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audit: ia32entry.S sign extend error codes when calling 64 bit code

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In the ia32entry syscall exit audit fastpath we have assembly code which calls
__audit_syscall_exit directly.  This code was, however, zeroes the upper 32
bits of the return code.  It then proceeded to call code which expects longs
to be 64bits long.  In order to handle code which expects longs to be 64bit we
sign extend the return code if that code is an error.  Thus the
__audit_syscall_exit function can correctly handle using the values in
snprintf("%ld").  This fixes the regression introduced in 5cbf1565f2.

Old record:
type=SYSCALL msg=audit(1306197182.256:281): arch=40000003 syscall=192 success=no exit=4294967283
New record:
type=SYSCALL msg=audit(1306197182.256:281): arch=40000003 syscall=192 success=no exit=-13

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
Eric Paris 2012-01-03 14:23:06 -05:00 committed by Al Viro
parent d7e7528bcd
commit f031cd2556
1 changed files with 3 additions and 1 deletions
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4
arch/x86/ia32/ia32entry.S
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@ -210,7 +210,9 @@ sysexit_from_sys_call:
sti
movl %eax,%esi /* second arg, syscall return value */
cmpl $-MAX_ERRNO,%eax /* is it an error ? */
setbe %al /* 1 if so, 0 if not */
jbe 1f
movslq %eax, %rsi /* if error sign extend to 64 bits */
1: setbe %al /* 1 if error, 0 if not */
movzbl %al,%edi /* zero-extend that into %edi */
call __audit_syscall_exit
movq RAX-ARGOFFSET(%rsp),%rax /* reload syscall return value */