Fix CVE-2018-1000097:

https://security-tracker.debian.org/tracker/CVE-2018-1000097
https://nvd.nist.gov/vuln/detail/CVE-2018-1000097

Patch taken from upstream bug report:
https://lists.gnu.org/archive/html/bug-gnu-utils/2018-02/msg00005.html

diff --git a/src/unshar.c b/src/unshar.c
index 80bc3a9..0fc3773 100644
--- a/src/unshar.c
+++ b/src/unshar.c
@@ -240,7 +240,7 @@ find_archive (char const * name, FILE * file, off_t start)
       off_t position = ftello (file);
 
       /* Read next line, fail if no more and no previous process.  */
-      if (!fgets (rw_buffer, BUFSIZ, file))
+      if (!fgets (rw_buffer, rw_base_size, file))
 	{
 	  if (!start)
 	    error (0, 0, _("Found no shell commands in %s"), name);
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<tr><td><span title='2020-03-03 15:00:32 +0100'>2020-03-03</span></td><td><a href='/guix/commit/gnu/services/herd.scm?id=8f5a0a97b1d04e8ade8c16694dcb72aed176c595'>services: herd: Add restart-service.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/herd.scm (restart-service): New exported procedure.
</span></span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2019-10-18 23:22:25 +0200'>2019-10-18</span></td><td><a href='/guix/commit/gnu/services/herd.scm?id=6aeae5b90b9513d316141c0131fd43c76a200f63'>herd: Define 'shepherd-message-port'.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/herd.scm (shepherd-message-port): New variable.
(display-message): Use it instead of 'current-error-port'.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-07-26 19:19:49 +0200'>2019-07-26</span></td><td><a href='/guix/commit/gnu/services/herd.scm?id=5c793753b31b1dcd9a554bce953124f7ae88ca9a'>guix system: Add 'reconfigure' module.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/scripts/system/reconfigure.scm: New file.
* Makefile.am (MODULES): Add it.
* guix/scripts/system.scm (bootloader-installer-script): Export variable.
* gnu/machine/ssh.scm (switch-to-system, upgrade-shepherd-services)
(install-bootloader): Delete variable.
* gnu/machine/ssh.scm (deploy-managed-host): Rewrite procedure.
* gnu/services/herd.scm (live-service): Export variable.
* gnu/services/herd.scm (live-service-canonical-name): New variable.
* tests/services.scm (live-service): Delete variable.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Jakob L. Kreuze</td></tr>
<tr><td><span title='2019-06-02 01:38:36 +0200'>2019-06-02</span></td><td><a href='/guix/commit/gnu/services/herd.scm?id=bb64b2e7c0ab14cf899c1d81892b59fa877d4d9c'>herd: Use the Guile 2.2 'setvbuf' API.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/herd.scm (open-connection): Use 'block for 'setvbuf'.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-01-17 14:04:22 +0100'>2019-01-17</span></td><td><a href='/guix/commit/gnu/services/herd.scm?id=ca0c43ecf02a5451ab0dd2f855032e316b4a4792'>services: herd: Allow to pass arguments to start-service.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/herd.scm (start-service)[arguments]: New optional argument.
</span></span></td><td>Mathieu Othacehe</td></tr>