I have an idea that will make all Linux servers running PHP more secure.
I want to configure php.ini File Uploads to scan any new file upload with ClamAV's clamscan.
Is it possible? How should I configure it?
While there are libraries for interacting with ClamAV within PHP scripts, there is no way to automatically scan all uploaded files automatically.
Mainly, due to flexibility. For example, if you run a security website to track various viruses and store a copy of each, ClamAV would get to them during the upload, rendering your website useless. The better approach would be to do this in the client code, and use one of the libraries in the link above to perform scanning.
Having said that, I don't believe this is something that's impossible to achieve. You can write a PHP extension that hooks into fileuploads to automatically run ClamAV on uploaded files.
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Im planning to add file manager (very basic once) because I never used FTP functions, and it looks easier (FTP connection loses when scripts is done). I would simply use POST request (or what should I?) instead of FTP functions. Is it good idea? Anyone knows restrictions?
As far as I can see only FTP functions are to post and receive files.
What you need to do is add dynamic form where you can select multiple files and upload them to specific directory of your chose.
You will need to get all available directories and files in them, probably with some kind of recursive function. More optimal way is to get directories/files of current folder and when you click on folder it will get files/folder for it.
Can it be done - sure. Is it a good idea - no. People will have access for uploading malicious files, we are not talking about images here, php scripts, shell scripts, executable viruses and so on...
If you are doing this only for yourself, for file posting and receiving I suggest you to use FTP clients for that.
I wouldn't recommend it, but it's probably best to use a 3rd party tool, rather than to write your own.
PHP File Manager
PHPfileNavigator2
FileManager
...
Keep in mind that both PHP and your webserver can put certain restrictions on the size of files that you can transfer, it is of course possible to change these in the configuration files.
im trying to implement on my site a system who let the user download a file that have to be change before the download.
I have a master file (a .exe program), that inside have a variable who has to be change for every different user.
The most simple solution is to change a variable inside a xml file every time the user want his personalized exe and then make the exe file to read the external file. BUT i dont want the user to download more than one file.
Is this possible? using php can i change a parametter inside a compiled program? Thanks for any help and suggestions!
If you really really know what you're doing and you know exactly the bits that need to be flipped inside the file, then yes, it's possible to modify the .exe file with PHP. Otherwise you have to make changes to the source or other files the .exe is built with and compile the program on the server before sending it to the user.
In theory it's certainly possible (PHP is turing complete), but as stated in other answers it will be hardly worth the hassle (considering the fact that you have to ask whether it is possible shows you'd have to investigate at last for days into the standard exe-format).
I'd recommend one of the following:
1) Zip the program with the configuration file; either use a separate launcher (e.g. Java [a JAR is a ZIP file]) or add a configuration file that is read by the program itself. There is a number of PHP libraries for generating ZIP files.
2) compile the program with the changed source on the server itself; however this can also become quite complicated depending on your server configuration and the programming environment you use. If you have never administered a virtual server I would not even slightly recommend that as an option.
3) If you can assume that the user got somewhat stable Internet access you might also consider to let hir download a standard executable, where additional configuration will be downloaded later on by the program itself (e.g. by transmitting the username to the server). However this creates dependencies you might want to avoid (your user probably can't use it on machines without Internet access and you should assert that your server is up most of the time).
While it's probably possible, I doubt it's worth the hassle. Unless you're trying to fight piracy or something. Why don't you just serve the user a custom .zip file with the .exe and a config .xml?
[edit after OP commented]
I presume what you're trying to edit is the facebook ID/username? Well, try to compile the base file with some unique string like "THISNEEDSTOBEREPLACED", then use some binary safe function to replace it. Though remember things can and will get tricky if the string lengths don't match.
Ok this might seems a bad idea or an obvious one. But let's imagine a CMS like PHPBB. And let's imagine you'd build one. I'd create just 1 file called PHPBB.install.php and running it it will create all folders and files needed with PHP. I mean, the user run it just once and every file and folder of the app is created via the PHP file.
Why to do this?
Well mostly because it's cleaner and you are pretty much sure it creates everything as you wish (obliviously checking everything about the server first). Also, having all the files backed-up inside a file you would be able to restore it very easily by deleting everything and reinstalling it running again PHPBB.install.php. Backing-up files like this will allow you to also prevent errors: How? When an error occurred in a file, this file is restored as it was and automatically re-run.
It would be too heavy!
The installation would happen only once and you'd be sure the user will not forget to place the files correctly. The error-preventing will worth the cause and it would also happen only once.
Now the questions:
Does this technique exists? If so, What's its name?
Why would you discourage it?
As others have said, an installer.
It requires the web server to have permission to write to the filesystem, and ends up having the files owned by the user the web server runs as. Even when one has the ability to change filesystem permissions, it's usually a longer process than just extracting an archive and having the initial setup verify permissions.
Does this technique exists? If so, What's its name?
I'd advise to read about __halt_compiler(). It allows you to mix PHP code with non-php data which is not parsed, so you may have PHP code ("installer") and binary data (e.g., compressed contents of all the files) in single PHP file.
1 - Yes, there is a single install file in PHPBB. You run through an online wizard defining your settings and then it installs automatically.
http://www.phpbb.com/support/documents.php?mode=install&version=3&sid=908f5766fc04868ccb985c1b1e6dee4b#quickinstall
2 - The only reason to discourage it would be if you want the user to understand exactly how the system works. Automatically installing it means the user has no need to understand the nitty gritty of it all - of course, many see this as a good thing.
I allow PDF files to be uploaded to my site (PHP).
I would like to offer the ability to also allow .zip files which contain PDF files in directories so it is easier for users to simply zip a directory and upload one file instead of uploading multiple zip files individual.
For those of you who offer a .zip file upload feature to your (PHP) website, what are the technical, security, and other issues you have faced?
Be careful how you unpack the zip, you could find yourself consuming far more resources than you expected. Perhaps some setrlimit(2) resource limits before unpacking would be wise.
The unzip(1) utility has several nice safety features built in; the -^ command line option turns off control-character filtering, so make sure you don't touch this :) and the -: command line option allows stupid pathnames like ../../../../etc/passwd. Make sure you're on at least version 5.50, so that those stupid pathnames are forbidden by default. (And don't use that command line option. I mention the options just so you can more easily find the documentation for them. :)
If you use an API, make sure it has options to prevent both kinds of silly filenames.
Assuming the .zip gets unpacked eventually you would have to make sure the directory they get unpacked in is unreachable by the the clients' browsers (with .htaccess or by placing it outside the web root directory), and even in that case I'd still monitor the contents of the unpacked .zip to make sure they didn't contain anything that might prove harmful (php or other files run by the server, html spoofs).
Another issue is i guess the upload_max_filesize set in php.ini, you can make sure it can be set big enough to suit your purposes before you start coding.
edit: also read sarnold's answer ;)
AFAIK, php can handle zip files pretty efficiently. Difficulties/Issues that I can think of is, while accessing the file where We need to extract the zip first, and then retrieve the actual needed file. Due to that reason, extracting a zip, might consume additional amount of server time, depending on the size of the file itself.
Where As, during uploads, I do not suppose there is any difficulties or issues specially emphasized on zip types.
I don't know anything about imagemagick, I have a need to convert images that users upload to gif format and resize and optimize said images as well. Before I look further into it, can someone please clarify whether imagemagick is a software or a standalone script? Meaning do I need to have it installed on my server or can I just uload the files and use the script's commands?
I'm referring to imagemagick for PHP.
It depends what you mean by "install."
If you are talking about the PHP extensions, then yeah, those have to be "installed."
If you are talking about the standalone binary programs, then no, they don't have to be "installed." If you can find a copy of the programs designed for the exact type and version of the operating system your server runs, you could place them somewhere accessible, give them execute permissions, and call them from your script. However, some shared hosting providers prohibit you from running compiled binaries in any way whatsoever, so this might not be such a good idea.
Your best bet is going to be either convincing your hosting provider to install it, or switching providers to one that already has it installed.
try MagickStudio
To convert, edit, or compose your image directly from a Web page, press Browse to browse and select your image file or enter the URL of your image. Next, set any of the optional parameters below. Finally, press view to continue.