From owner-svn-src-head@FreeBSD.ORG Wed Mar 13 22:01:32 2013 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id B87CDF5C; Wed, 13 Mar 2013 22:01:32 +0000 (UTC) (envelope-from tijl@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) by mx1.freebsd.org (Postfix) with ESMTP id 915ABFDA; Wed, 13 Mar 2013 22:01:32 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.6/8.14.6) with ESMTP id r2DM1WgL094804; Wed, 13 Mar 2013 22:01:32 GMT (envelope-from tijl@svn.freebsd.org) Received: (from tijl@localhost) by svn.freebsd.org (8.14.6/8.14.5/Submit) id r2DM1WIT094803; Wed, 13 Mar 2013 22:01:32 GMT (envelope-from tijl@svn.freebsd.org) Message-Id: <201303132201.r2DM1WIT094803@svn.freebsd.org> From: Tijl Coosemans Date: Wed, 13 Mar 2013 22:01:32 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r248256 - head/sys/kern X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 13 Mar 2013 22:01:32 -0000 Author: tijl Date: Wed Mar 13 22:01:31 2013 New Revision: 248256 URL: http://svnweb.freebsd.org/changeset/base/248256 Log: - Fix two possible overflows when testing if ELF program headers are on the first page: 1. Cast uint16_t operands in a multiplication to unsigned int because otherwise the implicit promotion to int results in a signed multiplication that can overflow and the behaviour on integer overflow is undefined. 2. Replace (offset + size > PAGE_SIZE) with (size > PAGE_SIZE - offset) because the sum may overflow. - Use the same tests to see if the path to the interpreter is on the first page. There's no overflow here because size is already limited by MAXPATHLEN, but the compiler optimises the new tests better. Also fix an off-by-one error. - Simplify tests to see if an ELF note program header is on the first page. This also fixes an off-by-one error. Reviewed by: kib MFC after: 1 week Modified: head/sys/kern/imgact_elf.c Modified: head/sys/kern/imgact_elf.c ============================================================================== --- head/sys/kern/imgact_elf.c Wed Mar 13 21:06:03 2013 (r248255) +++ head/sys/kern/imgact_elf.c Wed Mar 13 22:01:31 2013 (r248256) @@ -661,9 +661,8 @@ __elfN(load_file)(struct proc *p, const } /* Only support headers that fit within first page for now */ - /* (multiplication of two Elf_Half fields will not overflow) */ if ((hdr->e_phoff > PAGE_SIZE) || - (hdr->e_phentsize * hdr->e_phnum) > PAGE_SIZE - hdr->e_phoff) { + (u_int)hdr->e_phentsize * hdr->e_phnum > PAGE_SIZE - hdr->e_phoff) { error = ENOEXEC; goto fail; } @@ -743,7 +742,7 @@ __CONCAT(exec_, __elfN(imgact))(struct i */ if ((hdr->e_phoff > PAGE_SIZE) || - (hdr->e_phoff + hdr->e_phentsize * hdr->e_phnum) > PAGE_SIZE) { + (u_int)hdr->e_phentsize * hdr->e_phnum > PAGE_SIZE - hdr->e_phoff) { /* Only support headers in first page for now */ return (ENOEXEC); } @@ -762,8 +761,8 @@ __CONCAT(exec_, __elfN(imgact))(struct i case PT_INTERP: /* Path to interpreter */ if (phdr[i].p_filesz > MAXPATHLEN || - phdr[i].p_offset >= PAGE_SIZE || - phdr[i].p_offset + phdr[i].p_filesz >= PAGE_SIZE) + phdr[i].p_offset > PAGE_SIZE || + phdr[i].p_filesz > PAGE_SIZE - phdr[i].p_offset) return (ENOEXEC); interp = imgp->image_header + phdr[i].p_offset; interp_name_len = phdr[i].p_filesz; @@ -1553,9 +1552,8 @@ __elfN(parse_notes)(struct image_params const char *note_name; int i; - if (pnote == NULL || pnote->p_offset >= PAGE_SIZE || - pnote->p_filesz > PAGE_SIZE || - pnote->p_offset + pnote->p_filesz >= PAGE_SIZE) + if (pnote == NULL || pnote->p_offset > PAGE_SIZE || + pnote->p_filesz > PAGE_SIZE - pnote->p_offset) return (FALSE); note = note0 = (const Elf_Note *)(imgp->image_header + pnote->p_offset);