Fix CVE-2017-7853:

https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-7853
https://savannah.gnu.org/support/index.php?109265

Patch copied from upstream source repository:

https://git.savannah.gnu.org/cgit/osip.git/commit/?id=1ae06daf3b2375c34af23083394a6f010be24a45

From 1ae06daf3b2375c34af23083394a6f010be24a45 Mon Sep 17 00:00:00 2001
From: Aymeric Moizard <amoizard@gmail.com>
Date: Tue, 21 Feb 2017 17:16:26 +0100
Subject: [PATCH]  * fix bug report: sr #109265: SIP message body length
 underflow in libosip2-4.1.0    https://savannah.gnu.org/support/?109265   
 also applicable to current latest version

---
 src/osipparser2/osip_message_parse.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/osipparser2/osip_message_parse.c b/src/osipparser2/osip_message_parse.c
index 1628c60..aa35446 100644
--- a/src/osipparser2/osip_message_parse.c
+++ b/src/osipparser2/osip_message_parse.c
@@ -784,6 +784,12 @@ msg_osip_body_parse (osip_message_t * sip, const char *start_of_buf, const char
     if ('\n' == start_of_body[0] || '\r' == start_of_body[0])
       start_of_body++;
 
+    /* if message body is empty or contains a single CR/LF */
+    if (end_of_body <= start_of_body) {
+      osip_free (sep_boundary);
+      return OSIP_SYNTAXERROR;
+    }
+
     body_len = end_of_body - start_of_body;
 
     /* Skip CR before end boundary. */
-- 
2.13.1

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<tr><td><span title='2018-06-30 03:46:18 +0200'>2018-06-30</span></td><td><a href='/guix/commit/gnu/packages/ntp.scm?id=232568581b1a13619c3adb0e3362da0f38c7a1f1'>gnu: tlsdate: Bump COMPILE_DATE.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2018-06-29 15:25:23 +0200'>2018-06-29</span></td><td><a href='/guix/commit/gnu/packages/ntp.scm?id=efc1fd32880e7936ff5dc29e472cb26763559637'>gnu: tlsdate: Return #t from phases.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2018-04-11 01:03:46 +0200'>2018-04-11</span></td><td><a href='/guix/commit/gnu/packages/ntp.scm?id=0927b5bed6ca3e64e7f2eb5cf4c5daf2b99d3310'>gnu: tlsdate: Fix compilation on aarch64-linux-gnu.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-03-28 14:59:47 -0400'>2018-03-28</span></td><td><a href='/guix/commit/gnu/packages/ntp.scm?id=935806b822d898737f80d73cc615fba85bf8b0a7'>gnu: ntp: Update to 4.2.8p11 [security-fixes].</a><span class='msg-avail'>...</span></td><td>Leo Famulari</td></tr>
<tr><td><span title='2018-03-05 08:46:28 +0200'>2018-03-05</span></td><td><a href='/guix/commit/gnu/packages/ntp.scm?id=16718b6776b6cb918cddb3abb3bfcf2405b0b297'>services: Add openntpd service.</a><span class='msg-avail'>...</span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2017-11-27 13:29:18 -0500'>2017-11-27</span></td><td><a href='/guix/commit/gnu/packages/ntp.scm?id=080e023d45d4553ad419ee9f09088ad3a110a512'>gnu: openntpd: Enable use of TLS-based time constraints.</a><span class='msg-avail'>...</span></td><td>Leo Famulari</td></tr>
<tr><td><span title='2017-11-26 22:33:18 +0200'>2017-11-26</span></td><td><a href='/guix/commit/gnu/packages/ntp.scm?id=6dbad376a23d6031e135fadead4410d9a2d1fa68'>gnu: openntpd: Update to 6.2p3.</a><span class='msg-avail'>...</span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2017-09-24 20:40:58 +0300'>2017-09-24</span></td><td><a href='/guix/commit/gnu/packages/ntp.scm?id=3140844e33254316348135b03762eaeb04764544'>gnu: openntpd: Update to 6.2p2.</a><span class='msg-avail'>...</span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2017-07-19 01:42:08 +0200'>2017-07-19</span></td><td><a href='/guix/commit/gnu/packages/ntp.scm?id=644e5f17dfd2f5b3bbf656580d6f1f84c52e668a'>download: Add OpenBSD mirrors.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2017-07-19 01:06:55 +0200'>2017-07-19</span></td><td><a href='/guix/commit/gnu/packages/ntp.scm?id=b225b1bec25313941c8737f7e1ce872492edc533'>gnu: openntpd: Update to 6.1p1.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>