db: fix buffer overflow when (de)serializing mtime

We attempted to read/write modification time with 8 bytes, even though
`time_t` wasn't guaranteed to be 8 bytes in size.

By storing always storing mtime in an `int64_t`, we avoid this issue.

src/fsearch_database.c

@@ -298,7 +298,7 @@ db_load_entry_super_elements_from_memory(const uint8_t *data_block,
 
     if ((index_flags & DATABASE_INDEX_FLAG_MODIFICATION_TIME) != 0) {
         // mtime: modification time file/folder
-        time_t mtime = 0;
+        int64_t mtime = 0;
         data_block = copy_bytes_and_return_new_src(&mtime, data_block, 8);
 
         db_entry_set_mtime(entry, mtime);
@@ -759,7 +759,7 @@ db_save_entry_super_elements(FILE *fp,
 
     if ((index_flags & DATABASE_INDEX_FLAG_MODIFICATION_TIME) != 0) {
         // mtime: modification time of file/folder
-        const uint64_t mtime = db_entry_get_mtime(entry);
+        const int64_t mtime = db_entry_get_mtime(entry);
         bytes_written += write_data_to_file(fp, &mtime, 8, 1, write_failed);
         if (*write_failed == true) {
             g_debug("[db_save] failed to save modification time");

src/fsearch_database_entry.c

@@ -12,7 +12,7 @@ struct FsearchDatabaseEntry {
     FsearchDatabaseEntryFolder *parent;
     char *name;
     off_t size;
-    time_t mtime;
+    int64_t mtime;
 
     // idx: index of this entry in the sorted list at pos DATABASE_INDEX_TYPE_NAME
     uint32_t idx;
@@ -114,7 +114,7 @@ db_entry_append_full_path(FsearchDatabaseEntry *entry, GString *str) {
     g_string_append(str, entry->name[0] == '\0' ? G_DIR_SEPARATOR_S : entry->name);
 }
 
-time_t
+int64_t
 db_entry_get_mtime(FsearchDatabaseEntry *entry) {
     return entry ? entry->mtime : 0;
 }
@@ -336,7 +336,7 @@ db_entry_compare_entries_by_name(FsearchDatabaseEntry **a, FsearchDatabaseEntry
 }
 
 void
-db_entry_set_mtime(FsearchDatabaseEntry *entry, time_t mtime) {
+db_entry_set_mtime(FsearchDatabaseEntry *entry, int64_t mtime) {
     entry->mtime = mtime;
 }
 

src/fsearch_database_entry.h

@@ -45,7 +45,7 @@ void
 db_entry_set_idx(FsearchDatabaseEntry *entry, uint32_t idx);
 
 void
-db_entry_set_mtime(FsearchDatabaseEntry *entry, time_t mtime);
+db_entry_set_mtime(FsearchDatabaseEntry *entry, int64_t mtime);
 
 void
 db_entry_set_size(FsearchDatabaseEntry *entry, off_t size);
@@ -86,7 +86,7 @@ db_entry_append_path(FsearchDatabaseEntry *entry, GString *str);
 void
 db_entry_append_full_path(FsearchDatabaseEntry *entry, GString *str);
 
-time_t
+int64_t
 db_entry_get_mtime(FsearchDatabaseEntry *entry);
 
 off_t

src/fsearch_database_view.c

@@ -776,7 +776,7 @@ db_view_entry_append_path_for_idx(FsearchDatabaseView *view, uint32_t idx, GStri
     }
 }
 
-time_t
+int64_t
 db_view_entry_get_mtime_for_idx(FsearchDatabaseView *view, uint32_t idx) {
     g_assert(view);
 

src/fsearch_database_view.h

@@ -81,7 +81,7 @@ db_view_entry_get_path_full_for_idx(FsearchDatabaseView *view, uint32_t idx);
 void
 db_view_entry_append_path_for_idx(FsearchDatabaseView *view, uint32_t idx, GString *str);
 
-time_t
+int64_t
 db_view_entry_get_mtime_for_idx(FsearchDatabaseView *view, uint32_t idx);
 
 off_t

src/fsearch_query_matchers.c

@@ -66,7 +66,7 @@ uint32_t
 fsearch_query_matcher_date_modified(FsearchQueryNode *node, FsearchQueryMatchData *match_data) {
     FsearchDatabaseEntry *entry = fsearch_query_match_data_get_entry(match_data);
     if (entry) {
-        const time_t time = db_entry_get_mtime(entry);
+        const int64_t time = db_entry_get_mtime(entry);
         return cmp_num(time, node);
     }
     return 0;

src/fsearch_result_view.c

@@ -133,7 +133,7 @@ typedef struct {
     char *size;
     char *type;
     char *extension;
-    char time[100];
+    char *time;
 } DrawRowContext;
 
 static void
@@ -143,6 +143,7 @@ draw_row_ctx_free(DrawRowContext *ctx) {
     g_clear_pointer(&ctx->extension, g_free);
     g_clear_pointer(&ctx->type, g_free);
     g_clear_pointer(&ctx->size, g_free);
+    g_clear_pointer(&ctx->time, g_free);
     for (uint32_t i = 0; i < NUM_DATABASE_INDEX_TYPES; i++) {
         if (ctx->highlights[i]) {
             g_clear_pointer(&ctx->highlights[i], pango_attr_list_unref);
@@ -170,6 +171,8 @@ draw_row_ctx_new(FsearchDatabaseView *view, uint32_t row, GdkWindow *bin_window,
     bool ret = true;
     db_view_lock(view);
 
+    g_autoptr(GDateTime) dtime = NULL;
+
     const uint32_t num_items = db_view_get_num_entries(view);
     if (row >= num_items) {
         g_debug("[draw_row] row idx out of bound");
@@ -209,11 +212,14 @@ draw_row_ctx_new(FsearchDatabaseView *view, uint32_t row, GdkWindow *bin_window,
     off_t size = db_view_entry_get_size_for_idx(view, row);
     ctx->size = fsearch_file_utils_get_size_formatted(size, config->show_base_2_units);
 
-    const time_t mtime = db_view_entry_get_mtime_for_idx(view, row);
-    strftime(ctx->time,
-             100,
-             "%Y-%m-%d %H:%M", //"%Y-%m-%d %H:%M",
-             localtime(&mtime));
+    const int64_t mtime = db_view_entry_get_mtime_for_idx(view, row);
+    dtime = g_date_time_new_from_unix_local(mtime);
+    if (dtime) {
+        ctx->time = g_date_time_format(dtime, "%Y-%m-%d %H:%M");
+    }
+    else {
+        ctx->time = g_strdup(_("Date out of range"));
+    }
 
 out:
     db_view_unlock(view);
@@ -290,13 +296,15 @@ fsearch_result_view_query_tooltip(FsearchDatabaseView *view,
                                                      config->show_base_2_units);
         break;
     case DATABASE_INDEX_TYPE_MODIFICATION_TIME: {
-        const time_t mtime = db_view_entry_get_mtime_for_idx(view, row);
-        char mtime_formatted[100] = "";
-        strftime(mtime_formatted,
-                 sizeof(mtime_formatted),
-                 "%Y-%m-%d %H:%M", //"%Y-%m-%d %H:%M",
-                 localtime(&mtime));
-        text = g_strdup(mtime_formatted);
+        const int64_t mtime = db_view_entry_get_mtime_for_idx(view, row);
+        g_autoptr(GDateTime) dtime = g_date_time_new_from_unix_local(mtime);
+        if (dtime) {
+            text = g_date_time_format(dtime, "%Y-%m-%d %H:%M");
+        }
+        else {
+            text = g_strdup(_("Date out of range"));
+        }
+
         break;
     }
     default: