[PATCH 2/3] tipc: fix memory leak issue

[Ying Xue <ying.xue@windriver.com>]

syzbot found the following memory leak issue:

[   72.286706][ T7064] kmemleak: 1 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
BUG: memory leak
unreferenced object 0xffff888122bca200 (size 128):
  comm "syz-executor232", pid 7065, jiffies 4294943817 (age 8.880s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 18 a2 bc 22 81 88 ff ff  ..........."....
  backtrace:
    [<000000005bada299>] kmem_cache_alloc_trace+0x145/0x2c0
    [<00000000e7bcdc9f>] tipc_group_create_member+0x3c/0x190
    [<0000000005f56f40>] tipc_group_add_member+0x34/0x40
    [<0000000044406683>] tipc_nametbl_build_group+0x9b/0xf0
    [<000000009f71e803>] tipc_setsockopt+0x170/0x490
    [<000000007f61cbc2>] __sys_setsockopt+0x10f/0x220
    [<00000000cc630372>] __x64_sys_setsockopt+0x26/0x30
    [<00000000ec30be33>] do_syscall_64+0x76/0x1a0
    [<00000000271be3e6>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported-by: syzbot+f95d90c454864b3b5bc9@syzkaller.appspotmail.com
Signed-off-by: Hillf Danton <hdanton@sina.com>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
---
 net/tipc/group.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/net/tipc/group.c b/net/tipc/group.c
index 5f98d38..cbc540a 100644
--- a/net/tipc/group.c
+++ b/net/tipc/group.c
@@ -273,8 +273,8 @@ static struct tipc_member *tipc_group_find_node(struct tipc_group *grp,
 	return NULL;
 }
 
-static void tipc_group_add_to_tree(struct tipc_group *grp,
-				   struct tipc_member *m)
+struct tipc_member *tipc_group_add_to_tree(struct tipc_group *grp,
+					   struct tipc_member *m)
 {
 	u64 nkey, key = (u64)m->node << 32 | m->port;
 	struct rb_node **n, *parent = NULL;
@@ -282,7 +282,6 @@ static void tipc_group_add_to_tree(struct tipc_group *grp,
 
 	n = &grp->members.rb_node;
 	while (*n) {
-		tmp = container_of(*n, struct tipc_member, tree_node);
 		parent = *n;
 		tmp = container_of(parent, struct tipc_member, tree_node);
 		nkey = (u64)tmp->node << 32 | tmp->port;
@@ -291,17 +290,18 @@ static void tipc_group_add_to_tree(struct tipc_group *grp,
 		else if (key > nkey)
 			n = &(*n)->rb_right;
 		else
-			return;
+			return tmp;
 	}
 	rb_link_node(&m->tree_node, parent, n);
 	rb_insert_color(&m->tree_node, &grp->members);
+	return m;
 }
 
 static struct tipc_member *tipc_group_create_member(struct tipc_group *grp,
 						    u32 node, u32 port,
 						    u32 instance, int state)
 {
-	struct tipc_member *m;
+	struct tipc_member *m, *n;
 
 	m = kzalloc(sizeof(*m), GFP_ATOMIC);
 	if (!m)
@@ -315,10 +315,14 @@ static struct tipc_member *tipc_group_create_member(struct tipc_group *grp,
 	m->instance = instance;
 	m->bc_acked = grp->bc_snd_nxt - 1;
 	grp->member_cnt++;
-	tipc_group_add_to_tree(grp, m);
-	tipc_nlist_add(&grp->dests, m->node);
-	m->state = state;
-	return m;
+	n = tipc_group_add_to_tree(grp, m);
+	if (n == m) {
+		tipc_nlist_add(&grp->dests, m->node);
+		m->state = state;
+	} else {
+		kfree(m);
+	}
+	return n;
 }
 
 void tipc_group_add_member(struct tipc_group *grp, u32 node,
-- 
2.7.4