KASAN: use-after-free Read in bitmap_port_ext_cleanup

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: b07f636f Merge tag 'tpmdd-next-20200108' of git://git.infr..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16c03259e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=18698c0c240ba616
dashboard link: https://syzkaller.appspot.com/bug?extid=4c3cc6dbe7259dbf9054
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
userspace arch: i386
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10c365c6e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=117df9e1e00000

The bug was bisected to:

commit b9a1e627405d68d475a3c1f35e685ccfb5bbe668
Author: Cong Wang <xiyou.w...@gmail.com>
Date: Thu Jul 4 00:21:13 2019 +0000

hsr: implement dellink to clean up resources

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=118759e1e00000
final crash: https://syzkaller.appspot.com/x/report.txt?x=138759e1e00000
console output: https://syzkaller.appspot.com/x/log.txt?x=158759e1e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+4c3cc6...@syzkaller.appspotmail.com
Fixes: b9a1e627405d ("hsr: implement dellink to clean up resources")

==================================================================
BUG: KASAN: use-after-free in test_bit
include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline]
BUG: KASAN: use-after-free in bitmap_port_ext_cleanup+0xe6/0x2a0
net/netfilter/ipset/ip_set_bitmap_gen.h:51
Read of size 8 at addr ffff8880a87a47c0 by task syz-executor559/9563

CPU: 0 PID: 9563 Comm: syz-executor559 Not tainted 5.5.0-rc5-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+0x197/0x210 lib/dump_stack.c:118
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:639
check_memory_region_inline mm/kasan/generic.c:185 [inline]
check_memory_region+0x134/0x1a0 mm/kasan/generic.c:192
__kasan_check_read+0x11/0x20 mm/kasan/common.c:95
test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline]
bitmap_port_ext_cleanup+0xe6/0x2a0
net/netfilter/ipset/ip_set_bitmap_gen.h:51
bitmap_port_destroy+0x17c/0x1d0 net/netfilter/ipset/ip_set_bitmap_gen.h:65
ip_set_create+0xe47/0x1500 net/netfilter/ipset/ip_set_core.c:1165
nfnetlink_rcv_msg+0xcf2/0xfb0 net/netfilter/nfnetlink.c:229
netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
nfnetlink_rcv+0x1ba/0x460 net/netfilter/nfnetlink.c:563
netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
netlink_unicast+0x58c/0x7d0 net/netlink/af_netlink.c:1328
netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:639 [inline]
sock_sendmsg+0xd7/0x130 net/socket.c:659
____sys_sendmsg+0x753/0x880 net/socket.c:2330
___sys_sendmsg+0x100/0x170 net/socket.c:2384
__sys_sendmsg+0x105/0x1d0 net/socket.c:2417
__compat_sys_sendmsg net/compat.c:642 [inline]
__do_compat_sys_sendmsg net/compat.c:649 [inline]
__se_compat_sys_sendmsg net/compat.c:646 [inline]
__ia32_compat_sys_sendmsg+0x7a/0xb0 net/compat.c:646
do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline]
do_fast_syscall_32+0x27b/0xe16 arch/x86/entry/common.c:408
entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7f8ea39
Code: 00 00 00 89 d3 5b 5e 5f 5d c3 b8 80 96 98 00 eb c4 8b 04 24 c3 8b 1c
24 c3 8b 34 24 c3 8b 3c 24 c3 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90
90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000ffc15a2c EFLAGS: 00000202 ORIG_RAX: 0000000000000172
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020001080
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffc15b44
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 9563:
save_stack+0x23/0x90 mm/kasan/common.c:72
set_track mm/kasan/common.c:80 [inline]
__kasan_kmalloc mm/kasan/common.c:513 [inline]
__kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486
kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527
__do_kmalloc mm/slab.c:3656 [inline]
__kmalloc+0x163/0x770 mm/slab.c:3665
kmalloc include/linux/slab.h:561 [inline]
kzalloc include/linux/slab.h:670 [inline]
ip_set_alloc+0x38/0x5e net/netfilter/ipset/ip_set_core.c:255
init_map_port net/netfilter/ipset/ip_set_bitmap_port.c:234 [inline]
bitmap_port_create+0x3dc/0x7c0 net/netfilter/ipset/ip_set_bitmap_port.c:276
ip_set_create+0x6f1/0x1500 net/netfilter/ipset/ip_set_core.c:1111
nfnetlink_rcv_msg+0xcf2/0xfb0 net/netfilter/nfnetlink.c:229
netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
nfnetlink_rcv+0x1ba/0x460 net/netfilter/nfnetlink.c:563
netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
netlink_unicast+0x58c/0x7d0 net/netlink/af_netlink.c:1328
netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:639 [inline]
sock_sendmsg+0xd7/0x130 net/socket.c:659
____sys_sendmsg+0x753/0x880 net/socket.c:2330
___sys_sendmsg+0x100/0x170 net/socket.c:2384
__sys_sendmsg+0x105/0x1d0 net/socket.c:2417
__compat_sys_sendmsg net/compat.c:642 [inline]
__do_compat_sys_sendmsg net/compat.c:649 [inline]
__se_compat_sys_sendmsg net/compat.c:646 [inline]
__ia32_compat_sys_sendmsg+0x7a/0xb0 net/compat.c:646
do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline]
do_fast_syscall_32+0x27b/0xe16 arch/x86/entry/common.c:408
entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Freed by task 9563:
save_stack+0x23/0x90 mm/kasan/common.c:72
set_track mm/kasan/common.c:80 [inline]
kasan_set_free_info mm/kasan/common.c:335 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/common.c:474
kasan_slab_free+0xe/0x10 mm/kasan/common.c:483
__cache_free mm/slab.c:3426 [inline]
kfree+0x10a/0x2c0 mm/slab.c:3757
kvfree+0x61/0x70 mm/util.c:603
ip_set_free+0x16/0x20 net/netfilter/ipset/ip_set_core.c:276
bitmap_port_destroy+0xae/0x1d0 net/netfilter/ipset/ip_set_bitmap_gen.h:63
ip_set_create+0xe47/0x1500 net/netfilter/ipset/ip_set_core.c:1165
nfnetlink_rcv_msg+0xcf2/0xfb0 net/netfilter/nfnetlink.c:229
netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
nfnetlink_rcv+0x1ba/0x460 net/netfilter/nfnetlink.c:563
netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
netlink_unicast+0x58c/0x7d0 net/netlink/af_netlink.c:1328
netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:639 [inline]
sock_sendmsg+0xd7/0x130 net/socket.c:659
____sys_sendmsg+0x753/0x880 net/socket.c:2330
___sys_sendmsg+0x100/0x170 net/socket.c:2384
__sys_sendmsg+0x105/0x1d0 net/socket.c:2417
__compat_sys_sendmsg net/compat.c:642 [inline]
__do_compat_sys_sendmsg net/compat.c:649 [inline]
__se_compat_sys_sendmsg net/compat.c:646 [inline]
__ia32_compat_sys_sendmsg+0x7a/0xb0 net/compat.c:646
do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline]
do_fast_syscall_32+0x27b/0xe16 arch/x86/entry/common.c:408
entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

The buggy address belongs to the object at ffff8880a87a47c0
which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
32-byte region [ffff8880a87a47c0, ffff8880a87a47e0)
The buggy address belongs to the page:
page:ffffea0002a1e900 refcount:1 mapcount:0 mapping:ffff8880aa4001c0
index:0xffff8880a87a4fc1
raw: 00fffe0000000200 ffffea0002a25108 ffffea00027a3188 ffff8880aa4001c0
raw: ffff8880a87a4fc1 ffff8880a87a4000 000000010000002e 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8880a87a4680: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
ffff8880a87a4700: fb fb fb fb fc fc fc fc 00 05 fc fc fc fc fc fc
> ffff8880a87a4780: 00 05 fc fc fc fc fc fc fb fb fb fb fc fc fc fc
^
ffff8880a87a4800: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
ffff8880a87a4880: 06 fc fc fc fc fc fc fc 00 00 fc fc fc fc fc fc
==================================================================


---
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[Cong Wang]

map->members is freed by ip_set_free() right before using it in
mtype_ext_cleanup() again. So I think probably we just have to
move it down:

diff --git a/net/netfilter/ipset/ip_set_bitmap_gen.h
b/net/netfilter/ipset/ip_set_bitmap_gen.h
index 1abd6f0dc227..077a2cb65fcb 100644
--- a/net/netfilter/ipset/ip_set_bitmap_gen.h
+++ b/net/netfilter/ipset/ip_set_bitmap_gen.h
@@ -60,9 +60,9 @@ mtype_destroy(struct ip_set *set)
if (SET_WITH_TIMEOUT(set))
del_timer_sync(&map->gc);

- ip_set_free(map->members);
if (set->dsize && set->extensions & IPSET_EXT_DESTROY)
mtype_ext_cleanup(set);
+ ip_set_free(map->members);
ip_set_free(map);

set->data = NULL;

Thanks.

[Kadlecsik József]

Hi,

Yes, exactly. As you suggested, could you submit a patch?

Acked-by: Jozsef Kadlecsik <kad...@netfilter.org>

Best regards,
Jozsef

> diff --git a/net/netfilter/ipset/ip_set_bitmap_gen.h
> b/net/netfilter/ipset/ip_set_bitmap_gen.h
> index 1abd6f0dc227..077a2cb65fcb 100644
> --- a/net/netfilter/ipset/ip_set_bitmap_gen.h
> +++ b/net/netfilter/ipset/ip_set_bitmap_gen.h
> @@ -60,9 +60,9 @@ mtype_destroy(struct ip_set *set)
> if (SET_WITH_TIMEOUT(set))
> del_timer_sync(&map->gc);
>
> - ip_set_free(map->members);
> if (set->dsize && set->extensions & IPSET_EXT_DESTROY)
> mtype_ext_cleanup(set);
> + ip_set_free(map->members);
> ip_set_free(map);
>
> set->data = NULL;
>
> Thanks.
>

-
E-mail : kad...@blackhole.kfki.hu, kadlecsi...@wigner.mta.hu
PGP key : http://www.kfki.hu/~kadlec/pgp_public_key.txt
Address : Wigner Research Centre for Physics
H-1525 Budapest 114, POB. 49, Hungary