[patch] time: cast ->raw_interval to u64 to avoid shift overflow

[patch] time: cast ->raw_interval to u64 to avoid shift overflow

[Dan Carpenter]

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 <dan.carpenter@oracle.com>
---
I'm not super familiar with this code so please review my work
carefully.

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 5ce06a3..1d1ee67 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1113,7 +1113,7 @@ static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
 	accumulate_nsecs_to_secs(tk);
 
 	/* Accumulate raw time */
-	raw_nsecs = tk->raw_interval << shift;
+	raw_nsecs = (u64)tk->raw_interval << shift;
 	raw_nsecs += tk->raw_time.tv_nsec;
 	if (raw_nsecs >= NSEC_PER_SEC) {
 		u64 raw_secs = raw_nsecs;

[patch] time: cast ->raw_interval to u64 to avoid shift overflow

[Dan Carpenter]

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 <dan.carpenter@oracle.com>
---
I'm not super familiar with this code so please review my work
carefully.

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 5ce06a3..1d1ee67 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1113,7 +1113,7 @@ static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
 	accumulate_nsecs_to_secs(tk);
 
 	/* Accumulate raw time */
-	raw_nsecs = tk->raw_interval << shift;
+	raw_nsecs = (u64)tk->raw_interval << shift;
 	raw_nsecs += tk->raw_time.tv_nsec;
 	if (raw_nsecs >= NSEC_PER_SEC) {
 		u64 raw_secs = raw_nsecs;

Re: [patch] time: cast ->raw_interval to u64 to avoid shift overflow

[John Stultz]

On 10/09/2012 12:18 AM, Dan Carpenter wrote:
> 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 <dan.carpenter@oracle.com>

Yep. Looks like this would trigger if you had NOZ idle for more then 4 
seconds.

Thanks for the audit, and sending this in!

Thomas: Mind queuing this?  Probably should be marked for stable too.

Acked-by: John Stultz <johnstul@us.ibm.com>

Re: [patch] time: cast ->raw_interval to u64 to avoid shift overflow

[John Stultz]

On 10/09/2012 12:18 AM, Dan Carpenter wrote:
> 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 <dan.carpenter@oracle.com>

Yep. Looks like this would trigger if you had NOZ idle for more then 4 
seconds.

Thanks for the audit, and sending this in!

Thomas: Mind queuing this?  Probably should be marked for stable too.

Acked-by: John Stultz <johnstul@us.ibm.com>

[tip:timers/core] timekeeping: Cast raw_interval to u64 to avoid shift overflow

[tip-bot for Dan Carpenter]

Commit-ID:  5b3900cd409466c0070b234d941650685ad0c791
Gitweb:     http://git.kernel.org/tip/5b3900cd409466c0070b234d941650685ad0c791
Author:     Dan Carpenter <dan.carpenter@oracle.com>
AuthorDate: Tue, 9 Oct 2012 10:18:23 +0300
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Tue, 9 Oct 2012 21:27:14 +0200

timekeeping: Cast raw_interval to u64 to avoid shift overflow

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 <dan.carpenter@oracle.com>
Acked-by: John Stultz <johnstul@us.ibm.com>
Link: http://lkml.kernel.org/r/20121009071823.GA19159@elgon.mountain
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
---
 kernel/time/timekeeping.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 16280ff..3eb3fc7c 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1045,7 +1045,7 @@ static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
 	accumulate_nsecs_to_secs(tk);
 
 	/* Accumulate raw time */
-	raw_nsecs = tk->raw_interval << shift;
+	raw_nsecs = (u64)tk->raw_interval << shift;
 	raw_nsecs += tk->raw_time.tv_nsec;
 	if (raw_nsecs >= NSEC_PER_SEC) {
 		u64 raw_secs = raw_nsecs;