syzbot


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

Status: upstream: reported on 2025/08/28 18:56
Reported-by: syzbot+28994dee2bd7c56dd1e0@syzkaller.appspotmail.com
First crash: 1d06h, last: 11h41m
Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KMSAN: uninit-value in xfrm_state_find (4) net 19 2032 13m 100d 28/29 upstream: reported on 2025/05/21 19:14
upstream KMSAN: uninit-value in xfrm_state_find (2) net 17 19 507d 666d 0/29 auto-obsoleted due to no activity on 2024/07/18 11:50
android-54 KASAN: stack-out-of-bounds Read in xfrm_state_find 17 C 1 972d 972d 0/2 upstream: reported C repro on 2023/01/01 01:05
android-5-15 KASAN: stack-out-of-bounds Read in xfrm_state_find origin:upstream missing-backport 17 C error error 2 486d 972d 0/2 upstream: reported C repro on 2023/01/01 00:40
upstream KMSAN: uninit-value in xfrm_state_find (3) net 7 1 364d 364d 0/29 closed as invalid on 2024/10/09 09:35
upstream KASAN: slab-out-of-bounds Read in xfrm_state_find net 17 10 122d 276d 28/29 fixed on 2025/05/06 15:33
upstream KMSAN: uninit-value in xfrm_state_find net 17 C error done 215 833d 2632d 22/29 fixed on 2023/07/01 16:05
android-5-10 KASAN: stack-out-of-bounds Read in xfrm_state_find (2) 17 syz error error 1 972d 972d 0/2 auto-obsoleted due to no activity on 2023/05/14 02:28
android-5-10 KASAN: stack-out-of-bounds Read in xfrm_state_find 17 1 1391d 1391d 0/2 closed as invalid on 2022/02/03 13:56

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in __xfrm_state_lookup_all net/xfrm/xfrm_state.c:-1 [inline]
BUG: KASAN: slab-use-after-free in xfrm_state_find+0x2635/0x4510 net/xfrm/xfrm_state.c:1284
Read of size 1 at addr ffff88805f7d06f8 by task syz.3.289/6755

CPU: 0 PID: 6755 Comm: syz.3.289 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xac/0x220 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 __xfrm_state_lookup_all net/xfrm/xfrm_state.c:-1 [inline]
 xfrm_state_find+0x2635/0x4510 net/xfrm/xfrm_state.c:1284
 xfrm_tmpl_resolve_one net/xfrm/xfrm_policy.c:2502 [inline]
 xfrm_tmpl_resolve net/xfrm/xfrm_policy.c:2547 [inline]
 xfrm_resolve_and_create_bundle+0x727/0x2c20 net/xfrm/xfrm_policy.c:2841
 xfrm_lookup_with_ifid+0x261/0x19c0 net/xfrm/xfrm_policy.c:3175
 xfrm_lookup net/xfrm/xfrm_policy.c:3304 [inline]
 xfrm_lookup_route+0x3c/0x1b0 net/xfrm/xfrm_policy.c:3315
 ip_route_connect include/net/route.h:328 [inline]
 __ip4_datagram_connect+0x978/0x1230 net/ipv4/datagram.c:49
 __ip6_datagram_connect+0x9f1/0x1120 net/ipv6/datagram.c:195
 ip6_datagram_connect net/ipv6/datagram.c:278 [inline]
 ip6_datagram_connect_v6_only+0x63/0xa0 net/ipv6/datagram.c:290
 __sys_connect_file net/socket.c:2057 [inline]
 __sys_connect+0x397/0x420 net/socket.c:2074
 __do_sys_connect net/socket.c:2084 [inline]
 __se_sys_connect net/socket.c:2081 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2081
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f061798ebe9
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:00007f0618769038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f0617bb5fa0 RCX: 00007f061798ebe9
RDX: 000000000000001c RSI: 0000200000000000 RDI: 0000000000000004
RBP: 00007f0617a11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0617bb6038 R14: 00007f0617bb5fa0 R15: 00007ffc114d7eb8
 </TASK>

Allocated by task 6394:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:328
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
 slab_alloc_node mm/slub.c:3485 [inline]
 slab_alloc mm/slub.c:3493 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3500 [inline]
 kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3509
 kmem_cache_zalloc include/linux/slab.h:711 [inline]
 xfrm_state_alloc+0x22/0x2a0 net/xfrm/xfrm_state.c:661
 __find_acq_core+0x7d8/0x19d0 net/xfrm/xfrm_state.c:1598
 xfrm_find_acq+0x6a/0x90 net/xfrm/xfrm_state.c:2070
 xfrm_alloc_userspi+0x57a/0xa90 net/xfrm/xfrm_user.c:1613
 xfrm_user_rcv_msg+0x596/0x870 net/xfrm/xfrm_user.c:3169
 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545
 xfrm_netlink_rcv+0x79/0x90 net/xfrm/xfrm_user.c:3191
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x5bf/0x950 net/socket.c:2595
 ___sys_sendmsg+0x220/0x290 net/socket.c:2649
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2687 [inline]
 __se_sys_sendmsg+0x1a5/0x270 net/socket.c:2685
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff88805f7d0400
 which belongs to the cache xfrm_state of size 848
The buggy address is located 760 bytes inside of
 freed 848-byte region [ffff88805f7d0400, ffff88805f7d0750)

The buggy address belongs to the physical page:
page:ffffea00017df400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5f7d0
head:ffffea00017df400 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888140ed3a00 dead000000000122 0000000000000000
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x152820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 6304, tgid 6303 (syz.1.147), ts 111674470320, free_ts 111562150475
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554
 prep_new_page mm/page_alloc.c:1561 [inline]
 get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
 __alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
 alloc_slab_page+0x5d/0x170 mm/slub.c:1876
 allocate_slab mm/slub.c:2023 [inline]
 new_slab+0x87/0x2e0 mm/slub.c:2076
 ___slab_alloc+0xc6d/0x12f0 mm/slub.c:3230
 __slab_alloc mm/slub.c:3329 [inline]
 __slab_alloc_node mm/slub.c:3382 [inline]
 slab_alloc_node mm/slub.c:3475 [inline]
 slab_alloc mm/slub.c:3493 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3500 [inline]
 kmem_cache_alloc+0x1b7/0x2e0 mm/slub.c:3509
 kmem_cache_zalloc include/linux/slab.h:711 [inline]
 xfrm_state_alloc+0x22/0x2a0 net/xfrm/xfrm_state.c:661
 __find_acq_core+0x7d8/0x19d0 net/xfrm/xfrm_state.c:1598
 xfrm_find_acq+0x6a/0x90 net/xfrm/xfrm_state.c:2070
 xfrm_alloc_userspi+0x57a/0xa90 net/xfrm/xfrm_user.c:1613
 xfrm_user_rcv_msg+0x596/0x870 net/xfrm/xfrm_user.c:3169
 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545
 xfrm_netlink_rcv+0x79/0x90 net/xfrm/xfrm_user.c:3191
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1894
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1154 [inline]
 free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429
 free_large_kmalloc+0x101/0x1a0 mm/slab_common.c:984
 bpf_check+0x62c6/0xe970 kernel/bpf/verifier.c:20555
 bpf_prog_load+0x11cb/0x16d0 kernel/bpf/syscall.c:2744
 __sys_bpf+0x55a/0x800 kernel/bpf/syscall.c:5467
 __do_sys_bpf kernel/bpf/syscall.c:5571 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5569 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5569
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff88805f7d0580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805f7d0600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805f7d0680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff88805f7d0700: fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc
 ffff88805f7d0780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/29 14:08 linux-6.6.y cc1a1c5b404a 3e1beec6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in xfrm_state_find
2025/08/29 01:37 linux-6.6.y cc1a1c5b404a d401b9d7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in xfrm_state_find
2025/08/29 01:37 linux-6.6.y cc1a1c5b404a d401b9d7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in xfrm_state_find
2025/08/28 19:00 linux-6.6.y cc1a1c5b404a e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in xfrm_state_find
2025/08/28 18:56 linux-6.6.y cc1a1c5b404a e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in xfrm_state_find
* Struck through repros no longer work on HEAD.