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authorZeng Tao <prime.zeng@hisilicon.com>2020-09-01 12:30:13 +0300
committerThomas Gleixner <tglx@linutronix.de>2020-10-26 13:48:11 +0300
commitcb47755725da7b90fecbb2aa82ac3b24a7adb89b (patch)
treed1480795667ccb9760ea9b5fe6f36df8f6028aee /include/linux/time64.h
parent9010e3876e1c3f7b1c3769bee519d6a871589aca (diff)
downloadlinux-cb47755725da7b90fecbb2aa82ac3b24a7adb89b.tar.xz
time: Prevent undefined behaviour in timespec64_to_ns()
UBSAN reports: Undefined behaviour in ./include/linux/time64.h:127:27 signed integer overflow: 17179869187 * 1000000000 cannot be represented in type 'long long int' Call Trace: timespec64_to_ns include/linux/time64.h:127 [inline] set_cpu_itimer+0x65c/0x880 kernel/time/itimer.c:180 do_setitimer+0x8e/0x740 kernel/time/itimer.c:245 __x64_sys_setitimer+0x14c/0x2c0 kernel/time/itimer.c:336 do_syscall_64+0xa1/0x540 arch/x86/entry/common.c:295 Commit bd40a175769d ("y2038: itimer: change implementation to timespec64") replaced the original conversion which handled time clamping correctly with timespec64_to_ns() which has no overflow protection. Fix it in timespec64_to_ns() as this is not necessarily limited to the usage in itimers. [ tglx: Added comment and adjusted the fixes tag ] Fixes: 361a3bf00582 ("time64: Add time64.h header and define struct timespec64") Signed-off-by: Zeng Tao <prime.zeng@hisilicon.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/1598952616-6416-1-git-send-email-prime.zeng@hisilicon.com
Diffstat (limited to 'include/linux/time64.h')
-rw-r--r--include/linux/time64.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/time64.h b/include/linux/time64.h
index c9dcb3e5781f..5117cb5b5656 100644
--- a/include/linux/time64.h
+++ b/include/linux/time64.h
@@ -124,6 +124,10 @@ static inline bool timespec64_valid_settod(const struct timespec64 *ts)
*/
static inline s64 timespec64_to_ns(const struct timespec64 *ts)
{
+ /* Prevent multiplication overflow */
+ if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)
+ return KTIME_MAX;
+
return ((s64) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
}