commit 06e1fcdb45872a410165a9b4ab4c16bf41dced6a
author Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com> Thu Jun 16 10:48:06 2022 +0200
committer Manuel Pégourié-Gonnard <mpg@elzevir.fr> Mon Jun 20 21:04:31 2022 +0200
tree f36c1e6c637091389ba961838eadbf984d52817e
parent 8641102bc16a8193d93721f222729e5a07252fc3

Add comments when can_do() is safe to use

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>

library/ssl_cli.c

diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index eeb55c3..1140d9e 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -3000,6 +3000,8 @@
     peer_pk = &ssl->session_negotiate->peer_cert->pk;
 #endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 
+    /* This is a public key, so it can't be opaque, so can_do() is a good
+     * enough check to ensure pk_ec() is safe to use below. */
     if( ! mbedtls_pk_can_do( peer_pk, MBEDTLS_PK_ECKEY ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "server key not ECDH capable" ) );

library/ssl_tls.c

diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index b0379cd..0099b43 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -2697,7 +2697,9 @@
     {
         const mbedtls_pk_context *pk = &chain->pk;
 
-        /* If certificate uses an EC key, make sure the curve is OK */
+        /* If certificate uses an EC key, make sure the curve is OK.
+         * This is a public key, so it can't be opaque, so can_do() is a good
+         * enough check to ensure pk_ec() is safe to use here. */
         if( mbedtls_pk_can_do( pk, MBEDTLS_PK_ECKEY ) &&
             mbedtls_ssl_check_curve( ssl, mbedtls_pk_ec( *pk )->grp.id ) != 0 )
         {