From 316ea1aea8261f9cf96f252c811c3733bd90dec4 Mon Sep 17 00:00:00 2001
From: Ken Raeburn <raeburn@mit.edu>
Date: Fri, 29 Jun 2007 02:37:57 +0000
Subject: [PATCH] Check for error indication from localtime. In a few cases
 this means changing internal function signatures to allow for passing back
 the error indication up the call stack.

Thanks to Domagoj Babic for pointing out the possible null pointer
dereferences that would result if localtime fails.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@19656 dc483132-0cff-0310-8789-dd5450dbe970
---
 src/kadmin/cli/getdate.y | 62 +++++++++++++++++++++++++++++++++-------
 1 file changed, 51 insertions(+), 11 deletions(-)

diff --git a/src/kadmin/cli/getdate.y b/src/kadmin/cli/getdate.y
index 8b7fc5bae..530114598 100644
--- a/src/kadmin/cli/getdate.y
+++ b/src/kadmin/cli/getdate.y
@@ -586,6 +586,7 @@ Convert(Month, Day, Year, Hours, Minutes, Seconds, Meridian, DSTmode)
     time_t	tod;
     time_t	Julian;
     int		i;
+    struct tm	*tm;
 
     if (Year < 0)
 	Year = -Year;
@@ -610,41 +611,64 @@ Convert(Month, Day, Year, Hours, Minutes, Seconds, Meridian, DSTmode)
     if ((tod = ToSeconds(Hours, Minutes, Seconds, Meridian)) < 0)
 	return -1;
     Julian += tod;
-    if (DSTmode == DSTon
-     || (DSTmode == DSTmaybe && localtime(&Julian)->tm_isdst))
+    if (DSTmode == DSTon)
 	Julian -= 60 * 60;
+    else if (DSTmode == DSTmaybe) {
+	tm = localtime(&Julian);
+	if (tm == NULL)
+	    return -1;
+	else if (tm->tm_isdst)
+	    Julian -= 60 * 60;
+    }
     return Julian;
 }
 
 
 static time_t
-DSTcorrect(Start, Future)
+DSTcorrect(Start, Future, error)
     time_t	Start;
     time_t	Future;
+    int		*error;
 {
     time_t	StartDay;
     time_t	FutureDay;
+    struct tm	*tm;
 
-    StartDay = (localtime(&Start)->tm_hour + 1) % 24;
-    FutureDay = (localtime(&Future)->tm_hour + 1) % 24;
+    tm = localtime(&Start);
+    if (tm == NULL) {
+	*error = 1;
+	return -1;
+    }
+    StartDay = (tm->tm_hour + 1) % 24;
+    tm = localtime(&Future);
+    if (tm == NULL) {
+	*error = 1;
+	return -1;
+    }
+    FutureDay = (tm->tm_hour + 1) % 24;
     return (Future - Start) + (StartDay - FutureDay) * 60L * 60L;
 }
 
 
 static time_t
-RelativeDate(Start, DayOrdinal, DayNumber)
+RelativeDate(Start, DayOrdinal, DayNumber, error)
     time_t	Start;
     time_t	DayOrdinal;
     time_t	DayNumber;
+    int		*error;
 {
     struct tm	*tm;
     time_t	now;
 
     now = Start;
     tm = localtime(&now);
+    if (tm == NULL) {
+	*error = 1;
+	return -1;
+    }
     now += SECSPERDAY * ((DayNumber - tm->tm_wday + 7) % 7);
     now += 7 * SECSPERDAY * (DayOrdinal <= 0 ? DayOrdinal : DayOrdinal - 1);
-    return DSTcorrect(Start, now);
+    return DSTcorrect(Start, now, error);
 }
 
 
@@ -657,10 +681,13 @@ RelativeMonth(Start, RelMonth)
     time_t	Month;
     time_t	Year;
     time_t	ret;
+    int		error;
 
     if (RelMonth == 0)
 	return 0;
     tm = localtime(&Start);
+    if (tm == NULL)
+	return -1;
     Month = 12 * tm->tm_year + tm->tm_mon + RelMonth;
     Year = Month / 12;
     Month = Month % 12 + 1;
@@ -669,7 +696,10 @@ RelativeMonth(Start, RelMonth)
 		  MER24, DSTmaybe);
     if (ret == -1)
       return ret;
-    return DSTcorrect(Start, ret);
+    ret = DSTcorrect(Start, ret, &error);
+    if (error)
+	return -1;
+    return ret;
 }
 
 
@@ -865,6 +895,7 @@ get_date(p)
     time_t		Start;
     time_t		tod;
     time_t		delta;
+    int			error = 0;
 
     yyInput = p;
     if (now == NULL) {
@@ -875,10 +906,15 @@ get_date(p)
 	if (! (tm = gmtime (&ftz.time)))
 	    return -1;
 	gmt = *tm;	/* Make a copy, in case localtime modifies *tm.  */
-	ftz.timezone = difftm (&gmt, localtime (&ftz.time)) / 60;
+	tm = localtime(&ftz.time);
+	if (tm == NULL)
+	    return -1;
+	ftz.timezone = difftm (&gmt, tm) / 60;
     }
 
     tm = localtime(&now->time);
+    if (tm == NULL)
+	return -1;
     yyYear = tm->tm_year;
     yyMonth = tm->tm_mon + 1;
     yyDay = tm->tm_mday;
@@ -952,9 +988,11 @@ get_date(p)
      */
     if (yyHaveDate || yyHaveTime || yyHaveDay) {
 	Start = Convert(yyMonth, yyDay, yyYear, yyHour, yyMinutes, yySeconds,
-		    yyMeridian, yyDSTmode);
+			yyMeridian, yyDSTmode);
 	if (Start < 0)
 	    return -1;
+	if (error != 0)
+	    return -1;
     }
     else {
 	Start = now->time;
@@ -990,7 +1028,9 @@ get_date(p)
      * above and be able to cause failure.
      */
     if (yyHaveDay && !yyHaveDate) {
-	tod = RelativeDate(Start, yyDayOrdinal, yyDayNumber);
+	tod = RelativeDate(Start, yyDayOrdinal, yyDayNumber, &error);
+	if (error != 0)
+	    return -1;
 	Start += tod;
     }
 
-- 
2.26.2