Upstream patch for CVE-2012-4447.


diff -Naur tiff-4.0.3.orig/libtiff/tif_pixarlog.c tiff-4.0.3/libtiff/tif_pixarlog.c
--- tiff-4.0.3.orig/libtiff/tif_pixarlog.c	2012-07-04 15:26:31.000000000 -0400
+++ tiff-4.0.3/libtiff/tif_pixarlog.c	2012-12-12 16:43:18.931315699 -0500
@@ -644,6 +644,20 @@
 	return bytes;
 }
 
+static tmsize_t
+add_ms(tmsize_t m1, tmsize_t m2)
+{
+	tmsize_t bytes = m1 + m2;
+
+	/* if either input is zero, assume overflow already occurred */
+	if (m1 == 0 || m2 == 0)
+		bytes = 0;
+	else if (bytes <= m1 || bytes <= m2)
+		bytes = 0;
+
+	return bytes;
+}
+
 static int
 PixarLogFixupTags(TIFF* tif)
 {
@@ -671,9 +685,11 @@
 	    td->td_samplesperpixel : 1);
 	tbuf_size = multiply_ms(multiply_ms(multiply_ms(sp->stride, td->td_imagewidth),
 				      td->td_rowsperstrip), sizeof(uint16));
+	/* add one more stride in case input ends mid-stride */
+	tbuf_size = add_ms(tbuf_size, sizeof(uint16) * sp->stride);
 	if (tbuf_size == 0)
 		return (0);   /* TODO: this is an error return without error report through TIFFErrorExt */
-	sp->tbuf = (uint16 *) _TIFFmalloc(tbuf_size+sizeof(uint16)*sp->stride);
+	sp->tbuf = (uint16 *) _TIFFmalloc(tbuf_size);
 	if (sp->tbuf == NULL)
 		return (0);
 	if (sp->user_datafmt == PIXARLOGDATAFMT_UNKNOWN)