[PATCH 3.14 11/73] inetdevice: fixed signed integer overflow

Greg Kroah-Hartman
2014-12-05T23:33:32Z

From: Vincent BENAYOUN <vincent.benayoun@trust-in-soft.com>

[ Upstream commit 84bc88688e3f6ef843aa8803dbcd90168bb89faf ]

There could be a signed overflow in the following code.

The expression, (32-logmask) is comprised between 0 and 31 included.
It may be equal to 31.
In such a case the left shift will produce a signed integer overflow.
According to the C99 Standard, this is an undefined behavior.
A simple fix is to replace the signed int 1 with the unsigned int 1U.

Signed-off-by: Vincent BENAYOUN <vincent.benayoun@trust-in-soft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/linux/inetdevice.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/linux/inetdevice.h
+++ b/include/linux/inetdevice.h
@@ -242,7 +242,7 @@ static inline void in_dev_put(struct in_
static __inline__ __be32 inet_make_mask(int logmask)
{
if (logmask)
- return htonl(~((1<<(32-logmask))-1));
+ return htonl(~((1U<<(32-logmask))-1));
return 0;
}