ax25_connect(): syz.4.407 uses autobind, please contact [email protected]
==================================================================
BUG: KASAN: use-after-free in ax25_rt_autobind+0x2d8/0x5d4 net/ax25/ax25_route.c:424
Read of size 8 at addr ffff0000ef747608 by task syz.4.407/5382
CPU: 1 PID: 5382 Comm: syz.4.407 Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call trace:
dump_backtrace+0x0/0x43c arch/arm64/kernel/stacktrace.c:152
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
__dump_stack+0x30/0x40 lib/dump_stack.c:88
dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106
print_address_description+0x78/0x30c mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:434 [inline]
kasan_report+0xec/0x15c mm/kasan/report.c:451
__asan_report_load8_noabort+0x44/0x50 mm/kasan/report_generic.c:309
ax25_rt_autobind+0x2d8/0x5d4 net/ax25/ax25_route.c:424
ax25_connect+0x938/0x1120 net/ax25/af_ax25.c:1263
__sys_connect_file net/socket.c:1923 [inline]
__sys_connect+0x264/0x28c 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+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Allocated by task 4455:
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 mm/kasan/common.c:513 [inline]
__kasan_kmalloc+0xb0/0xf0 mm/kasan/common.c:522
kasan_kmalloc include/linux/kasan.h:264 [inline]
kmem_cache_alloc_trace+0x274/0x3fc mm/slub.c:3247
kmalloc include/linux/slab.h:604 [inline]
kzalloc include/linux/slab.h:735 [inline]
ax25_dev_device_up+0x5c/0x540 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
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]
__dev_notify_flags+0x250/0x46c net/core/dev.c:-1
dev_change_flags+0xc8/0x154 net/core/dev.c:8929
dev_ifsioc+0x504/0xef4 net/core/dev_ioctl.c:324
dev_ioctl+0x4d0/0xc94 net/core/dev_ioctl.c:587
sock_do_ioctl+0x18c/0x240 net/socket.c:1154
sock_ioctl+0x5c8/0x87c 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+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Freed by task 5323:
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+0x128/0x1e8 mm/slub.c:1731
slab_free mm/slub.c:3499 [inline]
kfree+0x170/0x40c mm/slub.c:4559
ax25_dev_put include/net/ax25.h:302 [inline]
ax25_release+0x564/0x814 net/ax25/af_ax25.c:1062
__sock_release net/socket.c:649 [inline]
sock_close+0xb4/0x1f8 net/socket.c:1336
__fput+0x1c0/0x7f8 fs/file_table.c:311
____fput+0x20/0x30 fs/file_table.c:339
task_work_run+0x12c/0x1e0 kernel/task_work.c:188
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
do_notify_resume+0x24b4/0x3128 arch/arm64/kernel/signal.c:949
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+0xf0/0x1e0 arch/arm64/kernel/entry-common.c:609
el0t_64_sync_handler+0xcc/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 ffff0000ef747600
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 8 bytes inside of
256-byte region [ffff0000ef747600, ffff0000ef747700)
The buggy address belongs to the page:
page:000000009feebec3 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff0000ef746200 pfn:0x12f746
head:000000009feebec3 order:1 compound_mapcount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 fffffc0003425a08 fffffc00033cc908 ffff0000c0002480
raw: ffff0000ef746200 0000000000100006 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff0000ef747500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff0000ef747580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff0000ef747600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff0000ef747680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff0000ef747700: 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 006f80754000030a
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
[006f80754000030a] address between user and kernel address ranges
Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 5382 Comm: syz.4.407 Tainted: G B 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : ax25_rt_autobind+0x2e4/0x5d4 net/ax25/ax25_route.c:424
lr : ax25_rt_autobind+0x2d8/0x5d4 net/ax25/ax25_route.c:424
sp : ffff80001f647a00
x29: ffff80001f647a00 x28: 1fffe0001bd9bf00 x27: ffff80001f647c45
x26: dfff800000000000 x25: 0000000000000000 x24: ffff0000efc84700
x23: 1fffe0001d1ce205 x22: 0000000000000000 x21: c38003aa00001853
x20: ffff80001f647c22 x19: ffff0000e8e71000 x18: 0000000000000003
x17: 0000000000000002 x16: ffff8000082d4c48 x15: 00000000ffffffff
x14: 0000000000ff0100 x13: 0000000000000001 x12: 0000000000080000
x11: 000000000001d928 x10: ffff800023e8a000 x9 : 0000000000000000
x8 : 187000754000030a x7 : 0000000000000000 x6 : 0000000000000001
x5 : ffff80001f647218 x4 : 0000000000000000 x3 : ffff800008184638
x2 : 0000000000000001 x1 : 0000000000000001 x0 : 0000000000000001
Call trace:
ax25_rt_autobind+0x2e4/0x5d4 net/ax25/ax25_route.c:424
ax25_connect+0x938/0x1120 net/ax25/af_ax25.c:1263
__sys_connect_file net/socket.c:1923 [inline]
__sys_connect+0x264/0x28c 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+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Code: 961021e4 f94002a8 910e2115 d343fea8 (387a6908)
---[ end trace 94695ef08df72cc4 ]---
----------------
Code disassembly (best guess):
0: 961021e4 bl 0xfffffffff8408790
4: f94002a8 ldr x8, [x21]
8: 910e2115 add x21, x8, #0x388
c: d343fea8 lsr x8, x21, #3
* 10: 387a6908 ldrb w8, [x8, x26] <-- trapping instruction