diff options
| author | Sasha Levin <sasha.levin@oracle.com> | 2014-12-03 19:22:48 -0500 |
|---|---|---|
| committer | Zefan Li <lizefan@huawei.com> | 2015-04-14 17:33:50 +0800 |
| commit | 370375c0a447eefedc19e872e5137eeff47162f2 (patch) | |
| tree | 57fbb90eb9b5fbb56fc8733bafaf252e1d85c9f6 | |
| parent | b25489c724b2775cb5eb3eb6d525ad355d1b1f47 (diff) | |
time: settimeofday: Validate the values of tv from user
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 <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
[jstultz: include trivial milisecond->microsecond correction noticed
by Andy]
Signed-off-by: John Stultz <john.stultz@linaro.org>
[lizf: Backported to 3.4: adjust filename]
Signed-off-by: Zefan Li <lizefan@huawei.com>
| -rw-r--r-- | include/linux/time.h | 13 | ||||
| -rw-r--r-- | kernel/time.c | 4 |
2 files changed, 17 insertions, 0 deletions
diff --git a/include/linux/time.h b/include/linux/time.h index 03dce74e217c..bf1bb618b352 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 a09529030093..0864d70da80d 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; } |