syzbot

 sign-in | mailing list | source | docs
🐞 Open [1636]
≡ Subsystems
🐞 Fixed [6115]
🐞 Invalid [15321]
⬇ Missing Backports [170]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
Total Repo Heatmap Subsystems Heatmap
💬 Send us feedback

KASAN: slab-out-of-bounds Write in __build_skb_around

Status: fixed on 2023/02/24 13:50
Subsystems: bpf net
[Documentation on labels]
Reported-by: syzbot+fda18eaa8c12534ccb3b@syzkaller.appspotmail.com
Fix commit: ce098da1497c skbuff: Introduce slab_build_skb()
First crash: 856d, last: 837d
Cause bisection: failed (error log, bisect log)
  
▶ ▼ Discussions (6)
Title Replies (including bot) Last reply
[PATCH net-next v3] skbuff: Introduce slab_build_skb() 5 (5) 2022/12/10 04:00
[PATCH net-next v2] skbuff: Introduce slab_build_skb() 2 (2) 2022/12/08 02:34
[PATCH] skbuff: Reallocate to ksize() in __build_skb_around() 6 (6) 2022/12/07 10:30
[PATCH bpf-next] bpf, test_run: fix alignment problem in bpf_test_init() 5 (5) 2022/12/07 06:45
Re: [syzbot] KASAN: slab-out-of-bounds Write in __build_skb_around 2 (2) 2022/12/06 18:31
[syzbot] KASAN: slab-out-of-bounds Write in __build_skb_around 0 (1) 2022/11/28 13:42
▶ ▼ Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: user-memory-access Write in __build_skb_around net 2 1203d 1203d 0/28 closed as invalid on 2022/01/10 10:36
upstream BUG: unable to handle kernel NULL pointer dereference in __build_skb_around net bpf C done 29 739d 745d 22/28 fixed on 2023/06/08 14:41

Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in __build_skb_around+0x235/0x340 net/core/skbuff.c:294
Write of size 32 at addr ffff88801ff53ac0 by task syz-executor746/5071

CPU: 0 PID: 5071 Comm: syz-executor746 Not tainted 6.1.0-rc8-next-20221207-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:306 [inline]
 print_report+0x15e/0x45d mm/kasan/report.c:417
 kasan_report+0xbf/0x1f0 mm/kasan/report.c:517
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x141/0x190 mm/kasan/generic.c:189
 memset+0x24/0x50 mm/kasan/shadow.c:44
 __build_skb_around+0x235/0x340 net/core/skbuff.c:294
 __build_skb+0x4f/0x60 net/core/skbuff.c:328
 build_skb+0x22/0x280 net/core/skbuff.c:340
 bpf_prog_test_run_skb+0x343/0x1e10 net/bpf/test_run.c:1131
 bpf_prog_test_run kernel/bpf/syscall.c:3644 [inline]
 __sys_bpf+0x1599/0x4ff0 kernel/bpf/syscall.c:4997
 __do_sys_bpf kernel/bpf/syscall.c:5083 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5081 [inline]
 __x64_sys_bpf+0x79/0xc0 kernel/bpf/syscall.c:5081
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f04aa189d29
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffeb94e6878 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f04aa189d29
RDX: 000000000000002c RSI: 0000000020000080 RDI: 000000000000000a
RBP: 00007f04aa14ded0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f04aa14df60
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Allocated by task 5071:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:371 [inline]
 ____kasan_kmalloc mm/kasan/common.c:330 [inline]
 __kasan_kmalloc+0xa5/0xb0 mm/kasan/common.c:380
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slab_common.c:968 [inline]
 __kmalloc+0x5a/0xd0 mm/slab_common.c:981
 kmalloc include/linux/slab.h:584 [inline]
 kzalloc include/linux/slab.h:720 [inline]
 bpf_test_init.isra.0+0xa5/0x150 net/bpf/test_run.c:778
 bpf_prog_test_run_skb+0x22e/0x1e10 net/bpf/test_run.c:1097
 bpf_prog_test_run kernel/bpf/syscall.c:3644 [inline]
 __sys_bpf+0x1599/0x4ff0 kernel/bpf/syscall.c:4997
 __do_sys_bpf kernel/bpf/syscall.c:5083 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5081 [inline]
 __x64_sys_bpf+0x79/0xc0 kernel/bpf/syscall.c:5081
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff88801ff53800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 704 bytes inside of
 1024-byte region [ffff88801ff53800, ffff88801ff53c00)

The buggy address belongs to the physical page:
page:ffffea00007fd400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1ff50
head:ffffea00007fd400 order:3 compound_mapcount:0 subpages_mapcount:0 compound_pincount:0
ksm flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffff888012441dc0 ffffea0001d3a600 0000000000000003
raw: 0000000000000000 0000000080100010 00000001ffffffff 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 4773, tgid 4773 (dhcpcd-run-hook), ts 36021800931, free_ts 35994303327
 prep_new_page mm/page_alloc.c:2531 [inline]
 get_page_from_freelist+0x119c/0x2ce0 mm/page_alloc.c:4283
 __alloc_pages+0x1cb/0x5b0 mm/page_alloc.c:5549
 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2285
 alloc_slab_page mm/slub.c:1851 [inline]
 allocate_slab+0x25f/0x350 mm/slub.c:1998
 new_slab mm/slub.c:2051 [inline]
 ___slab_alloc+0xa91/0x1400 mm/slub.c:3193
 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3292
 __slab_alloc_node mm/slub.c:3345 [inline]
 slab_alloc_node mm/slub.c:3442 [inline]
 __kmem_cache_alloc_node+0x1a4/0x430 mm/slub.c:3491
 __do_kmalloc_node mm/slab_common.c:967 [inline]
 __kmalloc+0x4a/0xd0 mm/slab_common.c:981
 kmalloc include/linux/slab.h:584 [inline]
 load_elf_phdrs+0x103/0x210 fs/binfmt_elf.c:481
 load_elf_binary+0x1db/0x52c0 fs/binfmt_elf.c:855
 search_binary_handler fs/exec.c:1735 [inline]
 exec_binprm fs/exec.c:1777 [inline]
 bprm_execve fs/exec.c:1851 [inline]
 bprm_execve+0x7ef/0x19f0 fs/exec.c:1808
 do_execveat_common+0x724/0x890 fs/exec.c:1956
 do_execve fs/exec.c:2030 [inline]
 __do_sys_execve fs/exec.c:2106 [inline]
 __se_sys_execve fs/exec.c:2101 [inline]
 __x64_sys_execve+0x93/0xc0 fs/exec.c:2101
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1446 [inline]
 free_pcp_prepare+0x65c/0xc00 mm/page_alloc.c:1496
 free_unref_page_prepare mm/page_alloc.c:3369 [inline]
 free_unref_page+0x1d/0x490 mm/page_alloc.c:3464
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x192/0x220 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x66/0x90 mm/kasan/common.c:302
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slab.h:761 [inline]
 slab_alloc_node mm/slub.c:3452 [inline]
 slab_alloc mm/slub.c:3460 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3467 [inline]
 kmem_cache_alloc+0x1e4/0x430 mm/slub.c:3476
 getname_flags.part.0+0x50/0x4f0 fs/namei.c:139
 getname_flags include/linux/audit.h:320 [inline]
 getname+0x92/0xd0 fs/namei.c:218
 do_sys_openat2+0xf5/0x4c0 fs/open.c:1304
 do_sys_open fs/open.c:1326 [inline]
 __do_sys_openat fs/open.c:1342 [inline]
 __se_sys_openat fs/open.c:1337 [inline]
 __x64_sys_openat+0x143/0x1f0 fs/open.c:1337
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffff88801ff53980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88801ff53a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88801ff53a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                           ^
 ffff88801ff53b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88801ff53b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (2536):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/12/10 23:26 linux-next 591cd61541b9 67be1ae7 .config strace log report syz C ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/04 23:24 linux-next 9e46a7996732 e080de16 .config strace log report syz C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/11/25 03:23 linux-next c35bd4e42885 62e26685 .config strace log report syz C ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/13 04:11 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/13 03:10 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/13 01:17 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/13 00:25 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 23:23 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 21:52 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 20:33 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 19:32 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 18:33 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 17:20 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 15:50 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 14:39 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 13:18 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 13:10 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 12:05 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 09:49 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 08:39 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 08:34 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 07:33 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 05:47 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 04:27 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 03:06 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/12 01:22 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 23:48 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 22:44 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 21:16 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 19:58 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 18:41 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 18:27 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 17:04 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 15:42 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 14:22 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 13:14 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 13:14 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 12:09 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 08:49 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 07:44 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 06:41 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 06:23 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 05:06 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 03:48 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 02:17 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/11 00:21 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/12/10 22:57 linux-next 591cd61541b9 67be1ae7 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
2022/11/24 13:34 linux-next c35bd4e42885 12c66417 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Write in __build_skb_around
* Struck through repros no longer work on HEAD.