Pullup ticket #4678 - requested by taca
net/ntp4: security update

Revisions pulled up:
- net/ntp4/Makefile                                             1.85
- net/ntp4/PLIST                                                1.18
- net/ntp4/distinfo                                             1.21

---
   Module Name:	pkgsrc
   Committed By:	taca
   Date:		Wed Apr  8 03:31:34 UTC 2015

   Modified Files:
   	pkgsrc/net/ntp4: Makefile PLIST distinfo

   Log Message:
   Update ntp4 package to 4.2.8p2.

   NTP 4.2.8p2 (Harlan Stenn <stenn@ntp.org>, 2015/04/xx)

   Focus: Security and Bug fixes, enhancements.

   Severity: MEDIUM

   In addition to bug fixes and enhancements, this release fixes the
   following medium-severity vulnerabilities involving private key
   authentication:

   * [Sec 2779] ntpd accepts unauthenticated packets with symmetric key crypto.

       References: Sec 2779 / CVE-2015-1798 / VU#374268
       Affects: All NTP4 releases starting with ntp-4.2.5p99 up to but not
   	including ntp-4.2.8p2 where the installation uses symmetric keys
   	to authenticate remote associations.
       CVSS: (AV:A/AC:M/Au:N/C:P/I:P/A:P) Base Score: 5.4
       Date Resolved: Stable (4.2.8p2) 07 Apr 2015
       Summary: When ntpd is configured to use a symmetric key to authenticate
   	a remote NTP server/peer, it checks if the NTP message
   	authentication code (MAC) in received packets is valid, but not if
   	there actually is any MAC included. Packets without a MAC are
   	accepted as if they had a valid MAC. This allows a MITM attacker to
   	send false packets that are accepted by the client/peer without
   	having to know the symmetric key. The attacker needs to know the
   	transmit timestamp of the client to match it in the forged reply
   	and the false reply needs to reach the client before the genuine
   	reply from the server. The attacker doesn't necessarily need to be
   	relaying the packets between the client and the server.

   	Authentication using autokey doesn't have this problem as there is
   	a check that requires the key ID to be larger than NTP_MAXKEY,
   	which fails for packets without a MAC.
       Mitigation:
           Upgrade to 4.2.8p2, or later, from the NTP Project Download Page
   	or the NTP Public Services Project Download Page
           Configure ntpd with enough time sources and monitor it properly.
       Credit: This issue was discovered by Miroslav Lichvar, of Red Hat.

   * [Sec 2781] Authentication doesn't protect symmetric associations against
     DoS attacks.

       References: Sec 2781 / CVE-2015-1799 / VU#374268
       Affects: All NTP releases starting with at least xntp3.3wy up to but
   	not including ntp-4.2.8p2 where the installation uses symmetric
   	key authentication.
       CVSS: (AV:A/AC:M/Au:N/C:P/I:P/A:P) Base Score: 5.4
       Note: the CVSS base Score for this issue could be 4.3 or lower, and
   	it could be higher than 5.4.
       Date Resolved: Stable (4.2.8p2) 07 Apr 2015
       Summary: An attacker knowing that NTP hosts A and B are peering with
   	each other (symmetric association) can send a packet to host A
   	with source address of B which will set the NTP state variables
   	on A to the values sent by the attacker. Host A will then send
   	on its next poll to B a packet with originate timestamp that
   	doesn't match the transmit timestamp of B and the packet will
   	be dropped. If the attacker does this periodically for both
   	hosts, they won't be able to synchronize to each other. This is
   	a known denial-of-service attack, described at
   	https://www.eecis.udel.edu/~mills/onwire.html .

   	According to the document the NTP authentication is supposed to
   	protect symmetric associations against this attack, but that
   	doesn't seem to be the case. The state variables are updated even
   	when authentication fails and the peers are sending packets with
   	originate timestamps that don't match the transmit timestamps on
   	the receiving side.

   	This seems to be a very old problem, dating back to at least
   	xntp3.3wy. It's also in the NTPv3 (RFC 1305) and NTPv4 (RFC 5905)
   	specifications, so other NTP implementations with support for
   	symmetric associations and authentication may be vulnerable too.
   	An update to the NTP RFC to correct this error is in-process.
       Mitigation:
           Upgrade to 4.2.8p2, or later, from the NTP Project Download Page
   	or the NTP Public Services Project Download Page
           Note that for users of autokey, this specific style of MITM attack
   	is simply a long-known potential problem.
           Configure ntpd with appropriate time sources and monitor ntpd.
   	Alert your staff if problems are detected.
       Credit: This issue was discovered by Miroslav Lichvar, of Red Hat.

   * New script: update-leap
   The update-leap script will verify and if necessary, update the
   leap-second definition file.
   It requires the following commands in order to work:

   	wget logger tr sed shasum

   Some may choose to run this from cron.  It needs more portability testing.


(tron)