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authorkamil <kamil@NetBSD.org>2018-06-12 00:42:17 +0000
committerkamil <kamil@NetBSD.org>2018-06-12 00:42:17 +0000
commit298e234d167fdffd4396d3d5a63bb15308ef3671 (patch)
tree10e671d0135e42bac4ec78bfe55f7010dc92e8ee
parent12bc31855a2a994de16274686c9dbe74710e4eca (diff)
Correct Undefined Behavior in gzip(1)
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>
-rw-r--r--usr.bin/gzip/gzip.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/usr.bin/gzip/gzip.c b/usr.bin/gzip/gzip.c
index 686d091ef85..60e05430a14 100644
--- a/usr.bin/gzip/gzip.c
+++ b/usr.bin/gzip/gzip.c
@@ -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 $ */
/*
* Copyright (c) 1997, 1998, 2003, 2004, 2006, 2008, 2009, 2010, 2011, 2015, 2017
@@ -31,7 +31,7 @@
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1997, 1998, 2003, 2004, 2006, 2008,\
2009, 2010, 2011, 2015, 2017 Matthew R. Green. All rights reserved.");
-__RCSID("$NetBSD: gzip.c,v 1.112 2017/08/23 13:04:17 christos Exp $");
+__RCSID("$NetBSD: gzip.c,v 1.113 2018/06/12 00:42:17 kamil Exp $");
#endif /* not lint */
/*
@@ -2118,12 +2118,16 @@ print_list(int fd, off_t out, const char *outfile, time_t ts)
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
}
}