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='2021-07-04 21:07:07 -0400'>2021-07-04</span></td><td><a href='/guix/commit/gnu/packages/perl-check.scm?id=d783ed7414096f59167428cb4df3f7aaf9e5922f'>gnu: Add perl-test-portability-files.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/perl-check.scm (perl-test-portability-files): New variable.
</span></span></td><td>Raghav Gururajan</td></tr>
<tr><td><span title='2021-03-29 17:18:38 +0300'>2021-03-29</span></td><td><a href='/guix/commit/gnu/packages/perl-check.scm?id=be34826886508a52babd05477d89d39bae6ff454'>gnu: perl-test-output: Update to 1.033.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/perl-check.scm (perl-test-output): Update to 1.033.
</span></span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2021-02-08 13:46:26 +0200'>2021-02-08</span></td><td><a href='/guix/commit/gnu/packages/perl-check.scm?id=b9f9f9a3f4a3efe19fad7c7f15a7e637f24510dd'>gnu: perl-test-trailingspace: Update to 0.0600.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/perl-check.scm (perl-test-trailingspace): Update to 0.0600.
</span></span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2021-02-08 13:46:26 +0200'>2021-02-08</span></td><td><a href='/guix/commit/gnu/packages/perl-check.scm?id=51f8be68316764dbf2a698ab4ffe3e421cf75eb8'>gnu: perl-test-simple: Update to 1.302183.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/perl-check.scm (perl-test-simple): Update to 1.302183.
</span></span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2021-02-08 13:46:25 +0200'>2021-02-08</span></td><td><a href='/guix/commit/gnu/packages/perl-check.scm?id=1e4565eabca2026320eae6ac36b1c3361ddb19f6'>gnu: perl-test-runvalgrind: Update to 0.2.2.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/perl-check.scm (perl-test-runvalgrind): Update to 0.2.2.
</span></span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2021-02-08 13:46:25 +0200'>2021-02-08</span></td><td><a href='/guix/commit/gnu/packages/perl-check.scm?id=072ef70a8e2b61679be25bc0af60d97afb26e827'>gnu: perl-test-requires: Update to 0.11.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/perl-check.scm (perl-test-requires): Update to 0.11.
</span></span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2021-02-08 13:46:25 +0200'>2021-02-08</span></td><td><a href='/guix/commit/gnu/packages/perl-check.scm?id=d2cb69dfd4752ec32de092e5fad92a93caa0861b'>gnu: perl-test-taint: Update to 1.08.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/perl-check.scm (perl-test-taint): Update to 1.08.
</span></span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2021-02-08 13:46:25 +0200'>2021-02-08</span></td><td><a href='/guix/commit/gnu/packages/perl-check.scm?id=bddb78e01a254e27574f0f55d4168816b8268c33'>gnu: perl-test-warnings: Update to 0.030.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/perl-check.scm (perl-test-warnings): Update to 0.030.
</span></span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2021-02-08 13:46:25 +0200'>2021-02-08</span></td><td><a href='/guix/commit/gnu/packages/perl-check.scm?id=6b1fb33bc7509397ee63fcb67b48d7046f202f26'>gnu: perl-test-warn: Update to 0.36.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/perl-check.scm (perl-test-warn): Update to 0.36.
</span></span></td><td>Efraim Flashner</td></tr>