From c25e394b8bbbc68136b9ad4942a20601948601d4 Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Wed, 3 Dec 2014 19:22:48 -0500 Subject: [PATCH] time: settimeofday: Validate the values of tv from user MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 6ada1fc0e1c4775de0e043e1bd3ae9d065491aa5 upstream. An unvalidated user input is multiplied by a constant, which can result in an undefined behaviour for large values. While this is validated later, we should avoid triggering undefined behaviour. Cc: Thomas Gleixner Cc: Ingo Molnar Signed-off-by: Sasha Levin [jstultz: include trivial milisecond->microsecond correction noticed by Andy] Signed-off-by: John Stultz [lizf: Backported to 3.4: adjust filename] Signed-off-by: Zefan Li Signed-off-by: D. Andrei Măceș --- include/linux/time.h | 13 +++++++++++++ kernel/time.c | 4 ++++ 2 files changed, 17 insertions(+) diff --git a/include/linux/time.h b/include/linux/time.h index 0baa48b3b2af..d4505f2b51e3 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -189,6 +189,19 @@ extern void getboottime(struct timespec *ts); extern void monotonic_to_bootbased(struct timespec *ts); extern void get_monotonic_boottime(struct timespec *ts); +static inline bool timeval_valid(const struct timeval *tv) +{ + /* Dates before 1970 are bogus */ + if (tv->tv_sec < 0) + return false; + + /* Can't have more microseconds then a second */ + if (tv->tv_usec < 0 || tv->tv_usec >= USEC_PER_SEC) + return false; + + return true; +} + extern struct timespec timespec_trunc(struct timespec t, unsigned gran); extern int timekeeping_valid_for_hres(void); extern u64 timekeeping_max_deferment(void); diff --git a/kernel/time.c b/kernel/time.c index ba744cf80696..d1a8e01ff3f2 100644 --- a/kernel/time.c +++ b/kernel/time.c @@ -186,6 +186,10 @@ SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv, if (tv) { if (copy_from_user(&user_tv, tv, sizeof(*tv))) return -EFAULT; + + if (!timeval_valid(&user_tv)) + return -EINVAL; + new_ts.tv_sec = user_tv.tv_sec; new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC; }