syzbot


KASAN: slab-use-after-free Read in full_proxy_read

Status: upstream: reported on 2025/01/17 16:52
Subsystems: bluetooth
[Documentation on labels]
Reported-by: syzbot+72d4e2d4ed673547627a@syzkaller.appspotmail.com
First crash: 37d, last: 27d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bluetooth?] KASAN: slab-use-after-free Read in full_proxy_read 0 (1) 2025/01/17 16:52

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in force_wakeup_read+0x136/0x150 drivers/bluetooth/hci_vhci.c:170
Read of size 1 at addr ffff888034868a31 by task syz.1.2387/16322

CPU: 1 UID: 0 PID: 16322 Comm: syz.1.2387 Tainted: G     U             6.13.0-syzkaller-04541-gdf60eac9efe8 #0
Tainted: [U]=USER
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:489
 kasan_report+0xd9/0x110 mm/kasan/report.c:602
 force_wakeup_read+0x136/0x150 drivers/bluetooth/hci_vhci.c:170
 full_proxy_read+0xfd/0x1b0 fs/debugfs/file.c:364
 vfs_read+0x1df/0xbe0 fs/read_write.c:563
 ksys_read+0x12b/0x250 fs/read_write.c:708
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0feb38cd29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0fec237038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f0feb5a5fa0 RCX: 00007f0feb38cd29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000009
RBP: 00007f0feb40e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f0feb5a5fa0 R15: 00007fff65090ca8
 </TASK>

Allocated by task 5829:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:901 [inline]
 kzalloc_noprof include/linux/slab.h:1037 [inline]
 vhci_open+0x4c/0x430 drivers/bluetooth/hci_vhci.c:634
 misc_open+0x35a/0x420 drivers/char/misc.c:165
 chrdev_open+0x237/0x6a0 fs/char_dev.c:414
 do_dentry_open+0xf59/0x1ea0 fs/open.c:938
 vfs_open+0x82/0x3f0 fs/open.c:1068
 do_open fs/namei.c:3828 [inline]
 path_openat+0x1e81/0x2d70 fs/namei.c:3987
 do_filp_open+0x20c/0x470 fs/namei.c:4014
 do_sys_openat2+0x17a/0x1e0 fs/open.c:1395
 do_sys_open fs/open.c:1410 [inline]
 __do_sys_openat fs/open.c:1426 [inline]
 __se_sys_openat fs/open.c:1421 [inline]
 __x64_sys_openat+0x175/0x210 fs/open.c:1421
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 14313:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:582
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2353 [inline]
 slab_free mm/slub.c:4613 [inline]
 kfree+0x14f/0x4b0 mm/slub.c:4761
 vhci_release+0xbb/0xf0 drivers/bluetooth/hci_vhci.c:670
 __fput+0x3f8/0xb60 fs/file_table.c:450
 task_work_run+0x14e/0x250 kernel/task_work.c:239
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0xad8/0x2d70 kernel/exit.c:938
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1087
 get_signal+0x2576/0x2610 kernel/signal.c:3036
 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888034868800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 561 bytes inside of
 freed 1024-byte region [ffff888034868800, ffff888034868c00)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34868
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801b041dc0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000001f5000000 0000000000000000
head: 00fff00000000040 ffff88801b041dc0 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000001f5000000 0000000000000000
head: 00fff00000000003 ffffea0000d21a01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 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 5500, tgid 5500 (dhcpcd), ts 41407726365, free_ts 41372471440
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1558
 prep_new_page mm/page_alloc.c:1566 [inline]
 get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3476
 __alloc_pages_noprof+0x221/0x2470 mm/page_alloc.c:4753
 alloc_pages_mpol_noprof+0x2c8/0x620 mm/mempolicy.c:2269
 alloc_slab_page mm/slub.c:2423 [inline]
 allocate_slab mm/slub.c:2589 [inline]
 new_slab+0x2c9/0x410 mm/slub.c:2642
 ___slab_alloc+0xbcd/0x1590 mm/slub.c:3830
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3920
 __slab_alloc_node mm/slub.c:3995 [inline]
 slab_alloc_node mm/slub.c:4156 [inline]
 __do_kmalloc_node mm/slub.c:4297 [inline]
 __kmalloc_node_track_caller_noprof+0x2ee/0x520 mm/slub.c:4317
 kmemdup_noprof+0x29/0x60 mm/util.c:135
 bpf_prog_store_orig_filter+0xff/0x1d0 net/core/filter.c:1155
 bpf_prog_create_from_user+0x1c3/0x2d0 net/core/filter.c:1439
 seccomp_prepare_filter kernel/seccomp.c:693 [inline]
 seccomp_prepare_user_filter kernel/seccomp.c:730 [inline]
 seccomp_set_mode_filter kernel/seccomp.c:1953 [inline]
 do_seccomp+0x7b6/0x2640 kernel/seccomp.c:2073
 prctl_set_seccomp+0x4b/0x70 kernel/seccomp.c:2126
 __do_sys_prctl+0x3a1/0x21b0 kernel/sys.c:2549
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5500 tgid 5500 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_unref_page+0x661/0x1080 mm/page_alloc.c:2659
 __put_partials+0x14c/0x170 mm/slub.c:3157
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4119 [inline]
 slab_alloc_node mm/slub.c:4168 [inline]
 kmem_cache_alloc_noprof+0x1c8/0x3b0 mm/slub.c:4175
 getname_flags.part.0+0x4c/0x550 fs/namei.c:139
 getname_flags include/linux/audit.h:322 [inline]
 getname+0x8d/0xe0 fs/namei.c:223
 getname_maybe_null include/linux/fs.h:2812 [inline]
 vfs_fstatat+0xdf/0xf0 fs/stat.c:361
 __do_sys_newfstatat+0x98/0x120 fs/stat.c:530
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888034868900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888034868980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888034868a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff888034868a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888034868b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (11):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/23 07:17 upstream df60eac9efe8 9d4f14f8 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-use-after-free Read in full_proxy_read
2025/01/20 23:14 upstream ffd294d346d1 6e87cfa2 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-use-after-free Read in full_proxy_read
2025/01/20 22:34 upstream ffd294d346d1 6e87cfa2 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-use-after-free Read in full_proxy_read
2025/01/19 03:34 upstream fda5e3f28400 f2cb035c .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-use-after-free Read in full_proxy_read
2025/01/18 22:38 upstream 595523945be0 f2cb035c .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-use-after-free Read in full_proxy_read
2025/01/18 17:44 upstream 595523945be0 f2cb035c .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-use-after-free Read in full_proxy_read
2025/01/15 20:39 upstream 619f0b6fad52 968edaf4 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-use-after-free Read in full_proxy_read
2025/01/14 15:44 upstream c45323b7560e 0dce2409 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-use-after-free Read in full_proxy_read
2025/01/14 01:19 upstream c45323b7560e b1f1cd88 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-use-after-free Read in full_proxy_read
2025/01/13 20:07 upstream 5bc55a333a2f 249ceea9 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-use-after-free Read in full_proxy_read
2025/01/13 16:41 upstream 5bc55a333a2f 249ceea9 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-use-after-free Read in full_proxy_read
* Struck through repros no longer work on HEAD.