Add TLSv1.3 server side external PSK support

[openssl.git] / ssl / statem / extensions.c

diff --git a/ssl/statem/extensions.c b/ssl/statem/extensions.c
index d40c34cd1c0b67f362235fa4353596b8e9b97720..7defbb1e003fe38698ff29c2a94998a21564fa6e 100644 (file)
--- a/ssl/statem/extensions.c
+++ b/ssl/statem/extensions.c
@@ -1227,17 +1227,27 @@ static int init_psk_kex_modes(SSL *s, unsigned int context)
 
 int tls_psk_do_binder(SSL *s, const EVP_MD *md, const unsigned char *msgstart,
                       size_t binderoffset, const unsigned char *binderin,
-                      unsigned char *binderout,
-                      SSL_SESSION *sess, int sign)
+                      unsigned char *binderout, SSL_SESSION *sess, int sign,
+                      int external)
 {
     EVP_PKEY *mackey = NULL;
     EVP_MD_CTX *mctx = NULL;
     unsigned char hash[EVP_MAX_MD_SIZE], binderkey[EVP_MAX_MD_SIZE];
     unsigned char finishedkey[EVP_MAX_MD_SIZE], tmpbinder[EVP_MAX_MD_SIZE];
     const char resumption_label[] = "res binder";
-    size_t bindersize, hashsize = EVP_MD_size(md);
+    const char external_label[] = "ext binder";
+    const char *label;
+    size_t bindersize, labelsize, hashsize = EVP_MD_size(md);
     int ret = -1;
 
+    if (external) {
+        label = external_label;
+        labelsize = sizeof(external_label) - 1;
+    } else {
+        label = resumption_label;
+        labelsize = sizeof(resumption_label) - 1;
+    }
+
     /* Generate the early_secret */
     if (!tls13_generate_secret(s, md, NULL, sess->master_key,
                                sess->master_key_length,
@@ -1259,10 +1269,8 @@ int tls_psk_do_binder(SSL *s, const EVP_MD *md, const unsigned char *msgstart,
     }
 
     /* Generate the binder key */
-    if (!tls13_hkdf_expand(s, md, s->early_secret,
-                           (unsigned char *)resumption_label,
-                           sizeof(resumption_label) - 1, hash, binderkey,
-                           hashsize)) {
+    if (!tls13_hkdf_expand(s, md, s->early_secret, (unsigned char *)label,
+                           labelsize, hash, binderkey, hashsize)) {
         SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
         goto err;
     }