From owner-freebsd-security@freebsd.org Mon May 15 17:15:15 2017 Return-Path: Delivered-To: freebsd-security@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 37CF2D6ED3C for ; Mon, 15 May 2017 17:15:15 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 0D9681248 for ; Mon, 15 May 2017 17:15:15 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from bugs.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id v4FHFE5t022653 for ; Mon, 15 May 2017 17:15:14 GMT (envelope-from bugzilla-noreply@freebsd.org) From: bugzilla-noreply@freebsd.org To: freebsd-security@FreeBSD.org Subject: [Bug 219154] [PATCH] buffer overflows in realpath(3) Date: Mon, 15 May 2017 17:15:15 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: bin X-Bugzilla-Version: CURRENT X-Bugzilla-Keywords: patch X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: commit-hook@freebsd.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: freebsd-security@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: 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-Mailman-Approved-At: Mon, 15 May 2017 17:28:54 +0000 X-BeenThere: freebsd-security@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Security issues \[members-only posting\]" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 15 May 2017 17:15:15 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D219154 --- Comment #5 from commit-hook@freebsd.org --- A commit references this bug: Author: kib Date: Mon May 15 17:14:53 UTC 2017 New revision: 318298 URL: https://svnweb.freebsd.org/changeset/base/318298 Log: Fix several buffer overflows in realpath(3). - The statement "left_len -=3D s - left;" does not take the slash into account if one was found. This results in the invariant "left[left_len] =3D=3D '\0'" being violated (and possible buffer overflows). The patch replaces the variable "s" with a size_t "next_token_len" for more clarity. - "slen" from readlink(2) can be 0 when encountering empty symlinks. Then, further down, "symlink[slen - 1]" underflows the buffer. When slen =3D=3D 0, realpath(3) should probably return ENOENT (http://austingroupbugs.net/view.php?id=3D825, https://lwn.net/Articles/551224/). Some other minor issues: - The condition "resolved_len >=3D PATH_MAX" cannot be true. - Similarly, "s - left >=3D sizeof(next_token)" cannot be true, as long as "sizeof(next_token) >=3D sizeof(left)". - Return ENAMETOOLONG when a resolved symlink from readlink(2) is too long for the symlink buffer (instead of just truncating it). - "resolved_len > 1" below the call to readlink(2) is always true as "strlcat(resolved, next_token, PATH_MAX);" always results in a string of length > 1. Also, "resolved[resolved_len - 1] =3D '\0';" is not needed; there can never be a trailing slash here. - The truncation check for "strlcat(symlink, left, sizeof(symlink));" should be against "sizeof(symlink)" (the third argument to strlcat) instead of "sizeof(left)". Submitted by: Jan Kokem??ller PR: 219154 MFC after: 2 weeks Changes: head/lib/libc/stdlib/realpath.c --=20 You are receiving this mail because: You are the assignee for the bug.=