From: Sasha Levin <[email protected]> 3.4.107-rc1 review patch. If anyone has any objections, please let me know.
------------------ commit 5e5aeb4367b450a28f447f6d5ab57d8f2ab16a5f upstream. Verify that the frequency value from userspace is valid and makes sense. Unverified values can cause overflows later on. Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Signed-off-by: Sasha Levin <[email protected]> [jstultz: Fix up bug for negative values and drop redunent cap check] Signed-off-by: John Stultz <[email protected]> [lizf: Backported to 3.4: adjust context] Signed-off-by: Zefan Li <[email protected]> --- kernel/time/ntp.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 8b70710..7666b24 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -660,6 +660,13 @@ int do_adjtimex(struct timex *txc) return result; } + if (txc->modes & ADJ_FREQUENCY) { + if (LONG_MIN / PPM_SCALE > txc->freq) + return -EINVAL; + if (LONG_MAX / PPM_SCALE < txc->freq) + return -EINVAL; + } + getnstimeofday(&ts); spin_lock_irq(&ntp_lock); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
