Thread (63 messages) 63 messages, 6 authors, 2012-12-06

[ 54/56] timekeeping: Cast raw_interval to u64 to avoid shift overflow

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2012-11-30 19:01:42
Also in: lkml

3.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <redacted>

commit 5b3900cd409466c0070b234d941650685ad0c791 upstream.

We fixed a bunch of integer overflows in timekeeping code during the 3.6
cycle.  I did an audit based on that and found this potential overflow.

Signed-off-by: Dan Carpenter <redacted>
Acked-by: John Stultz <redacted>
Link: http://lkml.kernel.org/r/20121009071823.GA19159@elgon.mountain
Signed-off-by: Thomas Gleixner <redacted>
Cc: Ben Hutchings <redacted>
[ herton: adapt for 3.5, timekeeper instead of tk pointer ]
Signed-off-by: Herton Ronaldo Krzesinski <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/time/timekeeping.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1014,7 +1014,7 @@ static cycle_t logarithmic_accumulation(
 	}
 
 	/* Accumulate raw time */
-	raw_nsecs = timekeeper.raw_interval << shift;
+	raw_nsecs = (u64)timekeeper.raw_interval << shift;
 	raw_nsecs += timekeeper.raw_time.tv_nsec;
 	if (raw_nsecs >= NSEC_PER_SEC) {
 		u64 raw_secs = raw_nsecs;

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