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authorJohn Wright <john.wright@hp.com>2009-04-29 16:32:01 -0400
committerIngo Molnar <mingo@elte.hu>2009-04-30 06:31:45 -0400
commit2f65dd475c6a8a997145ea83cc3d2d5e6dc55af1 (patch)
treeea094eebb66277be8f5d67884f3dd55a609d1bc4 /arch/x86/vdso
parent091438dd5668396328a3419abcbc6591159eb8d1 (diff)
x86: gettimeofday() vDSO: fix segfault when tv == NULL
According to the gettimeofday(2) manual: If either tv or tz is NULL, the corresponding structure is not set or returned. Since it is legal to give NULL as the tv argument, the code should make sure tv is not NULL before trying to dereference it. This issue manifests itself on x86_64 when vdso=0 is not on the kernel command-line and libc uses the vDSO for gettimeofday() (e.g. glibc >= 2.7). A simple reproducer: #include <stdio.h> #include <sys/time.h> int main(void) { struct timezone tz; gettimeofday(NULL, &tz); return 0; } See http://bugs.debian.org/466491 for more details. [ Impact: fix gettimeofday(NULL, &tz) segfault ] Signed-off-by: John Wright <john.wright@hp.com> Cc: Andi Kleen <ak@suse.de> Cc: John Wright <john.wright@hp.com> LKML-Reference: <1241037121-14805-1-git-send-email-john.wright@hp.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/vdso')
-rw-r--r--arch/x86/vdso/vclock_gettime.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index d9d35824c56f..6a40b78b46aa 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -104,11 +104,13 @@ notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
104{ 104{
105 long ret; 105 long ret;
106 if (likely(gtod->sysctl_enabled && gtod->clock.vread)) { 106 if (likely(gtod->sysctl_enabled && gtod->clock.vread)) {
107 BUILD_BUG_ON(offsetof(struct timeval, tv_usec) != 107 if (likely(tv != NULL)) {
108 offsetof(struct timespec, tv_nsec) || 108 BUILD_BUG_ON(offsetof(struct timeval, tv_usec) !=
109 sizeof(*tv) != sizeof(struct timespec)); 109 offsetof(struct timespec, tv_nsec) ||
110 do_realtime((struct timespec *)tv); 110 sizeof(*tv) != sizeof(struct timespec));
111 tv->tv_usec /= 1000; 111 do_realtime((struct timespec *)tv);
112 tv->tv_usec /= 1000;
113 }
112 if (unlikely(tz != NULL)) { 114 if (unlikely(tz != NULL)) {
113 /* Avoid memcpy. Some old compilers fail to inline it */ 115 /* Avoid memcpy. Some old compilers fail to inline it */
114 tz->tz_minuteswest = gtod->sys_tz.tz_minuteswest; 116 tz->tz_minuteswest = gtod->sys_tz.tz_minuteswest;