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

[upstream] KASAN: slab-out-of-bounds Write in crypto_dh_encode_key
Status: fixed on 2018/08/28 17:48
Reported-by: syzbot+6d38d558c25b53b8f4ed@syzkaller.appspotmail.com
Fix commit: 35f7d522 crypto: dh - fix calculating encoded key size
First crash: 223d, last: 195d

Sample crash report:

random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
==================================================================
BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:345 [inline]
BUG: KASAN: slab-out-of-bounds in dh_pack_data crypto/dh_helper.c:21 [inline]
BUG: KASAN: slab-out-of-bounds in crypto_dh_encode_key+0x80e/0x830 crypto/dh_helper.c:60
Write of size 4 at addr ffff8801adbd6f10 by task syz-executor186/4466

CPU: 0 PID: 4466 Comm: syz-executor186 Not tainted 4.18.0-rc3-next-20180709+ #2
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+0x1c9/0x2b4 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x30d mm/kasan/report.c:412
 __asan_report_store_n_noabort+0x12/0x14 mm/kasan/report.c:449
 memcpy include/linux/string.h:345 [inline]
 dh_pack_data crypto/dh_helper.c:21 [inline]
 crypto_dh_encode_key+0x80e/0x830 crypto/dh_helper.c:60
 __keyctl_dh_compute+0x707/0x1c00 security/keys/dh.c:316
 keyctl_dh_compute+0xc5/0x11f security/keys/dh.c:427
 __do_sys_keyctl security/keys/keyctl.c:1741 [inline]
 __se_sys_keyctl security/keys/keyctl.c:1637 [inline]
 __x64_sys_keyctl+0x12a/0x3b0 security/keys/keyctl.c:1637
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4403b9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 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 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 
RSP: 002b:00007ffcf524af58 EFLAGS: 00000213 ORIG_RAX: 00000000000000fa
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004403b9
RDX: 0000000020000540 RSI: 00000000200006c0 RDI: 0000000000000017
RBP: 00000000006ca018 R08: 0000000020c61fc8 R09: 00000000004002c8
R10: 0000000000000005 R11: 0000000000000213 R12: 0000000000401c40
R13: 0000000000401cd0 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 4466:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc4/0xe0 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]
 __keyctl_dh_compute+0x6e1/0x1c00 security/keys/dh.c:311
 keyctl_dh_compute+0xc5/0x11f security/keys/dh.c:427
 __do_sys_keyctl security/keys/keyctl.c:1741 [inline]
 __se_sys_keyctl security/keys/keyctl.c:1637 [inline]
 __x64_sys_keyctl+0x12a/0x3b0 security/keys/keyctl.c:1637
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 2899:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kfree+0xd9/0x260 mm/slab.c:3813
 single_release+0x8f/0xb0 fs/seq_file.c:596
 __fput+0x35d/0x930 fs/file_table.c:215
 ____fput+0x15/0x20 fs/file_table.c:251
 task_work_run+0x1ec/0x2a0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:192 [inline]
 exit_to_usermode_loop+0x313/0x370 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 ffff8801adbd6f00
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 16 bytes inside of
 32-byte region [ffff8801adbd6f00, ffff8801adbd6f20)
The buggy address belongs to the page:
page:ffffea0006b6f580 count:1 mapcount:0 mapping:ffff8801da8001c0 index:0xffff8801adbd6fc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea00075c0288 ffffea00075c0388 ffff8801da8001c0
raw: ffff8801adbd6fc1 ffff8801adbd6000 000000010000003e 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801adbd6e00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801adbd6e80: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8801adbd6f00: 00 00 03 fc fc fc fc fc 01 fc fc fc fc fc fc fc
                         ^
 ffff8801adbd6f80: 01 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801adbd7000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
==================================================================

All crashes (1401):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci-upstream-linux-next-kasan-gce-root	2018/07/09 08:37	linux-next	d00d6d9a	f25e5770	.config	log	report	syz	C	davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/07/09 07:42	linux-next	d00d6d9a	f25e5770	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/06 10:02	linux-next	116b181b	1beb8136	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/06 09:25	linux-next	116b181b	1beb8136	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/06 08:12	linux-next	116b181b	1beb8136	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/06 07:09	linux-next	116b181b	1beb8136	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/06 05:39	linux-next	116b181b	1beb8136	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/06 04:09	linux-next	116b181b	1beb8136	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/06 02:11	linux-next	116b181b	1beb8136	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/06 01:06	linux-next	116b181b	1beb8136	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/05 23:45	linux-next	116b181b	1beb8136	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/05 22:23	linux-next	116b181b	1beb8136	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/05 20:49	linux-next	116b181b	1beb8136	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/05 19:37	linux-next	116b181b	1beb8136	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/05 17:43	linux-next	116b181b	1beb8136	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/05 16:05	linux-next	116b181b	1beb8136	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/05 14:18	linux-next	116b181b	1beb8136	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/05 12:12	linux-next	116b181b	1beb8136	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/05 09:14	linux-next	116b181b	3476a2df	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/05 08:11	linux-next	116b181b	3476a2df	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/05 06:42	linux-next	116b181b	3476a2df	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/05 03:02	linux-next	116b181b	3476a2df	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/05 02:29	linux-next	116b181b	3476a2df	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/05 00:43	linux-next	116b181b	3476a2df	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 22:54	linux-next	116b181b	3476a2df	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 21:09	linux-next	116b181b	3476a2df	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 19:12	linux-next	116b181b	3476a2df	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 17:21	linux-next	116b181b	3476a2df	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 16:14	linux-next	116b181b	3476a2df	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 14:50	linux-next	116b181b	3476a2df	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 13:44	linux-next	116b181b	df7f6947	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 12:43	linux-next	116b181b	df7f6947	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 12:21	linux-next	116b181b	df7f6947	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 10:44	linux-next	116b181b	df7f6947	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 09:41	linux-next	116b181b	df7f6947	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 07:05	linux-next	116b181b	df7f6947	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 06:03	linux-next	116b181b	df7f6947	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 03:49	linux-next	116b181b	df7f6947	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 02:29	linux-next	116b181b	df7f6947	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 02:25	linux-next	116b181b	df7f6947	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/04 01:19	linux-next	116b181b	df7f6947	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2018/08/03 23:11	linux-next	116b181b	df7f6947	.config	log	report			davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org