[linux-pam] Add checks for localtime() returning NULL.

[Tomáš Mráz]

commit 11db6fd23dee9cf400a260b371edbd6091a96171
Author: Tomas Mraz <tmraz(a)fedoraproject.org&gt;
Date:   Fri Mar 4 14:19:01 2016 +0100

    Add checks for localtime() returning NULL.
    
    * modules/pam_lastlog/pam_lastlog.c (last_login_read): Check for localtime_r
    returning NULL.
    * modules/pam_tally2/pam_tally2.c (print_one): Check for localtime returning
    NULL.

 modules/pam_lastlog/pam_lastlog.c |   12 ++++++------
 modules/pam_tally2/pam_tally2.c   |    9 +++++----
 2 files changed, 11 insertions(+), 10 deletions(-)
---
diff --git a/modules/pam_lastlog/pam_lastlog.c b/modules/pam_lastlog/pam_lastlog.c
index 50d33e4..76a33e4 100644
--- a/modules/pam_lastlog/pam_lastlog.c
+++ b/modules/pam_lastlog/pam_lastlog.c
@@ -276,12 +276,12 @@ last_login_read(pam_handle_t *pamh, int announce, int last_fd, uid_t
uid, time_t
 		time_t ll_time;
 
 		ll_time = last_login.ll_time;
-		tm = localtime_r (&ll_time, &tm_buf);
-		strftime (the_time, sizeof (the_time),
-	        /* TRANSLATORS: "strftime options for date of last login" */
-			  _(" %a %b %e %H:%M:%S %Z %Y"), tm);
-
-		date = the_time;
+		if ((tm = localtime_r (&ll_time, &tm_buf)) != NULL) {
+			strftime (the_time, sizeof (the_time),
+		        /* TRANSLATORS: "strftime options for date of last login" */
+				  _(" %a %b %e %H:%M:%S %Z %Y"), tm);
+			date = the_time;
+		}
 	    }
 
 	    /* we want & have the host? */
diff --git a/modules/pam_tally2/pam_tally2.c b/modules/pam_tally2/pam_tally2.c
index e513f64..9187cbf 100644
--- a/modules/pam_tally2/pam_tally2.c
+++ b/modules/pam_tally2/pam_tally2.c
@@ -924,7 +924,7 @@ static void
 print_one(const struct tallylog *tally, uid_t uid)
 {
    static int once;
-   char *cp;
+   char *cp = "[UNKNOWN]";
    time_t fail_time;
    struct tm *tm;
    struct passwd *pwent;
@@ -933,9 +933,10 @@ print_one(const struct tallylog *tally, uid_t uid)
 
    pwent = getpwuid(uid);
    fail_time = tally->fail_time;
-   tm = localtime(&fail_time);
-   strftime (ptime, sizeof (ptime), "%D %H:%M:%S", tm);
-   cp = ptime;
+   if ((tm = localtime(&fail_time)) != NULL) {
+        strftime (ptime, sizeof (ptime), "%D %H:%M:%S", tm);
+        cp = ptime;
+   }
    if (pwent) {
         username = pwent->pw_name;
    }