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-rw-r--r--gif-check-for-overflow.patch61
1 files changed, 61 insertions, 0 deletions
diff --git a/gif-check-for-overflow.patch b/gif-check-for-overflow.patch
new file mode 100644
index 0000000..76054ba
--- /dev/null
+++ b/gif-check-for-overflow.patch
@@ -0,0 +1,61 @@
+From 6976bdc8ee9dd2c2954f91066f7b0f643769a379 Mon Sep 17 00:00:00 2001
+From: Robert Ancell <robert.ancell@canonical.com>
+Date: Thu, 3 Jun 2021 11:05:56 +1200
+Subject: [PATCH] gif: Check for overflow when compositing or clearing frames.
+
+Fixes: #190
+
+Similar to fix in 086e8adf4cc352cd11572f96066b001b545f354e
+---
+ gdk-pixbuf/io-gif-animation.c | 21 +++++++++++++--------
+ 1 file changed, 13 insertions(+), 8 deletions(-)
+
+diff --git a/gdk-pixbuf/io-gif-animation.c b/gdk-pixbuf/io-gif-animation.c
+index 8335cdd76..71d9265e6 100644
+--- a/gdk-pixbuf/io-gif-animation.c
++++ b/gdk-pixbuf/io-gif-animation.c
+@@ -369,7 +369,7 @@ composite_frame (GdkPixbufGifAnim *anim, GdkPixbufFrame *frame)
+ for (i = 0; i < n_indexes; i++) {
+ guint8 index = index_buffer[i];
+ guint x, y;
+- int offset;
++ gsize offset;
+
+ if (index == frame->transparent_index)
+ continue;
+@@ -379,11 +379,13 @@ composite_frame (GdkPixbufGifAnim *anim, GdkPixbufFrame *frame)
+ if (x >= anim->width || y >= anim->height)
+ continue;
+
+- offset = y * gdk_pixbuf_get_rowstride (anim->last_frame_data) + x * 4;
+- pixels[offset + 0] = frame->color_map[index * 3 + 0];
+- pixels[offset + 1] = frame->color_map[index * 3 + 1];
+- pixels[offset + 2] = frame->color_map[index * 3 + 2];
+- pixels[offset + 3] = 255;
++ if (g_size_checked_mul (&offset, gdk_pixbuf_get_rowstride (anim->last_frame_data), y) &&
++ g_size_checked_add (&offset, offset, x * 4)) {
++ pixels[offset + 0] = frame->color_map[index * 3 + 0];
++ pixels[offset + 1] = frame->color_map[index * 3 + 1];
++ pixels[offset + 2] = frame->color_map[index * 3 + 2];
++ pixels[offset + 3] = 255;
++ }
+ }
+
+ out:
+@@ -448,8 +450,11 @@ gdk_pixbuf_gif_anim_iter_get_pixbuf (GdkPixbufAnimationIter *anim_iter)
+ x_end = MIN (anim->last_frame->x_offset + anim->last_frame->width, anim->width);
+ y_end = MIN (anim->last_frame->y_offset + anim->last_frame->height, anim->height);
+ for (y = anim->last_frame->y_offset; y < y_end; y++) {
+- guchar *line = pixels + y * gdk_pixbuf_get_rowstride (anim->last_frame_data) + anim->last_frame->x_offset * 4;
+- memset (line, 0, (x_end - anim->last_frame->x_offset) * 4);
++ gsize offset;
++ if (g_size_checked_mul (&offset, gdk_pixbuf_get_rowstride (anim->last_frame_data), y) &&
++ g_size_checked_add (&offset, offset, anim->last_frame->x_offset * 4)) {
++ memset (pixels + offset, 0, (x_end - anim->last_frame->x_offset) * 4);
++ }
+ }
+ break;
+ case GDK_PIXBUF_FRAME_REVERT:
+--
+GitLab
+