Patch "rds: fix an integer overflow test in rds_info_getsockopt()" has been added to the 4.1-stable tree

Patch "rds: fix an integer overflow test in rds_info_getsockopt()" has been added to the 4.1-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    rds: fix an integer overflow test in rds_info_getsockopt()

to the 4.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     rds-fix-an-integer-overflow-test-in-rds_info_getsockopt.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Sat Sep 26 11:13:07 PDT 2015
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Sat, 1 Aug 2015 15:33:26 +0300
Subject: rds: fix an integer overflow test in rds_info_getsockopt()

From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit 468b732b6f76b138c0926eadf38ac88467dcd271 ]

"len" is a signed integer.  We check that len is not negative, so it
goes from zero to INT_MAX.  PAGE_SIZE is unsigned long so the comparison
is type promoted to unsigned long.  ULONG_MAX - 4095 is a higher than
INT_MAX so the condition can never be true.

I don't know if this is harmful but it seems safe to limit "len" to
INT_MAX - 4095.

Fixes: a8c879a7ee98 ('RDS: Info and stats')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/rds/info.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/rds/info.c
+++ b/net/rds/info.c
@@ -176,7 +176,7 @@ int rds_info_getsockopt(struct socket *s
 
 	/* check for all kinds of wrapping and the like */
 	start = (unsigned long)optval;
-	if (len < 0 || len + PAGE_SIZE - 1 < len || start + len < start) {
+	if (len < 0 || len > INT_MAX - PAGE_SIZE + 1 || start + len < start) {
 		ret = -EINVAL;
 		goto out;
 	}


Patches currently in stable-queue which might be from dan.carpenter@oracle.com are

queue-4.1/rds-fix-an-integer-overflow-test-in-rds_info_getsockopt.patch
queue-4.1/net-xen-netback-off-by-one-in-bug_on-condition.patch
queue-4.1/packet-missing-dev_put-in-packet_do_bind.patch