Subject: KASAN: slab-out-of-bounds Read in bitmap_port_destroy

From: syzbot <[email-masked]>
Date: Thu, 23 Jan 2020 15:17:09 -0800

Hello,

syzbot found the following crash on:

HEAD commit:    131701c6 Merge tag 'leds-5.5-rc8' of git://git.kernel.org/..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11897a11e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=83c00afca9cf5153
dashboard link: https://syzkaller.appspot.com/bug?extid=b96275fd6ad891076ced
compiler:       clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15fba721e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1339726ee00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email-masked]

==================================================================
BUG: KASAN: slab-out-of-bounds in test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline]
BUG: KASAN: slab-out-of-bounds in bitmap_port_ext_cleanup net/netfilter/ipset/ip_set_bitmap_gen.h:51 [inline]
BUG: KASAN: slab-out-of-bounds in bitmap_port_destroy+0x1d2/0x3c0 net/netfilter/ipset/ip_set_bitmap_gen.h:64
Read of size 8 at addr ffff88809e7c2080 by task syz-executor377/8828

CPU: 1 PID: 8828 Comm: syz-executor377 Not tainted 5.5.0-rc7-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+0x1fb/0x318 lib/dump_stack.c:118
 print_address_description+0x74/0x5c0 mm/kasan/report.c:374
 __kasan_report+0x149/0x1c0 mm/kasan/report.c:506
 kasan_report+0x26/0x50 mm/kasan/common.c:639
 check_memory_region_inline mm/kasan/generic.c:182 [inline]
 check_memory_region+0x2b6/0x2f0 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 net/netfilter/ipset/ip_set_bitmap_gen.h:51 [inline]
 bitmap_port_destroy+0x1d2/0x3c0 net/netfilter/ipset/ip_set_bitmap_gen.h:64
 ip_set_create+0xae0/0xfd0 net/netfilter/ipset/ip_set_core.c:1165
 nfnetlink_rcv_msg+0x9ae/0xcd0 net/netfilter/nfnetlink.c:229
 netlink_rcv_skb+0x19e/0x3e0 net/netlink/af_netlink.c:2477
 nfnetlink_rcv+0x1e0/0x1e50 net/netfilter/nfnetlink.c:563
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x767/0x920 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0xa2c/0xd50 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg net/socket.c:659 [inline]
 ____sys_sendmsg+0x4f7/0x7f0 net/socket.c:2330
 ___sys_sendmsg net/socket.c:2384 [inline]
 __sys_sendmsg+0x1ed/0x290 net/socket.c:2417
 __do_sys_sendmsg net/socket.c:2426 [inline]
 __se_sys_sendmsg net/socket.c:2424 [inline]
 __x64_sys_sendmsg+0x7f/0x90 net/socket.c:2424
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441399
Code: e8 fc ab 02 00 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 9b 09 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc59587e48 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441399
RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 0000000000011f0f R08: 00000000004002c8 R09: 00000000004002c8
R10: 0000000000000004 R11: 0000000000000246 R12: 00000000004021c0
R13: 0000000000402250 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 8828:
 save_stack mm/kasan/common.c:72 [inline]
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc+0x118/0x1c0 mm/kasan/common.c:513
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc+0x254/0x340 mm/slab.c:3665
 kmalloc include/linux/slab.h:561 [inline]
 kzalloc+0x21/0x40 include/linux/slab.h:670
 ip_set_alloc+0x32/0x60 net/netfilter/ipset/ip_set_core.c:255
 init_map_port net/netfilter/ipset/ip_set_bitmap_port.c:234 [inline]
 bitmap_port_create+0x32c/0x790 net/netfilter/ipset/ip_set_bitmap_port.c:276
 ip_set_create+0x421/0xfd0 net/netfilter/ipset/ip_set_core.c:1111
 nfnetlink_rcv_msg+0x9ae/0xcd0 net/netfilter/nfnetlink.c:229
 netlink_rcv_skb+0x19e/0x3e0 net/netlink/af_netlink.c:2477
 nfnetlink_rcv+0x1e0/0x1e50 net/netfilter/nfnetlink.c:563
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x767/0x920 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0xa2c/0xd50 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg net/socket.c:659 [inline]
 ____sys_sendmsg+0x4f7/0x7f0 net/socket.c:2330
 ___sys_sendmsg net/socket.c:2384 [inline]
 __sys_sendmsg+0x1ed/0x290 net/socket.c:2417
 __do_sys_sendmsg net/socket.c:2426 [inline]
 __se_sys_sendmsg net/socket.c:2424 [inline]
 __x64_sys_sendmsg+0x7f/0x90 net/socket.c:2424
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 8498:
 save_stack mm/kasan/common.c:72 [inline]
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:335 [inline]
 __kasan_slab_free+0x12e/0x1e0 mm/kasan/common.c:474
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:483
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10d/0x220 mm/slab.c:3757
 single_release+0x91/0xa0 fs/seq_file.c:609
 __fput+0x2e4/0x740 fs/file_table.c:280
 ____fput+0x15/0x20 fs/file_table.c:313
 task_work_run+0x176/0x1b0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop arch/x86/entry/common.c:164 [inline]
 prepare_exit_to_usermode+0x480/0x5b0 arch/x86/entry/common.c:195
 syscall_return_slowpath+0x113/0x4a0 arch/x86/entry/common.c:278
 do_syscall_64+0x11f/0x1c0 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88809e7c2080
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff88809e7c2080, ffff88809e7c20a0)
The buggy address belongs to the page:
page:ffffea000279f080 refcount:1 mapcount:0 mapping:ffff8880aa8001c0 index:0xffff88809e7c2fc1
raw: 00fffe0000000200 ffffea00028b5b08 ffffea0002a03b48 ffff8880aa8001c0
raw: ffff88809e7c2fc1 ffff88809e7c2000 000000010000003d 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809e7c1f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809e7c2000: fb fb fb fb fc fc fc fc 00 00 01 fc fc fc fc fc
>ffff88809e7c2080: 04 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc
                   ^
 ffff88809e7c2100: 05 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc
 ffff88809e7c2180: 00 00 01 fc fc fc fc fc 00 03 fc fc fc fc fc fc
==================================================================

---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at [email-masked].

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches