unzip: Unify EOF handling (libarchive#2175)

If EOF is encountered while reading the new filename after choosing 'r',
avoid out of boundary access and usage of undefined memory content by
treating it the same way as if the question itself was not answered.

Author: stoeckmann

unzip/bsdunzip.c

@@ -484,13 +484,8 @@ handle_existing_file(char **path)
 		fprintf(stderr,
 		    "replace %s? [y]es, [n]o, [A]ll, [N]one, [r]ename: ",
 		    *path);
-		if (fgets(buf, sizeof(buf), stdin) == NULL) {
-			clearerr(stdin);
-			printf("NULL\n(EOF or read error, "
-			    "treating as \"[N]one\"...)\n");
-			n_opt = 1;
-			return -1;
-		}
+		if (fgets(buf, sizeof(buf), stdin) == NULL)
+			goto stdin_err;
 		switch (*buf) {
 		case 'A':
 			o_opt = 1;
@@ -512,13 +507,21 @@ handle_existing_file(char **path)
 			*path = NULL;
 			alen = 0;
 			len = getline(path, &alen, stdin);
+			if (len < 1)
+				goto stdin_err;
 			if ((*path)[len - 1] == '\n')
 				(*path)[len - 1] = '\0';
 			return 0;
 		default:
 			break;
 		}
 	}
+stdin_err:
+	clearerr(stdin);
+	printf("NULL\n(EOF or read error, "
+		"treating as \"[N]one\"...)\n");
+	n_opt = 1;
+	return -1;
 }
 
 /*