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mips: rlimit incorrectly converts values

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Byte swap was applied in the wrong order with testing for
RLIM_INFINITY. On mips bigendian from an amd64 system this results in
infinity being misinterpretted as 2^31-1.

This is a serious bug because it causes setrlimit stack size to kill
all child processes. This means (for example) that 'make' can run no
children. The mechanism of failure:
1. parent sets stack size rlimit to 'infinity'
2. qemu screws this value up
3. child process fetches stack size as a large (but non-infinite) value
4. qemu tries to allocate stack before execution
5. stack allocation fails (too big) and child process dies

Signed-off-by: Wesley W. Terpstra <terpstra@debian.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
This commit is contained in:
Wesley W. Terpstra 2011-07-12 14:38:22 +03:00 committed by Riku Voipio
parent e6e5bd2dd1
commit 95b33b2f4f
1 changed files with 17 additions and 5 deletions
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22
linux-user/syscall.c
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@ -934,18 +934,30 @@ static inline abi_long host_to_target_rusage(abi_ulong target_addr,
static inline rlim_t target_to_host_rlim(target_ulong target_rlim)
{
if (target_rlim == TARGET_RLIM_INFINITY)
return RLIM_INFINITY;
target_ulong target_rlim_swap;
rlim_t result;
target_rlim_swap = tswapl(target_rlim);
if (target_rlim_swap == TARGET_RLIM_INFINITY || target_rlim_swap != (rlim_t)target_rlim_swap)
result = RLIM_INFINITY;
else
return tswapl(target_rlim);
result = target_rlim_swap;
return result;
}
static inline target_ulong host_to_target_rlim(rlim_t rlim)
{
target_ulong target_rlim_swap;
target_ulong result;
if (rlim == RLIM_INFINITY || rlim != (target_long)rlim)
return TARGET_RLIM_INFINITY;
target_rlim_swap = TARGET_RLIM_INFINITY;
else
return tswapl(rlim);
target_rlim_swap = rlim;
result = tswapl(target_rlim_swap);
return result;
}
static inline abi_long copy_from_user_timeval(struct timeval *tv,