check patch_delta bounds more carefully

[git.git] / delta.h

diff --git a/delta.h b/delta.h
index a15350d..9464f3e 100644 (file)
--- a/delta.h
+++ b/delta.h
@@ -16,7 +16,8 @@ extern void *patch_delta(void *src_buf, unsigned long src_size,
  * This must be called twice on the delta data buffer, first to get the
  * expected reference buffer size, and again to get the result buffer size.
  */
-static inline unsigned long get_delta_hdr_size(const unsigned char **datap)
+static inline unsigned long get_delta_hdr_size(const unsigned char **datap,
+                                              const unsigned char *top)
 {
        const unsigned char *data = *datap;
        unsigned char cmd;
@@ -26,7 +27,7 @@ static inline unsigned long get_delta_hdr_size(const unsigned char **datap)
                cmd = *data++;
                size |= (cmd & ~0x80) << i;
                i += 7;
-       } while (cmd & 0x80);
+       } while (cmd & 0x80 && data < top);
        *datap = data;
        return size;
 }