build_unc_path_to_root(const struct smb_vol *vol,
		const struct cifs_sb_info *cifs_sb)
{
	char *full_path, *pos;
	unsigned int pplen = vol->prepath ? strlen(vol->prepath) + 1 : 0;
	unsigned int unc_len = strnlen(vol->UNC, MAX_TREE_SIZE + 1);

	full_path = kmalloc(unc_len + pplen + 1, GFP_KERNEL);
	if (full_path == NULL)
		return ERR_PTR(-ENOMEM);

	strncpy(full_path, vol->UNC, unc_len);
 	pos = full_path + unc_len;
 
 	if (pplen) {
		*pos = CIFS_DIR_SEP(cifs_sb);
		strncpy(pos + 1, vol->prepath, pplen);
 		pos += pplen;
 	}
 
	*pos = '\0'; /* add trailing null */
	convert_delimiter(full_path, CIFS_DIR_SEP(cifs_sb));
	cifs_dbg(FYI, "%s: full_path=%s\n", __func__, full_path);
	return full_path;
}

This weakness involves numeric computation errors, such as integer overflows, underflows, or precision losses, which can lead to miscalculations and exploitable behaviors in software.