Add the ability to set a TLSv1.3 PSK via just the key bytes

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3670)

1 files changed, 46 insertions, 3 deletions

diff --git a/apps/s_server.c b/apps/s_server.c
index 20d2497e7b..d5e226ad7d 100644
--- a/apps/s_server.c
+++ b/apps/s_server.c
@@ -179,15 +179,55 @@ static unsigned int psk_server_cb(SSL *ssl, const char *identity,
 }
 #endif
 
+#define TLS13_AES_128_GCM_SHA256_BYTES  ((const unsigned char *)"\x13\x01")
+#define TLS13_AES_256_GCM_SHA384_BYTES  ((const unsigned char *)"\x13\x02")
+
 static int psk_find_session_cb(SSL *ssl, const unsigned char *identity,
                                size_t identity_len, SSL_SESSION **sess)
 {
+    SSL_SESSION *tmpsess = NULL;
+    unsigned char *key;
+    long key_len;
+    const SSL_CIPHER *cipher = NULL;
+
     if (strlen(psk_identity) != identity_len
             || memcmp(psk_identity, identity, identity_len) != 0)
         return 0;
 
-    SSL_SESSION_up_ref(psksess);
-    *sess = psksess;
+    if (psksess != NULL) {
+        SSL_SESSION_up_ref(psksess);
+        *sess = psksess;
+        return 1;
+    }
+
+    key = OPENSSL_hexstr2buf(psk_key, &key_len);
+    if (key == NULL) {
+        BIO_printf(bio_err, "Could not convert PSK key '%s' to buffer\n",
+                   psk_key);
+        return 0;
+    }
+
+    if (key_len == EVP_MD_size(EVP_sha256()))
+        cipher = SSL_CIPHER_find(ssl, TLS13_AES_128_GCM_SHA256_BYTES);
+    else if(key_len == EVP_MD_size(EVP_sha384()))
+        cipher = SSL_CIPHER_find(ssl, TLS13_AES_256_GCM_SHA384_BYTES);
+
+    if (cipher == NULL) {
+        /* Doesn't look like a suitable TLSv1.3 key. Ignore it */
+        OPENSSL_free(key);
+        return 0;
+    }
+
+    tmpsess = SSL_SESSION_new();
+    if (tmpsess == NULL
+            || !SSL_SESSION_set1_master_key(tmpsess, key, key_len)
+            || !SSL_SESSION_set_cipher(tmpsess, cipher)
+            || !SSL_SESSION_set_protocol_version(tmpsess, SSL_version(ssl))) {
+        OPENSSL_free(key);
+        return 0;
+    }
+    OPENSSL_free(key);
+    *sess = tmpsess;
 
     return 1;
 }
@@ -1974,9 +2014,12 @@ int s_server_main(int argc, char *argv[])
             ERR_print_errors(bio_err);
             goto end;
         }
-        SSL_CTX_set_psk_find_session_callback(ctx, psk_find_session_cb);
+
     }
 
+    if (psk_key != NULL || psksess != NULL)
+        SSL_CTX_set_psk_find_session_callback(ctx, psk_find_session_cb);
+
     SSL_CTX_set_verify(ctx, s_server_verify, verify_callback);
     if (!SSL_CTX_set_session_id_context(ctx,
                                         (void *)&s_server_session_id_context,