svn commit: r321293 - head/bin/date

[Ed Maste]

Author: emaste
Date: Thu Jul 20 15:28:48 2017
New Revision: 321293
URL: https://svnweb.freebsd.org/changeset/base/321293

Log:
  date: avoid crash on invalid time
  
  localtime(3) returns NULL when passed an invalid time_t but date(1)
  previously did not handle it. Exit with an error in that case.
  
  PR:		220828
  Reported by:	Vinícius Zavam
  Reviewed by:	cem, kevans
  Sponsored by:	The FreeBSD Foundation
  Differential Revision:	https://reviews.freebsd.org/D11660

Modified:
  head/bin/date/date.c

Modified: head/bin/date/date.c
==============================================================================
--- head/bin/date/date.c	Thu Jul 20 14:50:13 2017	(r321292)
+++ head/bin/date/date.c	Thu Jul 20 15:28:48 2017	(r321293)
@@ -85,7 +85,7 @@ main(int argc, char *argv[])
 	int set_timezone;
 	struct vary *v;
 	const struct vary *badv;
-	struct tm lt;
+	struct tm *lt;
 	struct stat sb;
 
 	v = NULL;
@@ -174,8 +174,10 @@ main(int argc, char *argv[])
 	if (*argv && **argv == '+')
 		format = *argv + 1;
 
-	lt = *localtime(&tval);
-	badv = vary_apply(v, &lt);
+	lt = localtime(&tval);
+	if (lt == NULL)
+		errx(1, "invalid time");
+	badv = vary_apply(v, lt);
 	if (badv) {
 		fprintf(stderr, "%s: Cannot apply date adjustment\n",
 			badv->arg);
@@ -191,7 +193,7 @@ main(int argc, char *argv[])
 		 */
 		setlocale(LC_TIME, "C");
 
-	(void)strftime(buf, sizeof(buf), format, &lt);
+	(void)strftime(buf, sizeof(buf), format, lt);
 	(void)printf("%s\n", buf);
 	if (fflush(stdout))
 		err(1, "stdout");
@@ -210,6 +212,8 @@ setthetime(const char *fmt, const char *p, int jflag, 
 	int century;
 
 	lt = localtime(&tval);
+	if (lt == NULL)
+		errx(1, "invalid time");
 	lt->tm_isdst = -1;		/* divine correct DST */
 
 	if (fmt != NULL) {