tools/nettle-pbkdf2.c: Check strdup return value.

ChangeLog

+2019-04-14  Niels Möller  <nisse@lysator.liu.se>
+
+	* tools/nettle-pbkdf2.c (main): Check strdup return value.
+
 2019-03-29  Niels Möller  <nisse@lysator.liu.se>
 
 	* aes.h (struct aes_ctx): Redefine using a union of key-size

tools/nettle-pbkdf2.c

@@ -144,6 +144,9 @@ main (int argc, char **argv)
     }
 
   salt = strdup (argv[0]);
+  if (!salt)
+    die ("strdup failed: Virtual memory exhausted.\n");
+
   salt_length = strlen(argv[0]);
   
   if (hex_salt)