EC2 user permissions

问题:

I just set up my first instance of AWS EC2 server and I'm running into an issue with permissions on a script uploading pictures. 'var/www' (and all subdirectories) owner is 'ec2-user' however the apache server is running as 'apache'. Therefore all directories created dynamically by the php script (using mkdir) have 'apache' as the owner (which it seems doesn't have write permissions) I could certainly change the apache user to 'ec2user' but I'm worried that might be a security risk. What's the correct way of doing this? Thanks for your help.

回答1:

This is a pure Linux permission problem, not an AWS problem. I just created an Amazon Linux instance and verified permissions in /var

 [ec2-user@ip-1-1-1-174 ~]$ ls -ald /var/www
 drwxr-xr-x 7 root root 4096 Oct 22 23:34 /var/www

As you see, ownership is root and not ec2-user. You should understand first what / why you see permission on /var/www/ to ec2-user

Should need to change the owner of that directory again, you can type :

 chown -R root:root /var/www

It is not a best practice to let your web server (httpd) write to /var/www nor to run that process with elevated privileges (such as root). Should your app really write to the local storage, use a different volume, mounted in a separate directory, where no executable are available.

回答2:

To set file permissions for the Apache web server

1- Add the www group to your EC2 instance with the following command:

[ec2-user ~]$ sudo groupadd www

2- Add the ec2-user user to the www group:

[ec2-user ~]$ sudo usermod -a -G www ec2-user

3- To refresh your permissions and include the new www group, log out:

[ec2-user ~]$ exit

4- Log back in again and verify that the www group exists with the groups:

[ec2-user ~]$ groups
> ec2-user wheel www

5- Change the group ownership of the /var/www directory and its contents to the www group:

[ec2-user ~]$ sudo chown -R root:www /var/www

6- Change the directory permissions of /var/www and its subdirectories to add group write permissions and set the group ID on subdirectories created in the future:

[ec2-user ~]$ sudo chmod 2775 /var/www
[ec2-user ~]$ find /var/www -type d -exec sudo chmod 2775 {} +

7- Recursively change the permissions for files in the /var/www directory and its subdirectories to add group write permissions:

[ec2-user ~]$ find /var/www -type f -exec sudo chmod 0664 {} +