From owner-svn-src-stable-9@FreeBSD.ORG Thu Mar 21 16:15:35 2013 Return-Path: Delivered-To: svn-src-stable-9@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 7F0F95B6; Thu, 21 Mar 2013 16:15:35 +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 588AB74A; Thu, 21 Mar 2013 16:15:35 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.6/8.14.6) with ESMTP id r2LGFZa7038245; Thu, 21 Mar 2013 16:15:35 GMT (envelope-from tijl@svn.freebsd.org) Received: (from tijl@localhost) by svn.freebsd.org (8.14.6/8.14.5/Submit) id r2LGFZOj038244; Thu, 21 Mar 2013 16:15:35 GMT (envelope-from tijl@svn.freebsd.org) Message-Id: <201303211615.r2LGFZOj038244@svn.freebsd.org> From: Tijl Coosemans Date: Thu, 21 Mar 2013 16:15:35 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-9@freebsd.org Subject: svn commit: r248587 - stable/9/sys/kern X-SVN-Group: stable-9 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-stable-9@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: SVN commit messages for only the 9-stable src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 21 Mar 2013 16:15:35 -0000 Author: tijl Date: Thu Mar 21 16:15:34 2013 New Revision: 248587 URL: http://svnweb.freebsd.org/changeset/base/248587 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 Modified: stable/9/sys/kern/imgact_elf.c Directory Properties: stable/9/sys/ (props changed) Modified: stable/9/sys/kern/imgact_elf.c ============================================================================== --- stable/9/sys/kern/imgact_elf.c Thu Mar 21 16:04:34 2013 (r248586) +++ stable/9/sys/kern/imgact_elf.c Thu Mar 21 16:15:34 2013 (r248587) @@ -663,9 +663,8 @@ __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; } @@ -747,7 +746,7 @@ __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); } @@ -766,8 +765,8 @@ __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; @@ -1555,9 +1554,8 @@ __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);