7200500: Launcher better input validation

Reviewed-by: darcy, jjh, mschoene
diff --git a/jdk/src/share/bin/parse_manifest.c b/jdk/src/share/bin/parse_manifest.c
index eb847bf..3fa759d 100644
--- a/jdk/src/share/bin/parse_manifest.c
+++ b/jdk/src/share/bin/parse_manifest.c
@@ -490,9 +490,9 @@
 #ifdef O_BINARY
         | O_BINARY /* use binary mode on windows */
 #endif
-        )) == -1)
+        )) == -1) {
         return (-1);
-
+    }
     info->manifest_version = NULL;
     info->main_class = NULL;
     info->jre_version = NULL;
@@ -539,12 +539,14 @@
     zentry  entry;
     void    *data = NULL;
 
-    fd = open(jarfile, O_RDONLY
+    if ((fd = open(jarfile, O_RDONLY
 #ifdef O_BINARY
         | O_BINARY /* use binary mode on windows */
 #endif
-        );
-    if (fd != -1 && find_file(fd, &entry, filename) == 0) {
+        )) == -1) {
+        return NULL;
+    }
+    if (find_file(fd, &entry, filename) == 0) {
         data = inflate_file(fd, &entry, size);
     }
     close(fd);
@@ -586,8 +588,9 @@
 #ifdef O_BINARY
         | O_BINARY /* use binary mode on windows */
 #endif
-        )) == -1)
+        )) == -1) {
         return (-1);
+    }
 
     if (rc = find_file(fd, &entry, manifest_name) != 0) {
         close(fd);