Commit 6ada1fc0 authored by Sasha Levin's avatar Sasha Levin Committed by John Stultz

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@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
[jstultz: include trivial milisecond->microsecond correction noticed
by Andy]
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
parent b2776bf7
...@@ -99,6 +99,19 @@ static inline bool timespec_valid_strict(const struct timespec *ts) ...@@ -99,6 +99,19 @@ static inline bool timespec_valid_strict(const struct timespec *ts)
return true; 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); extern struct timespec timespec_trunc(struct timespec t, unsigned gran);
#define CURRENT_TIME (current_kernel_time()) #define CURRENT_TIME (current_kernel_time())
......
...@@ -196,6 +196,10 @@ SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv, ...@@ -196,6 +196,10 @@ SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv,
if (tv) { if (tv) {
if (copy_from_user(&user_tv, tv, sizeof(*tv))) if (copy_from_user(&user_tv, tv, sizeof(*tv)))
return -EFAULT; return -EFAULT;
if (!timeval_valid(&user_tv))
return -EINVAL;
new_ts.tv_sec = user_tv.tv_sec; new_ts.tv_sec = user_tv.tv_sec;
new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC; new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC;
} }
......
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