When using the move_uploaded_file() function in PHP I get the error:
Warning: move_uploaded_file(...): failed to open stream: Permission denied in ...
On my server I have the public_html permissions like:
drwxr-sr-x 7 user www-data 4096 Apr 27 17:48 public_html
Which is recursively through-out the directory.
Have you got any ideas why this might not be working? Or what I can do to help me find out why this is not working.
The server is actually a cluster where the files are on a NAS and the php is on the cluster. I am performing all the permission commands on the device of the NAS as that is where the user FTP's to.
User www-data can not write to public_html directory. Use chmod on your public_html to give www-data write permission:
chmod 775 public_html -R
First off, the SUID and SGID only make sense when used with executable files.
From http://www.codecoffee.com/tipsforlinux/articles/028.html :
SUID (Set User ID) Bit
[...] in case I have an application whose owner is ' root ' and it has its SUID bit set, then when I run this application as a normal user, that application would still run as root. Since the SUID bit tells Linux that the the User ID root is set for this application and whenever this application executes it must execute as if root was executing it (since root owns this file)
SGID (Set Group ID) bit
Just like SUID, setting the SGID bit for a file sets your group ID to the file's group while the file is executing. IT is really useful in case you have a real multi-user setup where users access each others files. As a single homeuser I haven't really found a lot of use for SGID. But the basic concept is the same as the SUID, the files whose SGID bit are set would be used as if they belong to that group rather than to that user alone.
So if none of your web files need to be executed as a normal process, it is best to leave the SGID alone.
Finally if you didn't change your web server's security context, it (most probably, as you didn't mention any paths) tries to move a file which is located in a directory www-data can only read. To move a file you need write access to the directories where the file is and will be moved to. So www-data should be given write access to
/tmp, in which case nothing's to be done)