--- libsoup-2.58.1/libsoup/soup-filter-input-stream.c	2016-12-03 08:59:41.000000000 -0600
+++ libsoup-2.58.2/libsoup/soup-filter-input-stream.c	2017-08-10 07:06:09.000000000 -0500
@@ -198,7 +198,7 @@
 				     GCancellable           *cancellable,
 				     GError                **error)
 {
-	gssize nread;
+	gssize nread, read_length;
 	guint8 *p, *buf, *end;
 	gboolean eof = FALSE;
 	GError *my_error = NULL;
@@ -251,10 +251,11 @@
 	} else
 		buf = fstream->priv->buf->data;
 
-	/* Scan for the boundary */
-	end = buf + fstream->priv->buf->len;
-	if (!eof)
-		end -= boundary_length;
+	/* Scan for the boundary within the range we can possibly return. */
+	if (include_boundary)
+		end = buf + MIN (fstream->priv->buf->len, length) - boundary_length;
+	else
+		end = buf + MIN (fstream->priv->buf->len - boundary_length, length);
 	for (p = buf; p <= end; p++) {
 		if (*p == *(guint8*)boundary &&
 		    !memcmp (p, boundary, boundary_length)) {
@@ -268,10 +269,9 @@
 	if (!*got_boundary && fstream->priv->buf->len < length && !eof)
 		goto fill_buffer;
 
-	/* Return everything up to 'p' (which is either just after the boundary if
-	 * include_boundary is TRUE, just before the boundary if include_boundary is
-	 * FALSE, @boundary_len - 1 bytes before the end of the buffer, or end-of-
-	 * file).
-	 */
-	return read_from_buf (fstream, buffer, p - buf);
+	if (eof && !*got_boundary)
+		read_length = MIN (fstream->priv->buf->len, length);
+	else
+		read_length = p - buf;
+	return read_from_buf (fstream, buffer, read_length);
 }