[PATCH 3.10 201/319] IB/core: Fix use after free in send_leave function

Willy Tarreau
2017-02-05T19:26:15Z

From: Erez Shitrit <erezsh@mellanox.com>

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.

Fixes: faec2f7b96b5 ('IB/sa: Track multicast join/leave requests')
Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
drivers/infiniband/core/multicast.c | 13 ++-----------
1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/drivers/infiniband/core/multicast.c b/drivers/infiniband/core/multicast.c
index d2360a8..180d7f4 100644
--- a/drivers/infiniband/core/multicast.c
+++ b/drivers/infiniband/core/multicast.c
@@ -106,7 +106,6 @@ 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;
@@ -339,11 +338,7 @@ static int send_join(struct mcast_group *group, struct mcast_member *member)
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)
@@ -363,11 +358,7 @@ static int send_leave(struct mcast_group *group, u8 leave_state)
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,
--
2.8.0.rc2.1.gbe9624a