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tschechniker opened this issue Sep 12, 2016 · 5 comments
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ExecutableFinder generates wrong Path #19913

tschechniker opened this issue Sep 12, 2016 · 5 comments
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Bug Process Status: Reviewed

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@tschechniker
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Hi,

the executableFinder is generating a wrong path if you have open_basedir in action.

For example you have installed java in /usr/bin/java and your open_basedir is set to /usr/bin/ the ExecutableFinder will return /usr/bin//java. The problem is that the open_basedir restrictions now say your are not allowed to access /usr/bin//java because of the two slashes.

See: https://github.com/symfony/process/blob/master/ExecutableFinder.php#L82

/**
* $dir = /usr/bin/
* $name = java
* $suffix = '' (empty)
*/
if (is_file($file = $dir.DIRECTORY_SEPARATOR.$name.$suffix) && ('\\' === DIRECTORY_SEPARATOR || is_executable($file))) {

Best regards

Tobi
@xabbuh
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xabbuh commented Sep 28, 2016

I can confirm the issue.

Status: Reviewed

@xabbuh
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xabbuh commented Sep 28, 2016

@tschechniker Can you please check if /usr/bin/java in your case is a symlink to a file outside of your open_basedir? That's actually the only case where I was really able to reproduce your issue. Though I am not sure if we can actually avoid that then.

@xabbuh xabbuh mentioned this issue Sep 28, 2016
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@xabbuh
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xabbuh commented Sep 28, 2016

see #20077

fabpot added a commit that referenced this issue Sep 29, 2016
@fabpot
bug #20077 [Process] silent file operation to avoid open basedir issu…
07d4985 
…es (xabbuh)

This PR was submitted for the master branch but it was merged into the 2.7 branch instead (closes #20077).

Discussion
----------

[Process] silent file operation to avoid open basedir issues

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #19913
| License       | MIT
| Doc PR        |

Using file operations on a symlink that points to a file outside the directories being allowed by the open_basedir setting leads to PHP warnings being raised.

Commits
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30c9b1e silent file operation to avoid open basedir issues
@fabpot fabpot closed this as completed Sep 29, 2016
@tschechniker
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@xabbuh Yes /usr/bin/java is a symlink. This is standard on many Linux distros. But i don't see how the symlink will cause this issue. From my oppinion this is a logical issue.

So my open_basedir has the following content:

open_basedir=/var/www/;/usr/bin/

Now you are itterating over the open_basedir

$dirs[0] = "/var/www/"
$dirs[1] = "/usr/bin/"

Now you are searching for the executeable:
foreach($dirs a $dir) ...
$dir.DIRECTORY_SEPARATOR.$name.$suffix

==> "/usr/bin/".DIRECTORY_SEPARATOR."java".""

So from my side this is not a fault of the symlink

@xabbuh
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xabbuh commented Sep 30, 2016

@tschechniker It is as the symlink is pointing to a location outside of your open basedir config.

Please note that PHP evaluates the symlink before trying to figure out if the path is allowed:

All symbolic links are resolved, so it's not possible to avoid this restriction with a symlink. If the file doesn't exist then the symlink couldn't be resolved and the filename is compared to (a resolved) open_basedir .

see http://php.net/manual/en/ini.core.php#ini.open-basedir

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@fabpot @javiereguiluz @tschechniker @xabbuh @carsonbot