From 00110a639aea03250476a32349fd9093d54b2c46 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C5=99emysl=20Eric=20Janouch?= <p@janouch.name>
Date: Sat, 20 May 2023 23:46:39 +0200
Subject: [PATCH] Avoid use of NULL picture data pointers

The sanitizer would scream, and LibRaw would rather confusingly
return I/O errors.
---
 fiv-thumbnail.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/fiv-thumbnail.c b/fiv-thumbnail.c
index c552073..0933951 100644
--- a/fiv-thumbnail.c
+++ b/fiv-thumbnail.c
@@ -281,6 +281,12 @@ fiv_thumbnail_extract(GFile *target, FivThumbnailSize max_size, GError **error)
 	// TODO(p): Implement our own thumbnail extractors.
 	set_error(error, "unsupported file");
 #else  // HAVE_LIBRAW
+	// In this case, g_mapped_file_get_contents() returns NULL, causing issues.
+	if (!g_mapped_file_get_length(mf)) {
+		set_error(error, "empty file");
+		goto fail;
+	}
+
 	libraw_data_t *iprc = libraw_init(
 		LIBRAW_OPIONS_NO_MEMERR_CALLBACK | LIBRAW_OPIONS_NO_DATAERR_CALLBACK);
 	if (!iprc) {
@@ -535,7 +541,13 @@ fiv_thumbnail_produce(GFile *target, FivThumbnailSize max_size, GError **error)
 		return produce_fallback(target, max_size, error);
 	}
 
+	// In this case, g_mapped_file_get_bytes() has NULL data, causing issues.
 	gsize filesize = g_mapped_file_get_length(mf);
+	if (!filesize) {
+		set_error(error, "empty file");
+		return NULL;
+	}
+
 	gboolean color_managed = FALSE;
 	cairo_surface_t *surface =
 		render(target, g_mapped_file_get_bytes(mf), &color_managed, error);