From 4352d9d44b935e4d000be6ec89ddb55c2bf35f24 Mon Sep 17 00:00:00 2001 From: Richard Cochran Date: Mon, 4 Apr 2011 08:31:23 -0700 Subject: ntp: fix non privileged system time shifting The ADJ_SETOFFSET bit added in commit 094aa188 ("ntp: Add ADJ_SETOFFSET mode bit") also introduced a way for any user to change the system time. Sneaky or buggy calls to adjtimex() could set ADJ_OFFSET_SS_READ | ADJ_SETOFFSET which would result in a successful call to timekeeping_inject_offset(). This patch fixes the issue by adding the capability check. Signed-off-by: Richard Cochran Signed-off-by: Linus Torvalds --- kernel/time/ntp.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 5f1bb8e2008f..f6117a4c7cb8 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -652,6 +652,8 @@ int do_adjtimex(struct timex *txc) struct timespec delta; delta.tv_sec = txc->time.tv_sec; delta.tv_nsec = txc->time.tv_usec; + if (!capable(CAP_SYS_TIME)) + return -EPERM; if (!(txc->modes & ADJ_NANO)) delta.tv_nsec *= 1000; result = timekeeping_inject_offset(&delta); -- cgit v1.2.3