conn: add xmpp_conn_tls_cafile()

This function adds an external CAfile in PEM format as trusted
certificates.

examples/basic.c

@@ -49,6 +49,7 @@ int main(int argc, char **argv)
     xmpp_conn_t *conn;
     xmpp_log_t *log;
     char *jid, *pass, *host = NULL;
+    const char *cafile = NULL;
     long flags = 0;
     int tcp_keepalive = 0;
     int i;
@@ -67,12 +68,15 @@ int main(int argc, char **argv)
             flags |= XMPP_CONN_FLAG_LEGACY_AUTH;
         else if (strcmp(argv[i], "--tcp-keepalive") == 0)
             tcp_keepalive = 1;
+        else if (strncmp(argv[i], "--cafile=", strlen("--cafile=")) == 0)
+            cafile = argv[i] + strlen("--cafile=");
         else
             break;
     }
     if ((argc - i) < 2 || (argc - i) > 3) {
         fprintf(stderr, "Usage: basic [options] <jid> <pass> [<host>]\n\n"
                         "Options:\n"
+                        "  --cafile=<PATH>      CAfile for cert verification.\n"
                         "  --disable-tls        Disable TLS.\n"
                         "  --mandatory-tls      Deny plaintext connection.\n"
                         "  --trust-tls          Trust TLS certificate.\n"
@@ -111,6 +115,10 @@ int main(int argc, char **argv)
     if (tcp_keepalive)
         xmpp_conn_set_keepalive(conn, KA_TIMEOUT, KA_INTERVAL);
 
+    /* add external CAfile if needed */
+    if (cafile)
+        xmpp_conn_tls_cafile(conn, cafile);
+
     /* setup authentication information */
     xmpp_conn_set_jid(conn, jid);
     xmpp_conn_set_pass(conn, pass);

src/common.h

@@ -171,6 +171,7 @@ struct _xmpp_conn_t {
     int ka_interval; /* TCP keepalive interval */
 
     tls_t *tls;
+    char *tls_cafile;
     int tls_support;
     int tls_disabled;
     int tls_mandatory;

src/conn.c

@@ -137,6 +137,7 @@ xmpp_conn_t *xmpp_conn_new(xmpp_ctx_t *const ctx)
         conn->bound_jid = NULL;
 
         conn->is_raw = 0;
+        conn->tls_cafile = NULL;
         conn->tls_support = 0;
         conn->tls_disabled = 0;
         conn->tls_mandatory = 0;
@@ -338,6 +339,8 @@ int xmpp_conn_release(xmpp_conn_t *const conn)
             xmpp_free(ctx, conn->pass);
         if (conn->lang)
             xmpp_free(ctx, conn->lang);
+        if (conn->tls_cafile)
+            xmpp_free(ctx, conn->tls_cafile);
         xmpp_free(ctx, conn);
         released = 1;
     }
@@ -686,6 +689,28 @@ int xmpp_conn_tls_start(xmpp_conn_t *const conn)
     return conn_tls_start(conn);
 }
 
+/** Set external CAfile which will be used for TLS cert verification.
+ *
+ *  @return XMPP_EOK (0) on success a number less than 0 on failure
+ *
+ *  @ingroup Connections
+ */
+int xmpp_conn_tls_cafile(xmpp_conn_t *const conn, const char *cafile)
+{
+    FILE *f;
+
+    f = fopen(cafile, "r");
+    if (f == NULL) {
+        xmpp_debug(conn->ctx, "conn", "CAfile '%s' is not readable. errno=%d",
+                   cafile, errno);
+        return XMPP_EINVOP;
+    }
+    fclose(f);
+    conn->tls_cafile = xmpp_strdup(conn->ctx, cafile);
+
+    return conn->tls_cafile == NULL ? XMPP_EMEM : XMPP_EOK;
+}
+
 /** Cleanly disconnect the connection.
  *  This function is only called by the stream parser when </stream:stream>
  *  is received, and it not intended to be called by code outside of Strophe.
@@ -915,6 +940,10 @@ int conn_tls_start(xmpp_conn_t *const conn)
     }
 
     if (conn->tls != NULL) {
+        if (conn->tls_cafile != NULL) {
+            (void)tls_set_credentials(conn->tls, conn->tls_cafile);
+        }
+
         if (tls_start(conn->tls)) {
             conn->secured = 1;
         } else {

src/tls_openssl.c

@@ -318,9 +318,14 @@ void tls_free(tls_t *tls)
 
 int tls_set_credentials(tls_t *tls, const char *cafilename)
 {
-    UNUSED(tls);
-    UNUSED(cafilename);
-    return -1;
+    int ret;
+
+    ret = SSL_CTX_load_verify_locations(tls->ssl_ctx, cafilename, NULL);
+    if (ret != 1) {
+        xmpp_error(tls->ctx, "tls", "Failed to process CAfile: %s", cafilename);
+        _tls_log_error(tls->ctx);
+    }
+    return ret;
 }
 
 int tls_start(tls_t *tls)

strophe.h

@@ -271,6 +271,7 @@ int xmpp_conn_open_stream(xmpp_conn_t *const conn,
                           char **attributes,
                           size_t attributes_len);
 int xmpp_conn_tls_start(xmpp_conn_t *const conn);
+int xmpp_conn_tls_cafile(xmpp_conn_t *const conn, const char *cafile);
 
 void xmpp_disconnect(xmpp_conn_t *const conn);