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

0e3d1133ec29242e70fca1d2997a'>tree</a><a href='/guix/commit/gnu/packages/patches/libwpd-gcc-compat.patch?id=ab9f9b582e510e3d1133ec29242e70fca1d2997a'>commit</a><a href='/guix/diff/gnu/packages/patches/libwpd-gcc-compat.patch?id=ab9f9b582e510e3d1133ec29242e70fca1d2997a'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/packages/patches/libwpd-gcc-compat.patch'>
<input type='hidden' name='id' value='ab9f9b582e510e3d1133ec29242e70fca1d2997a'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=ab9f9b582e510e3d1133ec29242e70fca1d2997a'>root</a>/<a href='/guix/log/gnu?id=ab9f9b582e510e3d1133ec29242e70fca1d2997a'>gnu</a>/<a href='/guix/log/gnu/packages?id=ab9f9b582e510e3d1133ec29242e70fca1d2997a'>packages</a>/<a href='/guix/log/gnu/packages/patches?id=ab9f9b582e510e3d1133ec29242e70fca1d2997a'>patches</a>/<a href='/guix/log/gnu/packages/patches/libwpd-gcc-compat.patch?id=ab9f9b582e510e3d1133ec29242e70fca1d2997a'>libwpd-gcc-compat.patch</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/packages/patches/libwpd-gcc-compat.patch?id=ab9f9b582e510e3d1133ec29242e70fca1d2997a&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>