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author | Kevin Cernekee <cernekee@gmail.com> | 2012-06-05 15:05:20 -0700 |
---|---|---|
committer | Bernhard Reutner-Fischer <rep.dot.nop@gmail.com> | 2012-06-06 09:36:34 +0200 |
commit | 2952c70804b48bb5c87eea21df5e401969dc4ec1 (patch) | |
tree | 4b76809d374429ba398bb1e266ac02528ebd39f2 /libcrypt/sha512-crypt.c | |
parent | 3c58d95d918c7e2fda374c37a52f81b34b81e4ca (diff) |
MIPS: Use $a0 instead of $v0 for __syscall_error() argument
$a0 is saved across _dl_runtime_resolve(); $v0 is not. Unfortunately,
__syscall_error() uses $v0 for its argument, not $a0 as is the MIPS ABI
standard. This means that if lazy binding was used for __syscall_error(),
the errno value in $v0 could get corrupted.
The problem can be easily seen in testcases where syscalls in librt fail;
when librt tries to call __syscall_error() in libc, the argument gets
lost and errno gets set to a bogus value:
# ./tst-mqueue1 ; echo $?
mq_receive on O_WRONLY mqd_t did not fail with EBADF: Unknown error 2004684208
1
# ./tst-mqueue2 ; echo $?
mq_timedreceive with too small msg_len did not fail with EMSGSIZE: Unknown error 1997360560
1
# ./tst-mqueue4 ; echo $?
mq_timedsend did not fail with ETIMEDOUT: Unknown error 2008747440
1
When _dl_runtime_resolve() was taken out of the equation, the same test
cases passed:
# LD_BIND_NOW=y ./tst-mqueue1 ; echo $?
0
# LD_BIND_NOW=y ./tst-mqueue2 ; echo $?
0
# LD_BIND_NOW=y ./tst-mqueue4 ; echo $?
0
Changing __syscall_error() to look at $a0 instead of $v0 fixed the
problem.
(Note that there is also a "__syscall_error.c" file which presumably
uses the standard C calling conventions, but I do not think it is used
on MIPS.)
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
Diffstat (limited to 'libcrypt/sha512-crypt.c')
0 files changed, 0 insertions, 0 deletions