mips: rlimit incorrectly converts values
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>
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 90f6789..4b9e3b8 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -934,18 +934,30 @@
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,
