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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7-05-24</span></td><td><a href='/guix/commit/gnu/packages/scanner.scm?id=4febd4b0f4fc99eb9357180166764febc410812e'>gnu: sane-backends-minimal, sane-backends: Update to 1.0.27.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2016-12-17 23:13:05 +0100'>2016-12-17</span></td><td><a href='/guix/commit/gnu/packages/scanner.scm?id=a32d0c8304a60ad77ecae59aab9cb1c7241f8162'>gnu: sane-backends: Remove timestamps from the output.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2016-12-17 23:13:05 +0100'>2016-12-17</span></td><td><a href='/guix/commit/gnu/packages/scanner.scm?id=4c9287432824f396d5c614c3b2287f553cd9fb90'>gnu: Add and use sane-backends.</a><span class='msg-avail'>...</span></td><td>Andy Patterson</td></tr>
<tr><td><span title='2016-12-17 23:13:04 +0100'>2016-12-17</span></td><td><a href='/guix/commit/gnu/packages/scanner.scm?id=32aa37a2e7a5653915a5c1b1fdef7f726ceaf5d2'>gnu: Add and use sane-backends-minimal.</a><span class='msg-avail'>...</span></td><td>Andy Patterson</td></tr>
<tr><td><span title='2016-12-17 23:13:04 +0100'>2016-12-17</span></td><td><a href='/guix/commit/gnu/packages/scanner.scm?id=33a14e29f9a19c9e4e76bbba73e21e22d4bab0b9'>gnu: sane-backends: Disable backend generation.</a><span class='msg-avail'>...</span></td><td>Andy Patterson</td></tr>
<tr><td><span title='2016-10-09 17:50:28 -0400'>2016-10-09</span></td><td><a href='/guix/commit/gnu/packages/scanner.scm?id=d976eccd263f39651cbddf751bf09c8ddfd4305a'>gnu: sane-backends: Update to 1.0.25.</a><span class='msg-avail'>...</span></td><td>Al McElrath</td></tr>