| From a5dcb73b96a9d21431048bdaac02d9e96f386da3 Mon Sep 17 00:00:00 2001 |
| From: Davide Caratti <dcaratti@redhat.com> |
| Date: Wed, 28 Feb 2018 12:44:09 +0100 |
| Subject: net/smc: fix NULL pointer dereference on sock_create_kern() error path |
| |
| From: Davide Caratti <dcaratti@redhat.com> |
| |
| commit a5dcb73b96a9d21431048bdaac02d9e96f386da3 upstream. |
| |
| when sock_create_kern(..., a) returns an error, 'a' might not be a valid |
| pointer, so it shouldn't be dereferenced to read a->sk->sk_sndbuf and |
| and a->sk->sk_rcvbuf; not doing that caused the following crash: |
| |
| general protection fault: 0000 [#1] SMP KASAN |
| Dumping ftrace buffer: |
| (ftrace buffer empty) |
| Modules linked in: |
| CPU: 0 PID: 4254 Comm: syzkaller919713 Not tainted 4.16.0-rc1+ #18 |
| Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS |
| Google 01/01/2011 |
| RIP: 0010:smc_create+0x14e/0x300 net/smc/af_smc.c:1410 |
| RSP: 0018:ffff8801b06afbc8 EFLAGS: 00010202 |
| RAX: dffffc0000000000 RBX: ffff8801b63457c0 RCX: ffffffff85a3e746 |
| RDX: 0000000000000004 RSI: 00000000ffffffff RDI: 0000000000000020 |
| RBP: ffff8801b06afbf0 R08: 00000000000007c0 R09: 0000000000000000 |
| R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 |
| R13: ffff8801b6345c08 R14: 00000000ffffffe9 R15: ffffffff8695ced0 |
| FS: 0000000001afb880(0000) GS:ffff8801db200000(0000) |
| knlGS:0000000000000000 |
| CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 |
| CR2: 0000000020000040 CR3: 00000001b0721004 CR4: 00000000001606f0 |
| DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 |
| DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 |
| Call Trace: |
| __sock_create+0x4d4/0x850 net/socket.c:1285 |
| sock_create net/socket.c:1325 [inline] |
| SYSC_socketpair net/socket.c:1409 [inline] |
| SyS_socketpair+0x1c0/0x6f0 net/socket.c:1366 |
| do_syscall_64+0x282/0x940 arch/x86/entry/common.c:287 |
| entry_SYSCALL_64_after_hwframe+0x26/0x9b |
| RIP: 0033:0x4404b9 |
| RSP: 002b:00007fff44ab6908 EFLAGS: 00000246 ORIG_RAX: 0000000000000035 |
| RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004404b9 |
| RDX: 0000000000000000 RSI: 0000000000000001 RDI: 000000000000002b |
| RBP: 00007fff44ab6910 R08: 0000000000000002 R09: 00007fff44003031 |
| R10: 0000000020000040 R11: 0000000000000246 R12: ffffffffffffffff |
| R13: 0000000000000006 R14: 0000000000000000 R15: 0000000000000000 |
| Code: 48 c1 ea 03 80 3c 02 00 0f 85 b3 01 00 00 4c 8b a3 48 04 00 00 48 |
| b8 |
| 00 00 00 00 00 fc ff df 49 8d 7c 24 20 48 89 fa 48 c1 ea 03 <80> 3c 02 |
| 00 |
| 0f 85 82 01 00 00 4d 8b 7c 24 20 48 b8 00 00 00 00 |
| RIP: smc_create+0x14e/0x300 net/smc/af_smc.c:1410 RSP: ffff8801b06afbc8 |
| |
| Fixes: cd6851f30386 smc: remote memory buffers (RMBs) |
| Reported-and-tested-by: syzbot+aa0227369be2dcc26ebe@syzkaller.appspotmail.com |
| Signed-off-by: Davide Caratti <dcaratti@redhat.com> |
| Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| net/smc/af_smc.c | 4 +++- |
| 1 file changed, 3 insertions(+), 1 deletion(-) |
| |
| --- a/net/smc/af_smc.c |
| +++ b/net/smc/af_smc.c |
| @@ -1351,8 +1351,10 @@ static int smc_create(struct net *net, s |
| smc->use_fallback = false; /* assume rdma capability first */ |
| rc = sock_create_kern(net, PF_INET, SOCK_STREAM, |
| IPPROTO_TCP, &smc->clcsock); |
| - if (rc) |
| + if (rc) { |
| sk_common_release(sk); |
| + goto out; |
| + } |
| smc->sk.sk_sndbuf = max(smc->clcsock->sk->sk_sndbuf, SMC_BUF_MIN_SIZE); |
| smc->sk.sk_rcvbuf = max(smc->clcsock->sk->sk_rcvbuf, SMC_BUF_MIN_SIZE); |
| |