Subject: KASAN: use-after-free Read in tls_tx_records

From: syzbot <[email-masked]>
Date: Fri, 28 Sep 2018 06:09:03 -0700

Hello,

syzbot found the following crash on:

HEAD commit:    1042caa79e93 net-ipv4: remove 2 always zero parameters fro..
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13fff711400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6da69433212d7e87
dashboard link: https://syzkaller.appspot.com/bug?extid=c45f79b4e5e940da28a9
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email-masked]

EXT4-fs (sda1): resizing filesystem from 524032 to 6 blocks
EXT4-fs warning (device sda1): ext4_resize_fs:1930: can't shrink FS -  
resize aborted
EXT4-fs (sda1): resizing filesystem from 524032 to 6 blocks
EXT4-fs warning (device sda1): ext4_resize_fs:1930: can't shrink FS -  
resize aborted
==================================================================
BUG: KASAN: use-after-free in tls_tx_records+0x8b0/0x980  
net/tls/tls_sw.c:365
Read of size 8 at addr ffff8801ce46e040 by task syz-executor3/28575

CPU: 0 PID: 28575 Comm: syz-executor3 Not tainted 4.19.0-rc5+ #235
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+0x1c4/0x2b4 lib/dump_stack.c:113
  print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
  kasan_report_error mm/kasan/report.c:354 [inline]
  kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
  __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
  tls_tx_records+0x8b0/0x980 net/tls/tls_sw.c:365
  tls_sw_free_resources_tx+0x1ec/0xd20 net/tls/tls_sw.c:1552
  tls_sk_proto_close+0x605/0x750 net/tls/tls_main.c:278
  inet_release+0x104/0x1f0 net/ipv4/af_inet.c:428
  inet6_release+0x50/0x70 net/ipv6/af_inet6.c:458
  __sock_release+0xd7/0x250 net/socket.c:579
  sock_close+0x19/0x20 net/socket.c:1141
  __fput+0x385/0xa30 fs/file_table.c:278
  ____fput+0x15/0x20 fs/file_table.c:309
  task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
  tracehook_notify_resume include/linux/tracehook.h:193 [inline]
  exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
  prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
  syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
  do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457579
Code: 1d b4 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 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f2ccaa3bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000457579
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2ccaa3c6d4
R13: 00000000004ef912 R14: 00000000004cc460 R15: 00000000ffffffff

Allocated by task 28575:
  save_stack+0x43/0xd0 mm/kasan/kasan.c:448
  set_track mm/kasan/kasan.c:460 [inline]
  kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
  __do_kmalloc mm/slab.c:3718 [inline]
  __kmalloc+0x14e/0x760 mm/slab.c:3727
  kmalloc include/linux/slab.h:518 [inline]
  kzalloc include/linux/slab.h:707 [inline]
  get_rec+0x147/0x630 net/tls/tls_sw.c:653
  tls_sw_sendmsg+0x47e/0x17a0 net/tls/tls_sw.c:727
  inet_sendmsg+0x1a1/0x690 net/ipv4/af_inet.c:798
  sock_sendmsg_nosec net/socket.c:621 [inline]
  sock_sendmsg+0xd5/0x120 net/socket.c:631
  __sys_sendto+0x3d7/0x670 net/socket.c:1788
  __do_sys_sendto net/socket.c:1800 [inline]
  __se_sys_sendto net/socket.c:1796 [inline]
  __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1796
  do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 23411:
  save_stack+0x43/0xd0 mm/kasan/kasan.c:448
  set_track mm/kasan/kasan.c:460 [inline]
  __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
  kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
  __cache_free mm/slab.c:3498 [inline]
  kfree+0xcf/0x230 mm/slab.c:3813
  tls_encrypt_done+0x221/0x610 net/tls/tls_sw.c:417
  aead_request_complete include/crypto/internal/aead.h:75 [inline]
  pcrypt_aead_serial+0x7b/0xb0 crypto/pcrypt.c:123
  padata_serial_worker+0x4c6/0x760 kernel/padata.c:349
  process_one_work+0xc90/0x1b90 kernel/workqueue.c:2153
  worker_thread+0x17f/0x1390 kernel/workqueue.c:2296
  kthread+0x35a/0x420 kernel/kthread.c:246
  ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413

The buggy address belongs to the object at ffff8801ce46e040
  which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 0 bytes inside of
  2048-byte region [ffff8801ce46e040, ffff8801ce46e840)
The buggy address belongs to the page:
page:ffffea0007391b80 count:1 mapcount:0 mapping:ffff8801da800c40 index:0x0  
compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffffea00071b4f88 ffffea0007344f88 ffff8801da800c40
raw: 0000000000000000 ffff8801ce46e040 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff8801ce46df00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
  ffff8801ce46df80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff8801ce46e000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                            ^
  ffff8801ce46e080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff8801ce46e100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

---
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