commit d3f73349a7b54507bc4becf960bea9ffc2132a3b
author Jerry Yu <jerry.h.yu@arm.com> Thu Sep 09 15:42:32 2021 +0800
committer Jerry Yu <jerry.h.yu@arm.com> Mon Sep 27 16:34:58 2021 +0800
tree a353a43d2e5c991a0d7c6e48360bd3f7ba7bec05
parent 7bea4bac96227cd288ab79d744c7d0a12e0a9d77

tls13: add ecdh_read_public

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>

library/ecp.c

diff --git a/library/ecp.c b/library/ecp.c
index 0212069..a49cc45 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -79,6 +79,7 @@
 
 #include "bn_mul.h"
 #include "ecp_invasive.h"
+#include "ssl_misc.h"
 
 #include <string.h>
 
@@ -1051,6 +1052,39 @@
     return( ret );
 }
 
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
+
+int mbedtls_ecp_tls13_read_point( const mbedtls_ecp_group *grp,
+                                  mbedtls_ecp_point *pt,
+                                  const unsigned char **buf, size_t buf_len )
+{
+    unsigned char data_len;
+    const unsigned char *buf_start;
+    ECP_VALIDATE_RET( grp != NULL );
+    ECP_VALIDATE_RET( pt  != NULL );
+    ECP_VALIDATE_RET( buf != NULL );
+    ECP_VALIDATE_RET( *buf != NULL );
+
+    if( buf_len < 3 )
+        return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
+
+    data_len = ( *( *buf ) << 8 ) | *( *buf+1 );
+    *buf += 2;
+
+    if( data_len < 1 || data_len > buf_len - 2 )
+        return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
+
+    /*
+     * Save buffer start for read_binary and update buf
+     */
+    buf_start = *buf;
+    *buf += data_len;
+
+    return( mbedtls_ecp_point_read_binary( grp, pt, buf_start, data_len ) );
+}
+
+#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
+
 /*
  * Fast mod-p functions expect their argument to be in the 0..p^2 range.
  *