linux-toradex.git/arch/arm/kernel/ptrace.c, branch v3.17

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

ARM: 7474/1: get rid of TIF_SYSCALL_RESTARTSYS

2012-07-28T10:11:52+00:00

just let do_work_pending() return 1 on normal local restarts and
-1 on those that had been caused by ERESTART_RESTARTBLOCK (and 0
is still "all done, sod off to userland now").  And let the asm
glue flip scno to restart_syscall(2) one if it got negative from
us...

[will: resolved conflicts with audit fixes]

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

ARM: 7470/1: Revert "7443/1: Revert "new way of handling ERESTART_RESTARTBLOCK""

2012-07-28T10:11:51+00:00

This reverts commit 433e2f307beff8adba241646ce9108544e0c5a03.

Conflicts:

	arch/arm/kernel/ptrace.c

Reintroduce the new syscall restart handling in preparation for further
patches from Al Viro.

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

ARM: 7456/1: ptrace: provide separate functions for tracing syscall {entry,exit}

2012-07-09T16:44:14+00:00

The syscall_trace on ARM takes a `why' parameter to indicate whether or
not we are entering or exiting a system call. This can be confusing for
people looking at the code since (a) it conflicts with the why register
alias in the entry assembly code and (b) it is not immediately clear
what it represents.

This patch splits up the syscall_trace function into separate wrappers
for syscall entry and exit, allowing the low-level syscall handling
code to branch to the appropriate function.

Reported-by: Al Viro 
Reviewed-by: Catalin Marinas 
Signed-off-by: Will Deacon 
Signed-off-by: Russell King