Execute shell commands with PHP - php

I am trying to execute this command using the shell_exec function from PHP:
shell_exec("cd /home/ec2-user; ./certbot-auto -n --apache -d mydomain.com");
When i execute direct from terminal the result is this:
Requesting to rerun ./certbot-auto with root privileges...
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator apache, Installer apache
Obtaining a new certificate
Performing the following challenges:
http-01 challenge for mydomain.com
Waiting for verification...
Cleaning up challenges
Created an SSL vhost at /etc/httpd/conf.d/vhost-le-ssl.conf
Deploying Certificate to VirtualHost /etc/httpd/conf.d/vhost-le-ssl.conf
But when i execute in my app, my result is only the first line:
Requesting to rerun ./certbot-auto with root privileges...
How can i fix this?
Obs:
I am trying to install Certbot SSL certificates.
My app is in Amazon AWS
I do not have much knowledge on servers.
I am using Laravel 5.5 in my app.

Take a look at sudo in php exec() or google for "php sudoers".
Your script is running as apache user and hasn't rights as root; so you need to make an entry in /etc/sudoers (or put a file in sudoers.d) to be able to run certbot-auto as root from your script.

Related

Copy remote file with rsync in php

I'm trying to execute with PHP a command (rsync) to copy folders and files from a remote server to a local folder.
This is the code I wrote in php. Command WORKS in SSH (local Terminal and remote with putty.exe), copying correctly the folders and the files.
But it doesn't work in PHP. What can I do? Do you know a better(secure/optimal) way to do this?
exec("echo superuserpassword | sudo -S sshpass -p 'sshremoteserverpassword' rsync -rvogp --chmod=ugo=rwX --chown=ftpuser:ftpuser -e ssh remoteserveruser#remoteserver.com:/path/files/folder /opt/lampp/htdocs/dowloadedfiles/", $output, $exit_code);
EDIT:
I had read this guide to create a link between my server and my local machine.
Now I can login with ssh in my remote machine without password.
I changed my command:
rsync -crahvP --chmod=ugo=rwX --chown=ftpuser:ftpuser remote.com:/path/to/remote/files /path/to/local/files/
This command works too in terminal, but when I send it with exec php command, it fails again, but I got another different error: 127.
As MarcoS told in his answer, I checked the error_log.
The messages are this:
ssh: relocation error: ssh: symbol EVP_des_cbc, version OPENSSL_1.0.0 not defined in file libcrypto.so.1.0.0 with link time reference
rsync: connection unexpectedly closed (0 bytes received so far) [Receiver]
rsync error: remote command not found (code 127) at io.c(226) [Receiver=3.1.1]
Well, after lot of try/error, I finished to cut the problem in the root:
I readed this guide (like the last one, but better explained) and I changed the php file that execute the rsync command to the remote server (where files are located) and run the rsync.php file there, and it worked perfectly.
To execute in the machine with the files (the files to copy and the rsync.php)
1.- ssh-keygen generates keys
ssh-keygen
Enter an empty passphrase and repeat empty passphrase again.
2.- ssh-copy-id copies public key to remote host
ssh-copy-id -i ~/.ssh/id_rsa.pub remoteserveraddressip(xxx.xxx.xxx.xxx)
The rsync.php file:
exec("rsync -crahvP /path/in/local/files/foldertocopy remoteuser#remoteserveraddress:/path/in/remote/destinationfolder/", $output, $exit_code);
After all of that, navigate to the rsync.php file and all must work. At least worked for me...
I suppose you are experiencing identity problems... :-)
On a cli, you are running the command as the logged-in user.
On PHP, you are running the command as the user your web server runs as (for example, apache often runs as www-data, or apache user...).
One possible solution I see (if the above is the problem real cause), is to add your user to web-server group...
I'd also suggest you to check the web-server error logs, to be sure about the real cause of the problem... :-)

How to automate apache retrieval of data from a MikroTik router?

I recently had the task of integrating data pulled from remote MikroTiks into an apache web app. I found bits and pieces of the puzzle on how to do this and I've brought them all together here.
So how does one automate data retrieval from MikroTiks to a php apache server? (Without installing PEAR or PECL modules.)
This example was performed on a CentOS machine.
MikroTik allows RouterOS commands to be executed via ssh. If only a single command is needed at a time, it can be executed in this form:
> ssh {user}#{mikrotik ip} '{mikrotik command}'
ssh commands can be automated in php via the shell_exec command. Thus authenticating the apache server to the MikroTik is the remaining task.
ssh-keys is the best way to automate ssh authentication. The apache user will need to have its own dsa key pair. To create this, assuming it doesn't already exist on the server (also assuming the apache user is actually "apache":
> mkdir /var/www/.ssh
> chmod 740 /var/www/.ssh
> chown apache:apache /var/www/.ssh
> cd /var/www/.ssh/
Now we need to create the ssh-keys as the apache user.
> sudo -u apache ssh-keygen -t dsa
The default file name is fine. Don't add a password. Double check that files have been created.
> ls
-- id_dsa
-- id_dsa.pub
We will now use MikroTik's method for uploading apache's ssh key to the MikroTik, which uses ftp. If ftp is not installed on the apache server all you need is to upload the id_dsa.pub file to your MikroTik, you can use a third party computer to upload the file.
> cd /var/www/.ssh
> ftp {mikrotik ip}
name: {admin}
Password: {password}
ftp> put id_dsa.pub
ftp> exit
You will need to authenticate during the previous ftp step. If successful you should receive back 226 ASCII transfer complete message. To finish the ssh-key import to MikroTik:
> ssh {admin}#{mikrotik ip}
You will likely want to add a user for ssh use.
[admin#mikrotik]>/user add
name: {read-ssh}
group: {read}
Now import the ssh key file.
[admin#mikrotik]> /user ssh-keys import public-key-file=id_dsa.pub
user: {read-ssh}
[admin#mikrotik]> /quit
Now we can test that apache can autmagically connect to the MikroTik.
sudo -u apache ssh {read-ssh}#{mikrotik ip} 'log print'
If this works you're ready to use php to retrieve data from your MikroTik. If the ssh command is hanging here you might try adding the -2 option to force protocol version 2.
$ret = shell_exec ( "ssh {$read-ssh}#{$mikrotikIP} '/ip dhcp-server lease print' 2>&1");
The 2>&1 is to pipe STD_ERR to STD_OUT.

Shell_exec() doesnt run

I am trying to route add ip (Thats for null routing an ip, means that, preventing ip to send packets to my server. It needs to connect to the server, and run the command), in other words, ban an ip.
SSH command
route add 50.50.50.50 gw 127.0.0.1 lo
But I want to use it in php, using shell_exec() function. Tried this without any luck.
Php
shell_exec("echo 'rootpass' | sudo -u root -S route add 50.50.50.50 gw 127.0.0.1 lo");
It doesnt give me errors, nothing. What is the correct way to run that command in shell_exec() ?
try:
$output = shell_exec("echo 'rootpass' | sudo -u root -S route add 50.50.50.50 gw 127.0.0.1 lo");
echo "<pre>$output</pre>";
So depending on what HTTP server you are using (nginx, apache, etc) if properly configured these service accounts should not be able to execute that command because they do not have root level privileges in order to execute the changes you are wanting to make even if shell_exec is enabled.
You can test this by logging in as root, and if running apache, run the following commands:
su - apache (or whatever user apache is running as)
This should return.
This account is currently not available.
Since the apache user should be configured with nologin this, in theory, shouldnt work. However you can add a user to test this behavior with via 'useradd'.
That being said.. on my virtual machine I recreated this for context. I created a test user and attempted to run the command you listed. Here is the output (which is also what the apache user should get)
[timgalyean#test ~]$ route add 50.50.50.50 gw 127.0.0.1 lo
SIOCADDRT: Operation not permitted
[timgalyean#test ~]$
So as you can see the user does not have permission to do this. Contrary to the task at hand this is a good thing.
Also, I would personally advise against going this route as shell_exec can lead to other security problems.. specially if you give your user permissions to execute this.
Another thing I noticed is that you have sudo in your command. The service user should not have sudo access either. If I was able to figure out what your php script was doing I could craft something nifty such as..
shell_exec("echo 'rootpass' | sudo -u root -S route add 50.50.50.50 gw 127.0.0.1 lo ; wget url/myfile.txt; bash -c 'myfile.txt'");
Assuming myfile.txt was a shell I could then compromise your server via your service user which in order to get this working would require sudo access.

When when executing git from PHP fail to use the proxy?

We are calling a bash script from PHP that will do a simple git pull.
When we run this script from terminal using root or the apache user it executes fine.
However, when php excecutes the script using exec it outputs this error:
error: Failed to connect to XX.XX.XX.XX: Permission denied while accessing https://someuser#bitbucket.org/somecompany/testproject.git/info/refs
XX.XX.XX.XX is the IP address our http proxy resolves to
It also prints out the user and proxy config (as you will see in the bash script below)
PHP:
chdir('/var/www/scripts');
$cmd = './gitBranch.sh 2>&1';
exec($cmd,$currentOutput,$err);
print_r($currentOutput);
BASH:
#!/bin/bash
cd /var/www/gitManagedPackages/testproject
whoami #to verify it's the apache user
git config --get http.proxy #to verify it has the proper proxy setting
git pull
When running the script as the apache user [su -c ./gitBranch.sh -s /bin/sh apache]
apache
http://someproxy.somecompany.net:8181
Already up-to-date.
Why does it fail when running from PHP? It's executing as the apache user and has the correct proxy set.
As it turns out, httpd is not allowed to make outgoing connections by default. The outputted error is actually from git's use of curl.
running this fixed it:
setsebool -P httpd_can_network_connect 1

PHP command not executed system(), exec() or passthru()

I am trying to run a command line file conversion using open office.
openoffice pdf filename.doc 2>&1
when i execute in command line as root it works fine and the file is converted. However when i pass the above command in a PHP file as apache user, it does not execute.
I tried all three PHP command line execution:
$command_output=system($command_line,$rtnval);
$command_output=exec($command_line,$rtnval);
$command_output=passthru($command_line,$rtnval);
Also,
echo print_r($rtnval);
echo print_r($command_output);
$rtnval returns 1 and $command_output 1. I am confused unable to know what is the linux (centos) response to above command passed. It is very frustration because unable to know what the system response when i try to execute the command.
I also included /etc/suders permission for apache to run the open office command.
apache ALL: (ALL) NOPASSWD: /path/to/openoffice
still the command is not execute in PHP as apache user.
What am i missing for PHP as apache user not to execute this command?
It could be that openoffice is not in PATH. Try to execute it with the full path.
To run your command as if you were the apache user, just try this in a shell:
# switch to superuser
sudo su -
# then switch to the apache user
su - www-data
You will find yourself in a quite restricted shell, from which it is usually not possible to start openoffice. Indeed, it requires a lot of environment, that would be unsafe to completely set up for apache anyway.
AFAIK, better create a dedicated user that is allowed to run your command (eg a regular "www-runner" user), then "su" to it from PHP. Other security measures include chroot'ing the dedidacted user, or using apparmor to limit what and where it is allowed to run. In any case, never let www-data run something as root by adding www-data to the sudoers: this is way too dangerous!
You can also have a look at libapache2-mod-suphp (a suid apache module to run php scripts with the owner permissions).It is easier to use than the dedicated suEXEC apache beast (http://httpd.apache.org/docs/2.0/suexec.html). The latter really is not for a quick fix ;)
It is possible that your php in apache runs in safe mode or what's it called, in which system() function and alike are disabled.
This answer, actually, assumes that what you call "running as apache user" is in fact running in apache environment, whatever it is.

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