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authorSasha Levin <sasha.levin@oracle.com>2014-12-04 01:22:48 +0100
committerJohn Stultz <john.stultz@linaro.org>2015-01-07 18:49:14 +0100
commit6ada1fc0e1c4775de0e043e1bd3ae9d065491aa5 (patch)
treeb6a02726aa5f93ccb61e7161c7705590424f7830
parentLinux 3.18 (diff)
downloadlinux-6ada1fc0e1c4775de0e043e1bd3ae9d065491aa5.tar.xz
linux-6ada1fc0e1c4775de0e043e1bd3ae9d065491aa5.zip
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: Sasha Levin <sasha.levin@oracle.com> [jstultz: include trivial milisecond->microsecond correction noticed by Andy] Signed-off-by: John Stultz <john.stultz@linaro.org>
-rw-r--r--include/linux/time.h13
-rw-r--r--kernel/time/time.c4
2 files changed, 17 insertions, 0 deletions
diff --git a/include/linux/time.h b/include/linux/time.h
index 8c42cf8d2444..5989b0ead1ec 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 a9ae20fb0b11..22d5d3b73970 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;
}