I have a rails app (v4.2). I have two actions that permit an image upload using paperclip. I have paperclip validation on the mime types.
Anti-malware on the server found a bunch of PHP files in /tmp like this one:
/tmp/RackMultipart20190610-9668-u9nebk.php
I assume they are created in the file upload process.
Two questions:
How can I track down where they came from? Looking in my production.log, I see a bunch of 404s for posts to bogus joomla & wordpress .php paths but nothing that could have been responsible for these uploads.
How can I prevent them in the future?
I'm using rack attack and can block .php file extensions but how can I block file uploads in forms?
We have two places where signed in members can upload images or PDFs. How can I block all other attempts to upload files?
File uploading by-pass is a common technique for uploading webshell's and other stuff.
There are 2 basic methods that will help you to decrease the amount of file uploaded to your server:
MIME Content-type validation: If you validate the content-type of the uploaded file you (since you just want images) you can assure that only image-type files are uploaded:
:content_type => ["image/gif", "image/jpg", "image/jpeg", "image/png", "image/bmp", "image/x-bmp"]
But this still can be bypassed, so you need to add another verification:
File extension validation: You also should add a file extension validation to assure you only permit image-type extensions to your upload.
I've find a cool post where it shows a good implementation of file extension validation: https://stevenyue.com/blogs/validate-attachment-file-size-and-type-in-rails/
Make sure you implement both of these techniques and you should be fine.
Related
I want to upload large files on S3. I know there is an option multipart upload by which I can upload large file in parts. I read the documentation (http://docs.aws.amazon.com/mobile/sdkforios/developerguide/s3transfermanager.html) but didn't find any code for the multipart upload. I have successfully uploaded a file on server as a single file but I want to use multipart for large file.
Thanks.
IF you're still looking for a solution, you can check out my blog post on this subject: Taming the AWS framework to upload a large file to S3. For large files you will have to skip using the AWSTransferManager as it uses cognito credentials which are limited to an hour validity.
My website generates a file in javascript (audio recording) and I then want it to be uploaded to Amazon S3.
I first managed to get the uploading part working by sending the generated file to my server, where it is uploaded. However I would like now to upload the file directly to S3, without going through my server.
So I started to use the s3_direct_upload gem, which works great when using a file_field. However my file is generated by the javascript and :
- The value of a file field has to be set by the user for security reasons
- I do not want the user to have to interact with the upload
I tried to play with the S3Uploader class and to directly add data, without any success for now, it seems that I do not use the correct method.
Does anyone has any idea on how to achieve S3 direct upload without a file field ?
Thanks
Never mind, I found out that the S3Uploader class used by the s3_direct_upload gem has the same methods as the jQuery-File-Upload from which it is derived.
So one can call $("#s3_uploader").fileupload('send', {files: [f]});
And the f File will be uploaded to S3 directly
My application is using Rails 2 backend, Heroku for hosting, Paperclip for file uploads, and Amazon S3 for file storage.
Right now users can upload files with paperclip + s3 - this works flawlessly. After upload, an icon appears on their dashboard, linked to the file location (in s3 bucket). When the icon is clicked, the browser opens the file in a new window (for most file types - PDF, MP3, img, etc). Instead of opening, I want the file to be automatically downloaded when the user clicks the file's icon (like Gmail attachments). The solution should be able to work for any file type and cross-browser.
Is there a helper to do this in rails, or is javascript needed? I'm really stuck on this one so anything to point me in the right direction would be greatly appreciated. Thanks!
Please try the following:
class Test < ActiveRecord::Base
has_attached_file :testfile,
:storage => :s3,
# All your S3 config
:s3_headers => {"Content-Disposition" => "attachment"}
end
This should tell the Paperclip Gem to set the "Content-Disposition" header to the value "attachment" for newly uploaded files.
Note that you have to manually edit the already uploaded file, e.g. with Cyberduck or another FTP Client.
When you transfer the file, you need to set a Content-Disposition header with a value of attachment; filename=yourfilename.pdf. If it's transfered directly from S3, you'll need to tell S3 to set the Content-Disposition headers as well. Possibly also Content-Type.
Note that if you tell S3 to associate a Content-Disposition header, it will always transmit this header.
FWIW, here's Amazon's documentation on doing a PUT for an Object: http://docs.amazonwebservices.com/AmazonS3/latest/API/RESTObjectPUT.html
I'm writing a Rails application that serves files stored on a remote server to the end user.
In my case the files are stored on S3 but the user requests the file via the Rails-application (hiding the actual URL). If the file was on my servers local file-system, I could use the Apache header X-Sendfile to free up the Ruby process for other requests while Apache took over the task of sending the file to the client. But in my case - where the file is not on the local file-system, but on S3 - it seems that I'm forced to download it temporarily inside Rails before sending it to the client.
Isn't there a way for Apache to serve a "remote" file to the client that is not actually on the server it self. I don't mind if Apache has to download the file for this to work, as long as I don't have to tie up the Ruby process while it's going on.
Any suggestions?
Thomas, I have similar requirements/issues and I think I can answer your problem. First (and I'm not 100% sure you care for this part), hiding the S3 url is quite easy as Amazon allows you to point CNAMES to your bucket and use a custom URL instead of the amazon URL. To do that, you need to point your DNS to the correct amazon URL. When I set mine up it was similar to this: files.domain.com points to files.domain.com.s3.amazonaws.com. Then you need to create the bucket with the name of your custom URL (files.domain.com in this example). How to call that URL will be different depending on which gem you use, but a word of warning was that the attachment_fu plugin I was using was incorrectly sending me to files.domain.com/files.domain.com/name_of_file.... I couldn't find the setting to fix it, so a simple .sub method for the S3 portion of the plugin fixed it.
On to your other questions, to execute some rails code (like recording the hit in the db) before downloading you can simply do this:
def download
file = File.find(...
# code to record 'hit' to database
redirect_to 3Object.url_for(file.filename,
bucket,
:expires_in => 3.hours)
end
That code will still cause the file to be served by S3, but and still give you the ability to run some ruby. (Of course the above code won't work as is, you will need to point it to the correct file and bucket and my amazon keys are saved in a config file. The above is also using the syntax for the AWS::S3 gem - http://amazon.rubyforge.org/).
Second, the Content-Disposition: attachment issue is a bit more tricky. Hopefully, your situation is a bit more simple than mine and the following solution can work. Assuming the object 'file' (in this example) is the correct S3 object, you can set the disposition to attachment by
file.content_disposition = "attachment"
file.save
The above code can be executed after the file exists on the S3 server (unlike some other headers and permissions), which is nice and it can also be added when you upload the file (syntax depends on your plugin). I'm still trying to find a way to tell S3 to send it as an attachment and only when requested (not every time), and if you find that, please let me know your solution. I need to be able to sometimes download it and other times save embed images (for example) into HTML. I'm not using the above mentioned redirect but fortunately it seems that if you embed (such as a HTML image tag) a file with the content-disposition/attachment header, and the browser still displays the image normally (but I haven't throughly tested that across enough browsers to send it in the wild).
Hope that helps! Good luck.
I have a Rails application setup to receive file attachments using Paperclip.
Now I need to allow a .net/C# cell phone application to post files along with the XML in the same way (or some other way if necessary: they could encode the image as base64 and send - they tried that initially - including the binary data in the tag that would normally be a file field in the web application, but it did not work.
I have found nothing in the way of documentation and wondering if anybody has experience or advice.
Surprising that there is apparently no documentation for doing this anywhere to be found. I ended up stumbling across a document on the Basecamp website describing how their file attachment process works for API users and used it as a guideline.
http://developer.37signals.com/basecamp/
with help from this article about posting files:
http://www.codevil.com/index.php/2009/05/23/posting-and-getting-files-in-rubyrails/
I modified my initial setup so that, rather than passing the tag in the XML, they first post a file and receive an file ID in response.
Then they post the XML with that reference and their .
Then I use before_validation and after_save callbacks to set the file with Paperclip, and remove the tmp file after the save.