syzbot


KASAN: slab-out-of-bounds Write in sha512_final
Status: fixed on 2018/07/09 18:05
Reported-by: syzbot+@syzkaller.appspotmail.com
Fix commit: 3619dec5103d dh key: fix rounding up KDF output length
First crash: 1445d, last: 1428d

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 put_unaligned_be64 include/linux/unaligned/access_ok.h:65 [inline]
BUG: KASAN: slab-out-of-bounds in sha512_base_finish include/crypto/sha512_base.h:127 [inline]
BUG: KASAN: slab-out-of-bounds in sha512_final+0x34a/0x3e0 crypto/sha512_generic.c:153
Write of size 8 at addr ffff8801d41a79c0 by task syz-executor075/4514

CPU: 1 PID: 4514 Comm: syz-executor075 Not tainted 4.18.0-rc2+ #116
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+0x242/0x2fe mm/kasan/report.c:412
 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report.c:438
 put_unaligned_be64 include/linux/unaligned/access_ok.h:65 [inline]
 sha512_base_finish include/crypto/sha512_base.h:127 [inline]
 sha512_final+0x34a/0x3e0 crypto/sha512_generic.c:153
 crypto_shash_final+0x104/0x260 crypto/shash.c:152
 kdf_ctr security/keys/dh.c:186 [inline]
 keyctl_dh_compute_kdf security/keys/dh.c:217 [inline]
 __keyctl_dh_compute+0x1198/0x1be0 security/keys/dh.c:389
 keyctl_dh_compute+0xc5/0x11f security/keys/dh.c:425
 __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: 0033:0x43fff9
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 6b 45 00 00 c3 66 2e 0f 1f 84 00 00 00 00 
RSP: 002b:00007fff0bdcf328 EFLAGS: 00000217 ORIG_RAX: 00000000000000fa
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fff9
RDX: 0000000020a53ffb RSI: 0000000020000100 RDI: 0000000000000017
RBP: 00000000006ca018 R08: 0000000020000140 R09: 00000000004002c8
R10: 0000000000000018 R11: 0000000000000217 R12: 0000000000401920
R13: 00000000004019b0 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 4514:
 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_kdf security/keys/dh.c:211 [inline]
 __keyctl_dh_compute+0x1000/0x1be0 security/keys/dh.c:389
 keyctl_dh_compute+0xc5/0x11f security/keys/dh.c:425
 __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 1:
 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
 apply_wqattrs_cleanup+0x149/0x170 kernel/workqueue.c:3702
 apply_workqueue_attrs_locked+0x19a/0x250 kernel/workqueue.c:3835
 apply_workqueue_attrs+0x30/0x50 kernel/workqueue.c:3862
 alloc_and_link_pwqs kernel/workqueue.c:3985 [inline]
 __alloc_workqueue_key+0x74c/0x1190 kernel/workqueue.c:4091
 rpciod_start net/sunrpc/sched.c:1112 [inline]
 rpc_init_mempool+0x7c/0x188 net/sunrpc/sched.c:1160
 init_sunrpc+0xf/0xbb net/sunrpc/sunrpc_syms.c:87
 do_one_initcall+0x127/0x913 init/main.c:884
 do_initcall_level init/main.c:952 [inline]
 do_initcalls init/main.c:960 [inline]
 do_basic_setup init/main.c:978 [inline]
 kernel_init_freeable+0x49b/0x58e init/main.c:1135
 kernel_init+0x11/0x1b3 init/main.c:1061
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412

The buggy address belongs to the object at ffff8801d41a7980
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 0 bytes to the right of
 64-byte region [ffff8801d41a7980, ffff8801d41a79c0)
The buggy address belongs to the page:
page:ffffea00075069c0 count:1 mapcount:0 mapping:ffff8801da800340 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea00074ba408 ffffea0007599908 ffff8801da800340
raw: 0000000000000000 ffff8801d41a7000 0000000100000020 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d41a7880: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc
 ffff8801d41a7900: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff8801d41a7980: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
                                           ^
 ffff8801d41a7a00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8801d41a7a80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================

Crashes (21):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-root 2018/06/25 03:19 upstream 7daf201d7fe8 2064fc5c .config log report syz C
ci-upstream-kasan-gce 2018/06/24 23:38 upstream 7daf201d7fe8 2064fc5c .config log report syz C
ci-upstream-kasan-gce-386 2018/06/24 23:23 upstream 7daf201d7fe8 2064fc5c .config log report syz C
ci-upstream-kasan-gce-386 2018/06/09 17:21 upstream 7d3bf613e99a 866118af .config log report syz
ci-upstream-kasan-gce 2018/06/27 07:54 upstream 813835028e9a b0294c53 .config log report
ci-upstream-kasan-gce-root 2018/06/27 05:19 upstream 813835028e9a b0294c53 .config log report
ci-upstream-kasan-gce 2018/06/26 12:09 upstream 6f0d349d922b 2064fc5c .config log report
ci-upstream-kasan-gce 2018/06/26 06:57 upstream 6f0d349d922b 2064fc5c .config log report
ci-upstream-kasan-gce 2018/06/26 05:14 upstream 6f0d349d922b 2064fc5c .config log report
ci-upstream-kasan-gce 2018/06/25 04:48 upstream 7daf201d7fe8 2064fc5c .config log report
ci-upstream-kasan-gce 2018/06/23 23:50 upstream 5e2204832b20 2064fc5c .config log report
ci-upstream-kasan-gce 2018/06/11 11:55 upstream f0dc7f9c6dd9 ae8bdb50 .config log report
ci-upstream-kasan-gce-386 2018/06/27 02:51 upstream 813835028e9a b0294c53 .config log report
ci-upstream-kasan-gce-386 2018/06/26 23:57 upstream 813835028e9a b0294c53 .config log report
ci-upstream-kasan-gce-386 2018/06/25 12:05 upstream 6f0d349d922b 2064fc5c .config log report
ci-upstream-kasan-gce-386 2018/06/22 12:21 upstream 894b8c000ae6 095ef806 .config log report
ci-upstream-kasan-gce-386 2018/06/19 04:17 upstream ba4dbdedd3ed 45c54f75 .config log report
ci-upstream-kasan-gce-386 2018/06/18 23:08 upstream 9ffc59d57228 45c54f75 .config log report
ci-upstream-kasan-gce-386 2018/06/17 01:34 upstream 35773c93817c 27c5f59f .config log report
ci-upstream-kasan-gce-386 2018/06/14 17:43 upstream 2837461dbe6f 27c5f59f .config log report
ci-upstream-kasan-gce-386 2018/06/09 15:57 upstream 7d3bf613e99a 866118af .config log report