Date: Mon, 16 Jul 2018 00:23:09 +0000 (UTC) From: "Pedro F. Giffuni" <pfg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r336323 - stable/11/usr.bin/gzip Message-ID: <201807160023.w6G0N91L002821@repo.freebsd.org>
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Author: pfg Date: Mon Jul 16 00:23:09 2018 New Revision: 336323 URL: https://svnweb.freebsd.org/changeset/base/336323 Log: MFC r336113: gzip: fix for undefined behavior. Unportable left shift reported with MKSANITIZER=yes USE_SANITIZER=undefined: # progress -zf ./games.tgz tar -xp -C "./" -f - /public/src.git/usr.bin/gzip/gzip.c:2126:33: runtime error: left shift of 251 by 24 places cannot be represented in type 'int' 100% |****************************************************************************************************************| 44500 KiB 119.69 MiB/s 00:00 ETA Refactor the following code into something that is more clear and fix signed integer shift, by casting all buf[] elements to (unsigned int): unsigned char buf[8]; uint32_t usize; [...] else { usize = buf[4] | buf[5] << 8 | buf[6] << 16 | buf[7] << 24; [...] New version: usize = buf[4]; usize |= (unsigned int)buf[5] << 8; usize |= (unsigned int)buf[6] << 16; usize |= (unsigned int)buf[7] << 24; Only the "<< 24" part needs explicit cast, but for consistency make the integer promotion explicit and clear to a code reader. Sponsored by <The NetBSD Foundation> Obtained from: NetBSD (CVS rev. 1.113) Modified: stable/11/usr.bin/gzip/gzip.c Directory Properties: stable/11/ (props changed) Modified: stable/11/usr.bin/gzip/gzip.c ============================================================================== --- stable/11/usr.bin/gzip/gzip.c Mon Jul 16 00:20:18 2018 (r336322) +++ stable/11/usr.bin/gzip/gzip.c Mon Jul 16 00:23:09 2018 (r336323) @@ -1,4 +1,4 @@ -/* $NetBSD: gzip.c,v 1.112 2017/08/23 13:04:17 christos Exp $ */ +/* $NetBSD: gzip.c,v 1.113 2018/06/12 00:42:17 kamil Exp $ */ /*- * SPDX-License-Identifier: BSD-2-Clause-NetBSD @@ -2170,12 +2170,16 @@ print_list(int fd, off_t out, const char *outfile, tim maybe_warnx("read of uncompressed size"); else { - usize = buf[4] | buf[5] << 8 | - buf[6] << 16 | buf[7] << 24; + usize = buf[4]; + usize |= (unsigned int)buf[5] << 8; + usize |= (unsigned int)buf[6] << 16; + usize |= (unsigned int)buf[7] << 24; in = (off_t)usize; #ifndef SMALL - crc = buf[0] | buf[1] << 8 | - buf[2] << 16 | buf[3] << 24; + crc = buf[0]; + crc |= (unsigned int)buf[1] << 8; + crc |= (unsigned int)buf[2] << 16; + crc |= (unsigned int)buf[3] << 24; #endif } }
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