syzbot


KASAN: use-after-free Read in tipc_nl_node_dump_link

Status: fixed on 2020/07/20 08:03
Subsystems: tipc
[Documentation on labels]
Reported-by: syzbot+520f8704db2b68091d44@syzkaller.appspotmail.com
Fix commit: bf64ff4c2aac genetlink: get rid of family->attrbuf
First crash: 1459d, last: 1450d
Cause bisection: failed (error log, bisect log)
  
Discussions (3)
Title Replies (including bot) Last reply
[PATCH 5.7 000/244] 5.7.10-rc1 review 256 (256) 2020/07/27 17:31
[Patch net] genetlink: get rid of family->attrbuf 2 (2) 2020/06/30 00:16
KASAN: use-after-free Read in tipc_nl_node_dump_link 0 (1) 2020/06/26 17:19
Last patch testing requests (1)
Created Duration User Patch Repo Result
2020/06/26 23:46 18m xiyou.wangcong@gmail.com https://github.com/congwang/linux.git net OK

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in nla_len include/net/netlink.h:1135 [inline]
BUG: KASAN: use-after-free in nla_parse_nested_deprecated include/net/netlink.h:1218 [inline]
BUG: KASAN: use-after-free in tipc_nl_node_dump_link+0xdd6/0xdf0 net/tipc/node.c:2591
Read of size 2 at addr ffff88809ec28014 by task syz-executor491/6907

CPU: 0 PID: 6907 Comm: syz-executor491 Not tainted 5.8.0-rc2-syzkaller #0
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+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x436 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 nla_len include/net/netlink.h:1135 [inline]
 nla_parse_nested_deprecated include/net/netlink.h:1218 [inline]
 tipc_nl_node_dump_link+0xdd6/0xdf0 net/tipc/node.c:2591
 genl_lock_dumpit+0x7f/0xb0 net/netlink/genetlink.c:575
 netlink_dump+0x4cd/0xf60 net/netlink/af_netlink.c:2245
 __netlink_dump_start+0x643/0x900 net/netlink/af_netlink.c:2353
 genl_family_rcv_msg_dumpit+0x2ac/0x310 net/netlink/genetlink.c:638
 genl_family_rcv_msg net/netlink/genetlink.c:733 [inline]
 genl_rcv_msg+0x797/0x9e0 net/netlink/genetlink.c:753
 netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2469
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:764
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2352
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2406
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4456f9
Code: Bad RIP value.
RSP: 002b:00007fff47fc7fe8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004456f9
RDX: 0000000020004014 RSI: 00000000200000c0 RDI: 0000000000000003
RBP: 000000000000f82e R08: 0000000000000000 R09: 00000000004002e0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402890
R13: 0000000000402920 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 6908:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0xae/0x550 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1083 [inline]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1175 [inline]
 netlink_sendmsg+0x94f/0xd90 net/netlink/af_netlink.c:1893
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2352
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2406
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 6908:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x103/0x2c0 mm/slab.c:3757
 skb_free_head net/core/skbuff.c:590 [inline]
 skb_release_data+0x6d9/0x910 net/core/skbuff.c:610
 skb_release_all net/core/skbuff.c:664 [inline]
 __kfree_skb net/core/skbuff.c:678 [inline]
 consume_skb net/core/skbuff.c:837 [inline]
 consume_skb+0xc2/0x160 net/core/skbuff.c:831
 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
 netlink_unicast+0x53b/0x7d0 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2352
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2406
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88809ec28000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 20 bytes inside of
 1024-byte region [ffff88809ec28000, ffff88809ec28400)
The buggy address belongs to the page:
page:ffffea00027b0a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea000248d4c8 ffffea0002499b08 ffff8880aa000c40
raw: 0000000000000000 ffff88809ec28000 0000000100000002 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809ec27f00: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
 ffff88809ec27f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88809ec28000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff88809ec28080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809ec28100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (10):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/06/26 14:36 upstream 4a21185cda0f aea82c00 .config console log report syz C ci-upstream-kasan-gce
2020/06/26 14:28 upstream 4a21185cda0f aea82c00 .config console log report syz C ci-upstream-kasan-gce-smack-root
2020/06/26 14:06 upstream 4a21185cda0f aea82c00 .config console log report syz C ci-upstream-kasan-gce-root
2020/06/26 14:34 net-old f4926d513b4c aea82c00 .config console log report syz C ci-upstream-net-this-kasan-gce
2020/06/27 18:55 linux-next 36e3135df4d4 ffec44b5 .config console log report syz C ci-upstream-linux-next-kasan-gce-root
2020/07/06 03:59 upstream 7cc2a8ea1048 51095195 .config console log report ci-upstream-kasan-gce
2020/07/04 19:49 upstream 7cc2a8ea1048 51095195 .config console log report ci-upstream-kasan-gce-smack-root
2020/06/27 19:28 upstream 1590a2e1c681 ffec44b5 .config console log report ci-upstream-kasan-gce
2020/06/26 13:45 upstream 4a21185cda0f aea82c00 .config console log report ci-upstream-kasan-gce-root
2020/06/28 10:02 net-next-old 7bed14551659 ffec44b5 .config console log report ci-upstream-net-kasan-gce
* Struck through repros no longer work on HEAD.