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='2020-06-25 12:29:22 +0200'>2020-06-25</span></td><td><a href='/guix/commit/nix/libstore/optimise-store.cc?id=b930f0ba2115f71c323d4bf3d72efb763f716296'>daemon: Correctly handle EMLINK corner case when deduplicating.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-03-13 23:12:43 +0100'>2019-03-13</span></td><td><a href='/guix/commit/nix/libstore/optimise-store.cc?id=59e80445882f8b0379e54916f89510c0deda6698'>Remove traces of "GuixSD".</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-12-16 16:28:07 +0100'>2018-12-16</span></td><td><a href='/guix/commit/nix/libstore/optimise-store.cc?id=8327e733966cc4a93dfaadd1a761ca1088078baa'>daemon: Use unbranded phrases in comments and messages.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>