From 6ada1fc0e1c4775de0e043e1bd3ae9d065491aa5 Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Wed, 3 Dec 2014 19:22:48 -0500 Subject: 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 Cc: Ingo Molnar Cc: stable Signed-off-by: Sasha Levin [jstultz: include trivial milisecond->microsecond correction noticed by Andy] Signed-off-by: John Stultz --- kernel/time/time.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel/time') diff --git a/kernel/time/time.c b/kernel/time/time.c index a9ae20fb0b1..22d5d3b7397 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; } -- cgit v1.2.3-70-g09d2 From 5e5aeb4367b450a28f447f6d5ab57d8f2ab16a5f Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Wed, 3 Dec 2014 19:25:05 -0500 Subject: time: adjtimex: Validate the ADJ_FREQUENCY values Verify that the frequency value from userspace is valid and makes sense. Unverified values can cause overflows later on. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: stable Signed-off-by: Sasha Levin [jstultz: Fix up bug for negative values and drop redunent cap check] Signed-off-by: John Stultz --- kernel/time/ntp.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'kernel/time') diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 87a346fd6d6..28bf91c60a0 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -633,6 +633,13 @@ int ntp_validate_timex(struct timex *txc) if ((txc->modes & ADJ_SETOFFSET) && (!capable(CAP_SYS_TIME))) return -EPERM; + if (txc->modes & ADJ_FREQUENCY) { + if (LONG_MIN / PPM_SCALE > txc->freq) + return -EINVAL; + if (LONG_MAX / PPM_SCALE < txc->freq) + return -EINVAL; + } + return 0; } -- cgit v1.2.3-70-g09d2