Eric Dumazet dc56ad7028 af_unix: fix potential NULL deref in unix_dgram_connect() ... syzbot was able to trigger NULL deref in unix_dgram_connect() [1] This happens in if (unix_peer(sk)) sk->sk_state = other->sk_state = TCP_ESTABLISHED; // crash because @other is NULL Because locks have been dropped, unix_peer() might be non NULL, while @other is NULL (AF_UNSPEC case) We need to move code around, so that we no longer access unix_peer() and sk_state while locks have been released. [1] general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] CPU: 0 PID: 10341 Comm: syz-executor239 Not tainted 5.14.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:unix_dgram_connect+0x32a/0xc60 net/unix/af_unix.c:1226 Code: 00 00 45 31 ed 49 83 bc 24 f8 05 00 00 00 74 69 e8 eb 5b a6 f9 48 8d 7d 12 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 e0 07 00 00 RSP: 0018:ffffc9000a89fcd8 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000000004 RCX: 0000000000000000 RDX: 0000000000000002 RSI: ffffffff87cf4ef5 RDI: 0000000000000012 RBP: 0000000000000000 R08: 0000000000000000 R09: ffff88802e1917c3 R10: ffffffff87cf4eba R11: 0000000000000001 R12: ffff88802e191740 R13: 0000000000000000 R14: ffff88802e191d38 R15: ffff88802e1917c0 FS: 00007f3eb0052700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004787d0 CR3: 0000000029c0a000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __sys_connect_file+0x155/0x1a0 net/socket.c:1890 __sys_connect+0x161/0x190 net/socket.c:1907 __do_sys_connect net/socket.c:1917 [inline] __se_sys_connect net/socket.c:1914 [inline] __x64_sys_connect+0x6f/0xb0 net/socket.c:1914 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x446a89 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 a1 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3eb0052208 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 00000000004cc4d8 RCX: 0000000000446a89 RDX: 000000000000006e RSI: 0000000020000180 RDI: 0000000000000003 RBP: 00000000004cc4d0 R08: 00007f3eb0052700 R09: 0000000000000000 R10: 00007f3eb0052700 R11: 0000000000000246 R12: 00000000004cc4dc R13: 00007ffd791e79cf R14: 00007f3eb0052300 R15: 0000000000022000 Modules linked in: ---[ end trace 4eb809357514968c ]--- RIP: 0010:unix_dgram_connect+0x32a/0xc60 net/unix/af_unix.c:1226 Code: 00 00 45 31 ed 49 83 bc 24 f8 05 00 00 00 74 69 e8 eb 5b a6 f9 48 8d 7d 12 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 e0 07 00 00 RSP: 0018:ffffc9000a89fcd8 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000000004 RCX: 0000000000000000 RDX: 0000000000000002 RSI: ffffffff87cf4ef5 RDI: 0000000000000012 RBP: 0000000000000000 R08: 0000000000000000 R09: ffff88802e1917c3 R10: ffffffff87cf4eba R11: 0000000000000001 R12: ffff88802e191740 R13: 0000000000000000 R14: ffff88802e191d38 R15: ffff88802e1917c0 FS: 00007f3eb0052700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd791fe960 CR3: 0000000029c0a000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Fixes: 83301b5367 ("af_unix: Set TCP_ESTABLISHED for datagram sockets too") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Cong Wang <cong.wang@bytedance.com> Cc: Alexei Starovoitov <ast@kernel.org> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2021-08-31 11:31:52 +01:00
..
af_unix.c	af_unix: fix potential NULL deref in unix_dgram_connect()	2021-08-31 11:31:52 +01:00
diag.c	net: Use nlmsg_unicast() instead of netlink_unicast()	2021-07-13 09:28:29 -07:00
garbage.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 62	2019-05-24 17:36:46 +02:00
Kconfig	af_unix: Add OOB support	2021-08-04 09:55:52 +01:00
Makefile	af_unix: Implement ->psock_update_sk_prot()	2021-07-15 18:17:50 -07:00
scm.c	io_uring: move io_uring_get_socket() into io_uring.h	2020-09-30 20:32:33 -06:00
scm.h	net: split out functions related to registering inflight socket files	2019-02-28 08:24:23 -07:00
sysctl_net_unix.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152	2019-05-30 11:26:32 -07:00
unix_bpf.c	af_unix: Add unix_stream_proto for sockmap	2021-08-16 18:43:39 -07:00