diff --git a/ChangeLog b/ChangeLog
index 3f5e56f9d4..4273dda06d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -45,6 +45,10 @@ Features
      line arguments.
    * New unit tests for timing. Improve the self-test to be more robust
      when run on a heavily-loaded machine.
+   * Add alternative implementation support for CCM and CMAC (MBEDTLS_CCM_ALT,
+     MBEDTLS_CMAC_ALT). Submitted by Steve Cooreman, Silicon Labs.
+   * Add support for alternative implementations of GCM, selected by the
+     configuration flag MBEDTLS_GCM_ALT.
 
 New deprecations
    * Deprecate usage of RSA primitives with non-matching key-type
@@ -97,11 +101,14 @@ Bugfix
      MilenkoMitrovic, #1104
    * Fix mbedtls_timing_alarm(0) on Unix.
    * Fix use of uninitialized memory in mbedtls_timing_get_timer when reset=1.
+   * Fix possible memory leaks in mbedtls_gcm_self_test().
+   * Added missing return code checks in mbedtls_aes_self_test().
 
 Changes
    * Extend cert_write example program by options to set the CRT version
      and the message digest. Further, allow enabling/disabling of authority
      identifier, subject identifier and basic constraints extensions.
+   * Only run AES-192 self-test if AES-192 is available. Fixes #963.
 
 = mbed TLS 2.6.0 branch released 2017-08-10
 
diff --git a/include/mbedtls/aes.h b/include/mbedtls/aes.h
index 1829f72402..c8dd0f355b 100644
--- a/include/mbedtls/aes.h
+++ b/include/mbedtls/aes.h
@@ -36,9 +36,13 @@
 #define MBEDTLS_AES_ENCRYPT     1
 #define MBEDTLS_AES_DECRYPT     0
 
+/* Error codes in range 0x0020-0x0022 */
 #define MBEDTLS_ERR_AES_INVALID_KEY_LENGTH                -0x0020  /**< Invalid key length. */
 #define MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH              -0x0022  /**< Invalid data input length. */
 
+/* Error codes in range 0x0023-0x0023 */
+#define MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE               -0x0023  /**< Feature not available, e.g. unsupported AES key size. */
+
 #if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
     !defined(inline) && !defined(__cplusplus)
 #define inline __inline
diff --git a/include/mbedtls/ccm.h b/include/mbedtls/ccm.h
index ef75839baa..579402fd48 100644
--- a/include/mbedtls/ccm.h
+++ b/include/mbedtls/ccm.h
@@ -28,6 +28,10 @@
 #define MBEDTLS_ERR_CCM_BAD_INPUT      -0x000D /**< Bad input parameters to function. */
 #define MBEDTLS_ERR_CCM_AUTH_FAILED    -0x000F /**< Authenticated decryption failed. */
 
+#if !defined(MBEDTLS_CCM_ALT)
+// Regular implementation
+//
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -125,6 +129,18 @@ int mbedtls_ccm_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
                       const unsigned char *input, unsigned char *output,
                       const unsigned char *tag, size_t tag_len );
 
+#ifdef __cplusplus
+}
+#endif
+
+#else  /* !MBEDTLS_CCM_ALT */
+#include "ccm_alt.h"
+#endif /* !MBEDTLS_CCM_ALT */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
 /**
  * \brief          Checkup routine
diff --git a/include/mbedtls/cmac.h b/include/mbedtls/cmac.h
index 9a2b96bc92..4d3f2d2f4f 100644
--- a/include/mbedtls/cmac.h
+++ b/include/mbedtls/cmac.h
@@ -39,6 +39,8 @@ extern "C" {
 #define MBEDTLS_CIPHER_BLKSIZE_MAX      8   /* longest used by CMAC is 3DES */
 #endif
 
+#if !defined(MBEDTLS_CMAC_ALT)
+
 /**
  * CMAC context structure - Contains internal state information only
  */
@@ -154,6 +156,18 @@ int mbedtls_aes_cmac_prf_128( const unsigned char *key, size_t key_len,
                               unsigned char output[16] );
 #endif /* MBEDTLS_AES_C */
 
+#ifdef __cplusplus
+}
+#endif
+
+#else  /* !MBEDTLS_CMAC_ALT */
+#include "cmac_alt.h"
+#endif /* !MBEDTLS_CMAC_ALT */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #if defined(MBEDTLS_SELF_TEST) && ( defined(MBEDTLS_AES_C) || defined(MBEDTLS_DES_C) )
 /**
  * \brief          Checkup routine
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 69e997f85e..7c0681549e 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -266,7 +266,10 @@
 //#define MBEDTLS_ARC4_ALT
 //#define MBEDTLS_BLOWFISH_ALT
 //#define MBEDTLS_CAMELLIA_ALT
+//#define MBEDTLS_CCM_ALT
+//#define MBEDTLS_CMAC_ALT
 //#define MBEDTLS_DES_ALT
+//#define MBEDTLS_GCM_ALT
 //#define MBEDTLS_XTEA_ALT
 //#define MBEDTLS_MD2_ALT
 //#define MBEDTLS_MD4_ALT
diff --git a/include/mbedtls/error.h b/include/mbedtls/error.h
index d51bcdec36..4eb7b78ebf 100644
--- a/include/mbedtls/error.h
+++ b/include/mbedtls/error.h
@@ -52,7 +52,7 @@
  * GCM       2  0x0012-0x0014
  * BLOWFISH  2  0x0016-0x0018
  * THREADING 3  0x001A-0x001E
- * AES       2  0x0020-0x0022
+ * AES       2  0x0020-0x0022   0x0023-0x0023
  * CAMELLIA  2  0x0024-0x0026
  * XTEA      1  0x0028-0x0028
  * BASE64    2  0x002A-0x002C
diff --git a/include/mbedtls/gcm.h b/include/mbedtls/gcm.h
index 1b77aaedd4..8f3b565757 100644
--- a/include/mbedtls/gcm.h
+++ b/include/mbedtls/gcm.h
@@ -33,6 +33,8 @@
 #define MBEDTLS_ERR_GCM_AUTH_FAILED                       -0x0012  /**< Authenticated decryption failed. */
 #define MBEDTLS_ERR_GCM_BAD_INPUT                         -0x0014  /**< Bad input parameters to function. */
 
+#if !defined(MBEDTLS_GCM_ALT)
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -206,6 +208,18 @@ int mbedtls_gcm_finish( mbedtls_gcm_context *ctx,
  */
 void mbedtls_gcm_free( mbedtls_gcm_context *ctx );
 
+#ifdef __cplusplus
+}
+#endif
+
+#else  /* !MBEDTLS_GCM_ALT */
+#include "gcm_alt.h"
+#endif /* !MBEDTLS_GCM_ALT */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /**
  * \brief          Checkup routine
  *
@@ -217,4 +231,5 @@ int mbedtls_gcm_self_test( int verbose );
 }
 #endif
 
+
 #endif /* gcm.h */
diff --git a/library/aes.c b/library/aes.c
index 58603849cc..dba4a5f578 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -1235,9 +1235,11 @@ static const int aes_test_ctr_len[3] =
  */
 int mbedtls_aes_self_test( int verbose )
 {
-    int ret = 0, i, j, u, v;
+    int ret = 0, i, j, u, mode;
+    unsigned int keybits;
     unsigned char key[32];
     unsigned char buf[64];
+    const unsigned char *aes_tests;
 #if defined(MBEDTLS_CIPHER_MODE_CBC) || defined(MBEDTLS_CIPHER_MODE_CFB)
     unsigned char iv[16];
 #endif
@@ -1263,45 +1265,52 @@ int mbedtls_aes_self_test( int verbose )
     for( i = 0; i < 6; i++ )
     {
         u = i >> 1;
-        v = i  & 1;
+        keybits = 128 + u * 64;
+        mode = i & 1;
 
         if( verbose != 0 )
-            mbedtls_printf( "  AES-ECB-%3d (%s): ", 128 + u * 64,
-                             ( v == MBEDTLS_AES_DECRYPT ) ? "dec" : "enc" );
+            mbedtls_printf( "  AES-ECB-%3d (%s): ", keybits,
+                            ( mode == MBEDTLS_AES_DECRYPT ) ? "dec" : "enc" );
 
         memset( buf, 0, 16 );
 
-        if( v == MBEDTLS_AES_DECRYPT )
+        if( mode == MBEDTLS_AES_DECRYPT )
         {
-            mbedtls_aes_setkey_dec( &ctx, key, 128 + u * 64 );
-
-            for( j = 0; j < 10000; j++ )
-                mbedtls_aes_crypt_ecb( &ctx, v, buf, buf );
-
-            if( memcmp( buf, aes_test_ecb_dec[u], 16 ) != 0 )
-            {
-                if( verbose != 0 )
-                    mbedtls_printf( "failed\n" );
-
-                ret = 1;
-                goto exit;
-            }
+            ret = mbedtls_aes_setkey_dec( &ctx, key, keybits );
+            aes_tests = aes_test_ecb_dec[u];
         }
         else
         {
-            mbedtls_aes_setkey_enc( &ctx, key, 128 + u * 64 );
+            ret = mbedtls_aes_setkey_enc( &ctx, key, keybits );
+            aes_tests = aes_test_ecb_enc[u];
+        }
 
-            for( j = 0; j < 10000; j++ )
-                mbedtls_aes_crypt_ecb( &ctx, v, buf, buf );
+        /*
+         * 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( memcmp( buf, aes_test_ecb_enc[u], 16 ) != 0 )
-            {
-                if( verbose != 0 )
-                    mbedtls_printf( "failed\n" );
-
-                ret = 1;
+        for( j = 0; j < 10000; j++ )
+        {
+            ret = mbedtls_aes_crypt_ecb( &ctx, mode, buf, buf );
+            if( ret != 0 )
                 goto exit;
-            }
+        }
+
+        if( memcmp( buf, aes_tests, 16 ) != 0 )
+        {
+            ret = 1;
+            goto exit;
         }
 
         if( verbose != 0 )
@@ -1318,55 +1327,64 @@ int mbedtls_aes_self_test( int verbose )
     for( i = 0; i < 6; i++ )
     {
         u = i >> 1;
-        v = i  & 1;
+        keybits = 128 + u * 64;
+        mode = i & 1;
 
         if( verbose != 0 )
-            mbedtls_printf( "  AES-CBC-%3d (%s): ", 128 + u * 64,
-                             ( v == MBEDTLS_AES_DECRYPT ) ? "dec" : "enc" );
+            mbedtls_printf( "  AES-CBC-%3d (%s): ", keybits,
+                            ( mode == MBEDTLS_AES_DECRYPT ) ? "dec" : "enc" );
 
         memset( iv , 0, 16 );
         memset( prv, 0, 16 );
         memset( buf, 0, 16 );
 
-        if( v == MBEDTLS_AES_DECRYPT )
+        if( mode == MBEDTLS_AES_DECRYPT )
         {
-            mbedtls_aes_setkey_dec( &ctx, key, 128 + u * 64 );
-
-            for( j = 0; j < 10000; j++ )
-                mbedtls_aes_crypt_cbc( &ctx, v, 16, iv, buf, buf );
-
-            if( memcmp( buf, aes_test_cbc_dec[u], 16 ) != 0 )
-            {
-                if( verbose != 0 )
-                    mbedtls_printf( "failed\n" );
-
-                ret = 1;
-                goto exit;
-            }
+            ret = mbedtls_aes_setkey_dec( &ctx, key, keybits );
+            aes_tests = aes_test_cbc_dec[u];
         }
         else
         {
-            mbedtls_aes_setkey_enc( &ctx, key, 128 + u * 64 );
+            ret = mbedtls_aes_setkey_enc( &ctx, key, keybits );
+            aes_tests = aes_test_cbc_enc[u];
+        }
 
-            for( j = 0; j < 10000; j++ )
+        /*
+         * 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;
+        }
+
+        for( j = 0; j < 10000; j++ )
+        {
+            if( mode == MBEDTLS_AES_ENCRYPT )
             {
                 unsigned char tmp[16];
 
-                mbedtls_aes_crypt_cbc( &ctx, v, 16, iv, buf, buf );
-
                 memcpy( tmp, prv, 16 );
                 memcpy( prv, buf, 16 );
                 memcpy( buf, tmp, 16 );
             }
 
-            if( memcmp( prv, aes_test_cbc_enc[u], 16 ) != 0 )
-            {
-                if( verbose != 0 )
-                    mbedtls_printf( "failed\n" );
-
-                ret = 1;
+            ret = mbedtls_aes_crypt_cbc( &ctx, mode, 16, iv, buf, buf );
+            if( ret != 0 )
                 goto exit;
-            }
+
+        }
+
+        if( memcmp( buf, aes_tests, 16 ) != 0 )
+        {
+            ret = 1;
+            goto exit;
         }
 
         if( verbose != 0 )
@@ -1384,45 +1402,52 @@ int mbedtls_aes_self_test( int verbose )
     for( i = 0; i < 6; i++ )
     {
         u = i >> 1;
-        v = i  & 1;
+        keybits = 128 + u * 64;
+        mode = i & 1;
 
         if( verbose != 0 )
-            mbedtls_printf( "  AES-CFB128-%3d (%s): ", 128 + u * 64,
-                             ( v == MBEDTLS_AES_DECRYPT ) ? "dec" : "enc" );
+            mbedtls_printf( "  AES-CFB128-%3d (%s): ", keybits,
+                            ( mode == MBEDTLS_AES_DECRYPT ) ? "dec" : "enc" );
 
         memcpy( iv,  aes_test_cfb128_iv, 16 );
-        memcpy( key, aes_test_cfb128_key[u], 16 + u * 8 );
+        memcpy( key, aes_test_cfb128_key[u], keybits / 8 );
 
         offset = 0;
-        mbedtls_aes_setkey_enc( &ctx, key, 128 + u * 64 );
+        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( v == MBEDTLS_AES_DECRYPT )
+        if( mode == MBEDTLS_AES_DECRYPT )
         {
             memcpy( buf, aes_test_cfb128_ct[u], 64 );
-            mbedtls_aes_crypt_cfb128( &ctx, v, 64, &offset, iv, buf, buf );
-
-            if( memcmp( buf, aes_test_cfb128_pt, 64 ) != 0 )
-            {
-                if( verbose != 0 )
-                    mbedtls_printf( "failed\n" );
-
-                ret = 1;
-                goto exit;
-            }
+            aes_tests = aes_test_cfb128_pt;
         }
         else
         {
             memcpy( buf, aes_test_cfb128_pt, 64 );
-            mbedtls_aes_crypt_cfb128( &ctx, v, 64, &offset, iv, buf, buf );
+            aes_tests = aes_test_cfb128_ct[u];
+        }
 
-            if( memcmp( buf, aes_test_cfb128_ct[u], 64 ) != 0 )
-            {
-                if( verbose != 0 )
-                    mbedtls_printf( "failed\n" );
+        ret = mbedtls_aes_crypt_cfb128( &ctx, mode, 64, &offset, iv, buf, buf );
+        if( ret != 0 )
+            goto exit;
 
-                ret = 1;
-                goto exit;
-            }
+        if( memcmp( buf, aes_tests, 64 ) != 0 )
+        {
+            ret = 1;
+            goto exit;
         }
 
         if( verbose != 0 )
@@ -1440,51 +1465,41 @@ int mbedtls_aes_self_test( int verbose )
     for( i = 0; i < 6; i++ )
     {
         u = i >> 1;
-        v = i  & 1;
+        mode = i & 1;
 
         if( verbose != 0 )
             mbedtls_printf( "  AES-CTR-128 (%s): ",
-                             ( v == MBEDTLS_AES_DECRYPT ) ? "dec" : "enc" );
+                            ( mode == MBEDTLS_AES_DECRYPT ) ? "dec" : "enc" );
 
         memcpy( nonce_counter, aes_test_ctr_nonce_counter[u], 16 );
         memcpy( key, aes_test_ctr_key[u], 16 );
 
         offset = 0;
-        mbedtls_aes_setkey_enc( &ctx, key, 128 );
+        if( ( ret = mbedtls_aes_setkey_enc( &ctx, key, 128 ) ) != 0 )
+            goto exit;
 
-        if( v == MBEDTLS_AES_DECRYPT )
+        len = aes_test_ctr_len[u];
+
+        if( mode == MBEDTLS_AES_DECRYPT )
         {
-            len = aes_test_ctr_len[u];
             memcpy( buf, aes_test_ctr_ct[u], len );
-
-            mbedtls_aes_crypt_ctr( &ctx, len, &offset, nonce_counter, stream_block,
-                           buf, buf );
-
-            if( memcmp( buf, aes_test_ctr_pt[u], len ) != 0 )
-            {
-                if( verbose != 0 )
-                    mbedtls_printf( "failed\n" );
-
-                ret = 1;
-                goto exit;
-            }
+            aes_tests = aes_test_ctr_pt[u];
         }
         else
         {
-            len = aes_test_ctr_len[u];
             memcpy( buf, aes_test_ctr_pt[u], len );
+            aes_tests = aes_test_ctr_ct[u];
+        }
 
-            mbedtls_aes_crypt_ctr( &ctx, len, &offset, nonce_counter, stream_block,
-                           buf, buf );
+        ret = mbedtls_aes_crypt_ctr( &ctx, len, &offset, nonce_counter,
+                                     stream_block, buf, buf );
+        if( ret != 0 )
+            goto exit;
 
-            if( memcmp( buf, aes_test_ctr_ct[u], len ) != 0 )
-            {
-                if( verbose != 0 )
-                    mbedtls_printf( "failed\n" );
-
-                ret = 1;
-                goto exit;
-            }
+        if( memcmp( buf, aes_tests, len ) != 0 )
+        {
+            ret = 1;
+            goto exit;
         }
 
         if( verbose != 0 )
@@ -1498,6 +1513,9 @@ int mbedtls_aes_self_test( int verbose )
     ret = 0;
 
 exit:
+    if( ret != 0 && verbose != 0 )
+        mbedtls_printf( "failed\n" );
+
     mbedtls_aes_free( &ctx );
 
     return( ret );
diff --git a/library/ccm.c b/library/ccm.c
index 13a8fd1a24..9101e5f7c7 100644
--- a/library/ccm.c
+++ b/library/ccm.c
@@ -49,6 +49,8 @@
 #endif /* MBEDTLS_PLATFORM_C */
 #endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
 
+#if !defined(MBEDTLS_CCM_ALT)
+
 /* Implementation that should never be optimized out by the compiler */
 static void mbedtls_zeroize( void *v, size_t n ) {
     volatile unsigned char *p = (unsigned char*)v; while( n-- ) *p++ = 0;
@@ -348,6 +350,7 @@ int mbedtls_ccm_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
     return( 0 );
 }
 
+#endif /* !MBEDTLS_CCM_ALT */
 
 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
 /*
diff --git a/library/cmac.c b/library/cmac.c
index 6df56aa9a8..9dbff90386 100644
--- a/library/cmac.c
+++ b/library/cmac.c
@@ -65,6 +65,8 @@
 #endif /* MBEDTLS_SELF_TEST */
 #endif /* MBEDTLS_PLATFORM_C */
 
+#if !defined(MBEDTLS_CMAC_ALT) || defined(MBEDTLS_SELF_TEST)
+
 /* Implementation that should never be optimized out by the compiler */
 static void mbedtls_zeroize( void *v, size_t n ) {
     volatile unsigned char *p = (unsigned char*)v; while( n-- ) *p++ = 0;
@@ -164,7 +166,9 @@ exit:
 
     return( ret );
 }
+#endif /* !defined(MBEDTLS_CMAC_ALT) || defined(MBEDTLS_SELF_TEST) */
 
+#if !defined(MBEDTLS_CMAC_ALT)
 static void cmac_xor_block( unsigned char *output, const unsigned char *input1,
                             const unsigned char *input2,
                             const size_t block_size )
@@ -468,6 +472,8 @@ exit:
 }
 #endif /* MBEDTLS_AES_C */
 
+#endif /* !MBEDTLS_CMAC_ALT */
+
 #if defined(MBEDTLS_SELF_TEST)
 /*
  * CMAC test data for SP800-38B
diff --git a/library/error.c b/library/error.c
index 23e4953fca..151ca4eae9 100644
--- a/library/error.c
+++ b/library/error.c
@@ -520,6 +520,8 @@ void mbedtls_strerror( int ret, char *buf, size_t buflen )
         mbedtls_snprintf( buf, buflen, "AES - Invalid key length" );
     if( use_ret == -(MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH) )
         mbedtls_snprintf( buf, buflen, "AES - Invalid data input length" );
+    if( use_ret == -(MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE) )
+        mbedtls_snprintf( buf, buflen, "AES - Feature not available, e.g. unsupported AES key size" );
 #endif /* MBEDTLS_AES_C */
 
 #if defined(MBEDTLS_ASN1_PARSE_C)
diff --git a/library/gcm.c b/library/gcm.c
index fccb092bdd..294a86d3d4 100644
--- a/library/gcm.c
+++ b/library/gcm.c
@@ -46,6 +46,7 @@
 #endif
 
 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
+#include "mbedtls/aes.h"
 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
@@ -54,6 +55,8 @@
 #endif /* MBEDTLS_PLATFORM_C */
 #endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
 
+#if !defined(MBEDTLS_GCM_ALT)
+
 /*
  * 32-bit integer manipulation macros (big endian)
  */
@@ -508,6 +511,8 @@ void mbedtls_gcm_free( mbedtls_gcm_context *ctx )
     mbedtls_zeroize( ctx, sizeof( mbedtls_gcm_context ) );
 }
 
+#endif /* !MBEDTLS_GCM_ALT */
+
 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
 /*
  * AES-GCM test vectors from:
@@ -744,34 +749,48 @@ int mbedtls_gcm_self_test( int verbose )
     int i, j, ret;
     mbedtls_cipher_id_t cipher = MBEDTLS_CIPHER_ID_AES;
 
-    mbedtls_gcm_init( &ctx );
-
     for( j = 0; j < 3; j++ )
     {
         int key_len = 128 + 64 * j;
 
         for( i = 0; i < MAX_TESTS; i++ )
         {
+            mbedtls_gcm_init( &ctx );
+
             if( verbose != 0 )
                 mbedtls_printf( "  AES-GCM-%3d #%d (%s): ",
-                                 key_len, i, "enc" );
+                                key_len, i, "enc" );
 
-            mbedtls_gcm_setkey( &ctx, cipher, key[key_index[i]], key_len );
+            ret = mbedtls_gcm_setkey( &ctx, cipher, key[key_index[i]],
+                                      key_len );
+            /*
+             * 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 && key_len == 192 )
+            {
+                mbedtls_printf( "skipped\n" );
+                break;
+            }
+            else if( ret != 0 )
+            {
+                goto exit;
+            }
 
             ret = mbedtls_gcm_crypt_and_tag( &ctx, MBEDTLS_GCM_ENCRYPT,
-                                     pt_len[i],
-                                     iv[iv_index[i]], iv_len[i],
-                                     additional[add_index[i]], add_len[i],
-                                     pt[pt_index[i]], buf, 16, tag_buf );
+                                        pt_len[i],
+                                        iv[iv_index[i]], iv_len[i],
+                                        additional[add_index[i]], add_len[i],
+                                        pt[pt_index[i]], buf, 16, tag_buf );
+            if( ret != 0 )
+                goto exit;
 
-            if( ret != 0 ||
-                memcmp( buf, ct[j * 6 + i], pt_len[i] ) != 0 ||
-                memcmp( tag_buf, tag[j * 6 + i], 16 ) != 0 )
+            if ( memcmp( buf, ct[j * 6 + i], pt_len[i] ) != 0 ||
+                 memcmp( tag_buf, tag[j * 6 + i], 16 ) != 0 )
             {
-                if( verbose != 0 )
-                    mbedtls_printf( "failed\n" );
-
-                return( 1 );
+                ret = 1;
+                goto exit;
             }
 
             mbedtls_gcm_free( &ctx );
@@ -779,26 +798,31 @@ int mbedtls_gcm_self_test( int verbose )
             if( verbose != 0 )
                 mbedtls_printf( "passed\n" );
 
+            mbedtls_gcm_init( &ctx );
+
             if( verbose != 0 )
                 mbedtls_printf( "  AES-GCM-%3d #%d (%s): ",
-                                 key_len, i, "dec" );
+                                key_len, i, "dec" );
 
-            mbedtls_gcm_setkey( &ctx, cipher, key[key_index[i]], key_len );
+            ret = mbedtls_gcm_setkey( &ctx, cipher, key[key_index[i]],
+                                      key_len );
+            if( ret != 0 )
+                goto exit;
 
             ret = mbedtls_gcm_crypt_and_tag( &ctx, MBEDTLS_GCM_DECRYPT,
-                                     pt_len[i],
-                                     iv[iv_index[i]], iv_len[i],
-                                     additional[add_index[i]], add_len[i],
-                                     ct[j * 6 + i], buf, 16, tag_buf );
+                                        pt_len[i],
+                                        iv[iv_index[i]], iv_len[i],
+                                        additional[add_index[i]], add_len[i],
+                                        ct[j * 6 + i], buf, 16, tag_buf );
 
-            if( ret != 0 ||
-                memcmp( buf, pt[pt_index[i]], pt_len[i] ) != 0 ||
+            if( ret != 0 )
+                goto exit;
+
+            if( memcmp( buf, pt[pt_index[i]], pt_len[i] ) != 0 ||
                 memcmp( tag_buf, tag[j * 6 + i], 16 ) != 0 )
             {
-                if( verbose != 0 )
-                    mbedtls_printf( "failed\n" );
-
-                return( 1 );
+                ret = 1;
+                goto exit;
             }
 
             mbedtls_gcm_free( &ctx );
@@ -806,66 +830,51 @@ int mbedtls_gcm_self_test( int verbose )
             if( verbose != 0 )
                 mbedtls_printf( "passed\n" );
 
+            mbedtls_gcm_init( &ctx );
+
             if( verbose != 0 )
                 mbedtls_printf( "  AES-GCM-%3d #%d split (%s): ",
-                                 key_len, i, "enc" );
+                                key_len, i, "enc" );
 
-            mbedtls_gcm_setkey( &ctx, cipher, key[key_index[i]], key_len );
+            ret = mbedtls_gcm_setkey( &ctx, cipher, key[key_index[i]],
+                                      key_len );
+            if( ret != 0 )
+                goto exit;
 
             ret = mbedtls_gcm_starts( &ctx, MBEDTLS_GCM_ENCRYPT,
-                              iv[iv_index[i]], iv_len[i],
-                              additional[add_index[i]], add_len[i] );
+                                      iv[iv_index[i]], iv_len[i],
+                                      additional[add_index[i]], add_len[i] );
             if( ret != 0 )
-            {
-                if( verbose != 0 )
-                    mbedtls_printf( "failed\n" );
-
-                return( 1 );
-            }
+                goto exit;
 
             if( pt_len[i] > 32 )
             {
                 size_t rest_len = pt_len[i] - 32;
                 ret = mbedtls_gcm_update( &ctx, 32, pt[pt_index[i]], buf );
                 if( ret != 0 )
-                {
-                    if( verbose != 0 )
-                        mbedtls_printf( "failed\n" );
-
-                    return( 1 );
-                }
+                    goto exit;
 
                 ret = mbedtls_gcm_update( &ctx, rest_len, pt[pt_index[i]] + 32,
                                   buf + 32 );
                 if( ret != 0 )
-                {
-                    if( verbose != 0 )
-                        mbedtls_printf( "failed\n" );
-
-                    return( 1 );
-                }
+                    goto exit;
             }
             else
             {
                 ret = mbedtls_gcm_update( &ctx, pt_len[i], pt[pt_index[i]], buf );
                 if( ret != 0 )
-                {
-                    if( verbose != 0 )
-                        mbedtls_printf( "failed\n" );
-
-                    return( 1 );
-                }
+                    goto exit;
             }
 
             ret = mbedtls_gcm_finish( &ctx, tag_buf, 16 );
-            if( ret != 0 ||
-                memcmp( buf, ct[j * 6 + i], pt_len[i] ) != 0 ||
+            if( ret != 0 )
+                goto exit;
+
+            if( memcmp( buf, ct[j * 6 + i], pt_len[i] ) != 0 ||
                 memcmp( tag_buf, tag[j * 6 + i], 16 ) != 0 )
             {
-                if( verbose != 0 )
-                    mbedtls_printf( "failed\n" );
-
-                return( 1 );
+                ret = 1;
+                goto exit;
             }
 
             mbedtls_gcm_free( &ctx );
@@ -873,80 +882,75 @@ int mbedtls_gcm_self_test( int verbose )
             if( verbose != 0 )
                 mbedtls_printf( "passed\n" );
 
+            mbedtls_gcm_init( &ctx );
+
             if( verbose != 0 )
                 mbedtls_printf( "  AES-GCM-%3d #%d split (%s): ",
-                                 key_len, i, "dec" );
+                                key_len, i, "dec" );
 
-            mbedtls_gcm_setkey( &ctx, cipher, key[key_index[i]], key_len );
+            ret = mbedtls_gcm_setkey( &ctx, cipher, key[key_index[i]],
+                                      key_len );
+            if( ret != 0 )
+                goto exit;
 
             ret = mbedtls_gcm_starts( &ctx, MBEDTLS_GCM_DECRYPT,
                               iv[iv_index[i]], iv_len[i],
                               additional[add_index[i]], add_len[i] );
             if( ret != 0 )
-            {
-                if( verbose != 0 )
-                    mbedtls_printf( "failed\n" );
-
-                return( 1 );
-            }
+                goto exit;
 
             if( pt_len[i] > 32 )
             {
                 size_t rest_len = pt_len[i] - 32;
                 ret = mbedtls_gcm_update( &ctx, 32, ct[j * 6 + i], buf );
                 if( ret != 0 )
-                {
-                    if( verbose != 0 )
-                        mbedtls_printf( "failed\n" );
-
-                    return( 1 );
-                }
+                    goto exit;
 
                 ret = mbedtls_gcm_update( &ctx, rest_len, ct[j * 6 + i] + 32,
-                                  buf + 32 );
+                                          buf + 32 );
                 if( ret != 0 )
-                {
-                    if( verbose != 0 )
-                        mbedtls_printf( "failed\n" );
-
-                    return( 1 );
-                }
+                    goto exit;
             }
             else
             {
-                ret = mbedtls_gcm_update( &ctx, pt_len[i], ct[j * 6 + i], buf );
+                ret = mbedtls_gcm_update( &ctx, pt_len[i], ct[j * 6 + i],
+                                          buf );
                 if( ret != 0 )
-                {
-                    if( verbose != 0 )
-                        mbedtls_printf( "failed\n" );
-
-                    return( 1 );
-                }
+                    goto exit;
             }
 
             ret = mbedtls_gcm_finish( &ctx, tag_buf, 16 );
-            if( ret != 0 ||
-                memcmp( buf, pt[pt_index[i]], pt_len[i] ) != 0 ||
+            if( ret != 0 )
+                goto exit;
+
+            if( memcmp( buf, pt[pt_index[i]], pt_len[i] ) != 0 ||
                 memcmp( tag_buf, tag[j * 6 + i], 16 ) != 0 )
             {
-                if( verbose != 0 )
-                    mbedtls_printf( "failed\n" );
-
-                return( 1 );
+                ret = 1;
+                goto exit;
             }
 
             mbedtls_gcm_free( &ctx );
 
             if( verbose != 0 )
                 mbedtls_printf( "passed\n" );
-
         }
     }
 
     if( verbose != 0 )
         mbedtls_printf( "\n" );
 
-    return( 0 );
+    ret = 0;
+
+exit:
+    if( ret != 0 )
+    {
+        if( verbose != 0 )
+            mbedtls_printf( "failed\n" );
+        mbedtls_gcm_free( &ctx );
+    }
+
+    return( ret );
 }
 
 #endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
diff --git a/library/version_features.c b/library/version_features.c
index 5cbe8aca37..49bba11ef6 100644
--- a/library/version_features.c
+++ b/library/version_features.c
@@ -96,9 +96,18 @@ static const char *features[] = {
 #if defined(MBEDTLS_CAMELLIA_ALT)
     "MBEDTLS_CAMELLIA_ALT",
 #endif /* MBEDTLS_CAMELLIA_ALT */
+#if defined(MBEDTLS_CCM_ALT)
+    "MBEDTLS_CCM_ALT",
+#endif /* MBEDTLS_CCM_ALT */
+#if defined(MBEDTLS_CMAC_ALT)
+    "MBEDTLS_CMAC_ALT",
+#endif /* MBEDTLS_CMAC_ALT */
 #if defined(MBEDTLS_DES_ALT)
     "MBEDTLS_DES_ALT",
 #endif /* MBEDTLS_DES_ALT */
+#if defined(MBEDTLS_GCM_ALT)
+    "MBEDTLS_GCM_ALT",
+#endif /* MBEDTLS_GCM_ALT */
 #if defined(MBEDTLS_XTEA_ALT)
     "MBEDTLS_XTEA_ALT",
 #endif /* MBEDTLS_XTEA_ALT */