better input validation in linux template

templates/linux/main.c

@@ -111,10 +111,8 @@ int main() {
 
 
             case 'e':
-                if (k == NULL || c == NULL) {
-                    fprintf(stderr, c == NULL ? "Missing ciphertext buffer\r\n" : "Missing key\r\n");
-                    return 3;
-                }
+            case 'd':
+/*
                 fprintf(stderr, "mlen = %llu\r\n", mlen);
                 fprintf(stderr, "m = "); FPRINTF_HEX(stderr, m, mlen); fprintf(stderr, "\r\n");
                 fprintf(stderr, "adlen = %llu\r\n", adlen);
@@ -125,22 +123,42 @@ int main() {
                 fprintf(stderr, "ns = "); FPRINTF_HEX(stderr, nsec, nslen); fprintf(stderr, "\r\n");
                 fprintf(stderr, "klen = %llu\r\n", klen);
                 fprintf(stderr, "k = "); FPRINTF_HEX(stderr, k, klen); fprintf(stderr, "\r\n");
+*/
+                if (k == NULL) {
+                    fprintf(stderr, "Missing key\r\n");
+                    return 3;
+                }
 
-                fprintf(stderr, "Starting encryption\r\n");
-                res = crypto_aead_encrypt(c, &clen,
-                        m, mlen, ad, adlen, nsec, npub, k);
-                fprintf(stderr, "encryption finished %d\r\n", res);
-                break;
-
-            case 'd':
-                if (m == NULL || k == NULL) {
-                    fprintf(stderr, m == NULL ? "Missing message buffer\r\n" : "Missing key\r\n");
+                if (npub == NULL) {
+                    fprintf(stderr, "Missing nonce\r\n");
                     return 3;
                 }
-                fprintf(stderr, "starting decryption\r\n");
-                res = crypto_aead_decrypt(m, &mlen,
-                        nsec, c, clen, ad, adlen, npub, k);
-                fprintf(stderr, "decryption finished %d\r\n", res);
+
+                if (action == 'e') {
+
+                    if (c == NULL) {
+                        fprintf(stderr, "Missing ciphertext buffer\r\n");
+                        return 3;
+                    }
+
+                    fprintf(stderr, "Starting encryption\r\n");
+                    res = crypto_aead_encrypt(c, &clen,
+                            m, mlen, ad, adlen, nsec, npub, k);
+                    fprintf(stderr, "encryption finished %d\r\n", res);
+
+                } else if (action == 'd') {
+
+                    if (m == NULL) {
+                        fprintf(stderr, "Missing message buffer\r\n");
+                        return 3;
+                    }
+
+                    fprintf(stderr, "starting decryption\r\n");
+                    res = crypto_aead_decrypt(m, &mlen,
+                            nsec, c, clen, ad, adlen, npub, k);
+                    fprintf(stderr, "decryption finished %d\r\n", res);
+
+                }
                 break;
 
             default: