- backport forgotten Valid-Until patch from the obsolete experimental

    branch to prevent replay attacks better, thanks to Thomas Viehmann
    for the initial patch! (Closes: #499897)
* doc/apt.conf.5.xml:
  - document the new Valid-Until related options
* apt-pkg/contrib/strutl.cc:
  - split StrToTime() into HTTP1.1 and FTP date parser methods and
    use strptime() instead of some self-made scanf mangling
  - use the portable timegm shown in his manpage instead of a strange
    looking code copycat from wget
* ftparchive/writer.cc:
  - add ValidTime option to generate a Valid-Until header in Release file

2 files changed, 55 insertions, 21 deletions

diff --git a/apt-pkg/contrib/strutl.cc b/apt-pkg/contrib/strutl.cc
index c7d63ce8a..160450366 100644
--- a/apt-pkg/contrib/strutl.cc
+++ b/apt-pkg/contrib/strutl.cc
@@ -827,34 +827,66 @@ static int MonthConv(char *Month)
    }   
 }
 									/*}}}*/
-// timegm - Internal timegm function if gnu is not available		/*{{{*/
+// timegm - Internal timegm if the gnu version is not available		/*{{{*/
 // ---------------------------------------------------------------------
-/* Ripped this evil little function from wget - I prefer the use of 
-   GNU timegm if possible as this technique will have interesting problems
-   with leap seconds, timezones and other.
-   
-   Converts struct tm to time_t, assuming the data in tm is UTC rather
+/* Converts struct tm to time_t, assuming the data in tm is UTC rather
    than local timezone (mktime assumes the latter).
-   
-   Contributed by Roger Beeman <beeman@cisco.com>, with the help of
-   Mark Baushke <mdb@cisco.com> and the rest of the Gurus at CISCO. */
-
-/* Turned it into an autoconf check, because GNU is not the only thing which
-   can provide timegm. -- 2002-09-22, Joel Baker */
 
-#ifndef HAVE_TIMEGM // Now with autoconf!
+   This function is a nonstandard GNU extension that is also present on
+   the BSDs and maybe other systems. For others we follow the advice of
+   the manpage of timegm and use his portable replacement. */
+#ifndef HAVE_TIMEGM
 static time_t timegm(struct tm *t)
 {
-   time_t tl, tb;
-   
-   tl = mktime (t);
-   if (tl == -1)
-      return -1;
-   tb = mktime (gmtime (&tl));
-   return (tl <= tb ? (tl + (tl - tb)) : (tl - (tb - tl)));
+   char *tz = getenv("TZ");
+   setenv("TZ", "", 1);
+   tzset();
+   time_t ret = mktime(t);
+   if (tz)
+      setenv("TZ", tz, 1);
+   else
+      unsetenv("TZ");
+   tzset();
+   return ret;
 }
 #endif
 									/*}}}*/
+// FullDateToTime - Converts a HTTP1.1 full date strings into a time_t	/*{{{*/
+// ---------------------------------------------------------------------
+/* tries to parses a full date as specified in RFC2616 Section 3.3.1
+   with one exception: All timezones (%Z) are accepted but the protocol
+   says that it MUST be GMT, but this one is equal to UTC which we will
+   encounter from time to time (e.g. in Release files) so we accept all
+   here and just assume it is GMT (or UTC) later on */
+bool RFC1123StrToTime(const char* const str,time_t &time)
+{
+   struct tm Tm;
+   // Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 822, updated by RFC 1123
+   if (strptime(str, "%a, %d %b %Y %H:%M:%S %Z", &Tm) == NULL &&
+   // Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036
+       strptime(str, "%A, %d-%b-%y %H:%M:%S %Z", &Tm) == NULL &&
+   // Sun Nov  6 08:49:37 1994       ; ANSI C's asctime() format
+       strptime(str, "%a %b %d %H:%M:%S %Y", &Tm) == NULL)
+      return false;
+
+   time = timegm(&Tm);
+   return true;
+}
+									/*}}}*/
+// FTPMDTMStrToTime - Converts a ftp modification date into a time_t	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool FTPMDTMStrToTime(const char* const str,time_t &time)
+{
+   struct tm Tm;
+   // MDTM includes no whitespaces but recommend and ignored by strptime
+   if (strptime(str, "%Y %m %d %H %M %S", &Tm) == NULL)
+      return false;
+
+   time = timegm(&Tm);
+   return true;
+}
+									/*}}}*/
 // StrToTime - Converts a string into a time_t				/*{{{*/
 // ---------------------------------------------------------------------
 /* This handles all 3 populare time formats including RFC 1123, RFC 1036
diff --git a/apt-pkg/contrib/strutl.h b/apt-pkg/contrib/strutl.h
index e509145f9..a457ff047 100644
--- a/apt-pkg/contrib/strutl.h
+++ b/apt-pkg/contrib/strutl.h
@@ -45,7 +45,9 @@ string Base64Encode(const string &Str);
 string OutputInDepth(const unsigned long Depth, const char* Separator="  ");
 string URItoFileName(const string &URI);
 string TimeRFC1123(time_t Date);
-bool StrToTime(const string &Val,time_t &Result);
+bool RFC1123StrToTime(const char* const str,time_t &time) __must_check;
+bool FTPMDTMStrToTime(const char* const str,time_t &time) __must_check;
+__deprecated bool StrToTime(const string &Val,time_t &Result);
 string LookupTag(const string &Message,const char *Tag,const char *Default = 0);
 int StringToBool(const string &Text,int Default = -1);
 bool ReadMessages(int Fd, vector<string> &List);