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Date:   Mon, 26 Sep 2022 11:00:38 -0700
Message-ID: <000000000000212d3205e9984e12@google.com>
Subject: [syzbot] KASAN: use-after-free Write in sctp_auth_shkey_hold (2)
From:   syzbot <syzbot+a236dd8e9622ed8954a3@syzkaller.appspotmail.com>
To:     davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
        linux-kernel@vger.kernel.org, linux-sctp@vger.kernel.org,
        marcelo.leitner@gmail.com, netdev@vger.kernel.org,
        nhorman@tuxdriver.com, pabeni@redhat.com,
        syzkaller-bugs@googlegroups.com, vyasevich@gmail.com
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Precedence: bulk

Hello,

syzbot found the following issue on:

HEAD commit:    cb71b93c2dc3 Add linux-next specific files for 20220628
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=12e40342080000
kernel config:  https://syzkaller.appspot.com/x/.config?x=badbc1adb2d582eb
dashboard link: https://syzkaller.appspot.com/bug?extid=a236dd8e9622ed8954a3
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1689249a080000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1618ab1c080000

Bisection is inconclusive: the issue happens on the oldest tested release.

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1155cda4080000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=1355cda4080000
console output: https://syzkaller.appspot.com/x/log.txt?x=1555cda4080000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a236dd8e9622ed8954a3@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: use-after-free in atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:116 [inline]
BUG: KASAN: use-after-free in __refcount_add include/linux/refcount.h:193 [inline]
BUG: KASAN: use-after-free in __refcount_inc include/linux/refcount.h:250 [inline]
BUG: KASAN: use-after-free in refcount_inc include/linux/refcount.h:267 [inline]
BUG: KASAN: use-after-free in sctp_auth_shkey_hold+0x22/0xa0 net/sctp/auth.c:112
Write of size 4 at addr ffff88807cd4ad98 by task syz-executor284/3719

CPU: 0 PID: 3719 Comm: syz-executor284 Not tainted 5.19.0-rc4-next-20220628-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:317 [inline]
 print_report.cold+0x2ba/0x719 mm/kasan/report.c:433
 kasan_report+0xbe/0x1f0 mm/kasan/report.c:495
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
 atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:116 [inline]
 __refcount_add include/linux/refcount.h:193 [inline]
 __refcount_inc include/linux/refcount.h:250 [inline]
 refcount_inc include/linux/refcount.h:267 [inline]
 sctp_auth_shkey_hold+0x22/0xa0 net/sctp/auth.c:112
 sctp_set_owner_w net/sctp/socket.c:132 [inline]
 sctp_sendmsg_to_asoc+0xbd5/0x1a20 net/sctp/socket.c:1863
 sctp_sendmsg+0x1053/0x1d50 net/sctp/socket.c:2025
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:819
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:734
 __sys_sendto+0x21a/0x320 net/socket.c:2116
 __do_sys_sendto net/socket.c:2128 [inline]
 __se_sys_sendto net/socket.c:2124 [inline]
 __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2124
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f9b40d281d9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 a1 15 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9b40cb52d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f9b40db04b0 RCX: 00007f9b40d281d9
RDX: 0000000000000001 RSI: 0000000020000400 RDI: 0000000000000003
RBP: 00007f9b40d7d5dc R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9b40cb52f0
R13: 00007f9b40db04b8 R14: 0100000000000000 R15: 0000000000022000
 </TASK>

Allocated by task 3717:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:436 [inline]
 ____kasan_kmalloc mm/kasan/common.c:515 [inline]
 ____kasan_kmalloc mm/kasan/common.c:474 [inline]
 __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:524
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:733 [inline]
 sctp_auth_shkey_create+0x85/0x1f0 net/sctp/auth.c:84
 sctp_auth_asoc_copy_shkeys+0x1e8/0x350 net/sctp/auth.c:363
 sctp_association_init net/sctp/associola.c:257 [inline]
 sctp_association_new+0x189e/0x2330 net/sctp/associola.c:298
 sctp_connect_new_asoc+0x1ac/0x770 net/sctp/socket.c:1089
 sctp_sendmsg_new_asoc net/sctp/socket.c:1691 [inline]
 sctp_sendmsg+0x13d7/0x1d50 net/sctp/socket.c:1998
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:819
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:734
 __sys_sendto+0x21a/0x320 net/socket.c:2116
 __do_sys_sendto net/socket.c:2128 [inline]
 __se_sys_sendto net/socket.c:2124 [inline]
 __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2124
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

Freed by task 3720:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 kasan_set_track+0x21/0x30 mm/kasan/common.c:45
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
 ____kasan_slab_free mm/kasan/common.c:366 [inline]
 ____kasan_slab_free+0x166/0x1c0 mm/kasan/common.c:328
 kasan_slab_free include/linux/kasan.h:200 [inline]
 slab_free_hook mm/slub.c:1754 [inline]
 slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1780
 slab_free mm/slub.c:3534 [inline]
 kfree+0xe2/0x4d0 mm/slub.c:4562
 sctp_auth_shkey_destroy net/sctp/auth.c:101 [inline]
 sctp_auth_shkey_release+0x100/0x160 net/sctp/auth.c:107
 sctp_auth_set_key+0x443/0x960 net/sctp/auth.c:866
 sctp_setsockopt_auth_key net/sctp/socket.c:3640 [inline]
 sctp_setsockopt+0x4c33/0xa9a0 net/sctp/socket.c:4683
 __sys_setsockopt+0x2d6/0x690 net/socket.c:2251
 __do_sys_setsockopt net/socket.c:2262 [inline]
 __se_sys_setsockopt net/socket.c:2259 [inline]
 __x64_sys_setsockopt+0xba/0x150 net/socket.c:2259
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

The buggy address belongs to the object at ffff88807cd4ad80
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 24 bytes inside of
 32-byte region [ffff88807cd4ad80, ffff88807cd4ada0)

The buggy address belongs to the physical page:
page:ffffea0001f35280 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7cd4a
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 0000000000000000 dead000000000122 ffff888011841500
raw: 0000000000000000 0000000000400040 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 0x12820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY), pid 3653, tgid 3653 (kworker/1:6), ts 62971434672, free_ts 62952459810
 prep_new_page mm/page_alloc.c:2535 [inline]
 get_page_from_freelist+0x210d/0x3a30 mm/page_alloc.c:4282
 __alloc_pages+0x1c7/0x510 mm/page_alloc.c:5506
 alloc_pages+0x1aa/0x310 mm/mempolicy.c:2280
 alloc_slab_page mm/slub.c:1824 [inline]
 allocate_slab+0x27e/0x3d0 mm/slub.c:1969
 new_slab mm/slub.c:2029 [inline]
 ___slab_alloc+0x89d/0xef0 mm/slub.c:3031
 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3118
 slab_alloc_node mm/slub.c:3209 [inline]
 slab_alloc mm/slub.c:3251 [inline]
 kmem_cache_alloc_trace+0x323/0x3e0 mm/slub.c:3282
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:733 [inline]
 ref_tracker_alloc+0x14c/0x550 lib/ref_tracker.c:85
 __netdev_tracker_alloc include/linux/netdevice.h:3960 [inline]
 netdev_hold include/linux/netdevice.h:3989 [inline]
 dst_init+0xe0/0x520 net/core/dst.c:52
 dst_alloc+0x16b/0x1f0 net/core/dst.c:96
 ip6_dst_alloc+0x2e/0x90 net/ipv6/route.c:344
 icmp6_dst_alloc+0x6d/0x680 net/ipv6/route.c:3261
 ndisc_send_skb+0x10eb/0x1730 net/ipv6/ndisc.c:487
 ndisc_send_ns+0xa6/0x120 net/ipv6/ndisc.c:665
 addrconf_dad_work+0xbf9/0x12d0 net/ipv6/addrconf.c:4171
 process_one_work+0x991/0x1610 kernel/workqueue.c:2289
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1453 [inline]
 free_pcp_prepare+0x5e4/0xd20 mm/page_alloc.c:1503
 free_unref_page_prepare mm/page_alloc.c:3383 [inline]
 free_unref_page_list+0x16f/0xb90 mm/page_alloc.c:3525
 release_pages+0xbe8/0x1810 mm/swap.c:1017
 tlb_batch_pages_flush+0xa8/0x1a0 mm/mmu_gather.c:58
 tlb_flush_mmu_free mm/mmu_gather.c:255 [inline]
 tlb_flush_mmu mm/mmu_gather.c:262 [inline]
 tlb_finish_mmu+0x147/0x7e0 mm/mmu_gather.c:353
 exit_mmap+0x1fe/0x720 mm/mmap.c:3212
 __mmput+0x128/0x4c0 kernel/fork.c:1180
 mmput+0x5c/0x70 kernel/fork.c:1201
 exit_mm kernel/exit.c:510 [inline]
 do_exit+0xa09/0x29f0 kernel/exit.c:782
 do_group_exit+0xd2/0x2f0 kernel/exit.c:925
 __do_sys_exit_group kernel/exit.c:936 [inline]
 __se_sys_exit_group kernel/exit.c:934 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:934
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

Memory state around the buggy address:
 ffff88807cd4ac80: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807cd4ad00: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
>ffff88807cd4ad80: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
                            ^
 ffff88807cd4ae00: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807cd4ae80: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
==================================================================


---
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches