diff options
| author | Zeng Tao <prime.zeng@hisilicon.com> | 2020-09-01 17:30:13 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-11-18 18:24:57 +0100 |
| commit | 9cddbb8787ef3354bb08f19a0b08850bf67a6d16 (patch) | |
| tree | e46c0c13461cb91f0c5d06b19b65695158b212e9 | |
| parent | 45b52deae851b1eeca961cb0f73f43d3c8816df3 (diff) | |
time: Prevent undefined behaviour in timespec64_to_ns()
[ Upstream commit cb47755725da7b90fecbb2aa82ac3b24a7adb89b ]
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -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 367d5af899e8..10239cffd70f 100644 --- a/include/linux/time64.h +++ b/include/linux/time64.h @@ -197,6 +197,10 @@ static inline bool timespec64_valid_strict(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; } |