Bug #77124 [Opn->Ver]: FTP with SSL memory leak
Edit report at https://bugs.php.net/bug.php?id=77124&edit=1
ID: 77124
Updated by: cmb@php.net
Reported by: antoine dot guenard+php at gmail dot com
Summary: FTP with SSL memory leak
-Status: Open
+Status: Verified
Type: Bug
Package: FTP related
Operating System: Debian GNU/Linux 9 (stretch)
PHP Version: 7.2.12
Block user comment: N
Private report: N
New Comment:
It seems that we're leaking the SSL_CTX object[1] which is used to
initialize an SSL structure[2], but will only be freed[3] if the
latter fails. Moving the SSL_free() out of the if statement
(always-free-context.path) should solve the memory leak, and
doesn't appear to introduce any regression. Since I don't have
any experience with libopenssl, I'm not sure whether freeing the
context unconditionally here is okay, though.
[1] <https://github.com/php/php-src/blob/php-7.3.0RC5/ext/ftp/ftp.c#L275>
[2] <https://github.com/php/php-src/blob/php-7.3.0RC5/ext/ftp/ftp.c#L289>
[3] <https://github.com/php/php-src/blob/php-7.3.0RC5/ext/ftp/ftp.c#L292>
Previous Comments:
------------------------------------------------------------------------
[2018-11-08 16:33:57] cmb@php.net
The following patch has been added/updated:
Patch Name: always-free-context
Revision: 1541694836
URL: https://bugs.php.net/patch-display.php?bug=77124&patch=always-free-context&revision=1541694836
------------------------------------------------------------------------
[2018-11-08 14:20:29] antoine dot guenard+php at gmail dot com
Description:
------------
Tested on PHP 7.2.10, there might be memory leak while using ftp_login function and maybe other
functions with FTPS (FTP over SSL).
To reproduce the memory leak, you should open a connection to a FTP server with SSL and then try to
login with ftp_login. The test script uses a public FTP that supports SSL for testing but I could
reproduce with other FTP servers with valid or invalid credentials.
I also provided another test script (for Unix/Linux) that uses an infinite loop to have a better
view of the memory increasing at every turn just after ftp_login is called, see:
https://gist.githubusercontent.com/guenard/6fca07e5c99f959de42dbed67628acf9/raw/b1c97d732a3e8acf249cf415e067b7f0e94075ae/lopp-ftp-with-ssl-login-memory-leak.php
The closest issue I found was https://bugs.php.net/bug.php?id=65228 but it looks
like the patch has made it from PHP 5.5.x to PHP 7.2.x.
Test script:
---------------
<?php
$conn = @ftp_ssl_connect('test.rebex.net', 21);
@ftp_login($conn, '', '');
@ftp_close($conn);
Expected result:
----------------
No memory leak.
Actual result:
--------------
==9752== LEAK SUMMARY:
==9752== definitely lost: 947 bytes in 6 blocks
==9752== indirectly lost: 15,057 bytes in 219 blocks
==9752== possibly lost: 0 bytes in 0 blocks
==9752== still reachable: 4,267 bytes in 26 blocks
==9752== suppressed: 0 bytes in 0 blocks
------------------------------------------------------------------------
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