do not write null sha1s to on-disk index

diff --git a/patch-delta.c b/patch-delta.c
index e02e13bd4eb2a92626c2d6f9cbf264abb15de9c5..56e0a5ede22c9396fc897bf1d3444dce92d8916f 100644 (file)
--- a/patch-delta.c
+++ b/patch-delta.c
@@ -33,8 +33,7 @@ void *patch_delta(const void *src_buf, unsigned long src_size,
 
        /* now the result size */
        size = get_delta_hdr_size(&data, top);
-       dst_buf = xmalloc(size + 1);
-       dst_buf[size] = 0;
+       dst_buf = xmallocz(size);
 
        out = dst_buf;
        while (data < top) {
@@ -49,7 +48,7 @@ void *patch_delta(const void *src_buf, unsigned long src_size,
                        if (cmd & 0x20) cp_size |= (*data++ << 8);
                        if (cmd & 0x40) cp_size |= (*data++ << 16);
                        if (cp_size == 0) cp_size = 0x10000;
-                       if (cp_off + cp_size < cp_size ||
+                       if (unsigned_add_overflows(cp_off, cp_size) ||
                            cp_off + cp_size > src_size ||
                            cp_size > size)
                                break;