Patch "IB/core: Fix use after free in send_leave function" has been added to the 4.7-stable tree

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

IB/core: Fix use after free in send_leave function

to the 4.7-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:
ib-core-fix-use-after-free-in-send_leave-function.patch
and it can be found in the queue-4.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Erez Shitrit <[email protected]>
Date: Sun, 28 Aug 2016 10:58:30 +0300
Subject: IB/core: Fix use after free in send_leave function

From: Erez Shitrit <[email protected]>

commit 68c6bcdd8bd00394c234b915ab9b97c74104130c upstream.

The function send_leave sets the member: group->query_id (group->query_id = ret) after calling the sa_query, but leave_handler can be executed before the setting and it might delete the group object, and will get a memory corruption.

Additionally, this patch gets rid of group->query_id variable which is not used.

---
 drivers/infiniband/core/multicast.c |   13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

@@ -118,7 +118,6 @@ struct mcast_group {
 	atomic_t		refcount;
 	enum mcast_group_state	state;
 	struct ib_sa_query	*query;
-	int			query_id;
 	u16			pkey_index;
 	u8			leave_state;
 	int			retries;

@@ -352,11 +351,7 @@ static int send_join(struct mcast_group
 				       member->multicast.comp_mask,
 				       3000, GFP_KERNEL, join_handler, group,
 				       &group->query);
-	if (ret >= 0) {
-		group->query_id = ret;
-		ret = 0;
-	}
-	return ret;
+	return (ret > 0) ? 0 : ret;
 }
 
 static int send_leave(struct mcast_group *group, u8 leave_state)

@@ -376,11 +371,7 @@ static int send_leave(struct mcast_group
 				       IB_SA_MCMEMBER_REC_JOIN_STATE,
 				       3000, GFP_KERNEL, leave_handler,
 				       group, &group->query);
-	if (ret >= 0) {
-		group->query_id = ret;
-		ret = 0;
-	}
-	return ret;
+	return (ret > 0) ? 0 : ret;
 }
 
 static void join_group(struct mcast_group *group, struct mcast_member *member,

Patches currently in stable-queue which might be from [email protected] are

queue-4.7/ib-ipoib-fix-memory-corruption-in-ipoib-cm-mode-connect-flow.patch queue-4.7/ib-core-fix-use-after-free-in-send_leave-function.patch