libmm-glib,common-helpers: don't assume new_from_unix_utc() always succeeds

The g_date_time_new_from_unix_utc() method in glib2 may fail if the
given timestamp is too far into the future. The value is supposed to
be seconds since unix time origin, but internally it will be converted
into usecs, so any value longer than G_MAXINT64 / USEC_PER_SECOND
isn't allowed.

This is currently used in the CLI, and we're anyway ignoring the error
returned in that case, but at least it won't crash if it ever happens.

4 files changed, 29 insertions, 14 deletions

diff --git a/cli/mmcli-output.c b/cli/mmcli-output.c
index 1bb17f82..ef1c7cb3 100644
--- a/cli/mmcli-output.c
+++ b/cli/mmcli-output.c
@@ -621,11 +621,11 @@ mmcli_output_signal_quality (MMModemState state,
 /* (Custom) Bearer start date output */
 
 void
-mmcli_output_start_date (guint64    value)
+mmcli_output_start_date (guint64 value)
 {
     /* Merge value and recent flag in a single item in human output */
     if (selected_type == MMC_OUTPUT_TYPE_HUMAN) {
-        output_item_new_take_single (MMC_F_BEARER_STATS_START_DATE, mm_new_iso8601_time_from_unix_time (value));
+        output_item_new_take_single (MMC_F_BEARER_STATS_START_DATE, mm_new_iso8601_time_from_unix_time (value, NULL));
         return;
     }
 
diff --git a/libmm-glib/mm-common-helpers.c b/libmm-glib/mm-common-helpers.c
index 085177b7..0dff0e8c 100644
--- a/libmm-glib/mm-common-helpers.c
+++ b/libmm-glib/mm-common-helpers.c
@@ -1752,11 +1752,18 @@ date_time_format_iso8601 (GDateTime *dt)
 }
 
 gchar *
-mm_new_iso8601_time_from_unix_time (guint64 timestamp)
+mm_new_iso8601_time_from_unix_time (guint64   timestamp,
+                                    GError  **error)
 {
     g_autoptr(GDateTime) dt = NULL;
 
     dt = g_date_time_new_from_unix_utc ((gint64)timestamp);
+    if (!dt) {
+        g_set_error (error, MM_CORE_ERROR, MM_CORE_ERROR_INVALID_ARGS,
+                     "Invalid unix time: %" G_GUINT64_FORMAT,
+                     timestamp);
+        return NULL;
+    }
 
     return date_time_format_iso8601 (dt);
 }
diff --git a/libmm-glib/mm-common-helpers.h b/libmm-glib/mm-common-helpers.h
index 490f882d..a92d5b58 100644
--- a/libmm-glib/mm-common-helpers.h
+++ b/libmm-glib/mm-common-helpers.h
@@ -208,16 +208,17 @@ gboolean  mm_get_double_from_match_info          (GMatchInfo  *match_info,
 gchar    *mm_get_string_unquoted_from_match_info (GMatchInfo  *match_info,
                                                   guint32      match_index);
 
-gchar    *mm_new_iso8601_time_from_unix_time     (guint64  timestamp);
-gchar    *mm_new_iso8601_time                    (guint    year,
-                                                  guint    month,
-                                                  guint    day,
-                                                  guint    hour,
-                                                  guint    minute,
-                                                  guint    second,
-                                                  gboolean have_offset,
-                                                  gint     offset_minutes,
-                                                  GError **error);
+gchar    *mm_new_iso8601_time_from_unix_time     (guint64    timestamp,
+                                                  GError   **error);
+gchar    *mm_new_iso8601_time                    (guint      year,
+                                                  guint      month,
+                                                  guint      day,
+                                                  guint      hour,
+                                                  guint      minute,
+                                                  guint      second,
+                                                  gboolean   have_offset,
+                                                  gint       offset_minutes,
+                                                  GError   **error);
 
 /******************************************************************************/
 /* Type checkers and conversion utilities */
diff --git a/libmm-glib/tests/test-common-helpers.c b/libmm-glib/tests/test-common-helpers.c
index a1a2e61e..fff37a82 100644
--- a/libmm-glib/tests/test-common-helpers.c
+++ b/libmm-glib/tests/test-common-helpers.c
@@ -604,7 +604,8 @@ date_time_iso8601 (void)
     gchar *date = NULL;
     GError *error = NULL;
 
-    date = mm_new_iso8601_time_from_unix_time (1634307342);
+    date = mm_new_iso8601_time_from_unix_time (1634307342, &error);
+    g_assert_no_error (error);
     g_assert_cmpstr (date, ==, "2021-10-15T14:15:42Z");
     g_free (date);
 
@@ -636,6 +637,12 @@ date_time_iso8601 (void)
     g_assert_error (error, MM_CORE_ERROR, MM_CORE_ERROR_INVALID_ARGS);
     g_assert_null (date);
     g_clear_error (&error);
+
+    /* Too far into the future */
+    date = mm_new_iso8601_time_from_unix_time (G_MAXINT64, &error);
+    g_assert_error (error, MM_CORE_ERROR, MM_CORE_ERROR_INVALID_ARGS);
+    g_assert_null (date);
+    g_clear_error (&error);
 }
 
 /**************************************************************/