syzbot


KASAN: use-after-free Read in ax25_rt_autobind

Status: upstream: reported on 2025/03/21 16:25
Reported-by: syzbot+8309bf0e61f7480d036c@syzkaller.appspotmail.com
First crash: 31d, last: 7d08h

Sample crash report:
ax25_connect(): syz.1.1580 uses autobind, please contact jreuter@yaina.de
==================================================================
BUG: KASAN: use-after-free in ax25_rt_autobind+0x2e8/0x5f4 net/ax25/ax25_route.c:424
Read of size 8 at addr ffff0000d210bc08 by task syz.1.1580/9522

CPU: 1 PID: 9522 Comm: syz.1.1580 Not tainted 5.15.180-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 print_address_description+0x7c/0x3f0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0x174/0x1e4 mm/kasan/report.c:451
 __asan_report_load8_noabort+0x44/0x50 mm/kasan/report_generic.c:309
 ax25_rt_autobind+0x2e8/0x5f4 net/ax25/ax25_route.c:424
 ax25_connect+0x96c/0x1174 net/ax25/af_ax25.c:1263
 __sys_connect_file net/socket.c:1923 [inline]
 __sys_connect+0x268/0x290 net/socket.c:1940
 __do_sys_connect net/socket.c:1950 [inline]
 __se_sys_connect net/socket.c:1947 [inline]
 __arm64_sys_connect+0x7c/0x94 net/socket.c:1947
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Allocated by task 7971:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc+0xbc/0xfc mm/kasan/common.c:513
 __kasan_kmalloc+0x10/0x1c mm/kasan/common.c:522
 kasan_kmalloc include/linux/kasan.h:264 [inline]
 kmem_cache_alloc_trace+0x27c/0x47c mm/slub.c:3247
 kmalloc include/linux/slab.h:604 [inline]
 kzalloc include/linux/slab.h:735 [inline]
 ax25_dev_device_up+0x5c/0x548 net/ax25/ax25_dev.c:55
 ax25_device_event+0x504/0x590 net/ax25/af_ax25.c:139
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:391
 __dev_notify_flags+0x2b4/0x540 net/core/dev.c:-1
 dev_change_flags+0xc8/0x154 net/core/dev.c:8928
 dev_ifsioc+0x140/0xfe4 net/core/dev_ioctl.c:324
 dev_ioctl+0x4e0/0xd3c net/core/dev_ioctl.c:587
 sock_do_ioctl+0x1dc/0x2dc net/socket.c:1154
 sock_ioctl+0x4f4/0x8b0 net/socket.c:1257
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Freed by task 9463:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4c/0x84 mm/kasan/common.c:46
 kasan_set_free_info+0x28/0x4c mm/kasan/generic.c:360
 ____kasan_slab_free+0x118/0x164 mm/kasan/common.c:366
 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:374
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1705 [inline]
 slab_free_freelist_hook+0x128/0x1ec mm/slub.c:1731
 slab_free mm/slub.c:3499 [inline]
 kfree+0x178/0x410 mm/slub.c:4559
 ax25_dev_put include/net/ax25.h:302 [inline]
 ax25_release+0x57c/0x82c net/ax25/af_ax25.c:1062
 __sock_release net/socket.c:649 [inline]
 sock_close+0xb8/0x1fc net/socket.c:1336
 __fput+0x1c4/0x800 fs/file_table.c:311
 ____fput+0x20/0x30 fs/file_table.c:339
 task_work_run+0x130/0x1e4 kernel/task_work.c:188
 get_signal+0x1450/0x1550 kernel/signal.c:2672
 do_signal arch/arm64/kernel/signal.c:890 [inline]
 do_notify_resume+0x3d0/0x32b8 arch/arm64/kernel/signal.c:943
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline]
 el0_svc+0xfc/0x1f0 arch/arm64/kernel/entry-common.c:609
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Last potentially related work creation:
 kasan_save_stack+0x38/0x68 mm/kasan/common.c:38
 kasan_record_aux_stack+0xd4/0x11c mm/kasan/generic.c:348
 insert_work+0x64/0x394 kernel/workqueue.c:1366
 __queue_work+0xb84/0x114c kernel/workqueue.c:1532
 queue_work_on+0xc4/0x17c kernel/workqueue.c:1559
 queue_work include/linux/workqueue.h:512 [inline]
 addr_event+0x300/0x3f8 drivers/infiniband/core/roce_gid_mgmt.c:853
 inetaddr_event+0x108/0x1b0 drivers/infiniband/core/roce_gid_mgmt.c:869
 notifier_call_chain kernel/notifier.c:83 [inline]
 blocking_notifier_call_chain+0xf0/0x198 kernel/notifier.c:318
 __inet_del_ifa+0x768/0xe54 net/ipv4/devinet.c:443
 inet_del_ifa net/ipv4/devinet.c:480 [inline]
 inetdev_destroy net/ipv4/devinet.c:320 [inline]
 inetdev_event+0x444/0x1270 net/ipv4/devinet.c:1612
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:391
 call_netdevice_notifiers_info net/core/dev.c:2049 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2061 [inline]
 call_netdevice_notifiers net/core/dev.c:2075 [inline]
 unregister_netdevice_many+0xec8/0x18a8 net/core/dev.c:11133
 default_device_exit_batch+0x4c0/0x520 net/core/dev.c:11666
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x6bc/0xa9c net/core/net_namespace.c:618
 process_one_work+0x790/0x11b8 kernel/workqueue.c:2310
 worker_thread+0x910/0x1034 kernel/workqueue.c:2457
 kthread+0x37c/0x45c kernel/kthread.c:334
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870

Second to last potentially related work creation:
 kasan_save_stack+0x38/0x68 mm/kasan/common.c:38
 kasan_record_aux_stack+0xd4/0x11c mm/kasan/generic.c:348
 insert_work+0x64/0x394 kernel/workqueue.c:1366
 __queue_work+0xb84/0x114c kernel/workqueue.c:1532
 queue_work_on+0xc4/0x17c kernel/workqueue.c:1559
 queue_work include/linux/workqueue.h:512 [inline]
 call_usermodehelper_exec+0x238/0x484 kernel/umh.c:435
 call_modprobe kernel/kmod.c:98 [inline]
 __request_module+0x4c0/0xb34 kernel/kmod.c:170
 dev_load+0x194/0x1ec net/core/dev_ioctl.c:446
 dev_ioctl+0x3a4/0xd3c net/core/dev_ioctl.c:511
 sock_do_ioctl+0x1dc/0x2dc net/socket.c:1154
 sock_ioctl+0x4f4/0x8b0 net/socket.c:1257
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

The buggy address belongs to the object at ffff0000d210bc00
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 8 bytes inside of
 256-byte region [ffff0000d210bc00, ffff0000d210bd00)
The buggy address belongs to the page:
page:00000000d0ef1aa1 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff0000d210b800 pfn:0x11210a
head:00000000d0ef1aa1 order:1 compound_mapcount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 fffffc000320d108 fffffc000322c188 ffff0000c0002480
raw: ffff0000d210b800 000000000010000f 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000d210bb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000d210bb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff0000d210bc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff0000d210bc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000d210bd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
Unable to handle kernel paging request at virtual address 005b809da000050f
Mem abort info:
  ESR = 0x0000000096000004
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x04: level 0 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000004
  CM = 0, WnR = 0
[005b809da000050f] address between user and kernel address ranges
Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 9522 Comm: syz.1.1580 Tainted: G    B             5.15.180-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : ax25_rt_autobind+0x2f4/0x5f4 net/ax25/ax25_route.c:424
lr : ax25_rt_autobind+0x2e8/0x5f4 net/ax25/ax25_route.c:424
sp : ffff8000206679e0
x29: ffff8000206679e0 x28: ffff0000cfdee000 x27: ffff0000c9468f00
x26: dfff800000000000 x25: 0000000000000000 x24: ffff0000c9468f00
x23: 1fffe00019fbdc05 x22: c2e004ed0000287f x21: ffff0000cfdee010
x20: ffff800020667c02 x19: ffff0000cfdee000 x18: 0000000000000003
x17: 0000000000000002 x16: ffff80000824f3a0 x15: 00000000ffffffff
x14: ffff0000d35cb680 x13: 0000000000000001 x12: 0000000000080000
x11: 000000000002e8ae x10: ffff800025e39000 x9 : 0000000000000000
x8 : 185c009da000050f x7 : 0000000000000000 x6 : 0000000000000001
x5 : ffff800020667078 x4 : 0000000000000000 x3 : ffff80000819cb88
x2 : 0000000000000001 x1 : 0000000000000001 x0 : 0000000000000001
Call trace:
 ax25_rt_autobind+0x2f4/0x5f4 net/ax25/ax25_route.c:424
 ax25_connect+0x96c/0x1174 net/ax25/af_ax25.c:1263
 __sys_connect_file net/socket.c:1923 [inline]
 __sys_connect+0x268/0x290 net/socket.c:1940
 __do_sys_connect net/socket.c:1950 [inline]
 __se_sys_connect net/socket.c:1947 [inline]
 __arm64_sys_connect+0x7c/0x94 net/socket.c:1947
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Code: 97c53b6e f94002c8 910e2116 d343fec8 (387a6908) 
---[ end trace beaec32f558fc5aa ]---
----------------
Code disassembly (best guess):
   0:	97c53b6e 	bl	0xffffffffff14edb8
   4:	f94002c8 	ldr	x8, [x22]
   8:	910e2116 	add	x22, x8, #0x388
   c:	d343fec8 	lsr	x8, x22, #3
* 10:	387a6908 	ldrb	w8, [x8, x26] <-- trapping instruction

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/04/14 16:03 linux-5.15.y f7347f400572 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: use-after-free Read in ax25_rt_autobind
2025/03/21 16:24 linux-5.15.y 0c935c049b5c 62330552 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: use-after-free Read in ax25_rt_autobind
* Struck through repros no longer work on HEAD.