux-mips@linux-mips.org
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: linux-s390@vger.kernel.org
Cc: x86@kernel.org
Cc: Kees Cook 
Signed-off-by: Andy Lutomirski 
Signed-off-by: Kees Cook

ARM: 8087/1: ptrace: reload syscall number after secure_computing() check

2014-06-29T09:29:35+00:00

On the syscall tracing path, we call out to secure_computing() to allow
seccomp to check the syscall number being attempted. As part of this, a
SIGTRAP may be sent to the tracer and the syscall could be re-written by
a subsequent SET_SYSCALL ptrace request. Unfortunately, this new syscall
is ignored by the current code unless TIF_SYSCALL_TRACE is also set on
the current thread.

This patch slightly reworks the enter path of the syscall tracing code
so that we always reload the syscall number from
current_thread_info()->syscall after the potential ptrace traps.

Acked-by: Kees Cook 
Tested-by: Kees Cook 
Signed-off-by: Will Deacon 
Signed-off-by: Russell King

ptrace/arm: revert "hw_breakpoints: Fix racy access to ptrace breakpoints"

2013-07-09T17:33:25+00:00

This reverts commit bf0b8f4b55e5 ("hw_breakpoints: Fix racy access to
ptrace breakpoints").

The patch was fine but we can no longer race with SIGKILL after commit
9899d11f6544 ("ptrace: ensure arch_ptrace/ptrace_request can never race
with SIGKILL"), the __TASK_TRACED tracee can't be woken up and
->ptrace_bps[] can't go away.

Signed-off-by: Oleg Nesterov 
Acked-by: Will Deacon 
Cc: Benjamin Herrenschmidt 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Jan Kratochvil 
Cc: Michael Neuling 
Cc: Paul Mackerras 
Cc: Paul Mundt 
Cc: Prasad 
Cc: Russell King 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ARM: 7735/2: Preserve the user r/w register TPIDRURW on context switch and fork

2013-06-24T14:21:59+00:00

Since commit 6a1c53124aa1 the user writeable TLS register was zeroed to
prevent it from being used as a covert channel between two tasks.

There are more and more applications coming to Windows RT,
Wine could support them, but mostly they expect to have
the thread environment block (TEB) in TPIDRURW.

This patch preserves that register per thread instead of clearing it.
Unlike the TPIDRURO, which is already switched, the TPIDRURW
can be updated from userspace so needs careful treatment in the case that we
modify TPIDRURW and call fork(). To avoid this we must always read
TPIDRURW in copy_thread.

Signed-off-by: André Hentschel 
Signed-off-by: Will Deacon 
Signed-off-by: Jonathan Austin 
Signed-off-by: Russell King

ARM: 7595/1: syscall: rework ordering in syscall_trace_exit

2012-12-11T00:18:26+00:00

syscall_trace_exit is currently doing things back-to-front; invoking
the audit hook *after* signalling the debugger, which presents an
opportunity for the registers to be re-written by userspace in order to
bypass auditing constaints.

This patch fixes the ordering by moving the audit code first and the
tracehook code last. On the face of it, it looks like
current_thread_info()->syscall may be incorrect for the sys_exit
tracepoint, but that's actually not an issue because it will have been
set during syscall entry and cannot have changed since then.

Reported-by: Andrew Gabbasov 
Tested-by: Mark Rutland 
Signed-off-by: Will Deacon 
Signed-off-by: Russell King

ARM: 7578/1: arch/move secure_computing into trace

2012-11-19T14:14:17+00:00

There is very little difference in the TIF_SECCOMP and TIF_SYSCALL_WORK
path in entry-common.S, so merge TIF_SECCOMP into TIF_SYSCALL_WORK and
move seccomp into the syscall_trace_enter() handler.

Expanded some of the tracehook logic into the callers to make this code
more readable. Since tracehook needs to do register changing, this portion
is best left in its own function instead of copy/pasting into the callers.

Additionally, the return value for secure_computing() is now checked
and a -1 value will result in the system call being skipped.

Signed-off-by: Kees Cook 
Acked-by: Will Drewry 
Reviewed-by: Will Deacon 
Signed-off-by: Russell King

ARM: 7525/1: ptrace: use updated syscall number for syscall auditing

2012-09-19T20:50:50+00:00

When tracing system calls, a debugger may change the syscall number
in response to a SIGTRAP on syscall entry.

This patch ensures that the new syscall number is passed to the audit
code.

Signed-off-by: Will Deacon 
Signed-off-by: Russell King

ARM: 7524/1: support syscall tracing

2012-09-19T20:50:48+00:00

As specified by ftrace-design.txt, TIF_SYSCALL_TRACEPOINT was
added, as well as NR_syscalls in asm/unistd.h.  Additionally,
__sys_trace was modified to call trace_sys_enter and
trace_sys_exit when appropriate.

Tests #2 - #4 of "perf test" now complete successfully.

Signed-off-by: Steven Walter 
Signed-off-by: Wade Farnsworth 
Signed-off-by: Will Deacon 
Signed-off-by: Russell King