From owner-freebsd-bugs@freebsd.org Fri Oct 9 13:40:48 2020 Return-Path: Delivered-To: freebsd-bugs@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 14BFE3FB2AB for ; Fri, 9 Oct 2020 13:40:48 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.nyi.freebsd.org (unknown [127.0.1.3]) by mx1.freebsd.org (Postfix) with ESMTP id 4C78NH6twTz4PDF for ; Fri, 9 Oct 2020 13:40:47 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.nyi.freebsd.org (Postfix) id EC8EA3FAB77; Fri, 9 Oct 2020 13:40:47 +0000 (UTC) Delivered-To: bugs@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id EC5863FAB76 for ; Fri, 9 Oct 2020 13:40:47 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4C78NH62dVz4PTn for ; Fri, 9 Oct 2020 13:40:47 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2610:1c1:1:606c::50:1d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id B2C3F1A2FC for ; Fri, 9 Oct 2020 13:40:47 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.5]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id 099DelLC006548 for ; Fri, 9 Oct 2020 13:40:47 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 099Del2D006547 for bugs@FreeBSD.org; Fri, 9 Oct 2020 13:40:47 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 250223] FS-19-EXT3-4: Out of bounds read in mknodat-1 (fifo_close) Date: Fri, 09 Oct 2020 13:40:47 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 12.1-STABLE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: emaste@freebsd.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 09 Oct 2020 13:40:48 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D250223 Bug ID: 250223 Summary: FS-19-EXT3-4: Out of bounds read in mknodat-1 (fifo_close) Product: Base System Version: 12.1-STABLE Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: emaste@freebsd.org Reported by: Christopher Krah of Fraunhofer FKIE *Description of the vulnerability*: Mounting a specially crafted ext3 (and potentially any ext fs) may lead to an out-of-bounds read. The file system = of [1] yields a page fault (supervisor read data).=20 This happens in line 276 in /usr/src/sys/fs/fifofs/fifo_vnops.c: /* * Device close routine */ /* ARGSUSED */ static int fifo_close(ap) struct vop_close_args /* { struct vnode *a_vp; int a_fflag; struct ucred *a_cred; struct thread *a_td; } */ *ap; { struct vnode *vp; struct fifoinfo *fip; struct pipe *cpipe; vp =3D ap->a_vp; fip =3D vp->v_fifoinfo; # crash occurs here [...] In this snippet when setting the value of fip by accessing the v_fifoinfo f= ield fip is set to zero. (kgdb) p *vp $1 =3D {[...], {v_mountedhere =3D 0x0, v_unpcb =3D 0x0, v_rdev =3D 0x0, v_f= ifoinfo =3D 0x0} [...] } The corresponding assembly instruction is: 0xffffffff80a36b36 : mov r14,QWORD PTR [r12] And confirms the above. At the time of the crash r12 =3D 0x0 and hence acce= ssing the value at memory address 0x0 is causing the kernel DoS. That said, If an attacker would have access to r12 this may lead to an information leak. *Affected versions*: tested with FreeBSD 12.0-RELEASE AMD64.=20 *Workaround*: Do not load ext2fs=20 --- fsu reports Cannot be reproduced on CURRENT r349333, reproduced on 12 at r341666 --=20 You are receiving this mail because: You are the assignee for the bug.=