Github Issue #522: Detect cycles in the ISO directory tree

libarchive · Apr 12, 2015 · 01cfbca · 01cfbca
1 parent 39fc593
commit 01cfbca
Showing 1 changed file with 13 additions and 3 deletions.
diff --git a/libarchive/archive_read_support_format_iso9660.c b/libarchive/archive_read_support_format_iso9660.c
@@ -1752,12 +1752,12 @@ parse_file_info(struct archive_read *a, struct file_info *parent,
     const unsigned char *isodirrec)
 {
 	struct iso9660 *iso9660;
-	struct file_info *file;
+	struct file_info *file, *filep;
 	size_t name_len;
 	const unsigned char *rr_start, *rr_end;
 	const unsigned char *p;
 	size_t dr_len;
-	uint64_t fsize;
+	uint64_t fsize, offset;
 	int32_t location;
 	int flags;
 
@@ -1801,6 +1801,16 @@ parse_file_info(struct archive_read *a, struct file_info *parent,
 		return (NULL);
 	}
 
+	/* Sanity check that this entry does not create a cycle. */
+	offset = iso9660->logical_block_size * (uint64_t)location;
+	for (filep = parent; filep != NULL; filep = filep->parent) {
+		if (filep->offset == offset) {
+			archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
+			    "Directory structure contains loop");
+			return (NULL);
+		}
+	}
+
 	/* Create a new file entry and copy data from the ISO dir record. */
 	file = (struct file_info *)calloc(1, sizeof(*file));
 	if (file == NULL) {
@@ -1809,7 +1819,7 @@ parse_file_info(struct archive_read *a, struct file_info *parent,
 		return (NULL);
 	}
 	file->parent = parent;
-	file->offset = iso9660->logical_block_size * (uint64_t)location;
+	file->offset = offset;
 	file->size = fsize;
 	file->mtime = isodate7(isodirrec + DR_date_offset);
 	file->ctime = file->atime = file->mtime;