KASAN: use-after-free Read in generic_gcmaes_encrypt

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 739d0def85ca Merge branch 'hv_netvsc-Support-LRO-RSC-in-th..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1146ffae400000
kernel config: https://syzkaller.appspot.com/x/.config?x=e79b9299baeb2298
dashboard link: https://syzkaller.appspot.com/bug?extid=6d3612ba5e254e387153
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16200b9e400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=102311c6400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+6d3612...@syzkaller.appspotmail.com

random: sshd: uninitialized urandom read (32 bytes read)
==================================================================
BUG: KASAN: use-after-free in memcpy include/linux/string.h:345 [inline]
BUG: KASAN: use-after-free in generic_gcmaes_encrypt+0xc6/0x186
arch/x86/crypto/aesni-intel_glue.c:1291
Read of size 12 at addr ffff8801d7ad0900 by task kworker/0:1/14

CPU: 0 PID: 14 Comm: kworker/0:1 Not tainted 4.19.0-rc4+ #228
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+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
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:345 [inline]
generic_gcmaes_encrypt+0xc6/0x186 arch/x86/crypto/aesni-intel_glue.c:1291
crypto_aead_encrypt include/crypto/aead.h:335 [inline]
gcmaes_wrapper_encrypt+0x162/0x200 arch/x86/crypto/aesni-intel_glue.c:1127
crypto_aead_encrypt include/crypto/aead.h:335 [inline]
pcrypt_aead_enc+0xcb/0x190 crypto/pcrypt.c:143
padata_parallel_worker+0x49d/0x760 kernel/padata.c:86
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

Allocated by task 5474:
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:513 [inline]
tls_set_sw_offload+0xcc4/0x14b0 net/tls/tls_sw.c:1741
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:3038
__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 5472:
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_sk_proto_close+0x5fd/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: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

The buggy address belongs to the object at ffff8801d7ad0900
which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
32-byte region [ffff8801d7ad0900, ffff8801d7ad0920)
The buggy address belongs to the page:
page:ffffea00075eb400 count:1 mapcount:0 mapping:ffff8801da8001c0
index:0xffff8801d7ad0fc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea00075eb948 ffffea00075ff688 ffff8801da8001c0
raw: ffff8801d7ad0fc1 ffff8801d7ad0000 000000010000003f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8801d7ad0800: fb fb fb fb fc fc fc fc 00 00 fc fc fc fc fc fc
ffff8801d7ad0880: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
> ffff8801d7ad0900: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
^
ffff8801d7ad0980: fb fb fb fb fc fc fc fc 00 00 fc fc fc fc fc fc
ffff8801d7ad0a00: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
==================================================================


---
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[Ard Biesheuvel]

(+ Stefan)

[Steffen Klassert]

I'd say tls_sk_proto_close does not handle asynchronous crypto properly.
The pcrypt template is used here, so all crypto requests are processed
asynchronously. tls_sk_proto_close frees the needed recources before
the remaining crypto requests are finalized.

[syzbot]

syzbot has bisected this bug to:

commit a42055e8d2c30d4decfc13ce943d09c7b9dad221
Author: Vakul Garg <vakul...@nxp.com>
Date: Fri Sep 21 04:16:13 2018 +0000

net/tls: Add support for async encryption of records for performance

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=15e6797d200000
start commit: 5694cecd Merge tag 'arm64-upstream' of git://git.kernel.or..
git tree: upstream
final crash: https://syzkaller.appspot.com/x/report.txt?x=17e6797d200000
console output: https://syzkaller.appspot.com/x/log.txt?x=13e6797d200000
kernel config: https://syzkaller.appspot.com/x/.config?x=91a256823ef17263
dashboard link: https://syzkaller.appspot.com/bug?extid=6d3612ba5e254e387153
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=110db3c7400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=113fa5ed400000

Reported-by: syzbot+6d3612...@syzkaller.appspotmail.com
Fixes: a42055e8d2c3 ("net/tls: Add support for async encryption of records
for performance")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

[Eric Biggers]

On Thu, Mar 28, 2019 at 10:08:00AM -0700, syzbot wrote:
> syzbot has bisected this bug to:
>
> commit a42055e8d2c30d4decfc13ce943d09c7b9dad221
> Author: Vakul Garg <vakul...@nxp.com>
> Date: Fri Sep 21 04:16:13 2018 +0000
>
> net/tls: Add support for async encryption of records for performance
>

Last occurred in Jan 2019 and there have been lots of fixes to the above commit
since then.

#syz invalid