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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: dce0f886 Linux 4.19.132
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17010a3b100000
kernel config: https://syzkaller.appspot.com/x/.config?x=ea24367973479f36
dashboard link: https://syzkaller.appspot.com/bug?extid=8f55a4bc6151ae52c449
compiler: gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8f55a4...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in tls_fill_prepend include/net/tls.h:373 [inline]
BUG: KASAN: slab-out-of-bounds in tls_push_record+0x104c/0x1370 net/tls/tls_sw.c:220
Write of size 1 at addr ffff8880539c8000 by task syz-executor.2/19664

CPU: 0 PID: 19664 Comm: syz-executor.2 Not tainted 4.19.132-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2fe lib/dump_stack.c:118
print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
kasan_report_error.cold+0x8a/0x1c7 mm/kasan/report.c:354
kasan_report mm/kasan/report.c:412 [inline]
__asan_report_store1_noabort+0x88/0x90 mm/kasan/report.c:435
tls_fill_prepend include/net/tls.h:373 [inline]
tls_push_record+0x104c/0x1370 net/tls/tls_sw.c:220
tls_push_pending_closed_record net/tls/tls_main.c:203 [inline]
tls_push_pending_closed_record net/tls/tls_main.c:196 [inline]
tls_complete_pending_work include/net/tls.h:303 [inline]
tls_sk_proto_close+0x907/0xc20 net/tls/tls_main.c:270
inet_release+0xd7/0x1e0 net/ipv4/af_inet.c:427
inet6_release+0x4c/0x70 net/ipv6/af_inet6.c:472
__sock_release+0xcd/0x2a0 net/socket.c:579
sock_close+0x15/0x20 net/socket.c:1140
__fput+0x2ce/0x890 fs/file_table.c:278
task_work_run+0x148/0x1c0 kernel/task_work.c:113
get_signal+0x1b64/0x1f70 kernel/signal.c:2399
do_signal+0x8f/0x1670 arch/x86/kernel/signal.c:821
exit_to_usermode_loop+0x204/0x2a0 arch/x86/entry/common.c:163
prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45cba9
Code: 8d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 5b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f353d556c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: 0000000000004000 RBX: 0000000000504760 RCX: 000000000045cba9
RDX: 00000000e0ffffff RSI: 00000000200005c0 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 00000000000000d8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005
R13: 0000000000000a99 R14: 00000000004cd6c7 R15: 00007f353d5576d4

Allocated by task 3703:
kmem_cache_alloc+0x122/0x370 mm/slab.c:3559
getname_flags+0xce/0x590 fs/namei.c:140
user_path_at_empty+0x2a/0x50 fs/namei.c:2609
user_path_at include/linux/namei.h:57 [inline]
vfs_statx+0x113/0x210 fs/stat.c:185
vfs_lstat include/linux/fs.h:3134 [inline]
__do_sys_newlstat fs/stat.c:350 [inline]
__se_sys_newlstat+0x96/0x120 fs/stat.c:344
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 3703:
__cache_free mm/slab.c:3503 [inline]
kmem_cache_free+0x7f/0x260 mm/slab.c:3765
putname+0xe1/0x120 fs/namei.c:261
filename_lookup+0x3d0/0x5a0 fs/namei.c:2358
user_path_at include/linux/namei.h:57 [inline]
vfs_statx+0x113/0x210 fs/stat.c:185
vfs_lstat include/linux/fs.h:3134 [inline]
__do_sys_newlstat fs/stat.c:350 [inline]
__se_sys_newlstat+0x96/0x120 fs/stat.c:344
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880539c8240
which belongs to the cache names_cache of size 4096
The buggy address is located 576 bytes to the left of
4096-byte region [ffff8880539c8240, ffff8880539c9240)
The buggy address belongs to the page:
page:ffffea00014e7200 count:1 mapcount:0 mapping:ffff8880aa00ab40 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffffea000143ab88 ffffea00014e7288 ffff8880aa00ab40
raw: 0000000000000000 ffff8880539c8240 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8880539c7f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880539c7f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880539c8000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff8880539c8080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880539c8100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.