From owner-freebsd-bugs@freebsd.org Fri Oct 9 13:25:14 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 D664F3FA87F for ; Fri, 9 Oct 2020 13:25:14 +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 4C782L5NGsz4NvF for ; Fri, 9 Oct 2020 13:25:14 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.nyi.freebsd.org (Postfix) id B6E5D3FA87E; Fri, 9 Oct 2020 13:25:14 +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 B6A5F3FACEE for ; Fri, 9 Oct 2020 13:25:14 +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 4C782L4Lztz4P02 for ; Fri, 9 Oct 2020 13:25:14 +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 7497E1A537 for ; Fri, 9 Oct 2020 13:25:14 +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 099DPEwI088685 for ; Fri, 9 Oct 2020 13:25:14 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 099DPELC088684 for bugs@FreeBSD.org; Fri, 9 Oct 2020 13:25:14 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 250220] ext2: Denial Of Service in mknodat-0 Date: Fri, 09 Oct 2020 13:25:14 +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: CURRENT 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 13:25:14 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D250220 Bug ID: 250220 Summary: ext2: Denial Of Service in mknodat-0 Product: Base System Version: CURRENT 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 vulnerability*: The syscall sys_mknodat is vulnerable to a Kernel Denial of Service when a specially crafted EXT2 filesystem is loaded= . It seems that this behavior was already anticipated as of right now in function ext2_search_dirblockin /usr/src/sys/fs/ext2fs/ext2_lookup.c in line 727: if(ep->e2d_reclen =3D=3D 0 ||=20 (dirchk && ext2_dirbadentry(vdp, ep, offset)) { int i; ext2_dirbad(ip, *offp, "mangled entry"); The panic is finally thrown in the same file in line 807 after another if condition in a function called ext2_dirbad: if ((mp->mnt_flag & MNT_RDONLY) =3D=3D 0) panic("ext2_dirbad: %s: bad dir ino%ju at offset %ld: %s\n", mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number, (long)offset, how); Our corrupted file system pokes exactly 1 of the 2 occurrences of the funct= ion call to ext2_dirbad (made in /usr/src/sys/fs/ext2fs/ext2_lookup.c) , with t= he other being in line 535: ext2_dirbad(dp, i_offset, "i_size too small") *Affected versions*: Tested on FreeBSD 12.0 Release AMD64 *Workaround*: Do not load ext2fs --=20 You are receiving this mail because: You are the assignee for the bug.=