From: syzbot Subject: Re: KASAN: slab-out-of-bounds Write in rmd160_final Date: Thu, 07 Jun 2018 09:36:02 -0700 Message-ID: <000000000000022448056e0fe15d@google.com> References: <00000000000075cc63056e0d0707@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes To: davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Return-path: In-Reply-To: <00000000000075cc63056e0d0707@google.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org syzbot has found a reproducer for the following crash on: HEAD commit: 1c8c5a9d38f6 Merge git://git.kernel.org/pub/scm/linux/kern.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=14c7f96f800000 kernel config: https://syzkaller.appspot.com/x/.config?x=4f1acdf888c9d4e9 dashboard link: https://syzkaller.appspot.com/bug?extid=d04e58bd384f1fe0b112 compiler: gcc (GCC) 8.0.1 20180413 (experimental) syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=1432a66f800000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11b5034f800000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+d04e58bd384f1fe0b112@syzkaller.appspotmail.com 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 rmd160_final+0x201/0x240 crypto/rmd160.c:334 Write of size 4 at addr ffff8801d88781d8 by task syz-executor724/4532 CPU: 1 PID: 4532 Comm: syz-executor724 Not tainted 4.17.0+ #89 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 rmd160_final+0x201/0x240 crypto/rmd160.c:334 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:00007ffd9be52ed8 EFLAGS: 00000217 ORIG_RAX: 00000000000000fa RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043ffa9 RDX: 0000000020a53ffb RSI: 0000000020000100 RDI: 0000000000000017 RBP: 00000000006ca018 R08: 0000000020c61fc8 R09: 00000000004002c8 R10: 0000000000000005 R11: 0000000000000217 R12: 00000000004018d0 R13: 0000000000401960 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 4532: 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 2865: 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 ffff8801d88781c0 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 24 bytes inside of 32-byte region [ffff8801d88781c0, ffff8801d88781e0) The buggy address belongs to the page: page:ffffea0007621e00 count:1 mapcount:0 mapping:ffff8801d8878000 index:0xffff8801d8878fc1 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801d8878000 ffff8801d8878fc1 0000000100000018 raw: ffffea00070e71e0 ffffea00076222a0 ffff8801da8001c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d8878080: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc ffff8801d8878100: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc > ffff8801d8878180: fb fb fb fb fc fc fc fc 00 00 00 fc fc fc fc fc ^ ffff8801d8878200: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc ffff8801d8878280: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc ==================================================================