Run most of the code as root, not the invoking user. It doesn't really

gain us anything to run as the user since an attacker can just have
an setuid(0) in their egg.  Running as root solves potential problems
wrt signalling.

logging.c

@@ -161,15 +161,10 @@ do_logfile(msg)
     FILE *fp;
     mode_t oldmask;
     time_t now;
-    int oldeuid = geteuid();
     int maxlen = MAXLOGFILELEN;
 
     now = time((time_t) 0);
 
-    /* Become root if we are not already. */
-    if (oldeuid)
-	set_perms(PERM_ROOT, 0);
-
     oldmask = umask(077);
     fp = fopen(_PATH_SUDO_LOGFILE, "a");
     (void) umask(oldmask);
@@ -254,9 +249,6 @@ do_logfile(msg)
 	(void) lock_file(fileno(fp), SUDO_UNLOCK);
 	(void) fclose(fp);
     }
-
-    if (oldeuid)
-	set_perms(PERM_USER, 0);	/* relinquish root */
 }
 #endif /* LOGGING & SLOG_FILE */
 
@@ -299,20 +291,18 @@ log_auth(status, inform_user)
     mail_auth(status, logline);		/* send mail based on status */
 
     /* Inform the user if they failed to authenticate.  */
-    if (inform_user) {
+    if (inform_user && (status & VALIDATE_NOT_OK)) {
 	if (status & FLAG_NO_USER)
 	    (void) fprintf(stderr, "%s is not in the sudoers file.  %s",
 		user_name, "This incident will be reported.\n");
 	else if (status & FLAG_NO_HOST)
 	    (void) fprintf(stderr, "%s is not allowed to run sudo on %s.  %s",
 		user_name, user_shost, "This incident will be reported.\n");
-	else if (status & VALIDATE_NOT_OK)
+	else
 	    (void) fprintf(stderr,
 		"Sorry, user %s is not allowed to execute '%s%s%s' as %s on %s.\n",
 		user_name, user_cmnd, user_args ? " " : "",
 		user_args ? user_args : "", user_runas, user_host);
-	else
-	    (void) fprintf(stderr, "An unknown error has occurred.\n");
     }
 
     /*
@@ -351,6 +341,10 @@ log_error(va_alist)
     fmt = va_arg(ap, const char *);
 #endif
 
+    /* Become root if we are not already to avoid user control */
+    if (geteuid() != 0)
+	set_perms(PERM_ROOT, 0);
+
     /* Expand printf-style format + args. */
     evasprintf(&message, fmt, ap);
     va_end(ap);
@@ -409,6 +403,9 @@ log_error(va_alist)
 	free(message);
 }
 
+/*
+ * Send a message to ALERTMAIL
+ */
 #ifdef _PATH_SENDMAIL
 static void
 send_mail(line)
@@ -481,7 +478,7 @@ send_mail(line)
 	    user_name, line);
 	fclose(mail);
 	reapchild(0);
-	exit(0);
+	_exit(0);
     } else {
 	/* Parent, just return unless there is an error. */
 	if (pid == -1) {
@@ -510,6 +507,7 @@ mail_auth(status, line)
 {
     int mail_mask;
 
+    /* If any of these bits are set in status, we send mail. */
     mail_mask = VALIDATE_ERROR;
 #ifdef SEND_MAIL_WHEN_OK
     mail_mask |= VALIDATE_OK;