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| author | Zeng Tao <prime.zeng@hisilicon.com> | 2020-09-01 12:30:13 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-10-26 13:48:11 +0300 |
| commit | cb47755725da7b90fecbb2aa82ac3b24a7adb89b (patch) | |
| tree | d1480795667ccb9760ea9b5fe6f36df8f6028aee /include/linux/time64.h | |
| parent | 9010e3876e1c3f7b1c3769bee519d6a871589aca (diff) | |
| download | linux-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.h | 4 |
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; } |