svn commit: r321244 - stable/10/usr.sbin/cron/cron

[Ngie Cooper]

Author: ngie
Date: Wed Jul 19 20:29:07 2017
New Revision: 321244
URL: https://svnweb.freebsd.org/changeset/base/321244

Log:
  MFC r269550:
  r269550 (by peter):
  
  Check gethostname(2) return code - but even if it succeeds it may not
  null terminate.
  
  Temporarily use "From: $user@$hostname" rather than "From: $user".
  The latter exposes incompatible behavior if using dma(8).  sendmail(8)
  (and other alternatives) canonify either form on submission (even
  if masquerading), but dma will leak a non-compliant address to
  the internet.

Modified:
  stable/10/usr.sbin/cron/cron/do_command.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/usr.sbin/cron/cron/do_command.c
==============================================================================
--- stable/10/usr.sbin/cron/cron/do_command.c	Wed Jul 19 20:26:35 2017	(r321243)
+++ stable/10/usr.sbin/cron/cron/do_command.c	Wed Jul 19 20:29:07 2017	(r321244)
@@ -484,14 +484,17 @@ child_process(e, u)
 				auto char	mailcmd[MAX_COMMAND];
 				auto char	hostname[MAXHOSTNAMELEN];
 
-				(void) gethostname(hostname, MAXHOSTNAMELEN);
+				if (gethostname(hostname, MAXHOSTNAMELEN) == -1)
+					hostname[0] = '\0';
+				hostname[sizeof(hostname) - 1] = '\0';
 				(void) snprintf(mailcmd, sizeof(mailcmd),
 					       MAILARGS, MAILCMD);
 				if (!(mail = cron_popen(mailcmd, "w", e))) {
 					warn("%s", MAILCMD);
 					(void) _exit(ERROR_EXIT);
 				}
-				fprintf(mail, "From: %s (Cron Daemon)\n", usernm);
+				fprintf(mail, "From: Cron Daemon <%s@%s>\n",
+					usernm, hostname);
 				fprintf(mail, "To: %s\n", mailto);
 				fprintf(mail, "Subject: Cron <%s@%s> %s\n",
 					usernm, first_word(hostname, "."),