KASAN: use-after-free Read in tipc_udp_nl_dump_remoteip

* KASAN: use-after-free Read in tipc_udp_nl_dump_remoteip
@ 2019-10-07 18:59 syzbot
  2019-10-08 21:06 ` syzbot
  0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2019-10-07 18:59 UTC (permalink / raw)
  To: davem, jon.maloy, linux-kernel, netdev, syzkaller-bugs,
	tipc-discussion, ying.xue

Hello,

syzbot found the following crash on:

HEAD commit:    056ddc38 Merge branch 'stmmac-next'
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=164f0c57600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d9be300620399522
dashboard link: https://syzkaller.appspot.com/bug?extid=dbe02e13bcce52bcf182
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=137ecdfb600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15dd0d0b600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+dbe02e13bcce52bcf182@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in nla_parse_nested_deprecated  
include/net/netlink.h:1166 [inline]
BUG: KASAN: use-after-free in tipc_udp_nl_dump_remoteip+0xc19/0xc20  
net/tipc/udp_media.c:459
Read of size 2 at addr ffff888090c0f2d4 by task syz-executor616/8990

CPU: 1 PID: 8990 Comm: syz-executor616 Not tainted 5.4.0-rc1+ #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+0x172/0x1f0 lib/dump_stack.c:113
  print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
  __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
  kasan_report+0x12/0x20 mm/kasan/common.c:634
  __asan_report_load2_noabort+0x14/0x20 mm/kasan/generic_report.c:130
  nla_parse_nested_deprecated include/net/netlink.h:1166 [inline]
  tipc_udp_nl_dump_remoteip+0xc19/0xc20 net/tipc/udp_media.c:459
  genl_lock_dumpit+0x86/0xc0 net/netlink/genetlink.c:529
  netlink_dump+0x558/0xfb0 net/netlink/af_netlink.c:2244
  __netlink_dump_start+0x5b1/0x7d0 net/netlink/af_netlink.c:2352
  genl_family_rcv_msg_dumpit net/netlink/genetlink.c:614 [inline]
  genl_family_rcv_msg net/netlink/genetlink.c:710 [inline]
  genl_rcv_msg+0xc9b/0x1000 net/netlink/genetlink.c:730
  netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
  genl_rcv+0x29/0x40 net/netlink/genetlink.c:741
  netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
  netlink_unicast+0x531/0x710 net/netlink/af_netlink.c:1328
  netlink_sendmsg+0x8a5/0xd60 net/netlink/af_netlink.c:1917
  sock_sendmsg_nosec net/socket.c:637 [inline]
  sock_sendmsg+0xd7/0x130 net/socket.c:657
  ___sys_sendmsg+0x803/0x920 net/socket.c:2311
  __sys_sendmsg+0x105/0x1d0 net/socket.c:2356
  __do_sys_sendmsg net/socket.c:2365 [inline]
  __se_sys_sendmsg net/socket.c:2363 [inline]
  __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2363
  do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x445279
Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 0b cd fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffac1fc178 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000445279
RDX: 0000000000000000 RSI: 0000000020000200 RDI: 0000000000000005
RBP: 0000000000010907 R08: 0000000000000000 R09: 00000000004002e0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402410
R13: 00000000004024a0 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 8992:
  save_stack+0x23/0x90 mm/kasan/common.c:69
  set_track mm/kasan/common.c:77 [inline]
  __kasan_kmalloc mm/kasan/common.c:510 [inline]
  __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:483
  kasan_kmalloc+0x9/0x10 mm/kasan/common.c:524
  __do_kmalloc_node mm/slab.c:3615 [inline]
  __kmalloc_node_track_caller+0x4e/0x70 mm/slab.c:3629
  __kmalloc_reserve.isra.0+0x40/0xf0 net/core/skbuff.c:141
  __alloc_skb+0x10b/0x5e0 net/core/skbuff.c:209
  alloc_skb include/linux/skbuff.h:1049 [inline]
  netlink_alloc_large_skb net/netlink/af_netlink.c:1174 [inline]
  netlink_sendmsg+0x972/0xd60 net/netlink/af_netlink.c:1892
  sock_sendmsg_nosec net/socket.c:637 [inline]
  sock_sendmsg+0xd7/0x130 net/socket.c:657
  ___sys_sendmsg+0x803/0x920 net/socket.c:2311
  __sys_sendmsg+0x105/0x1d0 net/socket.c:2356
  __do_sys_sendmsg net/socket.c:2365 [inline]
  __se_sys_sendmsg net/socket.c:2363 [inline]
  __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2363
  do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 8992:
  save_stack+0x23/0x90 mm/kasan/common.c:69
  set_track mm/kasan/common.c:77 [inline]
  kasan_set_free_info mm/kasan/common.c:332 [inline]
  __kasan_slab_free+0x102/0x150 mm/kasan/common.c:471
  kasan_slab_free+0xe/0x10 mm/kasan/common.c:480
  __cache_free mm/slab.c:3425 [inline]
  kfree+0x10a/0x2c0 mm/slab.c:3756
  skb_free_head+0x93/0xb0 net/core/skbuff.c:591
  skb_release_data+0x42d/0x7c0 net/core/skbuff.c:611
  skb_release_all+0x4d/0x60 net/core/skbuff.c:665
  __kfree_skb net/core/skbuff.c:679 [inline]
  consume_skb net/core/skbuff.c:838 [inline]
  consume_skb+0xfb/0x3b0 net/core/skbuff.c:832
  netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
  netlink_unicast+0x539/0x710 net/netlink/af_netlink.c:1328
  netlink_sendmsg+0x8a5/0xd60 net/netlink/af_netlink.c:1917
  sock_sendmsg_nosec net/socket.c:637 [inline]
  sock_sendmsg+0xd7/0x130 net/socket.c:657
  ___sys_sendmsg+0x803/0x920 net/socket.c:2311
  __sys_sendmsg+0x105/0x1d0 net/socket.c:2356
  __do_sys_sendmsg net/socket.c:2365 [inline]
  __se_sys_sendmsg net/socket.c:2363 [inline]
  __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2363
  do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff888090c0f2c0
  which belongs to the cache kmalloc-512 of size 512
The buggy address is located 20 bytes inside of
  512-byte region [ffff888090c0f2c0, ffff888090c0f4c0)
The buggy address belongs to the page:
page:ffffea00024303c0 refcount:1 mapcount:0 mapping:ffff8880aa400a80  
index:0xffff888090c0fa40
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea0002441548 ffffea0002430608 ffff8880aa400a80
raw: ffff888090c0fa40 ffff888090c0f040 0000000100000005 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff888090c0f180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff888090c0f200: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
> ffff888090c0f280: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                  ^
  ffff888090c0f300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff888090c0f380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

---
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