Edit report at https://bugs.php.net/bug.php?id=52312&edit=1
ID: 52312
Comment by: rob dot j dot olmos at gmail dot com
Reported by: v dot damore at gmail dot com
Summary: PHP safe_mode/open_basedir - lstat performance
problem
Status: Analyzed
Type: Bug
Package: Safe Mode/open_basedir
Operating System: Linux
PHP Version: 5.2.13
Block user comment: N
Private report: N
New Comment:
At this point I think at the very least this issue should be in the docs for each of the config
sections. safe_mode, open_basedir, and realpath_cache_size sections.
Previous Comments:
------------------------------------------------------------------------
[2016-11-05 13:35:28] spam2 at rhsoft dot net
FRANKLY: why not check if "disable_functions" contains "link" and
"symlink" and in that case just use the realpath-cache as if there would not be a
open_basedir setting or even to avoid the overhead of check this add a
"realpath_cache_openbasedir" to config options where admins which disabled the link
functions can decide for themself?
------------------------------------------------------------------------
[2016-08-31 13:05:12] pierre dot renaudet at gmail dot com
We have this issue with Symfony(3.1.3), it's really poor performance with lot of stat on
file...
With the same project on Windows (IIS 7.5 - PHP 5.6.1
With open_basedir (empty) it's take ~300-350ms for the index
With open_basedir set (~9 path) it's take 3.5-10s for the index
I understand security problem, but why not just clear cache (before and/or after risky function)
things like that :
--------------------
diff --git a/ext/standard/link.c b/ext/standard/link.c
index 62e7295..a844f46 100644
--- a/ext/standard/link.c
+++ b/ext/standard/link.c
@@ -158,6 +158,11 @@ PHP_FUNCTION(symlink)
RETURN_FALSE;
}
+ /* Reset realpath_cache when open_basedir is not null to avoid security issues */
+ if(PG(open_basedir)){
+ realpath_cache_clean();
+ }
+
/* For the source, an expanded path must be used (in ZTS an other thread could have changed the
CWD).
* For the target the exact string given by the user must be used, relative or not, existing or
not.
* The target is relative to the link itself, not to the CWD. */
@@ -206,6 +211,11 @@ PHP_FUNCTION(link)
RETURN_FALSE;
}
+ /* Reset realpath_cache when open_basedir is not null to avoid security issues */
+ if(PG(open_basedir)){
+ realpath_cache_clean();
+ }
+
#ifndef ZTS
ret = link(topath, frompath);
#else
diff --git a/ext/standard/link_win32.c b/ext/standard/link_win32.c
index 7d43162..e47e265 100644
--- a/ext/standard/link_win32.c
+++ b/ext/standard/link_win32.c
@@ -168,6 +168,12 @@ PHP_FUNCTION(symlink)
php_error_docref(NULL, E_WARNING, "UTF-16 conversion failed (error %d)",
GetLastError());
RETURN_FALSE;
}
+
+ /* Reset realpath_cache when open_basedir is not null to avoid security issues */
+ if(PG(open_basedir)){
+ realpath_cache_clean();
+ }
+
/* For the source, an expanded path must be used (in ZTS an other thread could have changed the
CWD).
* For the target the exact string given by the user must be used, relative or not, existing or
not.
* The target is relative to the link itself, not to the CWD. */
@@ -223,6 +229,11 @@ PHP_FUNCTION(link)
RETURN_FALSE;
}
+ /* Reset realpath_cache when open_basedir is not null to avoid security issues */
+ if(PG(open_basedir)){
+ realpath_cache_clean();
+ }
+
#ifndef ZTS
ret = CreateHardLinkA(topath, frompath, NULL);
#else
diff --git a/main/main.c b/main/main.c
index bb98f27..7e5904e 100644
--- a/main/main.c
+++ b/main/main.c
@@ -2222,7 +2222,7 @@ int php_module_startup(sapi_module_struct *sf, zend_module_entry
*additional_mod
/* Disable realpath cache if an open_basedir is set */
if (PG(open_basedir) && *PG(open_basedir)) {
- CWDG(realpath_cache_size_limit) = 0;
+ /* CWDG(realpath_cache_size_limit) = 0; */
}
/* initialize stream wrappers registry
--------------
------------------------------------------------------------------------
[2016-04-26 09:19:07] ianphp at binkmail dot com
This problem causes extreme loading on otherwise powerful servers when using PHP7/FastCGI/IIS, so
bad in fact that it's unusable for busy sites on an otherwise powerful server.
Unfortunately because this is a Windows server, the workarounds are not applicable.
I think that patch proposal is a good start to getting this fixed.
------------------------------------------------------------------------
[2013-12-16 16:39:10] pembo13 at gmail dot com
I seem to be suffering from this bug on an Apache/Linux + nfs setup. I'm using open_basedir and
the performance is so poor, that I can't even really stress test the server any more.
------------------------------------------------------------------------
[2013-05-29 21:45:36] phpdotnet at hostultra dot com
This bug is a real performance killer.
I propose this solution...
1. Modify symlink() php function so that if open_basedir or safe_mode is on, it disallows relative
symlinks with .. components, instead it creates absolute symlink.
This prevents attacker from exploiting CVE-2006-5178.
2. Allow the realpath cache to work even if open_basedir or safe_mode is on.
I did this with my own php code.
Before
---------
last pid: 30437; load averages: 32.93, 24.67, 15.62
98 processes: 43 running, 46 sleeping, 9 lock
CPU: 2.7% user, 0.0% nice, 75.3% system, 0.5% interrupt, 21.5% idle
After
---------
last pid: 30582; load averages: 2.06, 3.57, 10.58
68 processes: 6 running, 62 sleeping
CPU: 6.8% user, 0.0% nice, 1.7% system, 0.9% interrupt, 90.6% idle
------------------------------------------------------------------------
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