syzbot


KASAN: slab-out-of-bounds Write in sha1_final

Status: fixed on 2018/07/09 18:05
Subsystems: crypto
[Documentation on labels]
Reported-by: syzbot+db8b846f704a6c3c9bcc@syzkaller.appspotmail.com
Fix commit: 3619dec5103d dh key: fix rounding up KDF output length
First crash: 2145d, last: 2125d

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_be32 include/linux/unaligned/access_ok.h:60 [inline]
BUG: KASAN: slab-out-of-bounds in sha1_base_finish include/crypto/sha1_base.h:102 [inline]
BUG: KASAN: slab-out-of-bounds in sha1_final+0x283/0x2e0 crypto/sha1_generic.c:58
Write of size 4 at addr ffff8801d8c1df58 by task syz-executor217/4518

CPU: 1 PID: 4518 Comm: syz-executor217 Not tainted 4.17.0+ #90
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+0x1b9/0x294 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_store4_noabort+0x17/0x20 mm/kasan/report.c:437
 put_unaligned_be32 include/linux/unaligned/access_ok.h:60 [inline]
 sha1_base_finish include/crypto/sha1_base.h:102 [inline]
 sha1_final+0x283/0x2e0 crypto/sha1_generic.c:58
 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+0x1184/0x1bc0 security/keys/dh.c:389
 keyctl_dh_compute+0xb9/0x100 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+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x43ffa9
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:00007ffff52e0ea8 EFLAGS: 00000217 ORIG_RAX: 00000000000000fa
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043ffa9
RDX: 0000000020000280 RSI: 0000000020000100 RDI: 0000000000000017
RBP: 00000000006ca018 R08: 0000000020000240 R09: 00000000004002c8
R10: 0000000000000005 R11: 0000000000000217 R12: 00000000004018d0
R13: 0000000000401960 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 4518:
 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+0xfe9/0x1bc0 security/keys/dh.c:389
 keyctl_dh_compute+0xb9/0x100 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+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 2868:
 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:609
 __fput+0x353/0x890 fs/file_table.c:209
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0x1e4/0x290 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:192 [inline]
 exit_to_usermode_loop+0x2bd/0x310 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
 do_syscall_64+0x6ac/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8801d8c1df40
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 24 bytes inside of
 32-byte region [ffff8801d8c1df40, ffff8801d8c1df60)
The buggy address belongs to the page:
page:ffffea0007630740 count:1 mapcount:0 mapping:ffff8801da8001c0 index:0xffff8801d8c1dfc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea000764c2c8 ffffea0007648508 ffff8801da8001c0
raw: ffff8801d8c1dfc1 ffff8801d8c1d000 0000000100000022 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d8c1de00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801d8c1de80: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8801d8c1df00: fb fb fb fb fc fc fc fc 00 00 00 fc fc fc fc fc
                                                    ^
 ffff8801d8c1df80: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801d8c1e000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
==================================================================

Crashes (201):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/06/08 06:55 upstream 68abbe729567 f7b27b7a .config console log report syz C ci-upstream-kasan-gce-root
2018/06/08 04:52 upstream 68abbe729567 645e75f8 .config console log report syz C ci-upstream-kasan-gce-root
2018/06/08 01:09 upstream 1c8c5a9d38f6 645e75f8 .config console log report syz C ci-upstream-kasan-gce
2018/06/08 00:21 upstream 1c8c5a9d38f6 645e75f8 .config console log report syz C ci-upstream-kasan-gce
2018/06/08 00:54 upstream 1c8c5a9d38f6 645e75f8 .config console log report syz ci-upstream-kasan-gce-386
2018/06/07 22:16 upstream 1c8c5a9d38f6 645e75f8 .config console log report syz ci-upstream-kasan-gce-386
2018/06/27 15:50 upstream 813835028e9a 43e60f7e .config console log report ci-upstream-kasan-gce
2018/06/27 15:47 upstream 813835028e9a 43e60f7e .config console log report ci-upstream-kasan-gce-root
2018/06/27 14:30 upstream 813835028e9a 43e60f7e .config console log report ci-upstream-kasan-gce-root
2018/06/27 12:58 upstream 813835028e9a 43e60f7e .config console log report ci-upstream-kasan-gce
2018/06/27 07:53 upstream 813835028e9a b0294c53 .config console log report ci-upstream-kasan-gce-root
2018/06/26 23:31 upstream 813835028e9a b0294c53 .config console log report ci-upstream-kasan-gce
2018/06/26 21:46 upstream 813835028e9a b0294c53 .config console log report ci-upstream-kasan-gce
2018/06/26 20:29 upstream 813835028e9a b0294c53 .config console log report ci-upstream-kasan-gce
2018/06/26 09:51 upstream 6f0d349d922b 2064fc5c .config console log report ci-upstream-kasan-gce
2018/06/26 05:32 upstream 6f0d349d922b 2064fc5c .config console log report ci-upstream-kasan-gce-root
2018/06/26 03:32 upstream 6f0d349d922b 2064fc5c .config console log report ci-upstream-kasan-gce
2018/06/25 23:37 upstream 6f0d349d922b 2064fc5c .config console log report ci-upstream-kasan-gce
2018/06/25 21:07 upstream 6f0d349d922b 2064fc5c .config console log report ci-upstream-kasan-gce
2018/06/25 19:36 upstream 6f0d349d922b 2064fc5c .config console log report ci-upstream-kasan-gce
2018/06/25 09:31 upstream 6f0d349d922b 2064fc5c .config console log report ci-upstream-kasan-gce
2018/06/25 07:50 upstream 7daf201d7fe8 2064fc5c .config console log report ci-upstream-kasan-gce-root
2018/06/25 05:44 upstream 7daf201d7fe8 2064fc5c .config console log report ci-upstream-kasan-gce-root
2018/06/24 15:06 upstream 77072ca59fdd 2064fc5c .config console log report ci-upstream-kasan-gce
2018/06/24 10:44 upstream 77072ca59fdd 2064fc5c .config console log report ci-upstream-kasan-gce
2018/06/24 09:01 upstream 77072ca59fdd 2064fc5c .config console log report ci-upstream-kasan-gce
2018/06/24 05:37 upstream 77072ca59fdd 2064fc5c .config console log report ci-upstream-kasan-gce
2018/06/23 20:59 upstream 5e2204832b20 2064fc5c .config console log report ci-upstream-kasan-gce-root
2018/06/23 20:46 upstream 5e2204832b20 2064fc5c .config console log report ci-upstream-kasan-gce-root
2018/06/22 11:46 upstream 894b8c000ae6 095ef806 .config console log report ci-upstream-kasan-gce-root
2018/06/22 06:43 upstream 27db64f65f1b 095ef806 .config console log report ci-upstream-kasan-gce-root
2018/06/21 23:57 upstream 27db64f65f1b 095ef806 .config console log report ci-upstream-kasan-gce-root
2018/06/21 21:31 upstream 1abd8a8f39cd 095ef806 .config console log report ci-upstream-kasan-gce
2018/06/21 19:49 upstream 1abd8a8f39cd 095ef806 .config console log report ci-upstream-kasan-gce-root
2018/06/21 16:44 upstream 1abd8a8f39cd 095ef806 .config console log report ci-upstream-kasan-gce-root
2018/06/21 15:43 upstream 1abd8a8f39cd 095ef806 .config console log report ci-upstream-kasan-gce
2018/06/27 06:10 upstream 813835028e9a b0294c53 .config console log report ci-upstream-kasan-gce-386
2018/06/27 04:42 upstream 813835028e9a b0294c53 .config console log report ci-upstream-kasan-gce-386
2018/06/26 16:28 upstream 6f0d349d922b b0294c53 .config console log report ci-upstream-kasan-gce-386
2018/06/26 04:22 upstream 6f0d349d922b 2064fc5c .config console log report ci-upstream-kasan-gce-386
2018/06/25 01:04 upstream 7daf201d7fe8 2064fc5c .config console log report ci-upstream-kasan-gce-386
2018/06/24 20:40 upstream 7daf201d7fe8 2064fc5c .config console log report ci-upstream-kasan-gce-386
2018/06/22 14:17 upstream 894b8c000ae6 095ef806 .config console log report ci-upstream-kasan-gce-386
2018/06/22 10:32 upstream 27db64f65f1b 095ef806 .config console log report ci-upstream-kasan-gce-386
2018/06/22 03:08 upstream 27db64f65f1b 095ef806 .config console log report ci-upstream-kasan-gce-386
2018/06/21 17:52 upstream 1abd8a8f39cd 095ef806 .config console log report ci-upstream-kasan-gce-386
2018/06/07 19:05 upstream 1c8c5a9d38f6 645e75f8 .config console log report ci-upstream-kasan-gce-386
* Struck through repros no longer work on HEAD.