cinterion: make sure FALSE sets GError in provcfg_response_to_cid()

The g_regex_match_full() method may return FALSE without setting the
GError, so that case needs to be considered.

Reported by Jan Mazura.

Fixes https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/issues/347

plugins/cinterion/mm-modem-helpers-cinterion.c

@@ -1514,12 +1514,24 @@ mm_cinterion_provcfg_response_to_cid (const gchar             *response,
     g_autoptr(GRegex)      r = NULL;
     g_autoptr(GMatchInfo)  match_info = NULL;
     g_autofree gchar      *mno = NULL;
+    GError                *inner_error = NULL;
 
     r = g_regex_new ("\\^SCFG:\\s*\"MEopMode/Prov/Cfg\",\\s*\"([0-9a-zA-Z*]*)\"", 0, 0, NULL);
     g_assert (r != NULL);
 
-    if (!g_regex_match_full (r, response, strlen (response), 0, 0, &match_info, error))
+    g_regex_match_full (r, response, strlen (response), 0, 0, &match_info, &inner_error);
+
+    if (inner_error) {
+        g_prefix_error (&inner_error, "Failed to match Prov/Cfg response: ");
+        g_propagate_error (error, inner_error);
         return FALSE;
+    }
+
+    if (!g_match_info_matches (match_info)) {
+        g_set_error (error, MM_CORE_ERROR, MM_CORE_ERROR_FAILED,
+                     "Couldn't match Prov/Cfg response");
+        return FALSE;
+    }
 
     mno = mm_get_string_unquoted_from_match_info (match_info, 1);
     if (mno && modem_family == MM_CINTERION_MODEM_FAMILY_IMT) {

plugins/cinterion/tests/test-modem-helpers-cinterion.c

@@ -1602,45 +1602,57 @@ test_smoni_response_to_signal (void)
 typedef struct {
     const gchar            *str;
     MMCinterionModemFamily  modem_family;
-    gdouble                 expected_cid;
+    gboolean                success;
+    guint                   expected_cid;
 } ProvcfgResponseTest;
 
-
 static const ProvcfgResponseTest provcfg_response_tests[] = {
     {
 
         .str          = "^SCFG: \"MEopMode/Prov/Cfg\",\"vdfde\"",
         .modem_family = MM_CINTERION_MODEM_FAMILY_DEFAULT,
+        .success      = TRUE,
         .expected_cid = 1,
     },
     {
 
         .str          = "* ^SCFG: \"MEopMode/Prov/Cfg\",\"attus\"",
         .modem_family = MM_CINTERION_MODEM_FAMILY_IMT,
+        .success      = TRUE,
         .expected_cid = 1,
     },
     {
 
         .str          = "* ^SCFG: \"MEopMode/Prov/Cfg\",\"2\"",
         .modem_family = MM_CINTERION_MODEM_FAMILY_DEFAULT,
+        .success      = TRUE,
         .expected_cid = 3,
     },
     {
 
         .str          = "* ^SCFG: \"MEopMode/Prov/Cfg\",\"vzwdcus\"",
         .modem_family = MM_CINTERION_MODEM_FAMILY_DEFAULT,
+        .success      = TRUE,
         .expected_cid = 3,
     },
     {
 
         .str          = "* ^SCFG: \"MEopMode/Prov/Cfg\",\"tmode\"",
         .modem_family = MM_CINTERION_MODEM_FAMILY_DEFAULT,
+        .success      = TRUE,
         .expected_cid = 2,
     },
     {
         .str          = "* ^SCFG: \"MEopMode/Prov/Cfg\",\"fallback*\"",
         .modem_family = MM_CINTERION_MODEM_FAMILY_DEFAULT,
+        .success      = TRUE,
         .expected_cid = 1,
+    },
+    {
+        /* commas not allowed by the regex */
+        .str          = "* ^SCFG: \"MEopMode/Prov/Cfg\",\"something,with,commas\"",
+        .modem_family = MM_CINTERION_MODEM_FAMILY_DEFAULT,
+        .success      = FALSE,
     }
 };
 
@@ -1660,9 +1672,14 @@ test_provcfg_response (void)
                                                        NULL,
                                                        &cid,
                                                        &error);
+        if (provcfg_response_tests[i].success) {
             g_assert_no_error (error);
             g_assert (result);
             g_assert_cmpuint (cid, ==, provcfg_response_tests[i].expected_cid);
+        } else {
+            g_assert (error);
+            g_assert (!result);
+        }
     }
 }