Don't lose leading '/' for pathnames exactly 101 bytes long.

Also, update the test harness to exercise this case.

2 files changed, 25 insertions, 8 deletions

diff --git a/lib/libarchive/archive_write_set_format_ustar.c b/lib/libarchive/archive_write_set_format_ustar.c
index f43c23a..390b1a0 100644
--- a/lib/libarchive/archive_write_set_format_ustar.c
+++ b/lib/libarchive/archive_write_set_format_ustar.c
@@ -279,6 +279,16 @@ __archive_write_format_header_ustar(struct archive_write *a, char h[512],
 		/* Store in two pieces, splitting at a '/'. */
 		p = strchr(pp + strlen(pp) - USTAR_name_size - 1, '/');
 		/*
+		 * If the separator we found is the first '/', find
+		 * the next one.  (This is a pathological case that
+		 * occurs for paths of exactly 101 bytes that start with
+		 * '/'; it occurs because the separating '/' is not
+		 * stored explicitly and the reconstruction assumes that
+		 * an empty prefix means there is no '/' separator.)
+		 */
+		if (p == pp)
+			p = strchr(p + 1, '/');
+		/*
 		 * If there is no path separator, or the prefix or
 		 * remaining name are too large, return an error.
 		 */
diff --git a/lib/libarchive/test/test_tar_filenames.c b/lib/libarchive/test/test_tar_filenames.c
index fb15a96..b534174 100644
--- a/lib/libarchive/test/test_tar_filenames.c
+++ b/lib/libarchive/test/test_tar_filenames.c
@@ -31,8 +31,8 @@ __FBSDID("$FreeBSD$");
  * filenames into prefix/suffix.
  */
 
-static void
-test_filename(int dlen, int flen)
+static
+test_filename(const char *prefix, int dlen, int flen)
 {
 	char buff[8192];
 	char filename[400];
@@ -40,12 +40,17 @@ test_filename(int dlen, int flen)
 	struct archive_entry *ae;
 	struct archive *a;
 	size_t used;
-	int i;
+	size_t prefix_length = 0;
+	int i = 0;
 
-	for (i = 0; i < dlen; i++)
+	if (prefix) {
+		strcpy(filename, prefix);
+		i = prefix_length = strlen(prefix);
+	}
+	for (; i < prefix_length + dlen; i++)
 		filename[i] = 'a';
 	filename[i++] = '/';
-	for (; i < dlen + flen + 1; i++)
+	for (; i < prefix_length + dlen + flen + 1; i++)
 		filename[i] = 'b';
 	filename[i++] = '\0';
 
@@ -111,7 +116,7 @@ test_filename(int dlen, int flen)
 	assertA(0 == archive_read_next_header(a, &ae));
 	failure("Pathname %d/%d: %s", dlen, flen, archive_entry_pathname(ae));
 	assertEqualString(filename, archive_entry_pathname(ae));
-	assert((S_IFREG | 0755) == archive_entry_mode(ae));
+	assertEqualInt((S_IFREG | 0755), archive_entry_mode(ae));
 
 	/*
 	 * Read the two dirs and check the names.
@@ -147,13 +152,15 @@ DEFINE_TEST(test_tar_filenames)
 	/* Repeat the following for a variety of dir/file lengths. */
 	for (dlen = 40; dlen < 60; dlen++) {
 		for (flen = 40; flen < 60; flen++) {
-			test_filename(dlen, flen);
+			test_filename(NULL, dlen, flen);
+			test_filename("/", dlen, flen);
 		}
 	}
 
 	for (dlen = 140; dlen < 160; dlen++) {
 		for (flen = 90; flen < 110; flen++) {
-			test_filename(dlen, flen);
+			test_filename(NULL, dlen, flen);
+			test_filename("/", dlen, flen);
 		}
 	}
 }