Messages in this thread Patch in this message | | | Date | Wed, 28 Aug 2019 15:26:15 -0700 | From | Jakub Kicinski <> | Subject | Re: general protection fault in tls_sk_proto_close (2) |
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On Tue, 27 Aug 2019 23:38:07 -0700, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: a55aa89a Linux 5.3-rc6 > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=16c26ebc600000 > kernel config: https://syzkaller.appspot.com/x/.config?x=2a6a2b9826fdadf9 > dashboard link: https://syzkaller.appspot.com/bug?extid=7a6ee4d0078eac6bf782 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1112a4de600000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+7a6ee4d0078eac6bf782@syzkaller.appspotmail.com
Hi John!
This is a loop where TLS calls it's own close function recursively. It seems we must have gotten BPF installed on top of TLS, and then it handed TLS TLS'es own sk_proto via tcp_update_ulp().
Can BPF on top of TLS be prevented somehow?
Quick fix should probably be something like:
diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c index 43252a801c3f..3f4962756fa4 100644 --- a/net/tls/tls_main.c +++ b/net/tls/tls_main.c @@ -816,6 +816,9 @@ static void tls_update(struct sock *sk, struct proto *p) ctx = tls_get_ctx(sk); if (likely(ctx)) { + if (p->setsockopt == tls_setsockopt) + return; + ctx->sk_proto_close = p->close; ctx->sk_proto = p; } else { > kasan: CONFIG_KASAN_INLINE enabled > kasan: GPF could be caused by NULL-ptr deref or user memory access > general protection fault: 0000 [#1] PREEMPT SMP KASAN > CPU: 1 PID: 10290 Comm: syz-executor.0 Not tainted 5.3.0-rc6 #120 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > RIP: 0010:tls_sk_proto_close+0xe5/0x990 net/tls/tls_main.c:298 > Code: 0f 85 3f 08 00 00 49 8b 84 24 c0 02 00 00 4d 8d 75 14 4c 89 f2 48 c1 > ea 03 48 89 85 50 ff ff ff 48 b8 00 00 00 00 00 fc ff df <0f> b6 04 02 4c > 89 f2 83 e2 07 38 d0 7f 08 84 c0 0f 85 2e 06 00 00 > RSP: 0018:ffff88809b23fb90 EFLAGS: 00010203 > RAX: dffffc0000000000 RBX: dffffc0000000000 RCX: ffffffff862cb8db > RDX: 0000000000000002 RSI: ffffffff862cb639 RDI: ffff8880a155ef00 > RBP: ffff88809b23fc48 R08: ffff888094344640 R09: ffffed10142abd9a > R10: ffffed10142abd99 R11: ffff8880a155eccb R12: ffff8880a155ec40 > R13: 0000000000000000 R14: 0000000000000014 R15: 0000000000000001 > FS: 00005555556a8940(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f353458e000 CR3: 00000000a9174000 CR4: 00000000001406e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > tls_sk_proto_close+0x35b/0x990 net/tls/tls_main.c:321 > tcp_bpf_close+0x17c/0x390 net/ipv4/tcp_bpf.c:582 > inet_release+0xed/0x200 net/ipv4/af_inet.c:427 > inet6_release+0x53/0x80 net/ipv6/af_inet6.c:470 > __sock_release+0xce/0x280 net/socket.c:590 > sock_close+0x1e/0x30 net/socket.c:1268 > __fput+0x2ff/0x890 fs/file_table.c:280 > ____fput+0x16/0x20 fs/file_table.c:313 > task_work_run+0x145/0x1c0 kernel/task_work.c:113 > tracehook_notify_resume include/linux/tracehook.h:188 [inline] > exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:163 > prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] > syscall_return_slowpath arch/x86/entry/common.c:274 [inline] > do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:299 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x413540 > Code: 01 f0 ff ff 0f 83 30 1b 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f > 44 00 00 83 3d 4d 2d 66 00 00 75 14 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff > ff 0f 83 04 1b 00 00 c3 48 83 ec 08 e8 0a fc ff ff > RSP: 002b:00007fff5d481778 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 > RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000413540 > RDX: 0000001b2e520000 RSI: 0000000000000000 RDI: 0000000000000005 > RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffffffffffff > R10: 0000000000000000 R11: 0000000000000246 R12: 000000000075bf20 > R13: 0000000000000003 R14: 0000000000761220 R15: ffffffffffffffff > Modules linked in: > ---[ end trace bdfd4385a0f1f76d ]--- > RIP: 0010:tls_sk_proto_close+0xe5/0x990 net/tls/tls_main.c:298 > Code: 0f 85 3f 08 00 00 49 8b 84 24 c0 02 00 00 4d 8d 75 14 4c 89 f2 48 c1 > ea 03 48 89 85 50 ff ff ff 48 b8 00 00 00 00 00 fc ff df <0f> b6 04 02 4c > 89 f2 83 e2 07 38 d0 7f 08 84 c0 0f 85 2e 06 00 00 > RSP: 0018:ffff88809b23fb90 EFLAGS: 00010203 > RAX: dffffc0000000000 RBX: dffffc0000000000 RCX: ffffffff862cb8db > RDX: 0000000000000002 RSI: ffffffff862cb639 RDI: ffff8880a155ef00 > RBP: ffff88809b23fc48 R08: ffff888094344640 R09: ffffed10142abd9a > R10: ffffed10142abd99 R11: ffff8880a155eccb R12: ffff8880a155ec40 > R13: 0000000000000000 R14: 0000000000000014 R15: 0000000000000001 > FS: 00005555556a8940(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f353458e000 CR3: 00000000a9174000 CR4: 00000000001406e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > syzbot can test patches for this bug, for details see: > https://goo.gl/tpsmEJ#testing-patches
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