KASAN: use-after-free Read in crypto_gcm_init_common

From: syzbot <syzbot+e736399a2c4054612307@syzkaller.appspotmail.com>
To: davem@davemloft.net, herbert@gondor.apana.org.au,
	linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
	syzkaller-bugs@googlegroups.com
Subject: KASAN: use-after-free Read in crypto_gcm_init_common
Date: Tue, 06 Nov 2018 17:38:04 -0800	[thread overview]
Message-ID: <00000000000060e0ae057a092be8@google.com> (raw)

Hello,

syzbot found the following crash on:

HEAD commit:    4710e78940d8 Merge tag 'nfs-for-4.20-2' of git://git.linux..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17a68093400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9384ecb1c973baed
dashboard link: https://syzkaller.appspot.com/bug?extid=e736399a2c4054612307
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17902f5b400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=111377e5400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+e736399a2c4054612307@syzkaller.appspotmail.com

startpar (5496) used greatest stack depth: 15744 bytes left
==================================================================
BUG: KASAN: use-after-free in memcpy include/linux/string.h:352 [inline]
BUG: KASAN: use-after-free in crypto_gcm_init_common+0xe2/0x710  
crypto/gcm.c:181
Read of size 12 at addr ffff8801d7b91b00 by task kworker/1:2/3205

CPU: 1 PID: 3205 Comm: kworker/1:2 Not tainted 4.19.0+ #320
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: pencrypt padata_parallel_worker
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x244/0x39d lib/dump_stack.c:113
  print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
  kasan_report_error mm/kasan/report.c:354 [inline]
  kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
  check_memory_region_inline mm/kasan/kasan.c:260 [inline]
  check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
  memcpy+0x23/0x50 mm/kasan/kasan.c:302
  memcpy include/linux/string.h:352 [inline]
  crypto_gcm_init_common+0xe2/0x710 crypto/gcm.c:181
  crypto_gcm_encrypt+0xe2/0x6b0 crypto/gcm.c:479
  crypto_aead_encrypt include/crypto/aead.h:364 [inline]
  pcrypt_aead_enc+0xd6/0x340 crypto/pcrypt.c:143
  padata_parallel_worker+0x49d/0x760 kernel/padata.c:86
  process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153
  worker_thread+0x17f/0x1390 kernel/workqueue.c:2296
  kthread+0x35a/0x440 kernel/kthread.c:246
  ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

Allocated by task 5668:
  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
  kmem_cache_alloc_trace+0x152/0x750 mm/slab.c:3620
  kmalloc include/linux/slab.h:546 [inline]
  tls_set_sw_offload+0xcb3/0x1390 net/tls/tls_sw.c:1945
  do_tls_setsockopt_conf net/tls/tls_main.c:467 [inline]
  do_tls_setsockopt net/tls/tls_main.c:514 [inline]
  tls_setsockopt+0x689/0x770 net/tls/tls_main.c:533
  sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2978
  __sys_setsockopt+0x1ba/0x3c0 net/socket.c:1902
  __do_sys_setsockopt net/socket.c:1913 [inline]
  __se_sys_setsockopt net/socket.c:1910 [inline]
  __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1910
  do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 5668:
  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:3817
  tls_sk_proto_close+0x5fa/0x750 net/tls/tls_main.c:277
  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:188 [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

The buggy address belongs to the object at ffff8801d7b91b00
  which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
  32-byte region [ffff8801d7b91b00, ffff8801d7b91b20)
The buggy address belongs to the page:
page:ffffea00075ee440 count:1 mapcount:0 mapping:ffff8801da8001c0  
index:0xffff8801d7b91fc1
flags: 0x2fffc0000000200(slab)
raw: 02fffc0000000200 ffffea00075effc8 ffff8801da801248 ffff8801da8001c0
raw: ffff8801d7b91fc1 ffff8801d7b91000 000000010000003f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff8801d7b91a00: fb fb fb fb fc fc fc fc 00 00 fc fc fc fc fc fc
  ffff8801d7b91a80: 00 00 fc fc fc fc fc fc fb fb fb fb fc fc fc fc
> ffff8801d7b91b00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
                    ^
  ffff8801d7b91b80: fb fb fb fb fc fc fc fc 00 00 fc fc fc fc fc fc
  ffff8801d7b91c00: 00 00 00 00 fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================

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