Fix AES-OFB support for errors, tests and self-test
Adds error handling into mbedtls_aes_crypt_ofb for AES errors, a self-test
for the OFB mode using NIST SP 800-38A test vectors and adds a check to
potential return errors in setting the AES encryption key in the OFB test
suite.
diff --git a/library/aes.c b/library/aes.c
index ef14671..267944a 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -1074,13 +1074,17 @@
const unsigned char *input,
unsigned char *output )
{
+ int ret = 0;
size_t n = *iv_off;
while( length-- )
{
if( n == 0 )
- mbedtls_aes_crypt_ecb( ctx, MBEDTLS_AES_ENCRYPT, iv, iv );
-
+ {
+ ret = mbedtls_aes_crypt_ecb( ctx, MBEDTLS_AES_ENCRYPT, iv, iv );
+ if( ret != 0 )
+ goto exit;
+ }
*output++ = *input++ ^ iv[n];
n = ( n + 1 ) & 0x0F;
@@ -1088,7 +1092,8 @@
*iv_off = n;
- return( 0 );
+exit:
+ return( ret );
}
#endif /* MBEDTLS_CIPHER_MODE_OFB */
@@ -1247,6 +1252,72 @@
};
#endif /* MBEDTLS_CIPHER_MODE_CFB */
+#if defined(MBEDTLS_CIPHER_MODE_OFB)
+/*
+ * AES-OFB test vectors from:
+ *
+ * http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf
+ */
+static const unsigned char aes_test_ofb_key[3][32] =
+{
+ { 0x2B, 0x7E, 0x15, 0x16, 0x28, 0xAE, 0xD2, 0xA6,
+ 0xAB, 0xF7, 0x15, 0x88, 0x09, 0xCF, 0x4F, 0x3C },
+ { 0x8E, 0x73, 0xB0, 0xF7, 0xDA, 0x0E, 0x64, 0x52,
+ 0xC8, 0x10, 0xF3, 0x2B, 0x80, 0x90, 0x79, 0xE5,
+ 0x62, 0xF8, 0xEA, 0xD2, 0x52, 0x2C, 0x6B, 0x7B },
+ { 0x60, 0x3D, 0xEB, 0x10, 0x15, 0xCA, 0x71, 0xBE,
+ 0x2B, 0x73, 0xAE, 0xF0, 0x85, 0x7D, 0x77, 0x81,
+ 0x1F, 0x35, 0x2C, 0x07, 0x3B, 0x61, 0x08, 0xD7,
+ 0x2D, 0x98, 0x10, 0xA3, 0x09, 0x14, 0xDF, 0xF4 }
+};
+
+static const unsigned char aes_test_ofb_iv[16] =
+{
+ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+ 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F
+};
+
+static const unsigned char aes_test_ofb_pt[64] =
+{
+ 0x6B, 0xC1, 0xBE, 0xE2, 0x2E, 0x40, 0x9F, 0x96,
+ 0xE9, 0x3D, 0x7E, 0x11, 0x73, 0x93, 0x17, 0x2A,
+ 0xAE, 0x2D, 0x8A, 0x57, 0x1E, 0x03, 0xAC, 0x9C,
+ 0x9E, 0xB7, 0x6F, 0xAC, 0x45, 0xAF, 0x8E, 0x51,
+ 0x30, 0xC8, 0x1C, 0x46, 0xA3, 0x5C, 0xE4, 0x11,
+ 0xE5, 0xFB, 0xC1, 0x19, 0x1A, 0x0A, 0x52, 0xEF,
+ 0xF6, 0x9F, 0x24, 0x45, 0xDF, 0x4F, 0x9B, 0x17,
+ 0xAD, 0x2B, 0x41, 0x7B, 0xE6, 0x6C, 0x37, 0x10
+};
+
+static const unsigned char aes_test_ofb_ct[3][64] =
+{
+ { 0x3B, 0x3F, 0xD9, 0x2E, 0xB7, 0x2D, 0xAD, 0x20,
+ 0x33, 0x34, 0x49, 0xF8, 0xE8, 0x3C, 0xFB, 0x4A,
+ 0x77, 0x89, 0x50, 0x8d, 0x16, 0x91, 0x8f, 0x03,
+ 0xf5, 0x3c, 0x52, 0xda, 0xc5, 0x4e, 0xd8, 0x25,
+ 0x97, 0x40, 0x05, 0x1e, 0x9c, 0x5f, 0xec, 0xf6,
+ 0x43, 0x44, 0xf7, 0xa8, 0x22, 0x60, 0xed, 0xcc,
+ 0x30, 0x4c, 0x65, 0x28, 0xf6, 0x59, 0xc7, 0x78,
+ 0x66, 0xa5, 0x10, 0xd9, 0xc1, 0xd6, 0xae, 0x5e },
+ { 0xCD, 0xC8, 0x0D, 0x6F, 0xDD, 0xF1, 0x8C, 0xAB,
+ 0x34, 0xC2, 0x59, 0x09, 0xC9, 0x9A, 0x41, 0x74,
+ 0xfc, 0xc2, 0x8b, 0x8d, 0x4c, 0x63, 0x83, 0x7c,
+ 0x09, 0xe8, 0x17, 0x00, 0xc1, 0x10, 0x04, 0x01,
+ 0x8d, 0x9a, 0x9a, 0xea, 0xc0, 0xf6, 0x59, 0x6f,
+ 0x55, 0x9c, 0x6d, 0x4d, 0xaf, 0x59, 0xa5, 0xf2,
+ 0x6d, 0x9f, 0x20, 0x08, 0x57, 0xca, 0x6c, 0x3e,
+ 0x9c, 0xac, 0x52, 0x4b, 0xd9, 0xac, 0xc9, 0x2a },
+ { 0xDC, 0x7E, 0x84, 0xBF, 0xDA, 0x79, 0x16, 0x4B,
+ 0x7E, 0xCD, 0x84, 0x86, 0x98, 0x5D, 0x38, 0x60,
+ 0x4f, 0xeb, 0xdc, 0x67, 0x40, 0xd2, 0x0b, 0x3a,
+ 0xc8, 0x8f, 0x6a, 0xd8, 0x2a, 0x4f, 0xb0, 0x8d,
+ 0x71, 0xab, 0x47, 0xa0, 0x86, 0xe8, 0x6e, 0xed,
+ 0xf3, 0x9d, 0x1c, 0x5b, 0xba, 0x97, 0xc4, 0x08,
+ 0x01, 0x26, 0x14, 0x1d, 0x67, 0xf3, 0x7b, 0xe8,
+ 0x53, 0x8f, 0x5a, 0x8b, 0xe7, 0x40, 0xe4, 0x84 }
+};
+#endif /* MBEDTLS_CIPHER_MODE_OFB */
+
#if defined(MBEDTLS_CIPHER_MODE_CTR)
/*
* AES-CTR test vectors from:
@@ -1538,6 +1609,69 @@
mbedtls_printf( "\n" );
#endif /* MBEDTLS_CIPHER_MODE_CFB */
+#if defined(MBEDTLS_CIPHER_MODE_OFB)
+ /*
+ * OFB mode
+ */
+ for( i = 0; i < 6; i++ )
+ {
+ u = i >> 1;
+ keybits = 128 + u * 64;
+ mode = i & 1;
+
+ if( verbose != 0 )
+ mbedtls_printf( " AES-OFB-%3d (%s): ", keybits,
+ ( mode == MBEDTLS_AES_DECRYPT ) ? "dec" : "enc" );
+
+ memcpy( iv, aes_test_ofb_iv, 16 );
+ memcpy( key, aes_test_ofb_key[u], keybits / 8 );
+
+ offset = 0;
+ ret = mbedtls_aes_setkey_enc( &ctx, key, keybits );
+ /*
+ * AES-192 is an optional feature that may be unavailable when
+ * there is an alternative underlying implementation i.e. when
+ * MBEDTLS_AES_ALT is defined.
+ */
+ if( ret == MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE && keybits == 192 )
+ {
+ mbedtls_printf( "skipped\n" );
+ continue;
+ }
+ else if( ret != 0 )
+ {
+ goto exit;
+ }
+
+ if( mode == MBEDTLS_AES_DECRYPT )
+ {
+ memcpy( buf, aes_test_ofb_ct[u], 64 );
+ aes_tests = aes_test_ofb_pt;
+ }
+ else
+ {
+ memcpy( buf, aes_test_ofb_pt, 64 );
+ aes_tests = aes_test_ofb_ct[u];
+ }
+
+ ret = mbedtls_aes_crypt_ofb( &ctx, 64, &offset, iv, buf, buf );
+ if( ret != 0 )
+ goto exit;
+
+ if( memcmp( buf, aes_tests, 64 ) != 0 )
+ {
+ ret = 1;
+ goto exit;
+ }
+
+ if( verbose != 0 )
+ mbedtls_printf( "passed\n" );
+ }
+
+ if( verbose != 0 )
+ mbedtls_printf( "\n" );
+#endif /* MBEDTLS_CIPHER_MODE_OFB */
+
#if defined(MBEDTLS_CIPHER_MODE_CTR)
/*
* CTR mode
