[syzbot] [bpf?] [net?] KASAN: slab-use-after-free Read in xsk_diag_dump

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 5c905279a1b7 Merge branch 'pds_core-error-handling-fixes'
git tree: net
console+strace: https://syzkaller.appspot.com/x/log.txt?x=16080070680000
kernel config: https://syzkaller.appspot.com/x/.config?x=1e4a882f77ed77bd
dashboard link: https://syzkaller.appspot.com/bug?extid=822d1359297e2694f873
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14ec63a7a80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=109926eba80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/98add120b6e5/disk-5c905279.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c9e9009eadbd/vmlinux-5c905279.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b840142cc0c1/bzImage-5c905279.xz

The issue was bisected to:

commit 18b1ab7aa76bde181bdb1ab19a87fa9523c32f21
Author: Magnus Karlsson <magnus....@intel.com>
Date: Mon Feb 28 09:45:52 2022 +0000

xsk: Fix race at socket teardown

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16c6229fa80000
final oops: https://syzkaller.appspot.com/x/report.txt?x=15c6229fa80000
console output: https://syzkaller.appspot.com/x/log.txt?x=11c6229fa80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+822d13...@syzkaller.appspotmail.com
Fixes: 18b1ab7aa76b ("xsk: Fix race at socket teardown")

==================================================================
BUG: KASAN: slab-use-after-free in xsk_diag_put_info net/xdp/xsk_diag.c:21 [inline]
BUG: KASAN: slab-use-after-free in xsk_diag_fill net/xdp/xsk_diag.c:114 [inline]
BUG: KASAN: slab-use-after-free in xsk_diag_dump+0x1573/0x15c0 net/xdp/xsk_diag.c:163
Read of size 4 at addr ffff8880789da0e0 by task syz-executor370/5025

CPU: 1 PID: 5025 Comm: syz-executor370 Not tainted 6.5.0-rc7-syzkaller-00108-g5c905279a1b7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:364 [inline]
print_report+0xc4/0x620 mm/kasan/report.c:475
kasan_report+0xda/0x110 mm/kasan/report.c:588
xsk_diag_put_info net/xdp/xsk_diag.c:21 [inline]
xsk_diag_fill net/xdp/xsk_diag.c:114 [inline]
xsk_diag_dump+0x1573/0x15c0 net/xdp/xsk_diag.c:163
netlink_dump+0x588/0xca0 net/netlink/af_netlink.c:2269
__netlink_dump_start+0x6d0/0x9c0 net/netlink/af_netlink.c:2376
netlink_dump_start include/linux/netlink.h:330 [inline]
xsk_diag_handler_dump+0x1a6/0x240 net/xdp/xsk_diag.c:190
__sock_diag_cmd net/core/sock_diag.c:238 [inline]
sock_diag_rcv_msg+0x316/0x440 net/core/sock_diag.c:269
netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2549
sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:280
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x539/0x800 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x93c/0xe30 net/netlink/af_netlink.c:1914
sock_sendmsg_nosec net/socket.c:725 [inline]
sock_sendmsg+0xd9/0x180 net/socket.c:748
sock_write_iter+0x29b/0x3d0 net/socket.c:1129
call_write_iter include/linux/fs.h:1877 [inline]
do_iter_readv_writev+0x21e/0x3c0 fs/read_write.c:735
do_iter_write+0x17f/0x830 fs/read_write.c:860
vfs_writev+0x221/0x700 fs/read_write.c:933
do_writev+0x285/0x370 fs/read_write.c:976
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fd9ce8b9df9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc3b052168 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd9ce8b9df9
RDX: 0000000000000001 RSI: 00000000200003c0 RDI: 0000000000000006
RBP: 0000000000000000 R08: 0000000000000006 R09: 0000000000000006
R10: 0000000000000006 R11: 0000000000000246 R12: 0000000000000000
R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001
</TASK>

Allocated by task 5025:
kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
kasan_set_track+0x25/0x30 mm/kasan/common.c:52
____kasan_kmalloc mm/kasan/common.c:374 [inline]
__kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:383
kasan_kmalloc include/linux/kasan.h:196 [inline]
__do_kmalloc_node mm/slab_common.c:985 [inline]
__kmalloc_node+0x60/0x100 mm/slab_common.c:992
kmalloc_node include/linux/slab.h:602 [inline]
kvmalloc_node+0x99/0x1a0 mm/util.c:604
kvmalloc include/linux/slab.h:720 [inline]
kvzalloc include/linux/slab.h:728 [inline]
alloc_netdev_mqs+0x9b/0x1240 net/core/dev.c:10594
rtnl_create_link+0xc9c/0xfd0 net/core/rtnetlink.c:3350
rtnl_newlink_create net/core/rtnetlink.c:3476 [inline]
__rtnl_newlink+0x108e/0x1940 net/core/rtnetlink.c:3706
rtnl_newlink+0x67/0xa0 net/core/rtnetlink.c:3719
rtnetlink_rcv_msg+0x439/0xd30 net/core/rtnetlink.c:6445
netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2549
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x539/0x800 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x93c/0xe30 net/netlink/af_netlink.c:1914
sock_sendmsg_nosec net/socket.c:725 [inline]
sock_sendmsg+0xd9/0x180 net/socket.c:748
____sys_sendmsg+0x6ac/0x940 net/socket.c:2494
___sys_sendmsg+0x135/0x1d0 net/socket.c:2548
__sys_sendmsg+0x117/0x1e0 net/socket.c:2577
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 5025:
kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
kasan_set_track+0x25/0x30 mm/kasan/common.c:52
kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:522
____kasan_slab_free mm/kasan/common.c:236 [inline]
____kasan_slab_free+0x15e/0x1b0 mm/kasan/common.c:200
kasan_slab_free include/linux/kasan.h:162 [inline]
slab_free_hook mm/slub.c:1792 [inline]
slab_free_freelist_hook+0x10b/0x1e0 mm/slub.c:1818
slab_free mm/slub.c:3801 [inline]
__kmem_cache_free+0xb8/0x2f0 mm/slub.c:3814
kvfree+0x47/0x50 mm/util.c:650
device_release+0xa1/0x240 drivers/base/core.c:2484
kobject_cleanup lib/kobject.c:682 [inline]
kobject_release lib/kobject.c:713 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1f7/0x5b0 lib/kobject.c:730
netdev_run_todo+0x7dd/0x11d0 net/core/dev.c:10366
rtnl_unlock net/core/rtnetlink.c:151 [inline]
rtnetlink_rcv_msg+0x446/0xd30 net/core/rtnetlink.c:6446
netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2549
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x539/0x800 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x93c/0xe30 net/netlink/af_netlink.c:1914
sock_sendmsg_nosec net/socket.c:725 [inline]
sock_sendmsg+0xd9/0x180 net/socket.c:748
____sys_sendmsg+0x6ac/0x940 net/socket.c:2494
___sys_sendmsg+0x135/0x1d0 net/socket.c:2548
__sys_sendmsg+0x117/0x1e0 net/socket.c:2577
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff8880789da000
which belongs to the cache kmalloc-cg-4k of size 4096
The buggy address is located 224 bytes inside of
freed 4096-byte region [ffff8880789da000, ffff8880789db000)

The buggy address belongs to the physical page:
page:ffffea0001e27600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x789d8
head:ffffea0001e27600 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000010200 ffff88801284f500 0000000000000000 0000000000000001
raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4479, tgid 4479 (udevd), ts 29735533397, free_ts 28964079298
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x2d2/0x350 mm/page_alloc.c:1570
prep_new_page mm/page_alloc.c:1577 [inline]
get_page_from_freelist+0x10a9/0x31e0 mm/page_alloc.c:3221
__alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4477
alloc_pages+0x1a9/0x270 mm/mempolicy.c:2292
alloc_slab_page mm/slub.c:1862 [inline]
allocate_slab+0x24e/0x380 mm/slub.c:2009
new_slab mm/slub.c:2062 [inline]
___slab_alloc+0x8bc/0x1570 mm/slub.c:3215
__slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3314
__slab_alloc_node mm/slub.c:3367 [inline]
slab_alloc_node mm/slub.c:3460 [inline]
__kmem_cache_alloc_node+0x137/0x350 mm/slub.c:3509
__do_kmalloc_node mm/slab_common.c:984 [inline]
__kmalloc_node+0x4f/0x100 mm/slab_common.c:992
kmalloc_node include/linux/slab.h:602 [inline]
kvmalloc_node+0x99/0x1a0 mm/util.c:604
kvmalloc include/linux/slab.h:720 [inline]
seq_buf_alloc fs/seq_file.c:38 [inline]
seq_read_iter+0x80b/0x1280 fs/seq_file.c:210
kernfs_fop_read_iter+0x4c8/0x680 fs/kernfs/file.c:279
call_read_iter include/linux/fs.h:1871 [inline]
new_sync_read fs/read_write.c:389 [inline]
vfs_read+0x4e0/0x930 fs/read_write.c:470
ksys_read+0x12f/0x250 fs/read_write.c:613
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1161 [inline]
free_unref_page_prepare+0x508/0xb90 mm/page_alloc.c:2348
free_unref_page+0x33/0x3b0 mm/page_alloc.c:2443
qlink_free mm/kasan/quarantine.c:166 [inline]
qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:185
kasan_quarantine_reduce+0x18b/0x1d0 mm/kasan/quarantine.c:292
__kasan_slab_alloc+0x65/0x90 mm/kasan/common.c:305
kasan_slab_alloc include/linux/kasan.h:186 [inline]
slab_post_alloc_hook mm/slab.h:762 [inline]
slab_alloc_node mm/slub.c:3470 [inline]
slab_alloc mm/slub.c:3478 [inline]
__kmem_cache_alloc_lru mm/slub.c:3485 [inline]
kmem_cache_alloc+0x172/0x3b0 mm/slub.c:3494
getname_flags.part.0+0x50/0x4d0 fs/namei.c:140
getname_flags include/linux/audit.h:319 [inline]
getname+0x90/0xe0 fs/namei.c:219
do_sys_openat2+0x100/0x1e0 fs/open.c:1401
do_sys_open fs/open.c:1422 [inline]
__do_sys_openat fs/open.c:1438 [inline]
__se_sys_openat fs/open.c:1433 [inline]
__x64_sys_openat+0x175/0x210 fs/open.c:1433
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
ffff8880789d9f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880789da000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880789da080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880789da100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880789da180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
This report is generated by a bot. It may contain errors.
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection

If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite bug's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[Daniel Borkmann]

Hi Magnus,

On 8/29/23 10:20 AM, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 5c905279a1b7 Merge branch 'pds_core-error-handling-fixes'
> git tree: net
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=16080070680000
> kernel config: https://syzkaller.appspot.com/x/.config?x=1e4a882f77ed77bd
> dashboard link: https://syzkaller.appspot.com/bug?extid=822d1359297e2694f873
> compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14ec63a7a80000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=109926eba80000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/98add120b6e5/disk-5c905279.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/c9e9009eadbd/vmlinux-5c905279.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/b840142cc0c1/bzImage-5c905279.xz
>
> The issue was bisected to:
>
> commit 18b1ab7aa76bde181bdb1ab19a87fa9523c32f21
> Author: Magnus Karlsson <magnus....@intel.com>
> Date: Mon Feb 28 09:45:52 2022 +0000
>
> xsk: Fix race at socket teardown

please take a look when you get a chance.

Thanks a lot,
Daniel

[Magnus Karlsson]

Already looking at it :-).

/Magnus

[Daniel Borkmann]

Awesome, thanks! :)

[syzbot]

> #syz test: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git 35d2b7ffffc1d9b3dc6c761010aa3338da49165b

Your commands are accepted, but please keep syzkall...@googlegroups.com mailing list in CC next time. It serves as a history of what happened with each bug report. Thank you.

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+822d13...@syzkaller.appspotmail.com

Tested on:

commit: 35d2b7ff bpf, sockmap: Fix preempt_rt splat when using..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git
console output: https://syzkaller.appspot.com/x/log.txt?x=144d5c9fa80000
kernel config: https://syzkaller.appspot.com/x/.config?x=634e05b4025da9da

dashboard link: https://syzkaller.appspot.com/bug?extid=822d1359297e2694f873
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=123a462fa80000

Note: testing is done by a robot and is best-effort only.