[moderation] [hams?] KASAN: slab-use-after-free Read in ax25_release

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3ec8d7572a69 CDC-NCM: add support for Apple's private inte..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=138726da980000
kernel config: https://syzkaller.appspot.com/x/.config?x=ce6b8d38d53fa4e
dashboard link: https://syzkaller.appspot.com/bug?extid=88d130bb1596c1546453
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [da...@davemloft.net edum...@google.com jre...@yaina.de ku...@kernel.org linux...@vger.kernel.org linux-...@vger.kernel.org net...@vger.kernel.org pab...@redhat.com]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b3766092cc55/disk-3ec8d757.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f93a2ef6cc54/vmlinux-3ec8d757.xz
kernel image: https://storage.googleapis.com/syzbot-assets/713bb5c240ed/bzImage-3ec8d757.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+88d130...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in ax25_release+0x877/0x950 net/ax25/af_ax25.c:1062
Read of size 1 at addr ffff888021c6d4cc by task syz-executor.3/9760

CPU: 0 PID: 9760 Comm: syz-executor.3 Not tainted 6.10.0-rc2-syzkaller-00761-g3ec8d7572a69 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
ax25_release+0x877/0x950 net/ax25/af_ax25.c:1062
__sock_release net/socket.c:659 [inline]
sock_close+0xbc/0x240 net/socket.c:1421
__fput+0x406/0x8b0 fs/file_table.c:422
task_work_run+0x24f/0x310 kernel/task_work.c:180
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218
do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbc5487cea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc8523d5f8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fbc549b5980 RCX: 00007fbc5487cea9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fbc549b5980 R08: 000000008136572d R09: 0000001e00000000
R10: 0000000080000000 R11: 0000000000000246 R12: 00000000000325b4
R13: 00007fbc549b405c R14: 0000000000000032 R15: 00007fbc549b5980
</TASK>

Allocated by task 9426:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
kasan_kmalloc include/linux/kasan.h:211 [inline]
kmalloc_trace_noprof+0x19c/0x2c0 mm/slub.c:4152
kmalloc_noprof include/linux/slab.h:660 [inline]
kzalloc_noprof include/linux/slab.h:778 [inline]
ax25_dev_device_up+0x58/0x620 net/ax25/ax25_dev.c:57
ax25_device_event+0x4ed/0x570 net/ax25/af_ax25.c:143
notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:93
__dev_notify_flags+0x207/0x400
dev_change_flags+0xf0/0x1a0 net/core/dev.c:8858
dev_ifsioc+0x7c8/0xe70 net/core/dev_ioctl.c:530
dev_ioctl+0x719/0x1340 net/core/dev_ioctl.c:787
sock_do_ioctl+0x240/0x460 net/socket.c:1236
sock_ioctl+0x629/0x8e0 net/socket.c:1341
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 9767:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
poison_slab_object+0xe0/0x150 mm/kasan/common.c:240
__kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2195 [inline]
slab_free mm/slub.c:4436 [inline]
kfree+0x149/0x360 mm/slub.c:4557
ax25_device_event+0x523/0x570 net/ax25/af_ax25.c:148
notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:93
__dev_notify_flags+0x207/0x400
dev_change_flags+0xf0/0x1a0 net/core/dev.c:8858
dev_ifsioc+0x7c8/0xe70 net/core/dev_ioctl.c:530
dev_ioctl+0x719/0x1340 net/core/dev_ioctl.c:787
sock_do_ioctl+0x240/0x460 net/socket.c:1236
sock_ioctl+0x629/0x8e0 net/socket.c:1341
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888021c6d400
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 204 bytes inside of
freed 256-byte region [ffff888021c6d400, ffff888021c6d500)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x21c6c
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
ksm flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffefff(slab)
raw: 00fff00000000040 ffff888015041b40 ffffea0000a5cc00 dead000000000003
raw: 0000000000000000 0000000000100010 00000001ffffefff 0000000000000000
head: 00fff00000000040 ffff888015041b40 ffffea0000a5cc00 dead000000000003
head: 0000000000000000 0000000000100010 00000001ffffefff 0000000000000000
head: 00fff00000000001 ffffea0000871b01 ffffffffffffffff 0000000000000000
head: ffff888000000002 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5115, tgid 5115 (syz-executor.3), ts 75925089521, free_ts 75915082958
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1468
prep_new_page mm/page_alloc.c:1476 [inline]
get_page_from_freelist+0x2e2d/0x2ee0 mm/page_alloc.c:3402
__alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4660
__alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
alloc_slab_page+0x5f/0x120 mm/slub.c:2264
allocate_slab+0x5a/0x2e0 mm/slub.c:2427
new_slab mm/slub.c:2480 [inline]
___slab_alloc+0xcd1/0x14b0 mm/slub.c:3666
__slab_alloc+0x58/0xa0 mm/slub.c:3756
__slab_alloc_node mm/slub.c:3809 [inline]
slab_alloc_node mm/slub.c:3988 [inline]
__do_kmalloc_node mm/slub.c:4120 [inline]
__kmalloc_noprof+0x257/0x400 mm/slub.c:4134
kmalloc_noprof include/linux/slab.h:664 [inline]
kzalloc_noprof include/linux/slab.h:778 [inline]
new_dir fs/proc/proc_sysctl.c:953 [inline]
get_subdir fs/proc/proc_sysctl.c:997 [inline]
sysctl_mkdir_p fs/proc/proc_sysctl.c:1292 [inline]
__register_sysctl_table+0xb53/0x1460 fs/proc/proc_sysctl.c:1373
neigh_sysctl_register+0x3f8/0x4e0 net/core/neighbour.c:3861
devinet_sysctl_register+0xaf/0x1f0 net/ipv4/devinet.c:2639
inetdev_init+0x296/0x4d0 net/ipv4/devinet.c:291
inetdev_event+0x338/0x15c0 net/ipv4/devinet.c:1565
notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:93
call_netdevice_notifiers_extack net/core/dev.c:2030 [inline]
call_netdevice_notifiers net/core/dev.c:2044 [inline]
register_netdevice+0x1570/0x19e0 net/core/dev.c:10408
veth_newlink+0x628/0xcd0 drivers/net/veth.c:1829
page last free pid 5115 tgid 5115 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1088 [inline]
free_unref_page+0xd22/0xea0 mm/page_alloc.c:2565
discard_slab mm/slub.c:2526 [inline]
__put_partials+0xeb/0x130 mm/slub.c:2994
put_cpu_partial+0x17c/0x250 mm/slub.c:3069
__slab_free+0x2ea/0x3d0 mm/slub.c:4306
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x9e/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3940 [inline]
slab_alloc_node mm/slub.c:4000 [inline]
kmem_cache_alloc_node_noprof+0x16b/0x320 mm/slub.c:4043
__alloc_skb+0x1c3/0x440 net/core/skbuff.c:656
netlink_sendmsg+0x631/0xcb0 net/netlink/af_netlink.c:1876
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:745
__sys_sendto+0x3a4/0x4f0 net/socket.c:2192
__do_sys_sendto net/socket.c:2204 [inline]
__se_sys_sendto net/socket.c:2200 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2200
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
ffff888021c6d380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888021c6d400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888021c6d480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888021c6d500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888021c6d580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


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