Commit-ID: 6ada1fc0e1c4775de0e043e1bd3ae9d065491aa5 Gitweb: http://git.kernel.org/tip/6ada1fc0e1c4775de0e043e1bd3ae9d065491aa5 Author: Sasha Levin <sasha.levin@xxxxxxxxxx> AuthorDate: Wed, 3 Dec 2014 19:22:48 -0500 Committer: John Stultz <john.stultz@xxxxxxxxxx> CommitDate: Wed, 7 Jan 2015 09:49:14 -0800 time: settimeofday: Validate the values of tv from user 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@xxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: stable <stable@xxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx> [jstultz: include trivial milisecond->microsecond correction noticed by Andy] Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx> --- include/linux/time.h | 13 +++++++++++++ kernel/time/time.c | 4 ++++ 2 files changed, 17 insertions(+) diff --git a/include/linux/time.h b/include/linux/time.h index 8c42cf8..5989b0e 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -99,6 +99,19 @@ static inline bool timespec_valid_strict(const struct timespec *ts) return true; } +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); #define CURRENT_TIME (current_kernel_time()) diff --git a/kernel/time/time.c b/kernel/time/time.c index a9ae20f..22d5d3b 100644 --- a/kernel/time/time.c +++ b/kernel/time/time.c @@ -196,6 +196,10 @@ 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; } -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html