diff options
| author | Sasha Levin <sasha.levin@oracle.com> | 2014-12-03 19:22:48 -0500 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2015-01-29 15:45:01 +0100 |
| commit | 7d191a70e81163aabc6e6ad1ad578ca4c6cc6981 (patch) | |
| tree | 4eed8402a942ed38c4d70239d5b611bbbe54e27b | |
| parent | 8dc75a54f3dc579f615840c4200b17b17665bce7 (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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -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 d5d229b2e5af..7d532a32ff3a 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -173,6 +173,19 @@ 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 3c49ab45f822..3eb322e518a3 100644 --- a/kernel/time.c +++ b/kernel/time.c @@ -195,6 +195,10 @@ 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; } |