Add support for fingerprint alg

lib/transport/tls-context.c

@@ -897,6 +897,13 @@ tls_context_set_client_sigalgs(TLSContext *self, const gchar *sigalgs, GError **
 #endif
 }
 
+void
+tls_context_set_fingerprint_alg(TLSContext *self, const gchar *fingerprint_alg)
+{
+  g_free(self->fingerprint_alg);
+  self->fingerprint_alg = g_strdup(fingerprint_alg);
+}
+
 gboolean
 tls_context_set_conf_cmds(TLSContext *self, GList *cmds, GError **error)
 {
@@ -984,6 +991,7 @@ _tls_context_free(TLSContext *self)
   g_free(self->ecdh_curve_list);
   g_free(self->sni);
   g_free(self->keylog_file_path);
+  g_free(self->fingerprint_alg);
 
   if(self->keylog_file)
     fclose(self->keylog_file);

lib/transport/tls-context.h

@@ -89,6 +89,7 @@ struct _TLSContext
   gchar *client_sigalgs;
   gchar *ecdh_curve_list;
   gchar *sni;
+  gchar *fingerprint_alg;
   gboolean ocsp_stapling_verify;
 
   SSL_CTX *ssl_ctx;
@@ -138,6 +139,7 @@ void tls_context_set_ecdh_curve_list(TLSContext *self, const gchar *ecdh_curve_l
 void tls_context_set_dhparam_file(TLSContext *self, const gchar *dhparam_file);
 void tls_context_set_sni(TLSContext *self, const gchar *sni);
 void tls_context_set_ocsp_stapling_verify(TLSContext *self, gboolean ocsp_stapling_verify);
+void tls_context_set_fingerprint_alg(TLSContext *self, const gchar *fingerprint_alg);
 const gchar *tls_context_get_key_file(TLSContext *self);
 EVTTAG *tls_context_format_tls_error_tag(TLSContext *self);
 EVTTAG *tls_context_format_location_tag(TLSContext *self);

lib/transport/tls-session.c

@@ -48,19 +48,29 @@ tls_session_configure_allow_compress(TLSSession *tls_session, gboolean allow_com
 }
 
 static gboolean
-tls_get_x509_digest(X509 *x, GString *hash_string)
+tls_get_x509_digest(const gchar *fingerprint_alg, X509 *x, GString *hash_string)
 {
   gint j;
   unsigned int n;
-  unsigned char md[EVP_MAX_MD_SIZE];
+  unsigned char buffer[EVP_MAX_MD_SIZE];
   g_assert(hash_string);
 
-  if (!X509_digest(x, EVP_sha1(), md, &n))
+  if (!fingerprint_alg)
+    fingerprint_alg = "sha1";
+  const EVP_MD *md = EVP_get_digestbyname(fingerprint_alg);
+  if (!md)
+    {
+      msg_error("Error validating trusted-keys(), unknown fingerprint-alg() specified",
+                evt_tag_str("fingerprint-alg", fingerprint_alg));
+      return FALSE;
+    }
+
+  if (!X509_digest(x, md, buffer, &n))
     return FALSE;
 
-  g_string_append(hash_string, "SHA1:");
+  g_string_append(hash_string, EVP_MD_name(md));
   for (j = 0; j < (int) n; j++)
-    g_string_append_printf(hash_string, "%02X%c", md[j], (j + 1 == (int) n) ?'\0' : ':');
+    g_string_append_printf(hash_string, ":%02X", buffer[j]);
 
   return TRUE;
 }
@@ -125,7 +135,7 @@ tls_session_verify_fingerprint(X509_STORE_CTX *ctx)
 
   hash = g_string_sized_new(EVP_MAX_MD_SIZE * 3);
 
-  if (tls_get_x509_digest(cert, hash))
+  if (tls_get_x509_digest(self->ctx->fingerprint_alg, cert, hash))
     {
       do
         {

modules/afsocket/afsocket-grammar.ym

@@ -199,6 +199,7 @@ systemd_syslog_grammar_set_source_driver(SystemDSyslogSourceDriver *sd)
 %token KW_KEYLOG_FILE
 %token KW_OCSP_STAPLING_VERIFY
 %token KW_CONF_CMDS
+%token KW_FINGERPRINT_ALG
 
 /* INCLUDE_DECLS */
 
@@ -858,6 +859,10 @@ tls_option
           {
             tls_session_set_trusted_fingerprints(last_tls_context, $3);
           }
+        | KW_FINGERPRINT_ALG '(' string ')'
+          {
+            tls_context_set_fingerprint_alg(last_tls_context, $3);
+          }
         | KW_TRUSTED_DN '(' string_list ')'
           {
             tls_session_set_trusted_dn(last_tls_context, $3);

modules/afsocket/afsocket-parser.c

@@ -68,6 +68,7 @@ static CfgLexerKeyword afsocket_keywords[] =
   { "allow_compress",     KW_ALLOW_COMPRESS },
   { "ocsp_stapling_verify", KW_OCSP_STAPLING_VERIFY },
   { "openssl_conf_cmds",  KW_CONF_CMDS},
+  { "fingerprint_alg",    KW_FINGERPRINT_ALG },
 
   { "localip",            KW_LOCALIP },
   { "ip",                 KW_IP },

news/feature-137.md

@@ -0,0 +1,13 @@
+Add `fingerprint-alg()` option to `tls()` blocks: SSL peers can be validated
+using the `trusted-keys()` option that takes a list of trusted public key
+fingerprints.  This was using the `sha1` algorithm, which is not considered
+safe anymore.  This option can be used to customize the message digest
+algorithm and accepts any known algorithms supported by OpenSSL. As of
+OpenSSL 3.0.10, the followings are supported (OpenSSL 3.0.10):
+
+Message Digest commands (see the `dgst' command for more details)
+blake2b512        blake2s256        md4               md5
+rmd160            sha1              sha224            sha256
+sha3-224          sha3-256          sha3-384          sha3-512
+sha384            sha512            sha512-224        sha512-256
+shake128          shake256          sm3