From d4fe284a64e4490ad172dfb907fe6d8dc683f50d Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sat, 22 May 2021 11:57:15 +0000 Subject: [PATCH] futex: Do not apply time namespace adjustment on FUTEX_LOCK_PI stable inclusion from stable-5.10.36 commit d19a456acaec3de1ed64952fe21974ae0cff376f bugzilla: 51867 CVE: NA -------------------------------- commit cdf78db4070967869e4d027c11f4dd825d8f815a upstream. FUTEX_LOCK_PI does not require to have the FUTEX_CLOCK_REALTIME bit set because it has been using CLOCK_REALTIME based absolute timeouts forever. Due to that, the time namespace adjustment which is applied when FUTEX_CLOCK_REALTIME is not set, will wrongly take place for FUTEX_LOCK_PI and wreckage the timeout. Exclude it from that procedure. Fixes: c2f7d08cccf4 ("futex: Adjust absolute futex timeouts with per time namespace offset") Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210422194704.984540159@linutronix.de Signed-off-by: Greg Kroah-Hartman Signed-off-by: Chen Jun Acked-by: Weilong Chen Signed-off-by: Zheng Zengkai --- kernel/futex.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/futex.c b/kernel/futex.c index cd8d4a20d2b8..3136aba17772 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -3784,7 +3784,7 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val, t = timespec64_to_ktime(ts); if (cmd == FUTEX_WAIT) t = ktime_add_safe(ktime_get(), t); - else if (!(op & FUTEX_CLOCK_REALTIME)) + else if (cmd != FUTEX_LOCK_PI && !(op & FUTEX_CLOCK_REALTIME)) t = timens_ktime_to_host(CLOCK_MONOTONIC, t); tp = &t; } @@ -3978,7 +3978,7 @@ SYSCALL_DEFINE6(futex_time32, u32 __user *, uaddr, int, op, u32, val, t = timespec64_to_ktime(ts); if (cmd == FUTEX_WAIT) t = ktime_add_safe(ktime_get(), t); - else if (!(op & FUTEX_CLOCK_REALTIME)) + else if (cmd != FUTEX_LOCK_PI && !(op & FUTEX_CLOCK_REALTIME)) t = timens_ktime_to_host(CLOCK_MONOTONIC, t); tp = &t; } -- GitLab