syzbot


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

Status: moderation: reported on 2024/06/11 09:05
Subsystems: bluetooth
[Documentation on labels]
Reported-by: syzbot+ea6dfacb2e01dc86e4c9@syzkaller.appspotmail.com
First crash: 7d15h, last: 7d15h

Sample crash report:
BUG: KASAN: slab-use-after-free in skb_free_head+0x1ae/0x1d0 net/core/skbuff.c:1074
Read of size 8 at addr ffff88801bd860d0 by task syz-executor.0/5233

CPU: 3 PID: 5233 Comm: syz-executor.0 Not tainted 6.10.0-rc3-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:488
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 skb_free_head+0x1ae/0x1d0 net/core/skbuff.c:1074
 skb_release_data+0x75c/0x980 net/core/skbuff.c:1108
 skb_release_all net/core/skbuff.c:1173 [inline]
 __kfree_skb net/core/skbuff.c:1187 [inline]
 kfree_skb_reason+0x12b/0x210 net/core/skbuff.c:1223
 kfree_skb include/linux/skbuff.h:1257 [inline]
 __hci_req_sync+0x61d/0x980 net/bluetooth/hci_request.c:184
 hci_req_sync+0x97/0xd0 net/bluetooth/hci_request.c:206
 hci_dev_cmd+0x634/0x960 net/bluetooth/hci_core.c:787
 hci_sock_ioctl+0x4f3/0x880 net/bluetooth/hci_sock.c:1150
 sock_do_ioctl+0x116/0x280 net/socket.c:1222
 sock_ioctl+0x22e/0x6c0 net/socket.c:1341
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:893
 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: 0033:0x7f3d1007cc4b
Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
RSP: 002b:00007ffe0ae9cee0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f3d1007cc4b
RDX: 00007ffe0ae9cf58 RSI: 00000000400448dd RDI: 0000000000000003
RBP: 000055556dc86430 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3d101ac9d8 R15: 000000000000000c
 </TASK>

Allocated by task 5239:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:312 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:338
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3941 [inline]
 slab_alloc_node mm/slub.c:4001 [inline]
 kmem_cache_alloc_noprof+0x121/0x2f0 mm/slub.c:4008
 skb_clone+0x190/0x3f0 net/core/skbuff.c:2052
 hci_send_cmd_sync net/bluetooth/hci_core.c:4123 [inline]
 hci_cmd_work+0x66a/0x710 net/bluetooth/hci_core.c:4143
 process_one_work+0x9fb/0x1b60 kernel/workqueue.c:3231
 process_scheduled_works kernel/workqueue.c:3312 [inline]
 worker_thread+0x6c8/0xf70 kernel/workqueue.c:3393
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Freed by task 5245:
 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:579
 poison_slab_object+0xf7/0x160 mm/kasan/common.c:240
 __kasan_slab_free+0x32/0x50 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2196 [inline]
 slab_free mm/slub.c:4437 [inline]
 kmem_cache_free+0x12f/0x3a0 mm/slub.c:4512
 kfree_skbmem+0x10e/0x200 net/core/skbuff.c:1131
 __kfree_skb net/core/skbuff.c:1188 [inline]
 kfree_skb_reason+0x138/0x210 net/core/skbuff.c:1223
 kfree_skb include/linux/skbuff.h:1257 [inline]
 hci_req_sync_complete+0x16c/0x270 net/bluetooth/hci_request.c:109
 hci_event_packet+0x963/0x1170 net/bluetooth/hci_event.c:7479
 hci_rx_work+0x2c4/0x1610 net/bluetooth/hci_core.c:4074
 process_one_work+0x9fb/0x1b60 kernel/workqueue.c:3231
 process_scheduled_works kernel/workqueue.c:3312 [inline]
 worker_thread+0x6c8/0xf70 kernel/workqueue.c:3393
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

The buggy address belongs to the object at ffff88801bd86000
 which belongs to the cache skbuff_head_cache of size 240
The buggy address is located 208 bytes inside of
 freed 240-byte region [ffff88801bd86000, ffff88801bd860f0)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1bd86
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 ffff888018ed8780 ffffea0000ac9800 dead000000000003
raw: 0000000000000000 0000000000190019 00000001ffffefff 0000000000000000
head: 00fff00000000040 ffff888018ed8780 ffffea0000ac9800 dead000000000003
head: 0000000000000000 0000000000190019 00000001ffffefff 0000000000000000
head: 00fff00000000001 ffffea00006f6181 ffffffffffffffff 0000000000000000
head: 0000000000000002 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 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 4909, tgid 4909 (dhcpcd), ts 37254810706, free_ts 37097762752
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1468
 prep_new_page mm/page_alloc.c:1476 [inline]
 get_page_from_freelist+0x136a/0x2e50 mm/page_alloc.c:3420
 __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4678
 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
 alloc_slab_page+0x56/0x110 mm/slub.c:2265
 allocate_slab mm/slub.c:2428 [inline]
 new_slab+0x84/0x260 mm/slub.c:2481
 ___slab_alloc+0xdac/0x1870 mm/slub.c:3667
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3757
 __slab_alloc_node mm/slub.c:3810 [inline]
 slab_alloc_node mm/slub.c:3989 [inline]
 kmem_cache_alloc_node_noprof+0xed/0x310 mm/slub.c:4044
 __alloc_skb+0x2b1/0x380 net/core/skbuff.c:656
 alloc_skb include/linux/skbuff.h:1308 [inline]
 nlmsg_new include/net/netlink.h:1015 [inline]
 inet6_rt_notify+0xf0/0x2b0 net/ipv6/route.c:6180
 fib6_add_rt2node net/ipv6/ip6_fib.c:1266 [inline]
 fib6_add+0x2503/0x4ba0 net/ipv6/ip6_fib.c:1495
 __ip6_ins_rt net/ipv6/route.c:1314 [inline]
 ip6_route_add+0x8d/0x190 net/ipv6/route.c:3857
 addrconf_prefix_route+0x2fe/0x510 net/ipv6/addrconf.c:2485
 inet6_addr_add+0x609/0xbe0 net/ipv6/addrconf.c:3062
 inet6_rtm_newaddr+0x11e7/0x1ab0 net/ipv6/addrconf.c:5047
 rtnetlink_rcv_msg+0x3c7/0xea0 net/core/rtnetlink.c:6635
page last free pid 5048 tgid 5048 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1088 [inline]
 free_unref_page+0x64a/0xe40 mm/page_alloc.c:2583
 __put_partials+0x14c/0x170 mm/slub.c:2995
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4e/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:322
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3941 [inline]
 slab_alloc_node mm/slub.c:4001 [inline]
 kmem_cache_alloc_noprof+0x121/0x2f0 mm/slub.c:4008
 getname_flags.part.0+0x50/0x4f0 fs/namei.c:139
 getname_flags include/linux/audit.h:322 [inline]
 getname+0x8f/0xe0 fs/namei.c:218
 do_sys_openat2+0x104/0x1e0 fs/open.c:1399
 do_sys_open fs/open.c:1420 [inline]
 __do_sys_openat fs/open.c:1436 [inline]
 __se_sys_openat fs/open.c:1431 [inline]
 __x64_sys_openat+0x175/0x210 fs/open.c:1431
 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:
 ffff88801bd85f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88801bd86000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801bd86080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
                                                 ^
 ffff88801bd86100: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
 ffff88801bd86180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/10 22:18 upstream 83a7eefedc9b c2e07261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-use-after-free Read in skb_free_head
* Struck through repros no longer work on HEAD.