make_reparse_data(): No changes until success ensured

diff --git a/src/reparse.c b/src/reparse.c
index 4df2a4b428831fd02cee77329a5ba198ba0a2514..fa6e282d21e2811ebc001433cf15a204ac5bd2a2 100644 (file)
--- a/src/reparse.c
+++ b/src/reparse.c
@@ -117,6 +117,19 @@ make_reparse_buffer(const struct reparse_data * restrict rpdata,
                (struct reparse_buffer_disk*)rpbuf;
        u8 *data;
 
+       if (rpdata->rptag == WIM_IO_REPARSE_TAG_SYMLINK)
+               data = rpbuf_disk->symlink.data;
+       else
+               data = rpbuf_disk->junction.data;
+
+       if ((data - rpbuf) + rpdata->substitute_name_nbytes +
+           rpdata->print_name_nbytes +
+           2 * sizeof(utf16lechar) > REPARSE_POINT_MAX_SIZE)
+       {
+               ERROR("Reparse data is too long!");
+               return WIMLIB_ERR_INVALID_REPARSE_DATA;
+       }
+
        rpbuf_disk->rptag = cpu_to_le32(rpdata->rptag);
        rpbuf_disk->rpreserved = cpu_to_le16(rpdata->rpreserved);
        rpbuf_disk->symlink.substitute_name_offset = cpu_to_le16(0);
@@ -124,23 +137,12 @@ make_reparse_buffer(const struct reparse_data * restrict rpdata,
        rpbuf_disk->symlink.print_name_offset = cpu_to_le16(rpdata->substitute_name_nbytes + 2);
        rpbuf_disk->symlink.print_name_nbytes = cpu_to_le16(rpdata->print_name_nbytes);
 
-       if (rpdata->rptag == WIM_IO_REPARSE_TAG_SYMLINK) {
+       if (rpdata->rptag == WIM_IO_REPARSE_TAG_SYMLINK)
                rpbuf_disk->symlink.rpflags = cpu_to_le32(rpdata->rpflags);
-               data = rpbuf_disk->symlink.data;
-       } else {
-               data = rpbuf_disk->junction.data;
-       }
 
        /* We null-terminate the substitute and print names, although this may
         * not be strictly necessary.  Note that the byte counts should not
         * include the null terminators. */
-       if (data + rpdata->substitute_name_nbytes +
-           rpdata->print_name_nbytes +
-           2 * sizeof(utf16lechar) - rpbuf > REPARSE_POINT_MAX_SIZE)
-       {
-               ERROR("Reparse data is too long!");
-               return WIMLIB_ERR_INVALID_REPARSE_DATA;
-       }
        data = mempcpy(data, rpdata->substitute_name, rpdata->substitute_name_nbytes);
        *(utf16lechar*)data = cpu_to_le16(0);
        data += 2;