--- contrib/libarchive/libarchive/archive_write.c.orig
+++ contrib/libarchive/libarchive/archive_write.c
@@ -459,8 +459,12 @@
 _archive_write_data(struct archive *_a, const void *buff, size_t s)
 {
 	struct archive_write *a = (struct archive_write *)_a;
+	const size_t max_write = INT_MAX;
 	__archive_check_magic(&a->archive, ARCHIVE_WRITE_MAGIC,
 	    ARCHIVE_STATE_DATA, "archive_write_data");
+	/* In particular, this catches attempts to pass negative values. */
+	if (s > max_write)
+		s = max_write;
 	archive_clear_error(&a->archive);
 	return ((a->format_write_data)(a, buff, s));
 }