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KASAN: use-after-free Read in unix_stream_read_actor

Status: upstream: reported C repro on 2023/11/11 01:48
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+0d6bc5d3e48bd509f184@syzkaller.appspotmail.com
First crash: 173d, last: 99d
Cause bisection: introduced by (bisect log) :
commit 876c14ad014d0e39c57cbfde53e13d17cdb6d645
Author: Rao Shoaib <rao.shoaib@oracle.com>
Date: Wed Aug 11 22:06:52 2021 +0000

  af_unix: fix holding spinlock in oob handling

Crash: KASAN: use-after-free Read in unix_stream_read_actor (log)
Repro: C syz .config
  
Fix bisection: fixed by (bisect log) :
commit d179189eec426fe4801e4b91efa1889faed12700
Author: Eric Dumazet <edumazet@google.com>
Date: Mon Nov 13 13:49:38 2023 +0000

  af_unix: fix use-after-free in unix_stream_read_actor()

  
▶ ▼ Bug presence (5)
Date Name Commit Repro Result
2023/12/26 android14-6.1 (ToT) 401a2769d990 C [report] KASAN: use-after-free Read in __skb_datagram_iter
2023/11/11 lts (merge base) 52a953d0934b C [report] KASAN: use-after-free Read in __skb_datagram_iter
2024/02/09 lts (merge base) ba6f5fb46511 C Didn't crash
2023/11/11 upstream (ToT) 3ca112b71f35 C [report] KASAN: slab-use-after-free Read in unix_stream_read_actor
2023/12/26 upstream (ToT) fbafc3e621c3 C Didn't crash
▶ ▼ Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 KASAN: use-after-free Read in unix_stream_read_actor origin:lts-only C done 1 171d 173d 3/3 fixed on 2023/12/13 18:20
linux-6.1 KASAN: use-after-free Read in unix_stream_read_actor origin:lts-only C done 1 169d 173d 3/3 fixed on 2023/12/18 16:47
android-5-15 KASAN: use-after-free Read in unix_stream_read_actor origin:upstream C 1 173d 173d 0/2 auto-obsoleted due to no activity on 2024/02/19 03:43
upstream KASAN: slab-use-after-free Read in unix_stream_read_actor net C error 6 157d 173d 25/26 fixed on 2024/01/20 21:18
▶ ▼ Last patch testing requests (3)
Created Duration User Patch Repo Result
2024/02/07 09:47 26m retest repro android14-6.1 OK log
2023/11/25 02:09 8m retest repro android14-6.1 report log
2023/11/25 01:51 11m retest repro android14-6.1 report log
▶ ▼ Fix bisection attempts (3)
Created Duration User Patch Repo Result
2024/03/02 03:59 3h15m bisect fix android14-6.1 job log (1)
2024/01/24 08:51 53m bisect fix android14-6.1 job log (0) log
2023/12/25 05:00 54m bisect fix android14-6.1 job log (0) log

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in unix_stream_read_actor+0xa3/0xb0 net/unix/af_unix.c:2920
Read of size 4 at addr ffff888109da2a44 by task syz-executor366/445

CPU: 1 PID: 445 Comm: syz-executor366 Not tainted 6.1.43-syzkaller-00006-g48c6c901fe0e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x151/0x1b7 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0x158/0x4e0 mm/kasan/report.c:427
 kasan_report+0x13c/0x170 mm/kasan/report.c:531
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:350
 unix_stream_read_actor+0xa3/0xb0 net/unix/af_unix.c:2920
 unix_stream_recv_urg+0x1b4/0x300 net/unix/af_unix.c:2647
 unix_stream_read_generic+0x2140/0x2220 net/unix/af_unix.c:2726
 unix_stream_recvmsg+0x222/0x2b0 net/unix/af_unix.c:2957
 ____sys_recvmsg+0x285/0x530
 ___sys_recvmsg net/socket.c:2743 [inline]
 __sys_recvmsg+0x2e9/0x3d0 net/socket.c:2773
 __do_sys_recvmsg net/socket.c:2783 [inline]
 __se_sys_recvmsg net/socket.c:2780 [inline]
 __x64_sys_recvmsg+0x7f/0x90 net/socket.c:2780
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f5e75189989
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 1b 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5e75100228 EFLAGS: 00000246 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 0000000000000023 RCX: 00007f5e75189989
RDX: 0000000040010083 RSI: 0000000020000140 RDI: 0000000000000004
RBP: 00007f5e7520c408 R08: 00007f5e751006c0 R09: 00007f5e751006c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5e7520c400
R13: 00007f5e7520c40c R14: 00007ffe5b635d80 R15: 00007ffe5b635e68
 </TASK>

Allocated by task 444:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:333
 kasan_slab_alloc include/linux/kasan.h:202 [inline]
 slab_post_alloc_hook+0x53/0x2c0 mm/slab.h:768
 slab_alloc_node mm/slub.c:3418 [inline]
 kmem_cache_alloc_node+0x18a/0x2d0 mm/slub.c:3463
 __alloc_skb+0xcc/0x2e0 net/core/skbuff.c:497
 alloc_skb include/linux/skbuff.h:1275 [inline]
 alloc_skb_with_frags+0xa6/0x680 net/core/skbuff.c:6148
 sock_alloc_send_pskb+0x915/0xa50 net/core/sock.c:2732
 sock_alloc_send_skb include/net/sock.h:1908 [inline]
 queue_oob+0x102/0x8e0 net/unix/af_unix.c:2114
 unix_stream_sendmsg+0xe10/0x1070 net/unix/af_unix.c:2251
 sock_sendmsg_nosec net/socket.c:716 [inline]
 sock_sendmsg net/socket.c:736 [inline]
 ____sys_sendmsg+0x5dc/0x9d0 net/socket.c:2482
 ___sys_sendmsg net/socket.c:2536 [inline]
 __sys_sendmsg+0x2a9/0x390 net/socket.c:2565
 __do_sys_sendmsg net/socket.c:2574 [inline]
 __se_sys_sendmsg net/socket.c:2572 [inline]
 __x64_sys_sendmsg+0x7f/0x90 net/socket.c:2572
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 444:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516
 ____kasan_slab_free+0x131/0x180 mm/kasan/common.c:241
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:249
 kasan_slab_free include/linux/kasan.h:178 [inline]
 slab_free_hook mm/slub.c:1744 [inline]
 slab_free_freelist_hook mm/slub.c:1770 [inline]
 slab_free mm/slub.c:3681 [inline]
 kmem_cache_free+0x291/0x510 mm/slub.c:3703
 kfree_skbmem+0x104/0x170
 __kfree_skb net/core/skbuff.c:869 [inline]
 consume_skb+0xb4/0x250 net/core/skbuff.c:1033
 queue_oob+0x52c/0x8e0 net/unix/af_unix.c:2145
 unix_stream_sendmsg+0xe10/0x1070 net/unix/af_unix.c:2251
 sock_sendmsg_nosec net/socket.c:716 [inline]
 sock_sendmsg net/socket.c:736 [inline]
 ____sys_sendmsg+0x5dc/0x9d0 net/socket.c:2482
 ___sys_sendmsg net/socket.c:2536 [inline]
 __sys_sendmsg+0x2a9/0x390 net/socket.c:2565
 __do_sys_sendmsg net/socket.c:2574 [inline]
 __se_sys_sendmsg net/socket.c:2572 [inline]
 __x64_sys_sendmsg+0x7f/0x90 net/socket.c:2572
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff888109da2a00
 which belongs to the cache skbuff_head_cache of size 256
The buggy address is located 68 bytes inside of
 256-byte region [ffff888109da2a00, ffff888109da2b00)

The buggy address belongs to the physical page:
page:ffffea0004276880 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x109da2
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 0000000000000000 dead000000000122 ffff888100b91800
raw: 0000000000000000 00000000000c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 444, tgid 442 (syz-executor366), ts 38100870369, free_ts 37664742630
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x213/0x220 mm/page_alloc.c:2586
 prep_new_page+0x1b/0x110 mm/page_alloc.c:2593
 get_page_from_freelist+0x2878/0x2910 mm/page_alloc.c:4410
 __alloc_pages+0x3a1/0x780 mm/page_alloc.c:5698
 allocate_slab mm/slub.c:1959 [inline]
 new_slab+0xce/0x4c0 mm/slub.c:2012
 ___slab_alloc+0x6f9/0xb80 mm/slub.c:3200
 __slab_alloc+0x5d/0xa0 mm/slub.c:3299
 slab_alloc_node mm/slub.c:3384 [inline]
 kmem_cache_alloc_node+0x1c9/0x2d0 mm/slub.c:3463
 __alloc_skb+0xcc/0x2e0 net/core/skbuff.c:497
 alloc_skb include/linux/skbuff.h:1275 [inline]
 alloc_skb_with_frags+0xa6/0x680 net/core/skbuff.c:6148
 sock_alloc_send_pskb+0x915/0xa50 net/core/sock.c:2732
 sock_alloc_send_skb include/net/sock.h:1908 [inline]
 queue_oob+0x102/0x8e0 net/unix/af_unix.c:2114
 unix_stream_sendmsg+0xe10/0x1070 net/unix/af_unix.c:2251
 sock_sendmsg_nosec net/socket.c:716 [inline]
 sock_sendmsg net/socket.c:736 [inline]
 ____sys_sendmsg+0x5dc/0x9d0 net/socket.c:2482
 ___sys_sendmsg net/socket.c:2536 [inline]
 __sys_sendmsg+0x2a9/0x390 net/socket.c:2565
 __do_sys_sendmsg net/socket.c:2574 [inline]
 __se_sys_sendmsg net/socket.c:2572 [inline]
 __x64_sys_sendmsg+0x7f/0x90 net/socket.c:2572
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1494 [inline]
 free_pcp_prepare mm/page_alloc.c:1568 [inline]
 free_unref_page_prepare+0x83d/0x850 mm/page_alloc.c:3500
 free_unref_page_list+0xf6/0x6c0 mm/page_alloc.c:3649
 release_pages+0xf7f/0xfe0 mm/swap.c:1055
 free_pages_and_swap_cache+0x8a/0xa0 mm/swap_state.c:314
 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
 tlb_flush_mmu mm/mmu_gather.c:261 [inline]
 tlb_finish_mmu+0x1e0/0x3f0 mm/mmu_gather.c:361
 exit_mmap+0x3e5/0x8a0 mm/mmap.c:3329
 __mmput+0x95/0x310 kernel/fork.c:1272
 mmput+0x56/0x170 kernel/fork.c:1295
 exit_mm kernel/exit.c:566 [inline]
 do_exit+0xb29/0x2b80 kernel/exit.c:862
 do_group_exit+0x21a/0x2d0 kernel/exit.c:1025
 get_signal+0x169d/0x1820 kernel/signal.c:2879
 arch_do_signal_or_restart+0xb0/0x16f0 arch/x86/kernel/signal.c:869
 exit_to_user_mode_loop+0x6b/0xa0 kernel/entry/common.c:168
 exit_to_user_mode_prepare+0x5a/0xa0 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
 syscall_exit_to_user_mode+0x26/0x130 kernel/entry/common.c:297
 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86

Memory state around the buggy address:
 ffff888109da2900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888109da2980: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
>ffff888109da2a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888109da2a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888109da2b00: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/11/11 01:46 android14-6.1 48c6c901fe0e d80eec66 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Read in unix_stream_read_actor
2023/11/11 01:50 android14-6.1 48c6c901fe0e d80eec66 .config console log report syz [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf KASAN: use-after-free Read in unix_stream_read_actor
* Struck through repros no longer work on HEAD.