tga: reject empty images (#2614)

Author: mstoeckl

src/codecs/tga/decoder.rs

@@ -87,6 +87,13 @@ impl<R: Read> TgaDecoder<R> {
         let raw_bytes_per_pixel = (header.pixel_depth as usize).div_ceil(8);
         let num_alpha_bits = header.image_desc & ALPHA_BIT_MASK;
 
+        if width == 0 || height == 0 {
+            return Err(ImageError::Decoding(DecodingError::new(
+                ImageFormat::Tga.into(),
+                "Invalid empty image",
+            )));
+        }
+
         // Validate header
         if ![8, 16, 24, 32].contains(&header.pixel_depth) || ![0, 8].contains(&num_alpha_bits) {
             return Err(ImageError::Unsupported(

src/codecs/tga/encoder.rs

@@ -11,13 +11,17 @@ enum EncoderError {
 
     /// Invalid TGA height.
     HeightInvalid(u32),
+
+    /// Empty
+    Empty(u32, u32),
 }
 
 impl fmt::Display for EncoderError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             EncoderError::WidthInvalid(s) => f.write_fmt(format_args!("Invalid TGA width: {s}")),
             EncoderError::HeightInvalid(s) => f.write_fmt(format_args!("Invalid TGA height: {s}")),
+            EncoderError::Empty(w, h) => f.write_fmt(format_args!("Invalid TGA size: {w}x{h}")),
         }
     }
 }
@@ -173,6 +177,10 @@ impl<W: Write> TgaEncoder<W> {
         );
 
         // Validate dimensions.
+        if width == 0 || height == 0 {
+            return Err(ImageError::from(EncoderError::Empty(width, height)));
+        }
+
         let width = u16::try_from(width)
             .map_err(|_| ImageError::from(EncoderError::WidthInvalid(width)))?;