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

diff --git a/src/kadmin/cli/getdate.y b/src/kadmin/cli/getdate.y
index 8b7fc5bae9eba82362ec40e1f519a3ce2a7dc5a0..530114598735797d171692ddc37a98552bedb90b 100644 (file)
--- 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;
     }