Add first draft or read_server_params

include/mbedtls/ecjpake.h

@@ -39,6 +39,7 @@ typedef struct
     mbedtls_ecp_point X2;               /**< Public key two                 */
     mbedtls_ecp_point X3;               /**< Public key three               */
     mbedtls_ecp_point X4;               /**< Public key four                */
+    mbedtls_ecp_point Xp;               /**< Peer's public key (Xs or Xc)   */
 
     mbedtls_mpi xa;                     /**< Our first secret (x1 or x3)    */
     mbedtls_mpi xb;                     /**< Our second secret (x2 or x4)   */
@@ -126,6 +127,7 @@ int mbedtls_ecjpake_tls_write_server_ext( mbedtls_ecjpake_context *ctx,
                             unsigned char *buf, size_t len, size_t *olen,
                             int (*f_rng)(void *, unsigned char *, size_t),
                             void *p_rng );
+
 /*
  * \brief           Read and process contents of the ServerHello extension
  *                  (excluding extension type and length bytes)
@@ -141,6 +143,40 @@ int mbedtls_ecjpake_tls_read_server_ext( mbedtls_ecjpake_context *ctx,
                                          const unsigned char *buf,
                                          size_t len );
 
+/*
+ * \brief           Generate and write ServerECJPAKEParams
+ *                  (the contents for the ServerKeyExchange)
+ *
+ * \param ctx       Context to use
+ * \param buf       Buffer to write the contents to
+ * \param len       Buffer size
+ * \param olen      Will be updated with the number of bytes written
+ * \param f_rng     RNG function
+ * \param p_rng     RNG parameter
+ *
+ * \return          0 if successfull,
+ *                  a negative error code otherwise
+ */
+int mbedtls_ecjpake_tls_write_server_params( mbedtls_ecjpake_context *ctx,
+                            unsigned char *buf, size_t len, size_t *olen,
+                            int (*f_rng)(void *, unsigned char *, size_t),
+                            void *p_rng );
+
+/*
+ * \brief           Read and process ServerECJPAKEParams
+ *                  (the contents for the ServerKeyExchange)
+ *
+ * \param ctx       Context to use
+ * \param buf       Pointer to the message
+ * \param len       Message length
+ *
+ * \return          0 if successfull,
+ *                  a negative error code otherwise
+ */
+int mbedtls_ecjpake_tls_read_server_params( mbedtls_ecjpake_context *ctx,
+                                            const unsigned char *buf,
+                                            size_t len );
+
 /*
  * \brief           Free a context's content
  *

library/ecjpake.c

@@ -51,6 +51,7 @@ void mbedtls_ecjpake_init( mbedtls_ecjpake_context *ctx )
     mbedtls_ecp_point_init( &ctx->X2 );
     mbedtls_ecp_point_init( &ctx->X3 );
     mbedtls_ecp_point_init( &ctx->X4 );
+    mbedtls_ecp_point_init( &ctx->Xp );
 
     mbedtls_mpi_init( &ctx->xa );
     mbedtls_mpi_init( &ctx->xb );
@@ -72,6 +73,7 @@ void mbedtls_ecjpake_free( mbedtls_ecjpake_context *ctx )
     mbedtls_ecp_point_free( &ctx->X2 );
     mbedtls_ecp_point_free( &ctx->X3 );
     mbedtls_ecp_point_free( &ctx->X4 );
+    mbedtls_ecp_point_free( &ctx->Xp );
 
     mbedtls_mpi_free( &ctx->xa );
     mbedtls_mpi_free( &ctx->xb );
@@ -497,6 +499,67 @@ int mbedtls_ecjpake_tls_write_server_ext( mbedtls_ecjpake_context *ctx,
                                 "server", buf, len, olen, f_rng, p_rng ) );
 }
 
+/*
+ * Read and process ServerECJPAKEParams (7.4.2.5)
+ */
+int mbedtls_ecjpake_tls_read_server_params( mbedtls_ecjpake_context *ctx,
+                                            const unsigned char *buf,
+                                            size_t len )
+{
+    int ret;
+    const unsigned char *p = buf;
+    const unsigned char *end = buf + len;
+    mbedtls_ecp_group grp;
+    mbedtls_ecp_point GB;
+    mbedtls_mpi one;
+
+    mbedtls_ecp_group_init( &grp );
+    mbedtls_ecp_point_init( &GB );
+    mbedtls_mpi_init( &one );
+
+    /*
+     * We need that before parsing in order to check Xs as we read it
+     * GB = X1 + X2 + X3 (7.4.2.5.1)
+     */
+    MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &one, 1 ) );
+    MBEDTLS_MPI_CHK( mbedtls_ecp_muladd( &ctx->grp, &GB, &one, &ctx->X1,
+                                                         &one, &ctx->X2 ) );
+    MBEDTLS_MPI_CHK( mbedtls_ecp_muladd( &ctx->grp, &GB, &one, &GB,
+                                                         &one, &ctx->X3 ) );
+
+    /*
+     * struct {
+     *     ECParameters curve_params;
+     *     ECJPAKEKeyKP ecjpake_key_kp;
+     * } ServerECJPAKEParams;
+     */
+    MBEDTLS_MPI_CHK( mbedtls_ecp_tls_read_group( &grp, &p, len ) );
+    MBEDTLS_MPI_CHK( ecjpake_kkp_read( ctx->md_info, &ctx->grp,
+                            &GB, &ctx->Xp, "server", &p, end ) );
+
+    if( p != end )
+    {
+        ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
+        goto cleanup;
+    }
+
+    /*
+     * Xs already checked, only thing left to check is the group
+     */
+    if( grp.id != ctx->grp.id )
+    {
+        ret = MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE;
+        goto cleanup;
+    }
+
+cleanup:
+    mbedtls_ecp_group_free( &grp );
+    mbedtls_ecp_point_free( &GB );
+    mbedtls_mpi_free( &one );
+
+    return( ret );
+}
+
 #if defined(MBEDTLS_SELF_TEST)
 
 #if defined(MBEDTLS_PLATFORM_C)
@@ -515,7 +578,7 @@ int mbedtls_ecjpake_self_test( int verbose )
 }
 #else
 
-static const unsigned char ecjpake_test_kkpp[] = {
+static const unsigned char ecjpake_test_cli_ext[] = {
     0x41, 0x04, 0xac, 0xcf, 0x01, 0x06, 0xef, 0x85, 0x8f, 0xa2, 0xd9, 0x19,
     0x33, 0x13, 0x46, 0x80, 0x5a, 0x78, 0xb5, 0x8b, 0xba, 0xd0, 0xb8, 0x44,
     0xe5, 0xc7, 0x89, 0x28, 0x79, 0x14, 0x61, 0x87, 0xdd, 0x26, 0x66, 0xad,
@@ -546,6 +609,55 @@ static const unsigned char ecjpake_test_kkpp[] = {
     0x8b, 0x01, 0x0e, 0x44, 0x3e, 0xf0
 };
 
+static const unsigned char ecjpake_test_srv_ext[] = {
+    0x41, 0x04, 0x7e, 0xa6, 0xe3, 0xa4, 0x48, 0x70, 0x37, 0xa9, 0xe0, 0xdb,
+    0xd7, 0x92, 0x62, 0xb2, 0xcc, 0x27, 0x3e, 0x77, 0x99, 0x30, 0xfc, 0x18,
+    0x40, 0x9a, 0xc5, 0x36, 0x1c, 0x5f, 0xe6, 0x69, 0xd7, 0x02, 0xe1, 0x47,
+    0x79, 0x0a, 0xeb, 0x4c, 0xe7, 0xfd, 0x65, 0x75, 0xab, 0x0f, 0x6c, 0x7f,
+    0xd1, 0xc3, 0x35, 0x93, 0x9a, 0xa8, 0x63, 0xba, 0x37, 0xec, 0x91, 0xb7,
+    0xe3, 0x2b, 0xb0, 0x13, 0xbb, 0x2b, 0x41, 0x04, 0x09, 0xf8, 0x5b, 0x3d,
+    0x20, 0xeb, 0xd7, 0x88, 0x5c, 0xe4, 0x64, 0xc0, 0x8d, 0x05, 0x6d, 0x64,
+    0x28, 0xfe, 0x4d, 0xd9, 0x28, 0x7a, 0xa3, 0x65, 0xf1, 0x31, 0xf4, 0x36,
+    0x0f, 0xf3, 0x86, 0xd8, 0x46, 0x89, 0x8b, 0xc4, 0xb4, 0x15, 0x83, 0xc2,
+    0xa5, 0x19, 0x7f, 0x65, 0xd7, 0x87, 0x42, 0x74, 0x6c, 0x12, 0xa5, 0xec,
+    0x0a, 0x4f, 0xfe, 0x2f, 0x27, 0x0a, 0x75, 0x0a, 0x1d, 0x8f, 0xb5, 0x16,
+    0x20, 0x93, 0x4d, 0x74, 0xeb, 0x43, 0xe5, 0x4d, 0xf4, 0x24, 0xfd, 0x96,
+    0x30, 0x6c, 0x01, 0x17, 0xbf, 0x13, 0x1a, 0xfa, 0xbf, 0x90, 0xa9, 0xd3,
+    0x3d, 0x11, 0x98, 0xd9, 0x05, 0x19, 0x37, 0x35, 0x14, 0x41, 0x04, 0x19,
+    0x0a, 0x07, 0x70, 0x0f, 0xfa, 0x4b, 0xe6, 0xae, 0x1d, 0x79, 0xee, 0x0f,
+    0x06, 0xae, 0xb5, 0x44, 0xcd, 0x5a, 0xdd, 0xaa, 0xbe, 0xdf, 0x70, 0xf8,
+    0x62, 0x33, 0x21, 0x33, 0x2c, 0x54, 0xf3, 0x55, 0xf0, 0xfb, 0xfe, 0xc7,
+    0x83, 0xed, 0x35, 0x9e, 0x5d, 0x0b, 0xf7, 0x37, 0x7a, 0x0f, 0xc4, 0xea,
+    0x7a, 0xce, 0x47, 0x3c, 0x9c, 0x11, 0x2b, 0x41, 0xcc, 0xd4, 0x1a, 0xc5,
+    0x6a, 0x56, 0x12, 0x41, 0x04, 0x36, 0x0a, 0x1c, 0xea, 0x33, 0xfc, 0xe6,
+    0x41, 0x15, 0x64, 0x58, 0xe0, 0xa4, 0xea, 0xc2, 0x19, 0xe9, 0x68, 0x31,
+    0xe6, 0xae, 0xbc, 0x88, 0xb3, 0xf3, 0x75, 0x2f, 0x93, 0xa0, 0x28, 0x1d,
+    0x1b, 0xf1, 0xfb, 0x10, 0x60, 0x51, 0xdb, 0x96, 0x94, 0xa8, 0xd6, 0xe8,
+    0x62, 0xa5, 0xef, 0x13, 0x24, 0xa3, 0xd9, 0xe2, 0x78, 0x94, 0xf1, 0xee,
+    0x4f, 0x7c, 0x59, 0x19, 0x99, 0x65, 0xa8, 0xdd, 0x4a, 0x20, 0x91, 0x84,
+    0x7d, 0x2d, 0x22, 0xdf, 0x3e, 0xe5, 0x5f, 0xaa, 0x2a, 0x3f, 0xb3, 0x3f,
+    0xd2, 0xd1, 0xe0, 0x55, 0xa0, 0x7a, 0x7c, 0x61, 0xec, 0xfb, 0x8d, 0x80,
+    0xec, 0x00, 0xc2, 0xc9, 0xeb, 0x12
+};
+
+static const unsigned char ecjpake_test_srv_kx[] = {
+    0x03, 0x00, 0x17, 0x41, 0x04, 0x0f, 0xb2, 0x2b, 0x1d, 0x5d, 0x11, 0x23,
+    0xe0, 0xef, 0x9f, 0xeb, 0x9d, 0x8a, 0x2e, 0x59, 0x0a, 0x1f, 0x4d, 0x7c,
+    0xed, 0x2c, 0x2b, 0x06, 0x58, 0x6e, 0x8f, 0x2a, 0x16, 0xd4, 0xeb, 0x2f,
+    0xda, 0x43, 0x28, 0xa2, 0x0b, 0x07, 0xd8, 0xfd, 0x66, 0x76, 0x54, 0xca,
+    0x18, 0xc5, 0x4e, 0x32, 0xa3, 0x33, 0xa0, 0x84, 0x54, 0x51, 0xe9, 0x26,
+    0xee, 0x88, 0x04, 0xfd, 0x7a, 0xf0, 0xaa, 0xa7, 0xa6, 0x41, 0x04, 0x55,
+    0x16, 0xea, 0x3e, 0x54, 0xa0, 0xd5, 0xd8, 0xb2, 0xce, 0x78, 0x6b, 0x38,
+    0xd3, 0x83, 0x37, 0x00, 0x29, 0xa5, 0xdb, 0xe4, 0x45, 0x9c, 0x9d, 0xd6,
+    0x01, 0xb4, 0x08, 0xa2, 0x4a, 0xe6, 0x46, 0x5c, 0x8a, 0xc9, 0x05, 0xb9,
+    0xeb, 0x03, 0xb5, 0xd3, 0x69, 0x1c, 0x13, 0x9e, 0xf8, 0x3f, 0x1c, 0xd4,
+    0x20, 0x0f, 0x6c, 0x9c, 0xd4, 0xec, 0x39, 0x22, 0x18, 0xa5, 0x9e, 0xd2,
+    0x43, 0xd3, 0xc8, 0x20, 0xff, 0x72, 0x4a, 0x9a, 0x70, 0xb8, 0x8c, 0xb8,
+    0x6f, 0x20, 0xb4, 0x34, 0xc6, 0x86, 0x5a, 0xa1, 0xcd, 0x79, 0x06, 0xdd,
+    0x7c, 0x9b, 0xce, 0x35, 0x25, 0xf5, 0x08, 0x27, 0x6f, 0x26, 0x83, 0x6c
+};
+
+#if 0
 /* For tests we don't need a secure RNG;
  * use the LGC from Numerical Recipes for simplicity */
 static int ecjpake_lgc( void *p, unsigned char *out, size_t len )
@@ -564,6 +676,7 @@ static int ecjpake_lgc( void *p, unsigned char *out, size_t len )
 
     return( 0 );
 }
+#endif
 
 #define TEST_ASSERT( x )    \
     do {                    \
@@ -583,8 +696,6 @@ int mbedtls_ecjpake_self_test( int verbose )
 {
     int ret;
     mbedtls_ecjpake_context ctx;
-    unsigned char buf[1000];
-    size_t len;
     char secret[] = "test passphrase";
 
     mbedtls_ecjpake_init( &ctx );
@@ -596,30 +707,23 @@ int mbedtls_ecjpake_self_test( int verbose )
                     sizeof( secret ) - 1 ) == 0 );
 
     if( verbose != 0 )
-        mbedtls_printf( "  ECJPAKE test #1 (client ext read): " );
+        mbedtls_printf( "  ECJPAKE test #1 (read in sequence): " );
+
+    /* This is not realistic because it uses the same context for client and
+     * server, but it ensures the context has all of X1 to X4 when reading the
+     * key exchange message, so this is convenient for a quick test */
 
     TEST_ASSERT( mbedtls_ecjpake_tls_read_client_ext( &ctx,
-                                    ecjpake_test_kkpp,
+                                    ecjpake_test_cli_ext,
-                            sizeof( ecjpake_test_kkpp ) ) == 0 );
+                            sizeof( ecjpake_test_cli_ext ) ) == 0 );
 
-    /* Corrupt message */
+    TEST_ASSERT( mbedtls_ecjpake_tls_read_server_ext( &ctx,
-    memcpy( buf, ecjpake_test_kkpp, sizeof( ecjpake_test_kkpp ) );
+                                    ecjpake_test_srv_ext,
-    buf[sizeof( ecjpake_test_kkpp ) - 1]--;
+                            sizeof( ecjpake_test_srv_ext ) ) == 0 );
-    TEST_ASSERT( mbedtls_ecjpake_tls_read_client_ext( &ctx,
-                                    buf, sizeof( ecjpake_test_kkpp ) )
-                    == MBEDTLS_ERR_ECP_VERIFY_FAILED );
 
-    if( verbose != 0 )
+    TEST_ASSERT( mbedtls_ecjpake_tls_read_server_params( &ctx,
-        mbedtls_printf( "passed\n" );
+                                    ecjpake_test_srv_kx,
-
+                            sizeof( ecjpake_test_srv_kx ) ) == 0 );
-    if( verbose != 0 )
-        mbedtls_printf( "  ECJPAKE test #2 (client ext write/read): " );
-
-    TEST_ASSERT( mbedtls_ecjpake_tls_write_client_ext( &ctx,
-                                     buf, sizeof( buf ), &len,
-                                     ecjpake_lgc, NULL ) == 0 );
-
-    TEST_ASSERT( mbedtls_ecjpake_tls_read_client_ext( &ctx, buf, len ) == 0 );
 
     if( verbose != 0 )
         mbedtls_printf( "passed\n" );