From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756317AbdLVRF0 (ORCPT ); Fri, 22 Dec 2017 12:05:26 -0500 Received: from mail-io0-f194.google.com ([209.85.223.194]:37663 "EHLO mail-io0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754212AbdLVRFV (ORCPT ); Fri, 22 Dec 2017 12:05:21 -0500 X-Google-Smtp-Source: ACJfBouUEsjUn0xFb7L+aOkjJWrt2AjoGMukphkSIvMYRHsR4Ote5gWKNnCLaNBSfTFiRmAkrBspkg== Date: Fri, 22 Dec 2017 11:05:17 -0600 From: Eric Biggers To: syzbot Cc: elfring@users.sourceforge.net, eparis@parisplace.org, gregkh@linuxfoundation.org, james.l.morris@oracle.com, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, paul@paul-moore.com, pombredanne@nexb.com, sds@tycho.nsa.gov, selinux@tycho.nsa.gov, serge@hallyn.com, syzkaller-bugs@googlegroups.com, tglx@linutronix.de Subject: Re: BUG: unable to handle kernel NULL pointer dereference in sidtab_search_core Message-ID: <20171222170517.GA588@zzz.localdomain> References: <94eb2c0d010a8dcf040560c0cdf5@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <94eb2c0d010a8dcf040560c0cdf5@google.com> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 19, 2017 at 11:48:02PM -0800, syzbot wrote: > Hello, > > syzkaller hit the following crash on > 6084b576dca2e898f5c101baef151f7bfdbb606d > git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master > compiler: gcc (GCC) 7.1.1 20170620 > .config is attached > Raw console output is attached. > C reproducer is attached > syzkaller reproducer is attached. See https://goo.gl/kgGztJ > for information about syzkaller reproducers > > > SELinux: security_compute_sid: unrecognized SID 1 > SELinux: security_compute_sid: unrecognized SID 1 > SELinux: security_compute_sid: unrecognized SID 1 > SELinux: security_compute_sid: unrecognized SID 1 > SELinux: security_compute_sid: unrecognized SID 1 > BUG: unable to handle kernel NULL pointer dereference at 0000000000000001 > IP: sidtab_search_core+0x88/0x110 security/selinux/ss/sidtab.c:100 > PGD 0 P4D 0 > Oops: 0000 [#1] SMP > Dumping ftrace buffer: > (ftrace buffer empty) > Modules linked in: > CPU: 1 PID: 4252 Comm: kworker/u4:1 Not tainted 4.15.0-rc3-next-20171214+ > #67 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > RIP: 0010:sidtab_search_core+0x88/0x110 security/selinux/ss/sidtab.c:100 > RSP: 0018:ffffc900028abc18 EFLAGS: 00010293 > RAX: ffff8802131a87c0 RBX: 0000000000000001 RCX: ffffffff8165d978 > RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff83fd17a0 > RBP: ffffc900028abc40 R08: 0000000000000001 R09: 0000000000000001 > R10: ffffc900028abbe0 R11: 0000000000000000 R12: 0000000000000001 > R13: 0000000000000001 R14: 0000000000000000 R15: ffff880214d93800 > FS: 0000000000000000(0000) GS:ffff88021fd00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000001 CR3: 0000000214e31000 CR4: 00000000001406e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > sidtab_search+0x1f/0x30 security/selinux/ss/sidtab.c:111 > security_compute_sid.part.11+0xe2/0x710 security/selinux/ss/services.c:1618 > security_compute_sid+0x92/0xa0 security/selinux/ss/services.c:1598 > security_transition_sid+0x57/0x70 security/selinux/ss/services.c:1764 > selinux_bprm_set_creds+0x215/0x2f0 security/selinux/hooks.c:2423 > security_bprm_set_creds+0x41/0x60 security/security.c:332 > prepare_binprm+0xae/0x1f0 fs/exec.c:1561 > do_execveat_common.isra.30+0x6f7/0xb90 fs/exec.c:1784 > do_execve+0x31/0x40 fs/exec.c:1848 > call_usermodehelper_exec_async+0x104/0x190 kernel/umh.c:100 > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:524 > Code: 8b 5b 50 48 85 db 75 e5 e8 e6 c9 c5 ff 49 8b 5f 18 48 85 db 75 10 eb > 43 e8 d6 c9 c5 ff 48 8b 5b 50 48 85 db 74 35 e8 c8 c9 c5 ff <44> 8b 23 41 83 > fc 02 76 e4 e8 ba c9 c5 ff 41 83 fc 03 75 1c 48 > RIP: sidtab_search_core+0x88/0x110 security/selinux/ss/sidtab.c:100 RSP: > ffffc900028abc18 > CR2: 0000000000000001 > ---[ end trace 571c0ea6c6959387 ]--- The reproducer for this is using AF_ALG and binding to the "pcrypt(gcm_base(ctr(aes-aesni),ghash-generic))" algorithm, so it's very likely running into the pcrypt_free() bug which is causing slab cache corruption: https://groups.google.com/forum/#!topic/syzkaller-bugs/NKn_ivoPOpk https://patchwork.kernel.org/patch/10126761/ So let's mark it as a duplicate: #syz dup: KASAN: use-after-free Read in __list_del_entry_valid (2)