diff --git a/tools/gif2tiff.c b/tools/gif2tiff.c

index 2731273..1e9b4b9 100644

--- a/tools/gif2tiff.c

+++ b/tools/gif2tiff.c

@@ -280,6 +280,10 @@ readgifimage(char* mode)

         fprintf(stderr, "no colormap present for image\n");

         return (0);

     }

+    if (width == 0 || height == 0) {

+        fprintf(stderr, "Invalid value of width or height\n");

+        return(0);

+    }

     if ((raster = (unsigned char*) _TIFFmalloc(width*height+EXTRAFUDGE)) == NULL) {

         fprintf(stderr, "not enough memory for image\n");

         return (0);

@@ -406,6 +410,10 @@ process(register int code, unsigned char** fill)

             fprintf(stderr, "bad input: code=%d is larger than clear=%d\n",code, clear);

             return 0;

         }

+        if (*fill >= raster + width*height) {

+            fprintf(stderr, "raster full before eoi code\n");

+            return 0;

+        }

 	*(*fill)++ = suffix[code];

 	firstchar = oldcode = code;

 	return 1;

@@ -436,6 +444,10 @@ process(register int code, unsigned char** fill)

     }

     oldcode = incode;

     do {

+        if (*fill >= raster + width*height) {

+            fprintf(stderr, "raster full before eoi code\n");

+            return 0;

+        }

 	*(*fill)++ = *--stackp;

     } while (stackp > stack);

     return 1;