IB/core: Fix use after free in send_leave function

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>

diff --git a/drivers/infiniband/core/multicast.c b/drivers/infiniband/core/multicast.c
index 3a3c5d7..51c79b2 100644 (file)
--- 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;
@@ -340,11 +339,7 @@ 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)
@@ -364,11 +359,7 @@ 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,