Avoid potentially undefined behavior.

Found by PVS Studio.

diff --git a/plugins/sudoers/sudoers.c b/plugins/sudoers/sudoers.c
index e57ee31c601ea8b3c8ef12dd4d3a96f29e91855a..7d7b3f5accb7f61ad4f63923be8e5ecf33df257d 100644 (file)
--- a/plugins/sudoers/sudoers.c
+++ b/plugins/sudoers/sudoers.c
@@ -274,7 +274,8 @@ sudoers_policy_main(int argc, char * const argv[], int pwflag, char *env_add[],
            sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
            goto done;
        }
-       memcpy(++NewArgv, argv, argc * sizeof(char *));
+       NewArgv++;      /* reserve an extra slot for --login */
+       memcpy(NewArgv, argv, argc * sizeof(char *));
        NewArgv[NewArgc] = NULL;
        if (ISSET(sudo_mode, MODE_LOGIN_SHELL) && runas_pw != NULL) {
            NewArgv[0] = strdup(runas_pw->pw_shell);