On Mon, Nov 19, 2018 at 4:23 AM syzbot <syzbot+0b05d8aa7cb185107483@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following crash on: > > HEAD commit: e119a369b0f1 Merge branch 'SMSC95xx-driver-updates' > git tree: net-next > console output: https://syzkaller.appspot.com/x/log.txt?x=124f5f7b400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=d86f24333880b605 > dashboard link: https://syzkaller.appspot.com/bug?extid=0b05d8aa7cb185107483 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > Unfortunately, I don't have any reproducer for this crash yet. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+0b05d8aa7cb185107483@xxxxxxxxxxxxxxxxxxxxxxxxx > > ================================================================== > BUG: KASAN: use-after-free in sctp_hash_transport+0x803/0x810 > net/sctp/input.c:958 > Read of size 8 at addr ffff8881c6b98cb0 by task syz-executor5/3552 > > CPU: 0 PID: 3552 Comm: syz-executor5 Not tainted 4.20.0-rc2+ #299 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x244/0x39d lib/dump_stack.c:113 > print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256 > kasan_report_error mm/kasan/report.c:354 [inline] > kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412 > __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 > sctp_hash_transport+0x803/0x810 net/sctp/input.c:958 Caused by: commit cd2b708750582e327789d8fb07c6eb5f79f7759f Author: Xin Long <lucien.xin@xxxxxxxxx> Date: Fri Feb 17 16:35:24 2017 +0800 sctp: check duplicate node before inserting a new transport A same fix is needed as: commit bab1be79a5169ac748d8292b20c86d874022d7ba Author: Xin Long <lucien.xin@xxxxxxxxx> Date: Mon Aug 27 18:38:31 2018 +0800 sctp: hold transport before accessing its asoc in sctp_transport_get_next > sctp_assoc_add_peer+0xa21/0x10d0 net/sctp/associola.c:724 > sctp_sendmsg_new_asoc+0x5da/0x11f0 net/sctp/socket.c:1757 > sctp_sendmsg+0x18a5/0x1da0 net/sctp/socket.c:2086 > inet_sendmsg+0x1a1/0x690 net/ipv4/af_inet.c:798 > sock_sendmsg_nosec net/socket.c:621 [inline] > sock_sendmsg+0xd5/0x120 net/socket.c:631 > ___sys_sendmsg+0x7fd/0x930 net/socket.c:2116 > __sys_sendmsg+0x11d/0x280 net/socket.c:2154 > __do_sys_sendmsg net/socket.c:2163 [inline] > __se_sys_sendmsg net/socket.c:2161 [inline] > __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x457569 > Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007f45462c7c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569 > RDX: 0000000000000000 RSI: 000000002001afc8 RDI: 0000000000000005 > RBP: 000000000072c0e0 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007f45462c86d4 > R13: 00000000004c381e R14: 00000000004d59e8 R15: 00000000ffffffff > > Allocated by task 3509: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 > kmem_cache_alloc_trace+0x152/0x750 mm/slab.c:3620 > kmalloc include/linux/slab.h:546 [inline] > kzalloc include/linux/slab.h:741 [inline] > sctp_association_new+0x14e/0x2290 net/sctp/associola.c:311 > sctp_sendmsg_new_asoc+0x39c/0x11f0 net/sctp/socket.c:1723 > sctp_sendmsg+0x18a5/0x1da0 net/sctp/socket.c:2086 > inet_sendmsg+0x1a1/0x690 net/ipv4/af_inet.c:798 > sock_sendmsg_nosec net/socket.c:621 [inline] > sock_sendmsg+0xd5/0x120 net/socket.c:631 > ___sys_sendmsg+0x7fd/0x930 net/socket.c:2116 > __sys_sendmsg+0x11d/0x280 net/socket.c:2154 > __do_sys_sendmsg net/socket.c:2163 [inline] > __se_sys_sendmsg net/socket.c:2161 [inline] > __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 3552: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 > kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 > __cache_free mm/slab.c:3498 [inline] > kfree+0xcf/0x230 mm/slab.c:3817 > sctp_association_destroy net/sctp/associola.c:437 [inline] > sctp_association_put+0x264/0x350 net/sctp/associola.c:889 > sctp_transport_destroy net/sctp/transport.c:180 [inline] > sctp_transport_put+0x186/0x1f0 net/sctp/transport.c:340 > sctp_hash_cmp+0x1ef/0x260 net/sctp/input.c:901 > __rhashtable_lookup.isra.24.constprop.29+0x3b6/0x7d0 > include/linux/rhashtable.h:483 > rhltable_lookup include/linux/rhashtable.h:566 [inline] > sctp_hash_transport+0x2f6/0x810 net/sctp/input.c:954 > sctp_assoc_add_peer+0xa21/0x10d0 net/sctp/associola.c:724 > sctp_sendmsg_new_asoc+0x5da/0x11f0 net/sctp/socket.c:1757 > sctp_sendmsg+0x18a5/0x1da0 net/sctp/socket.c:2086 > inet_sendmsg+0x1a1/0x690 net/ipv4/af_inet.c:798 > sock_sendmsg_nosec net/socket.c:621 [inline] > sock_sendmsg+0xd5/0x120 net/socket.c:631 > ___sys_sendmsg+0x7fd/0x930 net/socket.c:2116 > __sys_sendmsg+0x11d/0x280 net/socket.c:2154 > __do_sys_sendmsg net/socket.c:2163 [inline] > __se_sys_sendmsg net/socket.c:2161 [inline] > __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > The buggy address belongs to the object at ffff8881c6b98c00 > which belongs to the cache kmalloc-4k of size 4096 > The buggy address is located 176 bytes inside of > 4096-byte region [ffff8881c6b98c00, ffff8881c6b99c00) > The buggy address belongs to the page: > page:ffffea00071ae600 count:1 mapcount:0 mapping:ffff8881da800dc0 index:0x0 > compound_mapcount: 0 > flags: 0x2fffc0000010200(slab|head) > raw: 02fffc0000010200 ffffea0007175888 ffffea0006421308 ffff8881da800dc0 > raw: 0000000000000000 ffff8881c6b98c00 0000000100000001 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8881c6b98b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff8881c6b98c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > ffff8881c6b98c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff8881c6b98d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8881c6b98d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== > > > --- > 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@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with > syzbot.
