svn commit: r196962 - in head/lib/libarchive: . test

[Tim Kientzle]

Author: kientzle
Date: Tue Sep  8 05:02:41 2009
New Revision: 196962
URL: http://svn.freebsd.org/changeset/base/196962

Log:
  Fiz /usr/bin/unzip: A bug deep in libarchive's read-ahead logic
  (incorrect handling of zero-length reads before the copy buffer is
  allocated) is masked by the iso9660 taster.  Tar and cpio both enable
  that taster so were protected from the bug; unzip is susceptible.
  
  This both fixes the bug and updates the test harness to exercise
  this case.
  
  Submitted by: Ed Schouten diagnosed the bug and drafted a patch
  MFC after: 7 days

Modified:
  head/lib/libarchive/archive_read.c
  head/lib/libarchive/test/test_compat_zip.c

Modified: head/lib/libarchive/archive_read.c
==============================================================================
--- head/lib/libarchive/archive_read.c	Tue Sep  8 04:52:12 2009	(r196961)
+++ head/lib/libarchive/archive_read.c	Tue Sep  8 05:02:41 2009	(r196962)
@@ -928,9 +928,12 @@ __archive_read_filter_ahead(struct archi
 	for (;;) {
 
 		/*
-		 * If we can satisfy from the copy buffer, we're done.
+		 * If we can satisfy from the copy buffer (and the
+		 * copy buffer isn't empty), we're done.  In particular,
+		 * note that min == 0 is a perfectly well-defined
+		 * request.
 		 */
-		if (filter->avail >= min) {
+		if (filter->avail >= min && filter->avail > 0) {
 			if (avail != NULL)
 				*avail = filter->avail;
 			return (filter->next);

Modified: head/lib/libarchive/test/test_compat_zip.c
==============================================================================
--- head/lib/libarchive/test/test_compat_zip.c	Tue Sep  8 04:52:12 2009	(r196961)
+++ head/lib/libarchive/test/test_compat_zip.c	Tue Sep  8 05:02:41 2009	(r196962)
@@ -36,7 +36,7 @@ test_compat_zip_1(void)
 
 	assert((a = archive_read_new()) != NULL);
 	assertEqualIntA(a, ARCHIVE_OK, archive_read_support_compression_all(a));
-	assertEqualIntA(a, ARCHIVE_OK, archive_read_support_format_all(a));
+	assertEqualIntA(a, ARCHIVE_OK, archive_read_support_format_zip(a));
 	extract_reference_file(name);
 	assertEqualIntA(a, ARCHIVE_OK, archive_read_open_filename(a, name, 10240));