From c756891a4e1c08c43780e17aca1d2b849ef31d1a Mon Sep 17 00:00:00 2001 From: Ying Xue Date: Thu, 1 Aug 2013 08:29:18 -0400 Subject: [PATCH] tipc: fix oops when creating server socket fails When creation of TIPC internal server socket fails, we get an oops with the following dump: BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 IP: [] tipc_close_conn+0x59/0xb0 [tipc] PGD 13719067 PUD 12008067 PMD 0 Oops: 0000 [#1] SMP DEBUG_PAGEALLOC Modules linked in: tipc(+) CPU: 4 PID: 4340 Comm: insmod Not tainted 3.10.0+ #1 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 task: ffff880014360000 ti: ffff88001374c000 task.ti: ffff88001374c000 RIP: 0010:[] [] tipc_close_conn+0x59/0xb0 [tipc] RSP: 0018:ffff88001374dc98 EFLAGS: 00010292 RAX: 0000000000000000 RBX: ffff880012ac09d8 RCX: 0000000000000000 RDX: 0000000000000046 RSI: 0000000000000001 RDI: ffff880014360000 RBP: ffff88001374dcb8 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffa0016fa0 R13: ffffffffa0017010 R14: ffffffffa0017010 R15: ffff880012ac09d8 FS: 0000000000000000(0000) GS:ffff880016600000(0063) knlGS:00000000f76668d0 CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b CR2: 0000000000000020 CR3: 0000000012227000 CR4: 00000000000006e0 Stack: ffff88001374dcb8 ffffffffa0016fa0 0000000000000000 0000000000000001 ffff88001374dcf8 ffffffffa0012922 ffff88001374dce8 00000000ffffffea ffffffffa0017100 0000000000000000 ffff8800134241a8 ffffffffa0017150 Call Trace: [] tipc_server_stop+0xa2/0x1b0 [tipc] [] tipc_subscr_stop+0x15/0x20 [tipc] [] tipc_core_stop+0x1d/0x33 [tipc] [] tipc_init+0xd4/0xf8 [tipc] [] ? 0xffffffffa001efff [] do_one_initcall+0x3f/0x150 [] ? __blocking_notifier_call_chain+0x7d/0xd0 [] load_module+0x11aa/0x19c0 [] ? show_initstate+0x50/0x50 [] ? retint_restore_args+0xe/0xe [] SyS_init_module+0xd9/0x110 [] sysenter_dispatch+0x7/0x1f Code: 6c 24 70 4c 89 ef e8 b7 04 8f e1 8b 73 04 4c 89 e7 e8 7c 9e 32 e1 41 83 ac 24 b8 00 00 00 01 4c 89 ef e8 eb 0a 8f e1 48 8b 43 08 <4c> 8b 68 20 4d 8d a5 48 03 00 00 4c 89 e7 e8 04 05 8f e1 4c 89 RIP [] tipc_close_conn+0x59/0xb0 [tipc] RSP CR2: 0000000000000020 ---[ end trace b02321f40e4269a3 ]--- We have the following call chain: tipc_core_start() ret = tipc_subscr_start() ret = tipc_server_start(){ server->enabled = 1; ret = tipc_open_listening_sock() } I.e., the server->enabled flag is unconditionally set to 1, whatever the return value of tipc_open_listening_sock(). This causes a crash when tipc_core_start() tries to clean up resources after a failed initialization: if (ret == failed) tipc_subscr_stop() tipc_server_stop(){ if (server->enabled) tipc_close_conn(){ NULL reference of con->sock-sk OOPS! } } To avoid this, tipc_server_start() should only set server->enabled to 1 in case of a succesful socket creation. In case of failure, it should release all allocated resources before returning. Problem introduced in commit c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f ("tipc: introduce new TIPC server infrastructure") in v3.11-rc1. Note that it won't be seen often; it takes a module load under memory constrained conditions in order to trigger the failure condition. Signed-off-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: Paul Gortmaker Signed-off-by: David S. Miller --- net/tipc/server.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/net/tipc/server.c b/net/tipc/server.c index 19da5abe0fa6..fd3fa57a410e 100644 --- a/net/tipc/server.c +++ b/net/tipc/server.c @@ -355,8 +355,12 @@ static int tipc_open_listening_sock(struct tipc_server *s) return PTR_ERR(con); sock = tipc_create_listen_sock(con); - if (!sock) + if (!sock) { + idr_remove(&s->conn_idr, con->conid); + s->idr_in_use--; + kfree(con); return -EINVAL; + } tipc_register_callbacks(sock, con); return 0; @@ -563,9 +567,14 @@ int tipc_server_start(struct tipc_server *s) kmem_cache_destroy(s->rcvbuf_cache); return ret; } + ret = tipc_open_listening_sock(s); + if (ret < 0) { + tipc_work_stop(s); + kmem_cache_destroy(s->rcvbuf_cache); + return ret; + } s->enabled = 1; - - return tipc_open_listening_sock(s); + return ret; } void tipc_server_stop(struct tipc_server *s)