[gnome-desktop/gnome-3-24] thumbnail: Fix use of uninitialised value

[Bastien Nocera <hadess src gnome org>]

commit cf1b21309402f7125fb816da10786d866f8bc18e
Author: Bastien Nocera <hadess hadess net>
Date:   Thu Jul 13 17:44:30 2017 +0200

    thumbnail: Fix use of uninitialised value
    
    The pixbuf to be written as a placeholder thumbnail was never
    initialised to be empty, so might contain random data from the stack.
    Use gdk_pixbuf_fill() to solve this problem.
    
    Use of uninitialised value of size 8
       at 0x9A8ED44: crc32_little (crc32.c:287)
       by 0x9A8ED44: crc32_z (crc32.c:220)
       by 0x8A617FB: png_calculate_crc (png.c:153)
       by 0x8A7FACF: png_write_complete_chunk (pngwutil.c:187)
       by 0x8A801B1: png_compress_IDAT (pngwutil.c:1047)
       by 0x8A81F8E: png_write_filtered_row (pngwutil.c:2743)
       by 0x8A81F8E: png_write_find_filter (pngwutil.c:2713)
       by 0x8A7CF21: png_write_row (pngwrite.c:888)
       by 0x8A7D20E: png_write_rows (pngwrite.c:582)
       by 0x8263A08: real_save_png (io-png.c:1139)
       by 0x8263B0A: gdk_pixbuf__png_image_save (io-png.c:1166)
       by 0x8250FF8: gdk_pixbuf_real_save (gdk-pixbuf-io.c:2180)
       by 0x8251820: gdk_pixbuf_savev (gdk-pixbuf-io.c:2479)
       by 0x8251534: gdk_pixbuf_save (gdk-pixbuf-io.c:2418)
       by 0x5342324: save_thumbnail (gnome-desktop-thumbnail.c:1224)
       by 0x53424DD: gnome_desktop_thumbnail_factory_create_failed_thumbnail (gnome-desktop-thumbnail.c:1313)
       by 0x4E89B6A: eog_thumbnail_load (eog-thumbnail.c:518)
       by 0x4E6BA39: eog_job_thumbnail_run (eog-jobs.c:1270)
       by 0x4E69796: eog_job_run (eog-jobs.c:271)
       by 0x4E689A2: eog_job_process (eog-job-scheduler.c:153)
       by 0x4E688AA: eog_job_scheduler (eog-job-scheduler.c:128)
       by 0x97E4004: g_thread_proxy (gthread.c:784)
       by 0x9CAA36C: start_thread (in /usr/lib64/libpthread-2.25.so)
       by 0x9FD2E9E: clone (in /usr/lib64/libc-2.25.so)
    Uninitialised value was created by a stack allocation
       at 0x8262D5E: real_save_png (io-png.c:871)
    
    https://bugzilla.gnome.org/show_bug.cgi?id=784915

 libgnome-desktop/gnome-desktop-thumbnail.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/libgnome-desktop/gnome-desktop-thumbnail.c b/libgnome-desktop/gnome-desktop-thumbnail.c
index 775c578..328804d 100644
--- a/libgnome-desktop/gnome-desktop-thumbnail.c
+++ b/libgnome-desktop/gnome-desktop-thumbnail.c
@@ -1262,7 +1262,11 @@ save_thumbnail (GdkPixbuf  *pixbuf,
 static GdkPixbuf *
 make_failed_thumbnail (void)
 {
-  return gdk_pixbuf_new (GDK_COLORSPACE_RGB, TRUE, 8, 1, 1);
+  GdkPixbuf *pixbuf;
+
+  pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, TRUE, 8, 1, 1);
+  gdk_pixbuf_fill (pixbuf, 0x00000000);
+  return pixbuf;
 }
 
 /**