KASAN: slab-out-of-bounds Read in bitmap_ip_add

KASAN: slab-out-of-bounds Read in bitmap_ip_add

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    244dc268 Merge tag 'drm-fixes-2020-01-19' of git://anongit..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10edfa85e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cfbb8fa33f49f9f3
dashboard link: https://syzkaller.appspot.com/bug?extid=f3e96783d74ee8ea9aa3
compiler:       clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=159e60f1e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+f3e96783d74ee8ea9aa3@syzkaller.appspotmail.com

==================================================================
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_ip_do_add net/netfilter/ipset/ip_set_bitmap_ip.c:83 [inline]
BUG: KASAN: slab-out-of-bounds in bitmap_ip_add+0xdf/0x870 net/netfilter/ipset/ip_set_bitmap_gen.h:136
Read of size 8 at addr ffff888094088c80 by task syz-executor.4/9490

CPU: 1 PID: 9490 Comm: syz-executor.4 Not tainted 5.5.0-rc6-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_ip_do_add net/netfilter/ipset/ip_set_bitmap_ip.c:83 [inline]
 bitmap_ip_add+0xdf/0x870 net/netfilter/ipset/ip_set_bitmap_gen.h:136
 bitmap_ip_uadt+0x6bf/0xa60 net/netfilter/ipset/ip_set_bitmap_ip.c:186
 call_ad+0x10a/0x5b0 net/netfilter/ipset/ip_set_core.c:1716
 ip_set_ad+0x6a9/0x860 net/netfilter/ipset/ip_set_core.c:1804
 ip_set_uadd+0x37/0x50 net/netfilter/ipset/ip_set_core.c:1829
 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: 0033:0x45b159
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fddd7876c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fddd78776d4 RCX: 000000000045b159
RDX: 0000000000000000 RSI: 0000000020000300 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000008dc R14: 00000000004ca08f R15: 000000000075bf2c

Allocated by task 8928:
 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_ip net/netfilter/ipset/ip_set_bitmap_ip.c:223 [inline]
 bitmap_ip_create+0x48b/0xac0 net/netfilter/ipset/ip_set_bitmap_ip.c:327
 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 8538:
 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
 tomoyo_path_perm+0x6ae/0x850 security/tomoyo/file.c:842
 tomoyo_inode_getattr+0x1c/0x20 security/tomoyo/tomoyo.c:129
 security_inode_getattr+0xc0/0x140 security/security.c:1222
 vfs_getattr+0x2a/0x6d0 fs/stat.c:115
 vfs_statx fs/stat.c:191 [inline]
 vfs_stat include/linux/fs.h:3249 [inline]
 __do_sys_newstat fs/stat.c:341 [inline]
 __se_sys_newstat+0x95/0x150 fs/stat.c:337
 __x64_sys_newstat+0x5b/0x70 fs/stat.c:337
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff888094088c80
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff888094088c80, ffff888094088ca0)
The buggy address belongs to the page:
page:ffffea0002502200 refcount:1 mapcount:0 mapping:ffff8880aa8001c0 index:0xffff888094088fc1
raw: 00fffe0000000200 ffffea00028f8048 ffffea00029d9b88 ffff8880aa8001c0
raw: ffff888094088fc1 ffff888094088000 000000010000003f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888094088b80: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff888094088c00: 00 05 fc fc fc fc fc fc fb fb fb fb fc fc fc fc
>ffff888094088c80: 04 fc fc fc fc fc fc fc 00 00 01 fc fc fc fc fc
                   ^
 ffff888094088d00: 00 00 03 fc fc fc fc fc fb fb fb fb fc fc fc fc
 ffff888094088d80: fb fb fb fb fc fc fc fc 00 00 00 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 syzkaller@googlegroups.com.

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

Re: KASAN: slab-out-of-bounds Read in bitmap_ip_add

[syzbot]

syzbot has bisected this bug to:

commit 751ad98d5f881df91ba47e013b82422912381e8e
Author: Marco Elver <elver@google.com>
Date:   Fri Jul 12 03:54:00 2019 +0000

    asm-generic, x86: add bitops instrumentation for KASAN

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1287db66e00000
start commit:   244dc268 Merge tag 'drm-fixes-2020-01-19' of git://anongit..
git tree:       upstream
final crash:    https://syzkaller.appspot.com/x/report.txt?x=1187db66e00000
console output: https://syzkaller.appspot.com/x/log.txt?x=1687db66e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d9290aeb7e6cf1c4
dashboard link: https://syzkaller.appspot.com/bug?extid=f3e96783d74ee8ea9aa3
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1104c495e00000

Reported-by: syzbot+f3e96783d74ee8ea9aa3@syzkaller.appspotmail.com
Fixes: 751ad98d5f88 ("asm-generic, x86: add bitops instrumentation for KASAN")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Re: KASAN: slab-out-of-bounds Read in bitmap_ip_add

[Linus Torvalds]

On Sun, Jan 26, 2020 at 8:01 PM syzbot
<syzbot+f3e96783d74ee8ea9aa3@syzkaller.appspotmail.com> wrote:
>
> syzbot has bisected this bug to:

Ok, the bisection is obviously bogus - it just points to where the
KASAN support was added to _notice_ the problem.

But is somebody looking at the actual KASAN report itself?

  https://syzkaller.appspot.com/bug?extid=f3e96783d74ee8ea9aa3

It does look like nfnetlink_rcv_msg() ends up looking at a bit:

 bitmap_ip_do_add net/netfilter/ipset/ip_set_bitmap_ip.c:83 [inline]
 bitmap_ip_add+0xef/0xe60 net/netfilter/ipset/ip_set_bitmap_gen.h:136
 bitmap_ip_uadt+0x73e/0xa10 net/netfilter/ipset/ip_set_bitmap_ip.c:186
 call_ad+0x1a0/0x5a0 net/netfilter/ipset/ip_set_core.c:1716
 ip_set_ad.isra.0+0x572/0xb20 net/netfilter/ipset/ip_set_core.c:1804
 ip_set_uadd+0x37/0x50 net/netfilter/ipset/ip_set_core.c:1829
 nfnetlink_rcv_msg+0xcf2/0xfb0 net/netfilter/nfnetlink.c:229

that is past the allocation:

 ip_set_alloc+0x38/0x5e net/netfilter/ipset/ip_set_core.c:255
 init_map_ip net/netfilter/ipset/ip_set_bitmap_ip.c:223 [inline]
 bitmap_ip_create+0x6ec/0xc20 net/netfilter/ipset/ip_set_bitmap_ip.c:327
 ip_set_create+0x6f1/0x1500 net/netfilter/ipset/ip_set_core.c:1111
 nfnetlink_rcv_msg+0xcf2/0xfb0 net/netfilter/nfnetlink.c:229

Maybe this has already been fixed, but I'm just trying to follow-up on
the syzbot report..

           Linus

Re: KASAN: slab-out-of-bounds Read in bitmap_ip_add

[Cong Wang]

On Fri, Jan 31, 2020 at 12:58 PM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> On Sun, Jan 26, 2020 at 8:01 PM syzbot
> <syzbot+f3e96783d74ee8ea9aa3@syzkaller.appspotmail.com> wrote:
> >
> > syzbot has bisected this bug to:
>
> Ok, the bisection is obviously bogus - it just points to where the
> KASAN support was added to _notice_ the problem.
>
> But is somebody looking at the actual KASAN report itself?

It is supposed to be fixed by:

commit 32c72165dbd0e246e69d16a3ad348a4851afd415
Author: Kadlecsik József <kadlec@blackhole.kfki.hu>
Date:   Sun Jan 19 22:06:49 2020 +0100

    netfilter: ipset: use bitmap infrastructure completely

Thanks.

Re: KASAN: slab-out-of-bounds Read in bitmap_ip_add

[Linus Torvalds]

On Fri, Jan 31, 2020 at 1:02 PM Cong Wang <xiyou.wangcong@gmail.com> wrote:
>
> It is supposed to be fixed by commit 32c72165dbd0

Ahh, thanks, I missed that. I actually looked at the current code and
saw the bitmap_zalloc() and it all looked fine, and assumed there was
some other bug in the elements calculation.

I didn't realize that it looked fine because it had already been fixed.

Thanks,
             Linus

Re: KASAN: slab-out-of-bounds Read in bitmap_ip_add

[syzbot]

syzbot suspects this bug was fixed by commit:

commit 32c72165dbd0e246e69d16a3ad348a4851afd415
Author: Kadlecsik József <kadlec@blackhole.kfki.hu>
Date:   Sun Jan 19 21:06:49 2020 +0000

    netfilter: ipset: use bitmap infrastructure completely

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=13c6cb73e00000
start commit:   244dc268 Merge tag 'drm-fixes-2020-01-19' of git://anongit..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=d9290aeb7e6cf1c4
dashboard link: https://syzkaller.appspot.com/bug?extid=f3e96783d74ee8ea9aa3
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1104c495e00000

If the result looks correct, please mark the bug fixed by replying with:

#syz fix: netfilter: ipset: use bitmap infrastructure completely

For information about bisection process see: https://goo.gl/tpsmEJ#bisection