From b47d0f893ed984efb039389989f8b44641b95425 Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Mon, 20 Dec 2021 17:34:40 +0800
Subject: [PATCH 01/16] Replace SUPPORTED_ELLIPTIC_CURVES with SUPPORTED_GROUPS

According to RFC7919 and RFC8442 , they are same.

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_cli.c | 16 ++++++++--------
 library/ssl_srv.c |  6 +++---
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 32d4969132..32befc24c7 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -302,10 +302,10 @@ static int ssl_write_signature_algorithms_ext( mbedtls_ssl_context *ssl,
 
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
-static int ssl_write_supported_elliptic_curves_ext( mbedtls_ssl_context *ssl,
-                                                    unsigned char *buf,
-                                                    const unsigned char *end,
-                                                    size_t *olen )
+static int ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
+                                           unsigned char *buf,
+                                           const unsigned char *end,
+                                           size_t *olen )
 {
     unsigned char *p = buf;
     unsigned char *elliptic_curve_list = p + 6;
@@ -351,7 +351,7 @@ static int ssl_write_supported_elliptic_curves_ext( mbedtls_ssl_context *ssl,
     if( elliptic_curve_len == 0 )
         return( MBEDTLS_ERR_SSL_BAD_CONFIG );
 
-    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES, p, 0 );
+    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SUPPORTED_GROUPS, p, 0 );
     p += 2;
 
     MBEDTLS_PUT_UINT16_BE( elliptic_curve_len + 2, p, 0 );
@@ -1206,10 +1206,10 @@ static int ssl_write_client_hello( mbedtls_ssl_context *ssl )
     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
     if( uses_ec )
     {
-        if( ( ret = ssl_write_supported_elliptic_curves_ext( ssl, p + 2 + ext_len,
-                                                             end, &olen ) ) != 0 )
+        if( ( ret = ssl_write_supported_groups_ext( ssl, p + 2 + ext_len,
+                                                    end, &olen ) ) != 0 )
         {
-            MBEDTLS_SSL_DEBUG_RET( 1, "ssl_write_supported_elliptic_curves_ext", ret );
+            MBEDTLS_SSL_DEBUG_RET( 1, "ssl_write_supported_groups_ext", ret );
             return( ret );
         }
         ext_len += olen;
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index f34f2de30f..977ecc8f33 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -317,7 +317,7 @@ static int ssl_parse_signature_algorithms_ext( mbedtls_ssl_context *ssl,
 
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
-static int ssl_parse_supported_elliptic_curves( mbedtls_ssl_context *ssl,
+static int ssl_parse_supported_groups_ext( mbedtls_ssl_context *ssl,
                                                 const unsigned char *buf,
                                                 size_t len )
 {
@@ -1646,10 +1646,10 @@ read_record_header:
 
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
-            case MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES:
+            case MBEDTLS_TLS_EXT_SUPPORTED_GROUPS:
                 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported elliptic curves extension" ) );
 
-                ret = ssl_parse_supported_elliptic_curves( ssl, ext + 4, ext_size );
+                ret = ssl_parse_supported_groups_ext( ssl, ext + 4, ext_size );
                 if( ret != 0 )
                     return( ret );
                 break;

From ba07342cd6b2e95f58f1bf9e8298d4a54c429fda Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Mon, 20 Dec 2021 22:22:15 +0800
Subject: [PATCH 02/16] Add generic write_supported-groups_ext

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 include/mbedtls/ssl.h |   1 +
 library/ssl_misc.h    |  52 +++++++++++------
 library/ssl_tls.c     | 133 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 169 insertions(+), 17 deletions(-)

diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 072ebbe460..45b991b4ca 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -191,6 +191,7 @@
 
 /* Elliptic Curve Groups (ECDHE) */
 #define MBEDTLS_SSL_IANA_TLS_GROUP_NONE               0
+#define MBEDTLS_SSL_IANA_TLS_GROUP_SECT163K1     0x0001 /* RFC 4492 */
 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP192K1     0x0012
 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP192R1     0x0013
 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP224K1     0x0014
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 40e4aaff88..b74b0d9427 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -1626,23 +1626,6 @@ static inline int mbedtls_ssl_tls13_some_psk_enabled( mbedtls_ssl_context *ssl )
                    MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL ) );
 }
 
-/*
- * Helper functions for NamedGroup.
- */
-static inline int mbedtls_ssl_tls13_named_group_is_ecdhe( uint16_t named_group )
-{
-    return( named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP256R1 ||
-            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP384R1 ||
-            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP521R1 ||
-            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_X25519    ||
-            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_X448 );
-}
-
-static inline int mbedtls_ssl_tls13_named_group_is_dhe( uint16_t named_group )
-{
-    return( named_group >= MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE2048 &&
-            named_group <= MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE8192 );
-}
 
 static inline void mbedtls_ssl_handshake_set_state( mbedtls_ssl_context *ssl,
                                                     mbedtls_ssl_states state )
@@ -1743,4 +1726,39 @@ static inline const void *mbedtls_ssl_get_groups( const mbedtls_ssl_context *ssl
     #endif
 }
 
+/*
+ * Helper functions for NamedGroup.
+ */
+static inline int mbedtls_ssl_named_group_is_ecdhe( uint16_t named_group )
+{
+    /*
+     * RFC 4492 section 5.1.1
+     */
+    return( named_group >= MBEDTLS_SSL_IANA_TLS_GROUP_SECT163K1 &&
+            named_group <= MBEDTLS_SSL_IANA_TLS_GROUP_SECP521R1 );
+}
+
+static inline int mbedtls_ssl_tls13_named_group_is_ecdhe( uint16_t named_group )
+{
+    return( named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP256R1 ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP384R1 ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP521R1 ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_X25519    ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_X448 );
+}
+
+static inline int mbedtls_ssl_tls13_named_group_is_dhe( uint16_t named_group )
+{
+    return( named_group >= MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE2048 &&
+            named_group <= MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE8192 );
+}
+
+#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
+int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
+                                            unsigned char *buf,
+                                            unsigned char *end,
+                                            size_t *out_len );
+
+#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
+
 #endif /* ssl_misc.h */
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index d868e49650..11d3c4136d 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -7189,4 +7189,137 @@ int mbedtls_ssl_get_handshake_transcript( mbedtls_ssl_context *ssl,
 }
 #endif /* !MBEDTLS_USE_PSA_CRYPTO */
 
+#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
+/*
+ * Functions for writing supported_groups extension.
+ *
+ * Stucture of supported_groups from RFC8446:
+ *      enum {
+ *          secp256r1(0x0017), secp384r1(0x0018), secp521r1(0x0019),
+ *          x25519(0x001D), x448(0x001E),
+ *          ffdhe2048(0x0100), ffdhe3072(0x0101), ffdhe4096(0x0102),
+ *          ffdhe6144(0x0103), ffdhe8192(0x0104),
+ *          ffdhe_private_use(0x01FC..0x01FF),
+ *          ecdhe_private_use(0xFE00..0xFEFF),
+ *          (0xFFFF)
+ *      } NamedGroup;
+ *      struct {
+ *          NamedGroup named_group_list<2..2^16-1>;
+ *      } NamedGroupList;
+ */
+
+#define SSL_GROUP_IS_UNSUPPORTED    0
+#define SSL_GROUP_IS_ECDHE          1
+#define SSL_GROUP_IS_DHE            2
+static int ssl_check_group_type( const mbedtls_ssl_config *conf,
+                                 const uint16_t group )
+{
+#if defined(MBEDTLS_ECDH_C)
+#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
+    if( mbedtls_ssl_conf_is_tls12_only( conf )
+        && mbedtls_ssl_named_group_is_ecdhe( group ) )
+        return( SSL_GROUP_IS_ECDHE );
+#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
+
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
+    if( mbedtls_ssl_conf_is_tls13_only( conf )
+        && mbedtls_ssl_tls13_named_group_is_ecdhe( group ) )
+        return( SSL_GROUP_IS_ECDHE );
+#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
+
+#endif /* MBEDTLS_ECDH_C */
+    if( mbedtls_ssl_tls13_named_group_is_dhe( group ) )
+        return( SSL_GROUP_IS_DHE );
+
+    return( SSL_GROUP_IS_UNSUPPORTED );
+}
+
+int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
+                                            unsigned char *buf,
+                                            unsigned char *end,
+                                            size_t *out_len )
+{
+    unsigned char *p = buf ;
+    unsigned char *named_group_list; /* Start of named_group_list */
+    size_t named_group_list_len;     /* Length of named_group_list */
+    const uint16_t *group_list = mbedtls_ssl_get_groups( ssl );
+
+    *out_len = 0;
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
+    if( mbedtls_ssl_conf_is_tls13_only( ssl->conf )
+        && !mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
+        return( 0 );
+#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
+    MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding supported_groups extension" ) );
+
+    /* Check if we have space for header and length fields:
+     * - extension_type            (2 bytes)
+     * - extension_data_length     (2 bytes)
+     * - named_group_list_length   (2 bytes)
+     */
+    MBEDTLS_SSL_CHK_BUF_PTR( p, end, 6 );
+    p += 6;
+
+    named_group_list = p;
+
+    if( group_list == NULL )
+        return( MBEDTLS_ERR_SSL_BAD_CONFIG );
+
+    for ( ; *group_list != 0; group_list++ )
+    {
+        int group_type = ssl_check_group_type( ssl->conf, *group_list );
+        if( group_type == SSL_GROUP_IS_UNSUPPORTED )
+            continue;
+#if defined(MBEDTLS_ECDH_C)
+        if( group_type == SSL_GROUP_IS_ECDHE )
+        {
+            const mbedtls_ecp_curve_info *curve_info;
+            curve_info = mbedtls_ecp_curve_info_from_tls_id( *group_list );
+            if( curve_info == NULL )
+                continue;
+            MBEDTLS_SSL_DEBUG_MSG( 3, ( "NamedGroup: %s ( %x )",
+                                   curve_info->name, *group_list ) );
+        }
+#endif /* MBEDTLS_ECDH_C */
+
+        if( group_type == SSL_GROUP_IS_DHE )
+        {
+            /* Implement DHE group here. */
+            continue;
+        }
+
+        MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2);
+        MBEDTLS_PUT_UINT16_BE( *group_list, p, 0 );
+        p += 2;
+
+    }
+
+    /* Length of named_group_list*/
+    named_group_list_len = p - named_group_list;
+    if( named_group_list_len == 0 )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "No group available." ) );
+        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+    }
+
+    /* Write extension_type */
+    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SUPPORTED_GROUPS, buf, 0 );
+    /* Write extension_data_length */
+    MBEDTLS_PUT_UINT16_BE( named_group_list_len + 2, buf, 2 );
+    /* Write length of named_group_list */
+    MBEDTLS_PUT_UINT16_BE( named_group_list_len, buf, 4 );
+
+    MBEDTLS_SSL_DEBUG_BUF( 3, "Supported groups extension", buf + 4, named_group_list_len + 2 );
+
+    *out_len = p - buf;
+
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
+    ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_SUPPORTED_GROUPS;
+#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
+
+    return( 0 );
+}
+
+#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
+
 #endif /* MBEDTLS_SSL_TLS_C */

From 7581c11fc76a9001b2f26d5ba39d9937663cd206 Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Mon, 20 Dec 2021 22:25:41 +0800
Subject: [PATCH 03/16] Remove tls13_write_supported_groups_ext

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_tls13_client.c | 159 +------------------------------------
 1 file changed, 1 insertion(+), 158 deletions(-)

diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index 31d7dafdb9..5b6aee1f83 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -115,163 +115,6 @@ static int ssl_tls13_parse_supported_versions_ext( mbedtls_ssl_context *ssl,
 
 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
 
-/*
- * Functions for writing supported_groups extension.
- *
- * Stucture of supported_groups:
- *      enum {
- *          secp256r1(0x0017), secp384r1(0x0018), secp521r1(0x0019),
- *          x25519(0x001D), x448(0x001E),
- *          ffdhe2048(0x0100), ffdhe3072(0x0101), ffdhe4096(0x0102),
- *          ffdhe6144(0x0103), ffdhe8192(0x0104),
- *          ffdhe_private_use(0x01FC..0x01FF),
- *          ecdhe_private_use(0xFE00..0xFEFF),
- *          (0xFFFF)
- *      } NamedGroup;
- *      struct {
- *          NamedGroup named_group_list<2..2^16-1>;
- *      } NamedGroupList;
- */
-#if defined(MBEDTLS_ECDH_C)
-/*
- * In versions of TLS prior to TLS 1.3, this extension was named
- * 'elliptic_curves' and only contained elliptic curve groups.
- */
-static int ssl_tls13_write_named_group_list_ecdhe( mbedtls_ssl_context *ssl,
-                                                   unsigned char *buf,
-                                                   unsigned char *end,
-                                                   size_t *out_len )
-{
-    unsigned char *p = buf;
-
-    *out_len = 0;
-
-    const uint16_t *group_list = mbedtls_ssl_get_groups( ssl );
-
-    if( group_list == NULL )
-        return( MBEDTLS_ERR_SSL_BAD_CONFIG );
-
-    for ( ; *group_list != 0; group_list++ )
-    {
-        const mbedtls_ecp_curve_info *curve_info;
-        curve_info = mbedtls_ecp_curve_info_from_tls_id( *group_list );
-        if( curve_info == NULL )
-            continue;
-
-        if( !mbedtls_ssl_tls13_named_group_is_ecdhe( *group_list ) )
-            continue;
-
-        MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2);
-        MBEDTLS_PUT_UINT16_BE( *group_list, p, 0 );
-        p += 2;
-
-        MBEDTLS_SSL_DEBUG_MSG( 3, ( "NamedGroup: %s ( %x )",
-                                    curve_info->name, *group_list ) );
-    }
-
-    *out_len = p - buf;
-
-    return( 0 );
-}
-#else
-static int ssl_tls13_write_named_group_list_ecdhe( mbedtls_ssl_context *ssl,
-                                            unsigned char *buf,
-                                            unsigned char *end,
-                                            size_t *out_len )
-{
-    ((void) ssl);
-    ((void) buf);
-    ((void) end);
-    *out_len = 0;
-    return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
-}
-#endif /* MBEDTLS_ECDH_C */
-
-static int ssl_tls13_write_named_group_list_dhe( mbedtls_ssl_context *ssl,
-                                        unsigned char *buf,
-                                        unsigned char *end,
-                                        size_t *out_len )
-{
-    ((void) ssl);
-    ((void) buf);
-    ((void) end);
-    *out_len = 0;
-    MBEDTLS_SSL_DEBUG_MSG( 3, ( "write_named_group_dhe is not implemented" ) );
-    return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
-}
-
-static int ssl_tls13_write_supported_groups_ext( mbedtls_ssl_context *ssl,
-                                                 unsigned char *buf,
-                                                 unsigned char *end,
-                                                 size_t *out_len )
-{
-    unsigned char *p = buf ;
-    unsigned char *named_group_list; /* Start of named_group_list */
-    size_t named_group_list_len;     /* Length of named_group_list */
-    size_t output_len = 0;
-    int ret_ecdhe, ret_dhe;
-
-    *out_len = 0;
-
-    if( !mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
-        return( 0 );
-
-    MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding supported_groups extension" ) );
-
-    /* Check if we have space for header and length fields:
-     * - extension_type            (2 bytes)
-     * - extension_data_length     (2 bytes)
-     * - named_group_list_length   (2 bytes)
-     */
-    MBEDTLS_SSL_CHK_BUF_PTR( p, end, 6 );
-    p += 6;
-
-    named_group_list = p;
-    ret_ecdhe = ssl_tls13_write_named_group_list_ecdhe( ssl, p, end, &output_len );
-    if( ret_ecdhe != 0 )
-    {
-        MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_write_named_group_list_ecdhe", ret_ecdhe );
-    }
-    p += output_len;
-
-    ret_dhe = ssl_tls13_write_named_group_list_dhe( ssl, p, end, &output_len );
-    if( ret_dhe != 0 )
-    {
-        MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_write_named_group_list_dhe", ret_dhe );
-    }
-    p += output_len;
-
-    /* Both ECDHE and DHE failed. */
-    if( ret_ecdhe != 0 && ret_dhe != 0 )
-    {
-        MBEDTLS_SSL_DEBUG_MSG( 1, ( "Both ECDHE and DHE groups are fail. " ) );
-        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
-    }
-
-    /* Length of named_group_list*/
-    named_group_list_len = p - named_group_list;
-    if( named_group_list_len == 0 )
-    {
-        MBEDTLS_SSL_DEBUG_MSG( 1, ( "No group available." ) );
-        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
-    }
-
-    /* Write extension_type */
-    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SUPPORTED_GROUPS, buf, 0 );
-    /* Write extension_data_length */
-    MBEDTLS_PUT_UINT16_BE( named_group_list_len + 2, buf, 2 );
-    /* Write length of named_group_list */
-    MBEDTLS_PUT_UINT16_BE( named_group_list_len, buf, 4 );
-
-    MBEDTLS_SSL_DEBUG_BUF( 3, "Supported groups extension", buf + 4, named_group_list_len + 2 );
-
-    *out_len = p - buf;
-
-    ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_SUPPORTED_GROUPS;
-
-    return( 0 );
-}
-
 /*
  * Functions for writing key_share extension.
  */
@@ -777,7 +620,7 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
      *
      * It is REQUIRED for ECDHE cipher_suites.
      */
-    ret = ssl_tls13_write_supported_groups_ext( ssl, p, end, &output_len );
+    ret = mbedtls_ssl_write_supported_groups_ext( ssl, p, end, &output_len );
     if( ret != 0 )
         return( ret );
     p += output_len;

From 9d555ac003e301ee603a4f86a69008acbbdb0881 Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Mon, 20 Dec 2021 22:27:58 +0800
Subject: [PATCH 04/16] Remove TLS12 version write_supported_group_ext

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_cli.c | 66 ++---------------------------------------------
 1 file changed, 2 insertions(+), 64 deletions(-)

diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 32befc24c7..888523f183 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -302,68 +302,6 @@ static int ssl_write_signature_algorithms_ext( mbedtls_ssl_context *ssl,
 
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
-static int ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
-                                           unsigned char *buf,
-                                           const unsigned char *end,
-                                           size_t *olen )
-{
-    unsigned char *p = buf;
-    unsigned char *elliptic_curve_list = p + 6;
-    size_t elliptic_curve_len = 0;
-    const mbedtls_ecp_curve_info *info;
-    const uint16_t *group_list = mbedtls_ssl_get_groups( ssl );
-    *olen = 0;
-
-    /* Check there is room for header */
-    MBEDTLS_SSL_CHK_BUF_PTR( p, end, 6 );
-
-    MBEDTLS_SSL_DEBUG_MSG( 3,
-        ( "client hello, adding supported_elliptic_curves extension" ) );
-
-    if( group_list == NULL )
-        return( MBEDTLS_ERR_SSL_BAD_CONFIG );
-
-    for( ; *group_list != 0; group_list++ )
-    {
-        info = mbedtls_ecp_curve_info_from_tls_id( *group_list );
-        if( info == NULL )
-        {
-            MBEDTLS_SSL_DEBUG_MSG( 1,
-                ( "invalid curve in ssl configuration" ) );
-            return( MBEDTLS_ERR_SSL_BAD_CONFIG );
-        }
-
-        /* Check there is room for another curve */
-        MBEDTLS_SSL_CHK_BUF_PTR( elliptic_curve_list, end, elliptic_curve_len + 2 );
-
-        MBEDTLS_PUT_UINT16_BE( *group_list, elliptic_curve_list, elliptic_curve_len );
-        elliptic_curve_len += 2;
-
-        if( elliptic_curve_len > MBEDTLS_SSL_MAX_CURVE_LIST_LEN )
-        {
-            MBEDTLS_SSL_DEBUG_MSG( 3,
-                ( "malformed supported_elliptic_curves extension in config" ) );
-            return( MBEDTLS_ERR_SSL_BAD_CONFIG );
-        }
-    }
-
-    /* Empty elliptic curve list, this is a configuration error. */
-    if( elliptic_curve_len == 0 )
-        return( MBEDTLS_ERR_SSL_BAD_CONFIG );
-
-    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SUPPORTED_GROUPS, p, 0 );
-    p += 2;
-
-    MBEDTLS_PUT_UINT16_BE( elliptic_curve_len + 2, p, 0 );
-    p += 2;
-
-    MBEDTLS_PUT_UINT16_BE( elliptic_curve_len, p, 0 );
-    p += 2;
-
-    *olen = 6 + elliptic_curve_len;
-
-    return( 0 );
-}
 
 static int ssl_write_supported_point_formats_ext( mbedtls_ssl_context *ssl,
                                                   unsigned char *buf,
@@ -1206,8 +1144,8 @@ static int ssl_write_client_hello( mbedtls_ssl_context *ssl )
     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
     if( uses_ec )
     {
-        if( ( ret = ssl_write_supported_groups_ext( ssl, p + 2 + ext_len,
-                                                    end, &olen ) ) != 0 )
+        if( ( ret = mbedtls_ssl_write_supported_groups_ext( ssl, p + 2 + ext_len,
+                                                            end, &olen ) ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "ssl_write_supported_groups_ext", ret );
             return( ret );

From 175326108316d93656e3b34cc5fc36f6bf8ab974 Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Mon, 20 Dec 2021 22:32:09 +0800
Subject: [PATCH 05/16] change write_supported_groups_ext prototype

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_misc.h | 2 +-
 library/ssl_tls.c  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index b74b0d9427..598c3efc52 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -1756,7 +1756,7 @@ static inline int mbedtls_ssl_tls13_named_group_is_dhe( uint16_t named_group )
 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
 int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
                                             unsigned char *buf,
-                                            unsigned char *end,
+                                            const unsigned char *end,
                                             size_t *out_len );
 
 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 11d3c4136d..bab83ea2c7 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -7236,7 +7236,7 @@ static int ssl_check_group_type( const mbedtls_ssl_config *conf,
 
 int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
                                             unsigned char *buf,
-                                            unsigned char *end,
+                                            const unsigned char *end,
                                             size_t *out_len )
 {
     unsigned char *p = buf ;

From 1ea9d1068771af612ef7ee8467e6950fdabe40e8 Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Tue, 21 Dec 2021 13:41:49 +0800
Subject: [PATCH 06/16] fix test_ref_configs build fail

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_misc.h |  8 ++++++--
 library/ssl_tls.c  | 18 +++++++++++++-----
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 598c3efc52..cea8ab53af 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -1753,12 +1753,16 @@ static inline int mbedtls_ssl_tls13_named_group_is_dhe( uint16_t named_group )
             named_group <= MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE8192 );
 }
 
-#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
+#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) || \
+    defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
+    defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
 int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
                                             unsigned char *buf,
                                             const unsigned char *end,
                                             size_t *out_len );
 
-#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
+#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED ||
+          MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C ||
+          MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
 
 #endif /* ssl_misc.h */
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index bab83ea2c7..e2ad47b8cd 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -7189,7 +7189,9 @@ int mbedtls_ssl_get_handshake_transcript( mbedtls_ssl_context *ssl,
 }
 #endif /* !MBEDTLS_USE_PSA_CRYPTO */
 
-#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
+#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) || \
+    defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
+    defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
 /*
  * Functions for writing supported_groups extension.
  *
@@ -7214,7 +7216,7 @@ int mbedtls_ssl_get_handshake_transcript( mbedtls_ssl_context *ssl,
 static int ssl_check_group_type( const mbedtls_ssl_config *conf,
                                  const uint16_t group )
 {
-#if defined(MBEDTLS_ECDH_C)
+#if defined(MBEDTLS_ECP_C)
 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
     if( mbedtls_ssl_conf_is_tls12_only( conf )
         && mbedtls_ssl_named_group_is_ecdhe( group ) )
@@ -7226,8 +7228,10 @@ static int ssl_check_group_type( const mbedtls_ssl_config *conf,
         && mbedtls_ssl_tls13_named_group_is_ecdhe( group ) )
         return( SSL_GROUP_IS_ECDHE );
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
-
+#else
+    ((void) conf);
 #endif /* MBEDTLS_ECDH_C */
+
     if( mbedtls_ssl_tls13_named_group_is_dhe( group ) )
         return( SSL_GROUP_IS_DHE );
 
@@ -7267,10 +7271,12 @@ int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
 
     for ( ; *group_list != 0; group_list++ )
     {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ("got supported group(%04x)",*group_list));
         int group_type = ssl_check_group_type( ssl->conf, *group_list );
         if( group_type == SSL_GROUP_IS_UNSUPPORTED )
             continue;
-#if defined(MBEDTLS_ECDH_C)
+        MBEDTLS_SSL_DEBUG_MSG( 1, ("add supported group(%04x)",*group_list));
+#if defined(MBEDTLS_ECP_C)
         if( group_type == SSL_GROUP_IS_ECDHE )
         {
             const mbedtls_ecp_curve_info *curve_info;
@@ -7320,6 +7326,8 @@ int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
     return( 0 );
 }
 
-#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
+#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED ||
+          MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C ||
+          MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
 
 #endif /* MBEDTLS_SSL_TLS_C */

From 136320ba0b581970b99f2d73e8e5d248514de3f7 Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Tue, 21 Dec 2021 17:09:00 +0800
Subject: [PATCH 07/16] fix ci fail

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_misc.h | 2 +-
 tests/ssl-opt.sh   | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index cea8ab53af..f854ef1dfc 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -1735,7 +1735,7 @@ static inline int mbedtls_ssl_named_group_is_ecdhe( uint16_t named_group )
      * RFC 4492 section 5.1.1
      */
     return( named_group >= MBEDTLS_SSL_IANA_TLS_GROUP_SECT163K1 &&
-            named_group <= MBEDTLS_SSL_IANA_TLS_GROUP_SECP521R1 );
+            named_group < MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE2048 );
 }
 
 static inline int mbedtls_ssl_tls13_named_group_is_ecdhe( uint16_t named_group )
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 691c0e7d5b..b060e7b462 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -6585,7 +6585,7 @@ run_test    "Force a non ECC ciphersuite in the client side" \
             "$P_SRV debug_level=3" \
             "$P_CLI debug_level=3 force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA256" \
             0 \
-            -C "client hello, adding supported_elliptic_curves extension" \
+            -C "client hello, adding supported_groups extension" \
             -C "client hello, adding supported_point_formats extension" \
             -S "found supported elliptic curves extension" \
             -S "found supported point formats extension"
@@ -6609,7 +6609,7 @@ run_test    "Force an ECC ciphersuite in the client side" \
             "$P_SRV debug_level=3" \
             "$P_CLI debug_level=3 force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-CBC-SHA256" \
             0 \
-            -c "client hello, adding supported_elliptic_curves extension" \
+            -c "client hello, adding supported_groups extension" \
             -c "client hello, adding supported_point_formats extension" \
             -s "found supported elliptic curves extension" \
             -s "found supported point formats extension"

From ffef9c52d462458fd206854ab6af0073572f5505 Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Fri, 24 Dec 2021 22:31:08 +0800
Subject: [PATCH 08/16] fix alignment issue

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_srv.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 977ecc8f33..3794dada4e 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -318,8 +318,8 @@ static int ssl_parse_signature_algorithms_ext( mbedtls_ssl_context *ssl,
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
 static int ssl_parse_supported_groups_ext( mbedtls_ssl_context *ssl,
-                                                const unsigned char *buf,
-                                                size_t len )
+                                           const unsigned char *buf,
+                                           size_t len )
 {
     size_t list_size, our_size;
     const unsigned char *p;

From 7f029d8a9494283f8df9bb7013e0ebf51af204dc Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Tue, 11 Jan 2022 11:08:53 +0800
Subject: [PATCH 09/16] fix coding style issues

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_tls.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index e2ad47b8cd..bb533c957a 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -7294,7 +7294,7 @@ int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
             continue;
         }
 
-        MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2);
+        MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
         MBEDTLS_PUT_UINT16_BE( *group_list, p, 0 );
         p += 2;
 
@@ -7315,7 +7315,8 @@ int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
     /* Write length of named_group_list */
     MBEDTLS_PUT_UINT16_BE( named_group_list_len, buf, 4 );
 
-    MBEDTLS_SSL_DEBUG_BUF( 3, "Supported groups extension", buf + 4, named_group_list_len + 2 );
+    MBEDTLS_SSL_DEBUG_BUF( 3, "Supported groups extension",
+                           buf + 4, named_group_list_len + 2 );
 
     *out_len = p - buf;
 

From 63282b43210291931dc14341c94e198a54079c4d Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Tue, 11 Jan 2022 15:43:53 +0800
Subject: [PATCH 10/16] Refactor write supported group

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_tls.c | 76 +++++++++++++++++------------------------------
 1 file changed, 28 insertions(+), 48 deletions(-)

diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index bb533c957a..6ca63ccb08 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -7208,36 +7208,26 @@ int mbedtls_ssl_get_handshake_transcript( mbedtls_ssl_context *ssl,
  *      struct {
  *          NamedGroup named_group_list<2..2^16-1>;
  *      } NamedGroupList;
+ * From RFC8422:
+ * enum {
+ *      deprecated(1..22),
+ *      secp256r1 (23), secp384r1 (24), secp521r1 (25),
+ *      x25519(29), x448(30),
+ *      reserved (0xFE00..0xFEFF),
+ *      deprecated(0xFF01..0xFF02),
+ *      (0xFFFF)
+ *  } NamedCurve;
+ * struct {
+ *      NamedCurve named_curve_list<2..2^16-1>
+ *  } NamedCurveList;
+ *
+ * RFC8422 and RFC8446 share simillar structure and same extension id. The function
+ * only check if the curve/group is supported by library. It does not need check
+ * the IANA values. ECP module should check if the group/curve is deprecated or
+ * supported.
+ *
+ * DHE groups hasn't been supported yet.
  */
-
-#define SSL_GROUP_IS_UNSUPPORTED    0
-#define SSL_GROUP_IS_ECDHE          1
-#define SSL_GROUP_IS_DHE            2
-static int ssl_check_group_type( const mbedtls_ssl_config *conf,
-                                 const uint16_t group )
-{
-#if defined(MBEDTLS_ECP_C)
-#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
-    if( mbedtls_ssl_conf_is_tls12_only( conf )
-        && mbedtls_ssl_named_group_is_ecdhe( group ) )
-        return( SSL_GROUP_IS_ECDHE );
-#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
-
-#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
-    if( mbedtls_ssl_conf_is_tls13_only( conf )
-        && mbedtls_ssl_tls13_named_group_is_ecdhe( group ) )
-        return( SSL_GROUP_IS_ECDHE );
-#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
-#else
-    ((void) conf);
-#endif /* MBEDTLS_ECDH_C */
-
-    if( mbedtls_ssl_tls13_named_group_is_dhe( group ) )
-        return( SSL_GROUP_IS_DHE );
-
-    return( SSL_GROUP_IS_UNSUPPORTED );
-}
-
 int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
                                             unsigned char *buf,
                                             const unsigned char *end,
@@ -7272,31 +7262,21 @@ int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
     for ( ; *group_list != 0; group_list++ )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ("got supported group(%04x)",*group_list));
-        int group_type = ssl_check_group_type( ssl->conf, *group_list );
-        if( group_type == SSL_GROUP_IS_UNSUPPORTED )
-            continue;
-        MBEDTLS_SSL_DEBUG_MSG( 1, ("add supported group(%04x)",*group_list));
+
 #if defined(MBEDTLS_ECP_C)
-        if( group_type == SSL_GROUP_IS_ECDHE )
+        const mbedtls_ecp_curve_info *curve_info;
+        curve_info = mbedtls_ecp_curve_info_from_tls_id( *group_list );
+        if( curve_info != NULL )
         {
-            const mbedtls_ecp_curve_info *curve_info;
-            curve_info = mbedtls_ecp_curve_info_from_tls_id( *group_list );
-            if( curve_info == NULL )
-                continue;
+            MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
+            MBEDTLS_PUT_UINT16_BE( *group_list, p, 0 );
+            p += 2;
             MBEDTLS_SSL_DEBUG_MSG( 3, ( "NamedGroup: %s ( %x )",
                                    curve_info->name, *group_list ) );
-        }
-#endif /* MBEDTLS_ECDH_C */
-
-        if( group_type == SSL_GROUP_IS_DHE )
-        {
-            /* Implement DHE group here. */
             continue;
         }
-
-        MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
-        MBEDTLS_PUT_UINT16_BE( *group_list, p, 0 );
-        p += 2;
+#endif /* MBEDTLS_ECP_C */
+        /* Add DHE groups here */
 
     }
 

From f46b016058939d4cb131f40c7ef804ac4c0825f4 Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Tue, 11 Jan 2022 16:28:00 +0800
Subject: [PATCH 11/16] skip some extensions if ephemeral not enabled

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_tls.c           |  6 +---
 library/ssl_tls13_client.c  | 63 +++++++++++++++++++------------------
 library/ssl_tls13_generic.c | 10 ------
 3 files changed, 33 insertions(+), 46 deletions(-)

diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 6ca63ccb08..69fa39b466 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -7239,11 +7239,7 @@ int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
     const uint16_t *group_list = mbedtls_ssl_get_groups( ssl );
 
     *out_len = 0;
-#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
-    if( mbedtls_ssl_conf_is_tls13_only( ssl->conf )
-        && !mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
-        return( 0 );
-#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
+
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding supported_groups extension" ) );
 
     /* Check if we have space for header and length fields:
diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index 5b6aee1f83..9541fc33b5 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -219,9 +219,6 @@ static int ssl_tls13_write_key_share_ext( mbedtls_ssl_context *ssl,
 
     *out_len = 0;
 
-    if( !mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
-        return( 0 );
-
     /* Check if we have space for header and length fields:
      * - extension_type         (2 bytes)
      * - extension_data_length  (2 bytes)
@@ -620,36 +617,40 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
      *
      * It is REQUIRED for ECDHE cipher_suites.
      */
-    ret = mbedtls_ssl_write_supported_groups_ext( ssl, p, end, &output_len );
-    if( ret != 0 )
-        return( ret );
-    p += output_len;
+    /* Skip the extensions on the client if all allowed key exchanges
+     * are PSK-based. */
+    if( mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
+    {
+        ret = mbedtls_ssl_write_supported_groups_ext( ssl, p, end, &output_len );
+        if( ret != 0 )
+            return( ret );
+        p += output_len;
 
-    /* Write key_share extension
-     *
-     * We need to send the key shares under three conditions:
-     * 1) A certificate-based ciphersuite is being offered. In this case
-     *    supported_groups and supported_signature extensions have been
-     *    successfully added.
-     * 2) A PSK-based ciphersuite with ECDHE is offered. In this case the
-     *    psk_key_exchange_modes has been added as the last extension.
-     * 3) Or, in case all ciphers are supported ( which includes #1 and #2
-     *    from above )
-     */
-    ret = ssl_tls13_write_key_share_ext( ssl, p, end, &output_len );
-    if( ret != 0 )
-        return( ret );
-    p += output_len;
-
-    /* Write signature_algorithms extension
-     *
-     * It is REQUIRED for certificate authenticated cipher_suites.
-     */
-    ret = mbedtls_ssl_tls13_write_sig_alg_ext( ssl, p, end, &output_len );
-    if( ret != 0 )
-        return( ret );
-    p += output_len;
+        /* Write key_share extension
+        *
+        * We need to send the key shares under three conditions:
+        * 1) A certificate-based ciphersuite is being offered. In this case
+        *    supported_groups and supported_signature extensions have been
+        *    successfully added.
+        * 2) A PSK-based ciphersuite with ECDHE is offered. In this case the
+        *    psk_key_exchange_modes has been added as the last extension.
+        * 3) Or, in case all ciphers are supported ( which includes #1 and #2
+        *    from above )
+        */
+        ret = ssl_tls13_write_key_share_ext( ssl, p, end, &output_len );
+        if( ret != 0 )
+            return( ret );
+        p += output_len;
 
+        /* Write signature_algorithms extension
+        *
+        * It is REQUIRED for certificate authenticated cipher_suites.
+        */
+        ret = mbedtls_ssl_tls13_write_sig_alg_ext( ssl, p, end, &output_len );
+        if( ret != 0 )
+            return( ret );
+        p += output_len;
+    }
 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
 
 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
diff --git a/library/ssl_tls13_generic.c b/library/ssl_tls13_generic.c
index 1260740e5d..c789ed41c7 100644
--- a/library/ssl_tls13_generic.c
+++ b/library/ssl_tls13_generic.c
@@ -165,16 +165,6 @@ int mbedtls_ssl_tls13_write_sig_alg_ext( mbedtls_ssl_context *ssl,
 
     *out_len = 0;
 
-    /* Skip the extension on the client if all allowed key exchanges
-     * are PSK-based. */
-#if defined(MBEDTLS_SSL_CLI_C)
-    if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT &&
-        !mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
-    {
-        return( 0 );
-    }
-#endif /* MBEDTLS_SSL_CLI_C */
-
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "adding signature_algorithms extension" ) );
 
     /* Check if we have space for header and length field:

From 3ad14ac9e948382d5d947c40bc93ef7b5995da12 Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Tue, 11 Jan 2022 17:13:16 +0800
Subject: [PATCH 12/16] Add named group IANA value check

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 include/mbedtls/ssl.h |  1 -
 library/ssl_misc.h    | 55 +++++++++++++++++++++++++++++++++++++++----
 library/ssl_tls.c     | 29 +++++++++++++----------
 3 files changed, 67 insertions(+), 18 deletions(-)

diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 45b991b4ca..072ebbe460 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -191,7 +191,6 @@
 
 /* Elliptic Curve Groups (ECDHE) */
 #define MBEDTLS_SSL_IANA_TLS_GROUP_NONE               0
-#define MBEDTLS_SSL_IANA_TLS_GROUP_SECT163K1     0x0001 /* RFC 4492 */
 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP192K1     0x0012
 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP192R1     0x0013
 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP224K1     0x0014
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index f854ef1dfc..eb828a942b 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -1489,6 +1489,7 @@ static inline int mbedtls_ssl_conf_is_tls13_only( const mbedtls_ssl_config *conf
     }
     return( 0 );
 }
+
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
 
 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
@@ -1503,8 +1504,43 @@ static inline int mbedtls_ssl_conf_is_tls12_only( const mbedtls_ssl_config *conf
     }
     return( 0 );
 }
+
 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
 
+static inline int mbedtls_ssl_conf_is_tls13_enabled( const mbedtls_ssl_config *conf )
+{
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
+    if( conf->min_major_ver == MBEDTLS_SSL_MAJOR_VERSION_3 &&
+        conf->max_major_ver == MBEDTLS_SSL_MAJOR_VERSION_3 &&
+        conf->min_minor_ver <= MBEDTLS_SSL_MINOR_VERSION_4 &&
+        conf->max_minor_ver >= MBEDTLS_SSL_MINOR_VERSION_4 )
+    {
+        return( 1 );
+    }
+    return( 0 );
+#else
+    ((void) conf);
+    return( 0 );
+#endif
+}
+
+static inline int mbedtls_ssl_conf_is_tls12_enabled( const mbedtls_ssl_config *conf )
+{
+#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
+    if( conf->min_major_ver == MBEDTLS_SSL_MAJOR_VERSION_3 &&
+        conf->max_major_ver == MBEDTLS_SSL_MAJOR_VERSION_3 &&
+        conf->min_minor_ver <= MBEDTLS_SSL_MINOR_VERSION_3 &&
+        conf->max_minor_ver >= MBEDTLS_SSL_MINOR_VERSION_3 )
+    {
+        return( 1 );
+    }
+    return( 0 );
+#else
+    ((void) conf);
+    return( 0 );
+#endif
+}
+
 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && defined(MBEDTLS_SSL_PROTO_TLS1_3)
 static inline int mbedtls_ssl_conf_is_hybrid_tls12_tls13( const mbedtls_ssl_config *conf )
 {
@@ -1729,13 +1765,24 @@ static inline const void *mbedtls_ssl_get_groups( const mbedtls_ssl_context *ssl
 /*
  * Helper functions for NamedGroup.
  */
-static inline int mbedtls_ssl_named_group_is_ecdhe( uint16_t named_group )
+static inline int mbedtls_ssl_tls12_named_group_is_ecdhe( uint16_t named_group )
 {
     /*
-     * RFC 4492 section 5.1.1
+     * RFC 8422 section 5.1.1
      */
-    return( named_group >= MBEDTLS_SSL_IANA_TLS_GROUP_SECT163K1 &&
-            named_group < MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE2048 );
+    return( named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP192K1 ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP192R1 ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP224K1 ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP224R1 ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP256K1 ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP256R1 ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP384R1 ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP521R1 ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_BP256R1   ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_BP384R1   ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_BP512R1   ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_X25519    ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_X448 );
 }
 
 static inline int mbedtls_ssl_tls13_named_group_is_ecdhe( uint16_t named_group )
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 69fa39b466..844d5c3d9b 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -7221,10 +7221,7 @@ int mbedtls_ssl_get_handshake_transcript( mbedtls_ssl_context *ssl,
  *      NamedCurve named_curve_list<2..2^16-1>
  *  } NamedCurveList;
  *
- * RFC8422 and RFC8446 share simillar structure and same extension id. The function
- * only check if the curve/group is supported by library. It does not need check
- * the IANA values. ECP module should check if the group/curve is deprecated or
- * supported.
+ * RFC8422 and RFC8446 share simillar structure and same extension id.
  *
  * DHE groups hasn't been supported yet.
  */
@@ -7260,16 +7257,22 @@ int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
         MBEDTLS_SSL_DEBUG_MSG( 1, ("got supported group(%04x)",*group_list));
 
 #if defined(MBEDTLS_ECP_C)
-        const mbedtls_ecp_curve_info *curve_info;
-        curve_info = mbedtls_ecp_curve_info_from_tls_id( *group_list );
-        if( curve_info != NULL )
+        if( ( mbedtls_ssl_conf_is_tls13_enabled(ssl->conf) &&
+              mbedtls_ssl_tls13_named_group_is_ecdhe( *group_list ) ) ||
+            ( mbedtls_ssl_conf_is_tls12_enabled(ssl->conf) &&
+              mbedtls_ssl_tls12_named_group_is_ecdhe( *group_list ) ) )
         {
-            MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
-            MBEDTLS_PUT_UINT16_BE( *group_list, p, 0 );
-            p += 2;
-            MBEDTLS_SSL_DEBUG_MSG( 3, ( "NamedGroup: %s ( %x )",
-                                   curve_info->name, *group_list ) );
-            continue;
+            const mbedtls_ecp_curve_info *curve_info;
+            curve_info = mbedtls_ecp_curve_info_from_tls_id( *group_list );
+            if( curve_info != NULL )
+            {
+                MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
+                MBEDTLS_PUT_UINT16_BE( *group_list, p, 0 );
+                p += 2;
+                MBEDTLS_SSL_DEBUG_MSG( 3, ( "NamedGroup: %s ( %x )",
+                                    curve_info->name, *group_list ) );
+                continue;
+            }
         }
 #endif /* MBEDTLS_ECP_C */
         /* Add DHE groups here */

From 1510cea0f32f745c540fdbd10beaa9da563eec12 Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Wed, 12 Jan 2022 10:56:49 +0800
Subject: [PATCH 13/16] fix coding style issues

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_tls.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 844d5c3d9b..55c5e14e18 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -7252,14 +7252,14 @@ int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
     if( group_list == NULL )
         return( MBEDTLS_ERR_SSL_BAD_CONFIG );
 
-    for ( ; *group_list != 0; group_list++ )
+    for( ; *group_list != 0; group_list++ )
     {
-        MBEDTLS_SSL_DEBUG_MSG( 1, ("got supported group(%04x)",*group_list));
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "got supported group(%04x)", *group_list ) );
 
 #if defined(MBEDTLS_ECP_C)
-        if( ( mbedtls_ssl_conf_is_tls13_enabled(ssl->conf) &&
+        if( ( mbedtls_ssl_conf_is_tls13_enabled( ssl->conf ) &&
               mbedtls_ssl_tls13_named_group_is_ecdhe( *group_list ) ) ||
-            ( mbedtls_ssl_conf_is_tls12_enabled(ssl->conf) &&
+            ( mbedtls_ssl_conf_is_tls12_enabled( ssl->conf ) &&
               mbedtls_ssl_tls12_named_group_is_ecdhe( *group_list ) ) )
         {
             const mbedtls_ecp_curve_info *curve_info;
@@ -7279,7 +7279,7 @@ int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
 
     }
 
-    /* Length of named_group_list*/
+    /* Length of named_group_list */
     named_group_list_len = p - named_group_list;
     if( named_group_list_len == 0 )
     {

From f0fede56a6b994d577a1f3b93d6a068cd619fa80 Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Wed, 12 Jan 2022 10:57:47 +0800
Subject: [PATCH 14/16] minor performance improvement

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_misc.h | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index eb828a942b..515f684eec 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -1770,27 +1770,28 @@ static inline int mbedtls_ssl_tls12_named_group_is_ecdhe( uint16_t named_group )
     /*
      * RFC 8422 section 5.1.1
      */
-    return( named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP192K1 ||
+    return( named_group == MBEDTLS_SSL_IANA_TLS_GROUP_X25519    ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_BP256R1   ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_BP384R1   ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_BP512R1   ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_X448      ||
+            /* Below deprected curves should be removed with notice to users */
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP192K1 ||
             named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP192R1 ||
             named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP224K1 ||
             named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP224R1 ||
             named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP256K1 ||
             named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP256R1 ||
             named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP384R1 ||
-            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP521R1 ||
-            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_BP256R1   ||
-            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_BP384R1   ||
-            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_BP512R1   ||
-            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_X25519    ||
-            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_X448 );
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP521R1 );
 }
 
 static inline int mbedtls_ssl_tls13_named_group_is_ecdhe( uint16_t named_group )
 {
-    return( named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP256R1 ||
+    return( named_group == MBEDTLS_SSL_IANA_TLS_GROUP_X25519    ||
+            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP256R1 ||
             named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP384R1 ||
             named_group == MBEDTLS_SSL_IANA_TLS_GROUP_SECP521R1 ||
-            named_group == MBEDTLS_SSL_IANA_TLS_GROUP_X25519    ||
             named_group == MBEDTLS_SSL_IANA_TLS_GROUP_X448 );
 }
 

From b925f2180641f8931b5e356cedd21987a96f4f6b Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Wed, 12 Jan 2022 11:17:02 +0800
Subject: [PATCH 15/16] fix comment issues

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_srv.c          |  5 +++++
 library/ssl_tls.c          | 30 +++++++++++++++++-------------
 library/ssl_tls13_client.c | 24 ++++--------------------
 3 files changed, 26 insertions(+), 33 deletions(-)

diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 3794dada4e..f5af5c7c6f 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -317,6 +317,11 @@ static int ssl_parse_signature_algorithms_ext( mbedtls_ssl_context *ssl,
 
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
+/*
+ * The TLS 1.3 supported groups extension was defined to be a compatible
+ * generalization of the TLS 1.2 supported elliptic curves extension. They both
+ * share the same extension identifier.
+ */
 static int ssl_parse_supported_groups_ext( mbedtls_ssl_context *ssl,
                                            const unsigned char *buf,
                                            size_t len )
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 55c5e14e18..76449032f9 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -7193,9 +7193,11 @@ int mbedtls_ssl_get_handshake_transcript( mbedtls_ssl_context *ssl,
     defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
 /*
- * Functions for writing supported_groups extension.
+ * Function for writing a supported groups (TLS 1.3) or supported elliptic
+ * curves (TLS 1.2) extension.
  *
- * Stucture of supported_groups from RFC8446:
+ * The "extension_data" field of a supported groups extension contains a
+ * "NamedGroupList" value (TLS 1.3 RFC8446):
  *      enum {
  *          secp256r1(0x0017), secp384r1(0x0018), secp521r1(0x0019),
  *          x25519(0x001D), x448(0x001E),
@@ -7208,7 +7210,9 @@ int mbedtls_ssl_get_handshake_transcript( mbedtls_ssl_context *ssl,
  *      struct {
  *          NamedGroup named_group_list<2..2^16-1>;
  *      } NamedGroupList;
- * From RFC8422:
+ *
+ * The "extension_data" field of a supported elliptic curves extension contains
+ * a "NamedCurveList" value (TLS 1.2 RFC 8422):
  * enum {
  *      deprecated(1..22),
  *      secp256r1 (23), secp384r1 (24), secp521r1 (25),
@@ -7221,9 +7225,11 @@ int mbedtls_ssl_get_handshake_transcript( mbedtls_ssl_context *ssl,
  *      NamedCurve named_curve_list<2..2^16-1>
  *  } NamedCurveList;
  *
- * RFC8422 and RFC8446 share simillar structure and same extension id.
+ * The TLS 1.3 supported groups extension was defined to be a compatible
+ * generalization of the TLS 1.2 supported elliptic curves extension. They both
+ * share the same extension identifier.
  *
- * DHE groups hasn't been supported yet.
+ * DHE groups are not supported yet.
  */
 int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
                                             unsigned char *buf,
@@ -7264,15 +7270,13 @@ int mbedtls_ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
         {
             const mbedtls_ecp_curve_info *curve_info;
             curve_info = mbedtls_ecp_curve_info_from_tls_id( *group_list );
-            if( curve_info != NULL )
-            {
-                MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
-                MBEDTLS_PUT_UINT16_BE( *group_list, p, 0 );
-                p += 2;
-                MBEDTLS_SSL_DEBUG_MSG( 3, ( "NamedGroup: %s ( %x )",
-                                    curve_info->name, *group_list ) );
+            if( curve_info == NULL )
                 continue;
-            }
+            MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
+            MBEDTLS_PUT_UINT16_BE( *group_list, p, 0 );
+            p += 2;
+            MBEDTLS_SSL_DEBUG_MSG( 3, ( "NamedGroup: %s ( %x )",
+                                curve_info->name, *group_list ) );
         }
 #endif /* MBEDTLS_ECP_C */
         /* Add DHE groups here */
diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index 9541fc33b5..c6f8ce3d86 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -613,12 +613,11 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
     p += output_len;
 
 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
-    /* Write supported_groups extension
-     *
-     * It is REQUIRED for ECDHE cipher_suites.
+
+    /*
+     * Add the extensions related to (EC)DHE ephemeral key establishment only if
+     * enabled as per the configuration.
      */
-    /* Skip the extensions on the client if all allowed key exchanges
-     * are PSK-based. */
     if( mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
     {
         ret = mbedtls_ssl_write_supported_groups_ext( ssl, p, end, &output_len );
@@ -626,26 +625,11 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
             return( ret );
         p += output_len;
 
-        /* Write key_share extension
-        *
-        * We need to send the key shares under three conditions:
-        * 1) A certificate-based ciphersuite is being offered. In this case
-        *    supported_groups and supported_signature extensions have been
-        *    successfully added.
-        * 2) A PSK-based ciphersuite with ECDHE is offered. In this case the
-        *    psk_key_exchange_modes has been added as the last extension.
-        * 3) Or, in case all ciphers are supported ( which includes #1 and #2
-        *    from above )
-        */
         ret = ssl_tls13_write_key_share_ext( ssl, p, end, &output_len );
         if( ret != 0 )
             return( ret );
         p += output_len;
 
-        /* Write signature_algorithms extension
-        *
-        * It is REQUIRED for certificate authenticated cipher_suites.
-        */
         ret = mbedtls_ssl_tls13_write_sig_alg_ext( ssl, p, end, &output_len );
         if( ret != 0 )
             return( ret );

From d491ea4f1841bc45566355fe587a7c3ca7a9f2ea Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Thu, 13 Jan 2022 16:15:25 +0800
Subject: [PATCH 16/16] fix comment issue

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_srv.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index f5af5c7c6f..a8b1e7de6c 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -318,9 +318,43 @@ static int ssl_parse_signature_algorithms_ext( mbedtls_ssl_context *ssl,
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
 /*
+ * Function for parsing a supported groups (TLS 1.3) or supported elliptic
+ * curves (TLS 1.2) extension.
+ *
+ * The "extension_data" field of a supported groups extension contains a
+ * "NamedGroupList" value (TLS 1.3 RFC8446):
+ *      enum {
+ *          secp256r1(0x0017), secp384r1(0x0018), secp521r1(0x0019),
+ *          x25519(0x001D), x448(0x001E),
+ *          ffdhe2048(0x0100), ffdhe3072(0x0101), ffdhe4096(0x0102),
+ *          ffdhe6144(0x0103), ffdhe8192(0x0104),
+ *          ffdhe_private_use(0x01FC..0x01FF),
+ *          ecdhe_private_use(0xFE00..0xFEFF),
+ *          (0xFFFF)
+ *      } NamedGroup;
+ *      struct {
+ *          NamedGroup named_group_list<2..2^16-1>;
+ *      } NamedGroupList;
+ *
+ * The "extension_data" field of a supported elliptic curves extension contains
+ * a "NamedCurveList" value (TLS 1.2 RFC 8422):
+ * enum {
+ *      deprecated(1..22),
+ *      secp256r1 (23), secp384r1 (24), secp521r1 (25),
+ *      x25519(29), x448(30),
+ *      reserved (0xFE00..0xFEFF),
+ *      deprecated(0xFF01..0xFF02),
+ *      (0xFFFF)
+ *  } NamedCurve;
+ * struct {
+ *      NamedCurve named_curve_list<2..2^16-1>
+ *  } NamedCurveList;
+ *
  * The TLS 1.3 supported groups extension was defined to be a compatible
  * generalization of the TLS 1.2 supported elliptic curves extension. They both
  * share the same extension identifier.
+ *
+ * DHE groups are not supported yet.
  */
 static int ssl_parse_supported_groups_ext( mbedtls_ssl_context *ssl,
                                            const unsigned char *buf,