From 672ecbe1c977616aa720c9397589665b33e72610 Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Mon, 4 Dec 2017 10:31:43 -0800 Subject: [PATCH] tipc: fix a null pointer deref on error path In tipc_topsrv_kern_subscr() when s->tipc_conn_new() fails we call tipc_close_conn() to clean up, but in this case calling conn_put() is just enough. This fixes the folllowing crash: kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 0 PID: 3085 Comm: syzkaller064164 Not tainted 4.15.0-rc1+ #137 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: 00000000c24413a5 task.stack: 000000005e8160b5 RIP: 0010:__lock_acquire+0xd55/0x47f0 kernel/locking/lockdep.c:3378 RSP: 0018:ffff8801cb5474a8 EFLAGS: 00010002 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000004 RSI: 0000000000000000 RDI: ffffffff85ecb400 RBP: ffff8801cb547830 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff87489d60 R12: ffff8801cd2980c0 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000020 FS: 00000000014ee880(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffee2426e40 CR3: 00000001cb85a000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:175 spin_lock_bh include/linux/spinlock.h:320 [inline] tipc_subscrb_subscrp_delete+0x8f/0x470 net/tipc/subscr.c:201 tipc_subscrb_delete net/tipc/subscr.c:238 [inline] tipc_subscrb_release_cb+0x17/0x30 net/tipc/subscr.c:316 tipc_close_conn+0x171/0x270 net/tipc/server.c:204 tipc_topsrv_kern_subscr+0x724/0x810 net/tipc/server.c:514 tipc_group_create+0x702/0x9c0 net/tipc/group.c:184 tipc_sk_join net/tipc/socket.c:2747 [inline] tipc_setsockopt+0x249/0xc10 net/tipc/socket.c:2861 SYSC_setsockopt net/socket.c:1851 [inline] SyS_setsockopt+0x189/0x360 net/socket.c:1830 entry_SYSCALL_64_fastpath+0x1f/0x96 Fixes: 14c04493cb77 ("tipc: add ability to order and receive topology events in driver") Reported-by: syzbot Cc: Jon Maloy Cc: Ying Xue Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- net/tipc/server.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/tipc/server.c b/net/tipc/server.c index acaef80..2710101 100644 --- a/net/tipc/server.c +++ b/net/tipc/server.c @@ -511,7 +511,7 @@ bool tipc_topsrv_kern_subscr(struct net *net, u32 port, u32 type, s = con->server; scbr = s->tipc_conn_new(*conid); if (!scbr) { - tipc_close_conn(con); + conn_put(con); return false; } -- 2.7.4