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authorZeng Tao <prime.zeng@hisilicon.com>2020-09-01 11:30:13 +0200
committerThomas Gleixner <tglx@linutronix.de>2020-10-26 11:48:11 +0100
commitcb47755725da7b90fecbb2aa82ac3b24a7adb89b (patch)
treed1480795667ccb9760ea9b5fe6f36df8f6028aee /kernel/time/itimer.c
parenttimers: Remove unused inline funtion debug_timer_free() (diff)
downloadlinux-cb47755725da7b90fecbb2aa82ac3b24a7adb89b.tar.xz
linux-cb47755725da7b90fecbb2aa82ac3b24a7adb89b.zip
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 'kernel/time/itimer.c')
-rw-r--r--kernel/time/itimer.c4
1 files changed, 0 insertions, 4 deletions
diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c
index ca4e6d57d68b..00629e658ca1 100644
--- a/kernel/time/itimer.c
+++ b/kernel/time/itimer.c
@@ -172,10 +172,6 @@ static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
u64 oval, nval, ointerval, ninterval;
struct cpu_itimer *it = &tsk->signal->it[clock_id];
- /*
- * Use the to_ktime conversion because that clamps the maximum
- * value to KTIME_MAX and avoid multiplication overflows.
- */
nval = timespec64_to_ns(&value->it_value);
ninterval = timespec64_to_ns(&value->it_interval);