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Bug #41492 open_basedir bypass via readfile()
Submitted: 2007-05-24 15:55 UTC Modified: 2007-05-27 17:33 UTC
From: bugs dot php dot net at chsc dot dk Assigned:
Status: Closed Package: Safe Mode/open_basedir
PHP Version: 5.2.2 OS: Linux
Private report: No CVE-ID: None
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 [2007-05-24 15:55 UTC] bugs dot php dot net at chsc dot dk
file_exists() etc. does not allow checking the existence of files outside the directories specified in open_basedir.

Appearently readfile() does *not* have this restriction and thus allows checking the existence of files anywhere in the filesystem. If realpath($filename) returns a string (i.e. not false), the file exists. This is a circumvention of the open_basedir restriction in file_exists() etc.

Reproduce code:
The following should always be true, but it isn't when $dir is outside the directories specified in open_basedir:

var_dump(file_exists($dir) === (bool) realpath($dir));


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 [2007-05-27 17:33 UTC]
This bug has been fixed in CVS.

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