Working on GCM

compile_all.py

@@ -156,7 +156,7 @@ def main(argv):
             try:
                 b = build(d, template_dir)
                 test_script.write("echo \"TESTING %s\"\n" % d)
-                test_script.write("./test.py %s %s 2> %s | tee %s\n" % (
+                test_script.write("./test.py %s %s 2> %s | tee %s\n" % 
                         t,
                         os.path.join(b, 'test'),
                         os.path.join(b, 'test_stderr.log'),

mbed_aes_gcm/api.h

 #define CRYPTO_KEYBYTES 16
 #define CRYPTO_NSECBYTES 0 
 #define CRYPTO_NPUBBYTES 12 
-#define CRYPTO_ABYTES 0
+#define CRYPTO_ABYTES 16
 #define CRYPTO_NOOVERLAP 1 

mbed_aes_gcm/gcm.c

@@ -38,6 +38,7 @@
 #if defined(MBEDTLS_GCM_C)
 
 #include "gcm.h"
+#include "api.h"
 #include "crypto_aead.h"
 #include "platform_util.h"
 
@@ -87,7 +88,6 @@
 }
 #endif
 
-unsigned char tag_buf[16];
 
 
 /*
@@ -113,12 +113,16 @@ int crypto_aead_encrypt(
 {
   mbedtls_gcm_context ctx;
   int ret;
+  unsigned long long mask = 15;
+  unsigned long long mlenp = (mlen + mask) & (~mask);
+  unsigned char tag_buf[CRYPTO_ABYTES];
+  *clen = mlenp + CRYPTO_ABYTES;
 
   mbedtls_gcm_init( &ctx );
   ret = mbedtls_gcm_setkey( &ctx, MBEDTLS_CIPHER_ID_AES, k, 128);
   ret = mbedtls_gcm_crypt_and_tag( &ctx, 1, mlen, npub, 12, ad, adlen, m, c, 16, tag_buf );
   mbedtls_gcm_free( &ctx );
-  
+  memcpy(c + mlenp, tag_buf, CRYPTO_ABYTES);
   return ret;
 }
 
@@ -133,6 +137,11 @@ int crypto_aead_decrypt(
 {
   mbedtls_gcm_context ctx;
   int ret;
+  unsigned char tag_buf[CRYPTO_ABYTES];
+  
+  clen -= CRYPTO_ABYTES;
+  memcpy(tag_buf, c + clen, CRYPTO_ABYTES);
+  *mlen = clen;
 
   mbedtls_gcm_init( &ctx );
   ret = mbedtls_gcm_setkey( &ctx, MBEDTLS_CIPHER_ID_AES, k, 128);
@@ -830,7 +839,7 @@ int mbedtls_gcm_self_test( int verbose )
 {
     mbedtls_gcm_context ctx;
     unsigned char buf[64];
-    //unsigned char tag_buf[16];
+    unsigned char tag_buf[CRYPTO_ABYTES];
     int i, j, ret;
     mbedtls_cipher_id_t cipher = MBEDTLS_CIPHER_ID_AES;
 

mbed_aes_gcm/genkat_aead.c

@@ -84,7 +84,6 @@ int generate_test_vectors()
 	init_buffer(nonce, sizeof(nonce));
 	init_buffer(msg, sizeof(msg));
 	init_buffer(ad, sizeof(ad));
-  init_buffer(ct, sizeof(ct));
 
 	sprintf(fileName, "LWC_AEAD_KAT_%d_%d.txt", (CRYPTO_KEYBYTES * 8), (CRYPTO_NPUBBYTES * 8));
 
@@ -97,7 +96,6 @@ int generate_test_vectors()
 
 		for (unsigned long long adlen = 0; adlen <= MAX_ASSOCIATED_DATA_LENGTH; adlen++) {
 
-      clen = mlen;
 
 			fprintf(fp, "Count = %d\n", count++);
 
@@ -119,10 +117,11 @@ int generate_test_vectors()
 
 			fprintf(fp, "\n");
 
-      mlen2 = clen;
+
 			if ((func_ret = crypto_aead_decrypt(msg2, &mlen2, NULL, ct, clen, ad, adlen, nonce, key)) != 0) {
 				fprintf(fp, "crypto_aead_decrypt returned <%d>\n", func_ret);
 				ret_val = KAT_CRYPTO_FAILURE;
+			  fprint_bstr(fp, "PT = ", msg2, mlen2);
 				break;
 			}