Message-ID: <f6443f4c-c3ab-478e-ba1d-aedecdcb353f@oracle.com>
Date: Wed, 4 Sep 2024 10:32:06 -0700
From: Shoaib Rao <rao.shoaib@...cle.com>
To: Eric Dumazet <edumazet@...gle.com>,
        syzbot <syzbot+8811381d455e3e9ec788@...kaller.appspotmail.com>
Cc: davem@...emloft.net, kuba@...nel.org, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org, pabeni@...hat.com,
        syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [net?] KASAN: slab-use-after-free Read in
 unix_stream_read_actor (2)


On 9/4/2024 8:32 AM, Eric Dumazet wrote:
> On Wed, Sep 4, 2024 at 5:13 PM syzbot
> <syzbot+8811381d455e3e9ec788@...kaller.appspotmail.com> wrote:
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit:    fbdaffe41adc Merge branch 'am-qt2025-phy-rust'
>> git tree:       net-next
>> console+strace: https://urldefense.com/v3/__https://syzkaller.appspot.com/x/log.txt?x=13d7c44d980000__;!!ACWV5N9M2RV99hQ!O_wYwGadsms5089A9E28Dxx6WaVGOgSJ31BkCSFGtWTEPW52si4mQ-gN_xDf6oRUivpWe5nrmCinyPp6_w$
>> kernel config:  https://urldefense.com/v3/__https://syzkaller.appspot.com/x/.config?x=996585887acdadb3__;!!ACWV5N9M2RV99hQ!O_wYwGadsms5089A9E28Dxx6WaVGOgSJ31BkCSFGtWTEPW52si4mQ-gN_xDf6oRUivpWe5nrmChXq35SIA$
>> dashboard link: https://urldefense.com/v3/__https://syzkaller.appspot.com/bug?extid=8811381d455e3e9ec788__;!!ACWV5N9M2RV99hQ!O_wYwGadsms5089A9E28Dxx6WaVGOgSJ31BkCSFGtWTEPW52si4mQ-gN_xDf6oRUivpWe5nrmCgeHsuB4Q$
>> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
>> syz repro:      https://urldefense.com/v3/__https://syzkaller.appspot.com/x/repro.syz?x=14b395db980000__;!!ACWV5N9M2RV99hQ!O_wYwGadsms5089A9E28Dxx6WaVGOgSJ31BkCSFGtWTEPW52si4mQ-gN_xDf6oRUivpWe5nrmChfSXV14A$
>> C reproducer:   https://urldefense.com/v3/__https://syzkaller.appspot.com/x/repro.c?x=16d3fc53980000__;!!ACWV5N9M2RV99hQ!O_wYwGadsms5089A9E28Dxx6WaVGOgSJ31BkCSFGtWTEPW52si4mQ-gN_xDf6oRUivpWe5nrmChGWZhDug$
>>
>> Downloadable assets:
>> disk image: https://urldefense.com/v3/__https://storage.googleapis.com/syzbot-assets/feaa1b13b490/disk-fbdaffe4.raw.xz__;!!ACWV5N9M2RV99hQ!O_wYwGadsms5089A9E28Dxx6WaVGOgSJ31BkCSFGtWTEPW52si4mQ-gN_xDf6oRUivpWe5nrmChjbj6XGw$
>> vmlinux: https://urldefense.com/v3/__https://storage.googleapis.com/syzbot-assets/8e5dccd0377a/vmlinux-fbdaffe4.xz__;!!ACWV5N9M2RV99hQ!O_wYwGadsms5089A9E28Dxx6WaVGOgSJ31BkCSFGtWTEPW52si4mQ-gN_xDf6oRUivpWe5nrmChlarTUfA$
>> kernel image: https://urldefense.com/v3/__https://storage.googleapis.com/syzbot-assets/75151f74f4c9/bzImage-fbdaffe4.xz__;!!ACWV5N9M2RV99hQ!O_wYwGadsms5089A9E28Dxx6WaVGOgSJ31BkCSFGtWTEPW52si4mQ-gN_xDf6oRUivpWe5nrmCgl9hRVww$
>>
>> Bisection is inconclusive: the first bad commit could be any of:
>>
>> 06ab21c3cb6e dt-bindings: net: mediatek,net: add top-level constraints
>> 70d16e13368c dt-bindings: net: renesas,etheravb: add top-level constraints
>>
>> bisection log:  https://urldefense.com/v3/__https://syzkaller.appspot.com/x/bisect.txt?x=11d42e63980000__;!!ACWV5N9M2RV99hQ!O_wYwGadsms5089A9E28Dxx6WaVGOgSJ31BkCSFGtWTEPW52si4mQ-gN_xDf6oRUivpWe5nrmCjDvB9Flg$
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+8811381d455e3e9ec788@...kaller.appspotmail.com
>>
>> ==================================================================
>> BUG: KASAN: slab-use-after-free in unix_stream_read_actor+0xa6/0xb0 net/unix/af_unix.c:2959
>> Read of size 4 at addr ffff8880326abcc4 by task syz-executor178/5235
>>
>> CPU: 0 UID: 0 PID: 5235 Comm: syz-executor178 Not tainted 6.11.0-rc5-syzkaller-00742-gfbdaffe41adc #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
>> Call Trace:
>>   <TASK>
>>   __dump_stack lib/dump_stack.c:93 [inline]
>>   dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
>>   print_address_description mm/kasan/report.c:377 [inline]
>>   print_report+0x169/0x550 mm/kasan/report.c:488
>>   kasan_report+0x143/0x180 mm/kasan/report.c:601
>>   unix_stream_read_actor+0xa6/0xb0 net/unix/af_unix.c:2959
>>   unix_stream_recv_urg+0x1df/0x320 net/unix/af_unix.c:2640
>>   unix_stream_read_generic+0x2456/0x2520 net/unix/af_unix.c:2778
>>   unix_stream_recvmsg+0x22b/0x2c0 net/unix/af_unix.c:2996
>>   sock_recvmsg_nosec net/socket.c:1046 [inline]
>>   sock_recvmsg+0x22f/0x280 net/socket.c:1068
>>   ____sys_recvmsg+0x1db/0x470 net/socket.c:2816
>>   ___sys_recvmsg net/socket.c:2858 [inline]
>>   __sys_recvmsg+0x2f0/0x3e0 net/socket.c:2888
>>   do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>>   do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>>   entry_SYSCALL_64_after_hwframe+0x77/0x7f
>> RIP: 0033:0x7f5360d6b4e9
>> Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 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 b8 ff ff ff f7 d8 64 89 01 48
>> RSP: 002b:00007fff29b3a458 EFLAGS: 00000246 ORIG_RAX: 000000000000002f
>> RAX: ffffffffffffffda RBX: 00007fff29b3a638 RCX: 00007f5360d6b4e9
>> RDX: 0000000000002001 RSI: 0000000020000640 RDI: 0000000000000003
>> RBP: 00007f5360dde610 R08: 0000000000000000 R09: 0000000000000000
>> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
>> R13: 00007fff29b3a628 R14: 0000000000000001 R15: 0000000000000001
>>   </TASK>
>>
>> Allocated by task 5235:
>>   kasan_save_stack mm/kasan/common.c:47 [inline]
>>   kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
>>   unpoison_slab_object mm/kasan/common.c:312 [inline]
>>   __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338
>>   kasan_slab_alloc include/linux/kasan.h:201 [inline]
>>   slab_post_alloc_hook mm/slub.c:3988 [inline]
>>   slab_alloc_node mm/slub.c:4037 [inline]
>>   kmem_cache_alloc_node_noprof+0x16b/0x320 mm/slub.c:4080
>>   __alloc_skb+0x1c3/0x440 net/core/skbuff.c:667
>>   alloc_skb include/linux/skbuff.h:1320 [inline]
>>   alloc_skb_with_frags+0xc3/0x770 net/core/skbuff.c:6528
>>   sock_alloc_send_pskb+0x91a/0xa60 net/core/sock.c:2815
>>   sock_alloc_send_skb include/net/sock.h:1778 [inline]
>>   queue_oob+0x108/0x680 net/unix/af_unix.c:2198
>>   unix_stream_sendmsg+0xd24/0xf80 net/unix/af_unix.c:2351
>>   sock_sendmsg_nosec net/socket.c:730 [inline]
>>   __sock_sendmsg+0x221/0x270 net/socket.c:745
>>   ____sys_sendmsg+0x525/0x7d0 net/socket.c:2597
>>   ___sys_sendmsg net/socket.c:2651 [inline]
>>   __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2680
>>   do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>>   do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>>   entry_SYSCALL_64_after_hwframe+0x77/0x7f
>>
>> Freed by task 5235:
>>   kasan_save_stack mm/kasan/common.c:47 [inline]
>>   kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
>>   kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
>>   poison_slab_object+0xe0/0x150 mm/kasan/common.c:240
>>   __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
>>   kasan_slab_free include/linux/kasan.h:184 [inline]
>>   slab_free_hook mm/slub.c:2252 [inline]
>>   slab_free mm/slub.c:4473 [inline]
>>   kmem_cache_free+0x145/0x350 mm/slub.c:4548
>>   unix_stream_read_generic+0x1ef6/0x2520 net/unix/af_unix.c:2917
>>   unix_stream_recvmsg+0x22b/0x2c0 net/unix/af_unix.c:2996
>>   sock_recvmsg_nosec net/socket.c:1046 [inline]
>>   sock_recvmsg+0x22f/0x280 net/socket.c:1068
>>   __sys_recvfrom+0x256/0x3e0 net/socket.c:2255
>>   __do_sys_recvfrom net/socket.c:2273 [inline]
>>   __se_sys_recvfrom net/socket.c:2269 [inline]
>>   __x64_sys_recvfrom+0xde/0x100 net/socket.c:2269
>>   do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>>   do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>>   entry_SYSCALL_64_after_hwframe+0x77/0x7f
>>
>> The buggy address belongs to the object at ffff8880326abc80
>>   which belongs to the cache skbuff_head_cache of size 240
>> The buggy address is located 68 bytes inside of
>>   freed 240-byte region [ffff8880326abc80, ffff8880326abd70)
>>
>> The buggy address belongs to the physical page:
>> page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x326ab
>> ksm flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
>> page_type: 0xfdffffff(slab)
>> raw: 00fff00000000000 ffff88801eaee780 ffffea0000b7dc80 dead000000000003
>> raw: 0000000000000000 00000000800c000c 00000001fdffffff 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 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 4686, tgid 4686 (udevadm), ts 32357469485, free_ts 28829011109
>>   set_page_owner include/linux/page_owner.h:32 [inline]
>>   post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1493
>>   prep_new_page mm/page_alloc.c:1501 [inline]
>>   get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3439
>>   __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4695
>>   __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
>>   alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
>>   alloc_slab_page+0x5f/0x120 mm/slub.c:2321
>>   allocate_slab+0x5a/0x2f0 mm/slub.c:2484
>>   new_slab mm/slub.c:2537 [inline]
>>   ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3723
>>   __slab_alloc+0x58/0xa0 mm/slub.c:3813
>>   __slab_alloc_node mm/slub.c:3866 [inline]
>>   slab_alloc_node mm/slub.c:4025 [inline]
>>   kmem_cache_alloc_node_noprof+0x1fe/0x320 mm/slub.c:4080
>>   __alloc_skb+0x1c3/0x440 net/core/skbuff.c:667
>>   alloc_skb include/linux/skbuff.h:1320 [inline]
>>   alloc_uevent_skb+0x74/0x230 lib/kobject_uevent.c:289
>>   uevent_net_broadcast_untagged lib/kobject_uevent.c:326 [inline]
>>   kobject_uevent_net_broadcast+0x2fd/0x580 lib/kobject_uevent.c:410
>>   kobject_uevent_env+0x57d/0x8e0 lib/kobject_uevent.c:608
>>   kobject_synth_uevent+0x4ef/0xae0 lib/kobject_uevent.c:207
>>   uevent_store+0x4b/0x70 drivers/base/bus.c:633
>>   kernfs_fop_write_iter+0x3a1/0x500 fs/kernfs/file.c:334
>>   new_sync_write fs/read_write.c:497 [inline]
>>   vfs_write+0xa72/0xc90 fs/read_write.c:590
>> page last free pid 1 tgid 1 stack trace:
>>   reset_page_owner include/linux/page_owner.h:25 [inline]
>>   free_pages_prepare mm/page_alloc.c:1094 [inline]
>>   free_unref_page+0xd22/0xea0 mm/page_alloc.c:2612
>>   kasan_depopulate_vmalloc_pte+0x74/0x90 mm/kasan/shadow.c:408
>>   apply_to_pte_range mm/memory.c:2797 [inline]
>>   apply_to_pmd_range mm/memory.c:2841 [inline]
>>   apply_to_pud_range mm/memory.c:2877 [inline]
>>   apply_to_p4d_range mm/memory.c:2913 [inline]
>>   __apply_to_page_range+0x8a8/0xe50 mm/memory.c:2947
>>   kasan_release_vmalloc+0x9a/0xb0 mm/kasan/shadow.c:525
>>   purge_vmap_node+0x3e3/0x770 mm/vmalloc.c:2208
>>   __purge_vmap_area_lazy+0x708/0xae0 mm/vmalloc.c:2290
>>   _vm_unmap_aliases+0x79d/0x840 mm/vmalloc.c:2885
>>   change_page_attr_set_clr+0x2fe/0xdb0 arch/x86/mm/pat/set_memory.c:1881
>>   change_page_attr_set arch/x86/mm/pat/set_memory.c:1922 [inline]
>>   set_memory_nx+0xf2/0x130 arch/x86/mm/pat/set_memory.c:2110
>>   free_init_pages arch/x86/mm/init.c:924 [inline]
>>   free_kernel_image_pages arch/x86/mm/init.c:943 [inline]
>>   free_initmem+0x79/0x110 arch/x86/mm/init.c:970
>>   kernel_init+0x31/0x2b0 init/main.c:1476
>>   ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
>>   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
>>
>> Memory state around the buggy address:
>>   ffff8880326abb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>   ffff8880326abc00: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc
>>> ffff8880326abc80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>                                             ^
>>   ffff8880326abd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
>>   ffff8880326abd80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
>> ==================================================================
>>
>>
>> ---
>> This report is generated by a bot. It may contain errors.
>> See https://urldefense.com/v3/__https://goo.gl/tpsmEJ__;!!ACWV5N9M2RV99hQ!O_wYwGadsms5089A9E28Dxx6WaVGOgSJ31BkCSFGtWTEPW52si4mQ-gN_xDf6oRUivpWe5nrmCj0yiM5oA$  for more information about syzbot.
>> syzbot engineers can be reached at syzkaller@...glegroups.com.
>>
>> syzbot will keep track of this issue. See:
>> https://urldefense.com/v3/__https://goo.gl/tpsmEJ*status__;Iw!!ACWV5N9M2RV99hQ!O_wYwGadsms5089A9E28Dxx6WaVGOgSJ31BkCSFGtWTEPW52si4mQ-gN_xDf6oRUivpWe5nrmCglGrElYg$  for how to communicate with syzbot.
>> For information about bisection process see: https://urldefense.com/v3/__https://goo.gl/tpsmEJ*bisection__;Iw!!ACWV5N9M2RV99hQ!O_wYwGadsms5089A9E28Dxx6WaVGOgSJ31BkCSFGtWTEPW52si4mQ-gN_xDf6oRUivpWe5nrmChS6eLfFw$
>>
>> If the report is already addressed, let syzbot know by replying with:
>> #syz fix: exact-commit-title
>>
>> If you want syzbot to run the reproducer, reply with:
>> #syz test: git://repo/address.git branch-or-commit-hash
>> If you attach or paste a git patch, syzbot will apply it before testing.
>>
>> If you want to overwrite report's subsystems, reply with:
>> #syz set subsystems: new-subsystem
>> (See the list of subsystem names on the web dashboard)
>>
>> If the report is a duplicate of another one, reply with:
>> #syz dup: exact-subject-of-another-report
>>
>> If you want to undo deduplication, reply with:
>> #syz undup
>
> Another af_unix OOB issue.
>
> Rao can you take a look ?
>
> Thanks.

Sure I will take a look.

Shoaib

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