LibGfx: Add missing stream error handling in GIF frame descriptor parse

If we try to read a sentinel byte but the stream is fresh out of data,
we have to take care of the stream error and bail out right away, or
we'll hit an assertion when exiting the function soon after.

Fixes #3486.

1 files changed, 3 insertions, 0 deletions

diff --git a/Libraries/LibGfx/GIFLoader.cpp b/Libraries/LibGfx/GIFLoader.cpp
index 421b7dbe75..6f9272d607 100644
--- a/Libraries/LibGfx/GIFLoader.cpp
+++ b/Libraries/LibGfx/GIFLoader.cpp
@@ -446,6 +446,9 @@ static bool load_gif_frame_descriptors(GIFLoadingContext& context)
         u8 sentinel = 0;
         stream >> sentinel;
 
+        if (stream.handle_any_error())
+            return false;
+
         if (sentinel == 0x21) {
             u8 extension_type = 0;
             stream >> extension_type;