Fix <https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-9169>.

Taken from this upstream commit, sans ChangeLog updates:
https://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=583dd860d5b833037175247230a328f0050dbfe9

diff --git a/posix/regexec.c b/posix/regexec.c
index 91d5a797b8..084b1222d9 100644
--- a/posix/regexec.c
+++ b/posix/regexec.c
@@ -1293,8 +1293,10 @@ proceed_next_node (const re_match_context_t *mctx, Idx nregs, regmatch_t *regs,
 	      else if (naccepted)
 		{
 		  char *buf = (char *) re_string_get_buffer (&mctx->input);
-		  if (memcmp (buf + regs[subexp_idx].rm_so, buf + *pidx,
-			      naccepted) != 0)
+		  if (mctx->input.valid_len - *pidx < naccepted
+		      || (memcmp (buf + regs[subexp_idx].rm_so, buf + *pidx,
+				  naccepted)
+			  != 0))
 		    return -1;
 		}
 	    }
s</option>
</select> <input type='submit' value='switch'/></form></td></tr>
<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
<table class='tabs'><tr><td>
<a href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=d2b7d14db4a1ba454d781f5ea796c4a457aaef02'>refs</a><a class='active' href='/guix/log/tests/utils.scm'>log</a><a href='/guix/tree/tests/utils.scm?id=d2b7d14db4a1ba454d781f5ea796c4a457aaef02'>tree</a><a href='/guix/commit/tests/utils.scm?id=d2b7d14db4a1ba454d781f5ea796c4a457aaef02'>commit</a><a href='/guix/diff/tests/utils.scm?id=d2b7d14db4a1ba454d781f5ea796c4a457aaef02'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/tests/utils.scm'>
<input type='hidden' name='id' value='d2b7d14db4a1ba454d781f5ea796c4a457aaef02'/><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=d2b7d14db4a1ba454d781f5ea796c4a457aaef02'>root</a>/<a href='/guix/log/tests?id=d2b7d14db4a1ba454d781f5ea796c4a457aaef02'>tests</a>/<a href='/guix/log/tests/utils.scm?id=d2b7d14db4a1ba454d781f5ea796c4a457aaef02'>utils.scm</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/tests/utils.scm?id=d2b7d14db4a1ba454d781f5ea796c4a457aaef02&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2024-04-15 22:36:42 +0200'>2024-04-15</span></td><td><a href='/guix/commit/tests/utils.scm?id=54be7795b5cc2f6cad05f8649121372c9d5af806'>utils: Don’t re-export ‘call-with-temporary-output-file’.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/utils.scm: Remove re-export of ‘call-with-temporary-output-file’.
Autoload a number of modules.
* guix/download.scm, guix/import/hackage.scm,
guix/import/hexpm.scm, guix/import/opam.scm,
guix/import/pypi.scm, tests/cpio.scm, tests/egg.scm,
tests/opam.scm, tests/publish.scm, tests/store-database.scm,
tests/utils.scm: Adjust imports accordingly.

Change-Id: I3f5e94631397996a30be2ea4ff8b50a3371e8ee7
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2024-02-23 19:02:16 +0100'>2024-02-23</span></td><td><a href='/guix/commit/tests/utils.scm?id=50e514c1bc674b1c36344407c8c4b418d17759c5'>utils: Add find-definition-insertion-location procedure.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/utils.scm (find-definition-insertion-location): Add and export
procedure.
* tests/utils.scm ("find-definition-insertion-location"): Add test.

Change-Id: Ie17e1b4a94790f58518ce121411a38d357f49feb
Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Herman Rimm</td></tr>
<tr><td><span title='2024-02-23 19:01:55 +0100'>2024-02-23</span></td><td><a href='/guix/commit/tests/utils.scm?id=babd39e84389c544e8dab44be8ddec57e52709c9'>utils: Add insert-expression procedure.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/utils.scm (define-module): Use (guix read-print) and export
(insert-expression).
(insert-expression): Add procedure.
* tests/utils.scm ("insert-expression"): Add test.

Change-Id: I971a43a78aa6ecaaef33c1a7a0db4b287eb85036
Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Herman Rimm</td></tr>
<tr><td><span title='2023-12-11 11:53:54 +0200'>2023-12-11</span></td><td><a href='/guix/commit/tests/utils.scm?id=520e3d267ecc3964af301ab9341462e905f234c6'>guix: Add target-avr?.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/utils.scm (target-avr?): New procedure.
* tests/utils.scm: Add tests for target-avr? procedure.

Change-Id: Iaa0fa97a2b6bc45d45f907f43157f1548a0ba3fa
Signed-off-by: Efraim Flashner &lt;efraim@flashner.co.il&gt;
</span></span></td><td>Jean-Pierre De Jesus DIAZ</td></tr>