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KASAN: use-after-free Write in nf_nat_ipv6_manip_pkt

Status: fixed on 2018/03/06 13:29
Subsystems: netfilter
[Documentation on labels]
Reported-by: syzbot+10005f4292fc9cc89de7@syzkaller.appspotmail.com
Fix commit: b078556aecd7 netfilter: ipv6: fix use-after-free Write in nf_nat_ipv6_manip_pkt
First crash: 2258d, last: 2258d
▶ ▼ Discussions (8)
Title Replies (including bot) Last reply
[PATCH 3.16 000/410] 3.16.57-rc1 review 426 (426) 2018/11/12 17:42
[PATCH 4.4 00/63] 4.4.122-stable review 79 (79) 2018/04/06 07:51
[PATCH 4.9 00/86] 4.9.88-stable review 97 (97) 2018/03/22 17:47
[PATCH 3.18 00/25] 3.18.100-stable review 30 (30) 2018/03/18 10:14
[PATCH 4.15 000/146] 4.15.10-stable review 160 (160) 2018/03/15 10:19
[PATCH 4.14 000/140] 4.14.27-stable review 150 (150) 2018/03/14 18:26
[PATCH 00/14] Netfilter/IPVS fixes for net 16 (16) 2018/03/03 01:32
KASAN: use-after-free Write in nf_nat_ipv6_manip_pkt 0 (1) 2018/02/18 22:59

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in nf_nat_ipv6_manip_pkt+0x47c/0x490 net/ipv6/netfilter/nf_nat_l3proto_ipv6.c:106
Write of size 16 at addr ffff8801ca885820 by task syzkaller752805/4167

CPU: 1 PID: 4167 Comm: syzkaller752805 Not tainted 4.16.0-rc1+ #318
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report+0x23b/0x360 mm/kasan/report.c:412
 __asan_report_store_n_noabort+0x12/0x14 mm/kasan/report.c:449
 nf_nat_ipv6_manip_pkt+0x47c/0x490 net/ipv6/netfilter/nf_nat_l3proto_ipv6.c:106
 nf_nat_packet+0x3cb/0x560 net/netfilter/nf_nat_core.c:506
 nf_nat_ipv6_fn+0x679/0xa80 net/ipv6/netfilter/nf_nat_l3proto_ipv6.c:329
 nf_nat_ipv6_local_fn+0x33/0x5d0 net/ipv6/netfilter/nf_nat_l3proto_ipv6.c:407
 ip6table_nat_local_fn+0x2c/0x40 net/ipv6/netfilter/ip6table_nat.c:69
 nf_hook_entry_hookfn include/linux/netfilter.h:120 [inline]
 nf_hook_slow+0xba/0x1a0 net/netfilter/core.c:483
 nf_hook include/linux/netfilter.h:243 [inline]
 __ip6_local_out+0x517/0xaa0 net/ipv6/output_core.c:164
 ip6_local_out+0x2d/0x160 net/ipv6/output_core.c:174
 ip6_send_skb+0xa1/0x330 net/ipv6/ip6_output.c:1677
 ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1697
 rawv6_push_pending_frames net/ipv6/raw.c:616 [inline]
 rawv6_sendmsg+0x2f96/0x40c0 net/ipv6/raw.c:935
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:764
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:640
 ___sys_sendmsg+0x767/0x8b0 net/socket.c:2046
 __sys_sendmsg+0xe5/0x210 net/socket.c:2080
 SYSC_sendmsg net/socket.c:2091 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2087
 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x446ea9
RSP: 002b:00007fffd288b578 EFLAGS: 00000217 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000000000000003e RCX: 0000000000446ea9
RDX: 0000000000000000 RSI: 00000000209f2fc8 RDI: 0000000000000004
RBP: 00007fffd288b688 R08: 0000000000008a7f R09: 0000000000008a7f
R10: 0000000000000000 R11: 0000000000000217 R12: 00007fffd288b688
R13: 0000000000404370 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 4167:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:552
 __do_kmalloc_node mm/slab.c:3669 [inline]
 __kmalloc_node_track_caller+0x47/0x70 mm/slab.c:3683
 __kmalloc_reserve.isra.39+0x41/0xd0 net/core/skbuff.c:137
 __alloc_skb+0x13b/0x780 net/core/skbuff.c:205
 alloc_skb include/linux/skbuff.h:983 [inline]
 sock_wmalloc+0x140/0x1d0 net/core/sock.c:1937
 __ip6_append_data.isra.44+0x26b9/0x3390 net/ipv6/ip6_output.c:1416
 ip6_append_data+0x189/0x290 net/ipv6/ip6_output.c:1571
 rawv6_sendmsg+0x1e09/0x40c0 net/ipv6/raw.c:928
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:764
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:640
 ___sys_sendmsg+0x767/0x8b0 net/socket.c:2046
 __sys_sendmsg+0xe5/0x210 net/socket.c:2080
 SYSC_sendmsg net/socket.c:2091 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2087
 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 4167:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527
 __cache_free mm/slab.c:3485 [inline]
 kfree+0xd9/0x260 mm/slab.c:3800
 skb_free_head+0x74/0xb0 net/core/skbuff.c:550
 pskb_expand_head+0x36b/0x1210 net/core/skbuff.c:1490
 __pskb_pull_tail+0x14a/0x17f0 net/core/skbuff.c:1873
 skb_make_writable+0x15b/0x750 net/netfilter/core.c:528
 tcp_manip_pkt+0x82/0x2d0 net/netfilter/nf_nat_proto_tcp.c:51
 nf_nat_ipv6_manip_pkt+0x22d/0x490 net/ipv6/netfilter/nf_nat_l3proto_ipv6.c:99
 nf_nat_packet+0x3cb/0x560 net/netfilter/nf_nat_core.c:506
 nf_nat_ipv6_fn+0x679/0xa80 net/ipv6/netfilter/nf_nat_l3proto_ipv6.c:329
 nf_nat_ipv6_local_fn+0x33/0x5d0 net/ipv6/netfilter/nf_nat_l3proto_ipv6.c:407
 ip6table_nat_local_fn+0x2c/0x40 net/ipv6/netfilter/ip6table_nat.c:69
 nf_hook_entry_hookfn include/linux/netfilter.h:120 [inline]
 nf_hook_slow+0xba/0x1a0 net/netfilter/core.c:483
 nf_hook include/linux/netfilter.h:243 [inline]
 __ip6_local_out+0x517/0xaa0 net/ipv6/output_core.c:164
 ip6_local_out+0x2d/0x160 net/ipv6/output_core.c:174
 ip6_send_skb+0xa1/0x330 net/ipv6/ip6_output.c:1677
 ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1697
 rawv6_push_pending_frames net/ipv6/raw.c:616 [inline]
 rawv6_sendmsg+0x2f96/0x40c0 net/ipv6/raw.c:935
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:764
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:640
 ___sys_sendmsg+0x767/0x8b0 net/socket.c:2046
 __sys_sendmsg+0xe5/0x210 net/socket.c:2080
 SYSC_sendmsg net/socket.c:2091 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2087
 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff8801ca885780
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 160 bytes inside of
 512-byte region [ffff8801ca885780, ffff8801ca885980)
The buggy address belongs to the page:
page:ffffea00072a2140 count:1 mapcount:0 mapping:ffff8801ca885000 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801ca885000 0000000000000000 0000000100000006
raw: ffffea00072a20e0 ffffea00072a2220 ffff8801db000940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801ca885700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801ca885780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801ca885800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff8801ca885880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801ca885900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/02/18 14:50 upstream c786427f57b6 833f78c7 .config console log report syz C ci-upstream-kasan-gce
2018/02/18 14:50 net-next-old 1ec010e70593 833f78c7 .config console log report syz C ci-upstream-net-kasan-gce
* Struck through repros no longer work on HEAD.