On Tue, Mar 2, 2021 at 8:25 PM syzbot <syzbot+9ec037722d2603a9f...@syzkaller.appspotmail.com> wrote: > > syzbot has found a reproducer for the following issue on: > > HEAD commit: 7a7fd0de Merge branch 'kmap-conversion-for-5.12' of git://.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=13693866d00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=779a2568b654c1c6 > dashboard link: https://syzkaller.appspot.com/bug?extid=9ec037722d2603a9f52e > compiler: Debian clang version 11.0.1-2 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1576737ad00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=107bdcead00000
This wasn't arranged :) But the reproducer indeed contains NLBL_CIPSOV4_C_REMOVE and is repeated in a loop... > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+9ec037722d2603a9f...@syzkaller.appspotmail.com > > ================================================================== > BUG: KASAN: use-after-free in cipso_v4_genopt+0x1078/0x1700 > net/ipv4/cipso_ipv4.c:1784 > Read of size 1 at addr ffff8881437d5710 by task syz-executor557/8392 > > CPU: 1 PID: 8392 Comm: syz-executor557 Not tainted 5.12.0-rc1-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:79 [inline] > dump_stack+0x125/0x19e lib/dump_stack.c:120 > print_address_description+0x5f/0x3a0 mm/kasan/report.c:232 > __kasan_report mm/kasan/report.c:399 [inline] > kasan_report+0x15e/0x210 mm/kasan/report.c:416 > cipso_v4_genopt+0x1078/0x1700 net/ipv4/cipso_ipv4.c:1784 > cipso_v4_sock_setattr+0x7c/0x460 net/ipv4/cipso_ipv4.c:1866 > netlbl_sock_setattr+0x28e/0x2f0 net/netlabel/netlabel_kapi.c:995 > smack_netlbl_add security/smack/smack_lsm.c:2404 [inline] > smack_socket_post_create+0x13b/0x280 security/smack/smack_lsm.c:2774 > security_socket_post_create+0x6f/0xd0 security/security.c:2122 > __sock_create+0x62f/0x8c0 net/socket.c:1424 > sock_create net/socket.c:1459 [inline] > __sys_socket+0xde/0x2d0 net/socket.c:1501 > __do_sys_socket net/socket.c:1510 [inline] > __se_sys_socket net/socket.c:1508 [inline] > __x64_sys_socket+0x76/0x80 net/socket.c:1508 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x440999 > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 14 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 c0 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007ffcfe002d48 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 > RAX: ffffffffffffffda RBX: 000000000000b3fc RCX: 0000000000440999 > RDX: 0000000000000002 RSI: 0000000000000003 RDI: 0000040000000002 > RBP: 0000000000000000 R08: 00007ffcfe002ee8 R09: 00007ffcfe002ee8 > R10: 0000000000000012 R11: 0000000000000246 R12: 00007ffcfe002d5c > R13: 431bde82d7b634db R14: 00000000004ae018 R15: 00000000004004a0 > > Allocated by task 1: > kasan_save_stack mm/kasan/common.c:38 [inline] > kasan_set_track mm/kasan/common.c:46 [inline] > set_alloc_info mm/kasan/common.c:427 [inline] > ____kasan_kmalloc+0xc2/0xf0 mm/kasan/common.c:506 > kasan_kmalloc include/linux/kasan.h:233 [inline] > kmem_cache_alloc_trace+0x21b/0x340 mm/slub.c:2934 > kmalloc include/linux/slab.h:554 [inline] > smk_cipso_doi+0x1af/0x4e0 security/smack/smackfs.c:696 > init_smk_fs+0xe2/0x24e security/smack/smackfs.c:3010 > do_one_initcall+0x12b/0x310 init/main.c:1226 > do_initcall_level+0x14a/0x1f5 init/main.c:1299 > do_initcalls+0x4b/0x8c init/main.c:1315 > kernel_init_freeable+0x2e3/0x406 init/main.c:1537 > kernel_init+0xd/0x290 init/main.c:1424 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 > > Freed by task 0: > kasan_save_stack mm/kasan/common.c:38 [inline] > kasan_set_track+0x3d/0x70 mm/kasan/common.c:46 > kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:357 > ____kasan_slab_free+0x100/0x140 mm/kasan/common.c:360 > kasan_slab_free include/linux/kasan.h:199 [inline] > slab_free_hook mm/slub.c:1562 [inline] > slab_free_freelist_hook+0x13a/0x200 mm/slub.c:1600 > slab_free mm/slub.c:3161 [inline] > kfree+0xcf/0x2b0 mm/slub.c:4213 > rcu_do_batch kernel/rcu/tree.c:2559 [inline] > rcu_core+0x7a0/0x1220 kernel/rcu/tree.c:2794 > __do_softirq+0x318/0x714 kernel/softirq.c:345 > > Last potentially related work creation: > kasan_save_stack+0x27/0x50 mm/kasan/common.c:38 > kasan_record_aux_stack+0xee/0x120 mm/kasan/generic.c:345 > __call_rcu kernel/rcu/tree.c:3039 [inline] > call_rcu+0x12f/0x8a0 kernel/rcu/tree.c:3114 > cipso_v4_doi_remove+0x2e2/0x310 net/ipv4/cipso_ipv4.c:531 > netlbl_cipsov4_remove+0x219/0x390 net/netlabel/netlabel_cipso_v4.c:715 > genl_family_rcv_msg_doit net/netlink/genetlink.c:739 [inline] > genl_family_rcv_msg net/netlink/genetlink.c:783 [inline] > genl_rcv_msg+0xe4e/0x1280 net/netlink/genetlink.c:800 > netlink_rcv_skb+0x190/0x3a0 net/netlink/af_netlink.c:2502 > genl_rcv+0x24/0x40 net/netlink/genetlink.c:811 > netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline] > netlink_unicast+0x786/0x940 net/netlink/af_netlink.c:1338 > netlink_sendmsg+0x9ae/0xd50 net/netlink/af_netlink.c:1927 > sock_sendmsg_nosec net/socket.c:654 [inline] > sock_sendmsg net/socket.c:674 [inline] > ____sys_sendmsg+0x519/0x800 net/socket.c:2350 > ___sys_sendmsg net/socket.c:2404 [inline] > __sys_sendmsg+0x2bf/0x370 net/socket.c:2433 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xae > > The buggy address belongs to the object at ffff8881437d5700 > which belongs to the cache kmalloc-64 of size 64 > The buggy address is located 16 bytes inside of > 64-byte region [ffff8881437d5700, ffff8881437d5740) > The buggy address belongs to the page: > page:000000003e519aab refcount:1 mapcount:0 mapping:0000000000000000 > index:0xffff8881437d5b00 pfn:0x1437d5 > flags: 0x57ff00000000200(slab) > raw: 057ff00000000200 ffffea000511ff88 ffffea00051d0a48 ffff888010841640 > raw: ffff8881437d5b00 0000000000200019 00000001ffffffff 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8881437d5600: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc > ffff8881437d5680: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc > >ffff8881437d5700: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ^ > ffff8881437d5780: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc > ffff8881437d5800: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc > ================================================================== >
