Skip to content

Fix path_info pointer underflow in CGI fix_pathinfo handling #23411

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
iliaal wants to merge 1 commit into
base: PHP-8.4
Choose a base branch
from
+39 −2
Open

Fix path_info pointer underflow in CGI fix_pathinfo handling #23411

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 2 additions & 2 deletions sapi/cgi/cgi_main.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1285,9 +1285,9 @@ static void init_request_info(fcgi_request *request)
*/
size_t slen = len - strlen(pt);
size_t pilen = env_path_info ? strlen(env_path_info) : 0;
char *path_info = env_path_info ? env_path_info + pilen - slen : NULL;
char *path_info = (env_path_info && pilen > slen) ? env_path_info + pilen - slen : NULL;

if (orig_path_info != path_info) {
if (path_info != NULL && orig_path_info != path_info) {
if (orig_path_info) {
char old;

Expand Down
37 changes: 37 additions & 0 deletions sapi/cgi/tests/fix_pathinfo_underflow.phpt
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,37 @@
--TEST--
cgi fix_pathinfo with PATH_INFO shorter than the stripped suffix
--SKIPIF--
<?php include "skipif.inc"; ?>
--FILE--
<?php

include "include.inc";

$php = get_cgi_path();
reset_env_vars();

$d = __DIR__ . '/fix_pathinfo_underflow';
@mkdir($d);
$f = $d . '/info.php';
file_put_contents($f, '<?php echo "PI=[", $_SERVER["PATH_INFO"] ?? "unset", "]", "\n"; ');

putenv("REDIRECT_STATUS=1");
putenv("SCRIPT_FILENAME=" . $f . "/" . str_repeat("a", 300));
putenv("PATH_INFO=/");
putenv("SCRIPT_NAME=/info.php");
putenv("REQUEST_METHOD=GET");
putenv("QUERY_STRING=");

echo `$php -n -d cgi.fix_pathinfo=1 $f`;

echo "Done\n";

@unlink($f);
@rmdir($d);
Comment on lines +29 to +30

@NickSdot NickSdot Aug 22, 2026

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Suggested change
@unlink($f);
@rmdir($d);
?>
--CLEAN--
<?php
$d = __DIR__ . '/fix_pathinfo_underflow';
@unlink($d . '/info.php');
@rmdir($d);

?>
--EXPECTF--
X-Powered-By: PHP/%s
Content-type: text/html%r; charset=.*|%r

PI=[/]
Done
Loading