Bug #14076 Updated: fopen() and touch() fail to create file under safe mode

ID: 14076 Comment by: phpbugs@noerenberg.de Old Reported By: a.genkin@utoronto.ca Reported By: phpbugs@noerenberg.de Status: Open Bug Type: *Directory/Filesystem functions Operating System: Linux PHP Version: 4.0.6 New Comment: I've verified that this problem still exists in PHP 4.1.1. Hajo Noerenberg Previous Comments: ------------------------------------------------------------------------ [2002-01-16 13:42:52] phpbugs@noerenberg.de As a workaround you can use relative paths in all of your fopen()-calls: fopen("./test.html") always works (I think php prepends the *expanded path* then -- see the last paragraph in my previous comment). Hajo ------------------------------------------------------------------------ [2002-01-16 13:21:11] phpbugs@noerenberg.de This problem has nothing to do with wrong file/directory modes. I'm quite sure that it is a bug in the PHP-realpath-code. Please consider the following setup layout: /var/www/ = symlink to /mnt/sda1/www /var/www/domain.com = apache document_root = php open_basedir /var/www/domain.com/test.html = test file for fopen() I've added some debug code to fopen_wrappers.c : php_error(E_NOTICE, "check_specific_open_basedir ( comparing resolved name %s to resolved_basedir %s )", resolved_name, resolved_basedir); if (strncmp(resolved_basedir, resolved_name, strlen(resolved_basedir)) == 0) { Trying to fopen("/var/www/domain.com/test.html") results in two cases: 1. /var/www/domain.com/test.html already exists PHP Warning: check_specific_open_basedir ( comparing resolved name /mnt/sda1/www/domain.com/test.html to resolved_basedir /mnt/sda1/www/domain.com/test.html ) -> fopen() succeeds 2. /var/www/domain.com/test.html does *not* exist PHP Warning: check_specific_open_basedir ( comparing resolved name /var/www/domain.com/test.html to resolved_basedir /mnt/sda1/www/domain.com/test.html ) -> fopen() fails with "open basedir restriction in effect"-error As you can see in the debug output, PHP does not correctly expand the file path if the file does not exists ! Trying to fopen("/mnt/sda1/www/domain.com/test.html") always succeeds because PHP does not need to expand the filename anymore (-> strncmp is always true ). Hajo (Linux 2.2 - PHP 4.0.6 - afaik the problem still exists in 4.1.X) ------------------------------------------------------------------------ [2001-11-19 13:50:10] a.genkin@utoronto.ca Well, the fact that it can create a *new directory* in the same directory, already means that the apache process has sufficient permissions to also create a file in it. However, these are the permissions: webedit@penguin:/var/www/tmp/submit$ ls -lad ./ drwxrwx--- 18 webedit www 4096 Nov 15 19:13 ./ Apache runs as user www', and the scripts are owned by user webedit'. Note that the directory is owned by the same user as the script, and writeable to Apache, so the requirements of safe mode are met. Thank you for your response. -- Arcady Genkin ------------------------------------------------------------------------ [2001-11-19 12:37:01] bate@php.net Post please the mod of your directory and tell me the user and group of your apache. Maybe the apache dont have rights to create a new file in your directory but he owns the newfile and can remove/edit this file. ------------------------------------------------------------------------ [2001-11-15 18:53:16] a.genkin@utoronto.ca Under safe mode, fopen("filename", "w") fails to create a file if it doesn't exist, complaining about open_basedir restriction. However, the filename refers to the file in the directory configured in the open_basedir. Besides, if the same file is created manually, fopen() can open it for writing without any problems. The directory is writeable to the web server. $dir = '/var/www/tmp/submit'; // Fails if the file doesn't exist. // Succeeds if the file does exist fopen( "$dir/file.txt", "w" ); // Fails if the file doesn't exist. mkdir( "$dir/foo", 0700 ); // SUCCEEDS!!! Notice the same path. ------------------------------------------------------------------------ Edit this bug report at http://bugs.php.net/?id=14076&edit=1