File tiff-CVE-2025-8176.patch of Package tiff.40031

https://gitlab.com/libtiff/libtiff/-/merge_requests/727
Index: tiff-4.0.9/tools/tiffdither.c
===================================================================
--- tiff-4.0.9.orig/tools/tiffdither.c
+++ tiff-4.0.9/tools/tiffdither.c
@@ -93,7 +93,7 @@ fsdither(TIFF* in, TIFF* out)
 	nextptr = nextline;
 	for (j = 0; j < imagewidth; ++j)
 		*nextptr++ = *inptr++;
-	for (i = 1; i < imagelength; ++i) {
+	for (i = 0; i < imagelength; ++i) {
 		tmpptr = thisline;
 		thisline = nextline;
 		nextline = tmpptr;
@@ -136,7 +136,7 @@ fsdither(TIFF* in, TIFF* out)
 					nextptr[0] += v / 16;
 			}
 		}
-		if (TIFFWriteScanline(out, outline, i-1, 0) < 0)
+		if (TIFFWriteScanline(out, outline, i, 0) < 0)
 			goto skip_on_error;
 	}
 	goto exit_label;
Index: tiff-4.0.9/tools/tiffmedian.c
===================================================================
--- tiff-4.0.9.orig/tools/tiffmedian.c
+++ tiff-4.0.9/tools/tiffmedian.c
@@ -829,7 +829,7 @@ quant_fsdither(TIFF* in, TIFF* out)
 	outline = (unsigned char *) _TIFFmalloc(TIFFScanlineSize(out));
 
 	GetInputLine(in, 0, goto bad);		/* get first line */
-	for (i = 1; i <= imagelength; ++i) {
+	for (i = 0; i < imagelength; ++i) {
 		SWAP(short *, thisline, nextline);
 		lastline = (i >= imax);
 		if (i <= imax)
@@ -900,7 +900,7 @@ quant_fsdither(TIFF* in, TIFF* out)
 				nextptr += 3;
 			}
 		}
-		if (TIFFWriteScanline(out, outline, i-1, 0) < 0)
+		if (TIFFWriteScanline(out, outline, i, 0) < 0)
 			break;
 	}
 bad: