C++: Add some practical details to the examples.

Author: geoffw0

cpp/ql/src/Security/CWE/CWE-732/DoNotCreateWorldWritable.c

@@ -1,18 +1,38 @@
 void write_default_config_bad() {
 	// BAD - this is world-writable so any user can overwrite the config
 	int out = creat(OUTFILE, 0666);
-	dprintf(out, DEFAULT_CONFIG);
+	if (out < 0) {
+		// handle error
+	}
+
+	dprintf(out, "%s", DEFAULT_CONFIG);
+	close(out);
 }
 
 void write_default_config_good() {
 	// GOOD - this allows only the current user to modify the file
 	int out = creat(OUTFILE, S_IWUSR | S_IRUSR);
-	dprintf(out, DEFAULT_CONFIG);
+	if (out < 0) {
+		// handle error
+	}
+
+	dprintf(out, "%s", DEFAULT_CONFIG);
+	close(out);
 }
 
 void write_default_config_good_2() {
 	// GOOD - this allows only the current user to modify the file
 	int out = open(OUTFILE, O_WRONLY | O_CREAT, S_IWUSR | S_IRUSR);
+	if (out < 0) {
+		// handle error
+	}
+
 	FILE *fd = fdopen(out, "w");
-	fprintf(fd, DEFAULT_CONFIG);
+	if (fd == NULL) {
+		close(out);
+		// handle error
+	}
+
+	fprintf(fd, "%s", DEFAULT_CONFIG);
+	fclose(fd);
 }