StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

POStoring PHP(/PHP-FPM/Apache)'s temporary-from-upload files in RAM rather than the filesystem (or encrypted only)?
text
Body
copied!<h2>Original question</h2> <p>So the project I'm working on is deathly paranoid about file uploads.<br> In the scope of this question, I'm not using that term in regards to payloads; I'm talking <em>confidentiality</em>.</p> <p>Programs can always crash and leave temporary files loafing around in the filesystem. That's normal. The <em>slightly</em> confidentiality-paranoid can write a cronjob that hits the temporary file folder every few minutes and deletes anything older than a few seconds prior to the cronjob call (not <em>everything</em>, simply because otherwise it might catch a file in process of being uploaded).</p> <p>...unfortunately, we take this paranoid a step further:</p> <p>Ideally, we'd love to never see temporary files from file uploads anywhere but in process-associated RAM.</p> <p><strong>Is there a way to teach PHP to look for temporary file as blobs in memory rather than in the filesystem?</strong> We use PHP-FPM as a CGI handler and Apache as our webserver, in case that makes it any easier. (Note also: 'Filesystem' is the keyword here, rather than 'disc', since there are of course ways to map the filesystem to RAM, but that doesn't fix the accessibility and automatic post-crash-clean-up issue.)</p> <p><strong>Alternatively, is there a way these temporary files can be <em>encrypted</em> immediately when they're being written to disc</strong>, so that they're never held in the file system without encryption?</p> <hr> <h2>Thread overview</h2> <p>I can unfortunately only accept <em>one</em> answer - but to anyone reading this, the entire thread is <em>extremely</em> valuable and contains the collective insights of many people. Depending on what <em>you</em> are hoping to achieve, the accepted answer <em>may not be interesting to you</em>. If you've come here through a search engine, <strong>please take a moment to read the whole thread</strong>.</p> <p>Here is a compilation of usecases as I see them for quick reference:</p> <h3>Re: PHP's temporary files</h3> <ul> <li><p>RAM instead of disc (e.g. due to I/O concerns) → <a href="https://stackoverflow.com/questions/5701508/storing-php-php-fpm-apaches-temporary-from-upload-files-in-ram-rather-than-the/5702449#5702449">RAMdisk</a>/comparable (<em>plasmid87</em>, <em>Joe Hopfgartner</em>)</p></li> <li><p>Immediate (per-filesystem-user) encryption → <a href="https://stackoverflow.com/questions/5701508/storing-php-php-fpm-apaches-temporary-from-upload-files-in-ram-rather-than-the/5733277#5733277">encFS</a> (<em>ADW</em>) (+ <a href="https://stackoverflow.com/questions/5701508/storing-php-php-fpm-apaches-temporary-from-upload-files-in-ram-rather-than-the/5879171#5879171">a gotcha</a> as per <em>Sander Marechal</em>)</p></li> <li><p>Secure file permissions → <a href="https://stackoverflow.com/questions/5701508/storing-php-php-fpm-apaches-temporary-from-upload-files-in-ram-rather-than-the/5905221#5905221">restrictive native Linux permissions (optionally per <strong>vhost</strong>)</a> (<em>Gilles</em>) or SELinux (see various comments)</p></li> <li><p><strong>Process-attached memory instead of filesystem (so a process crash removes the files)</strong> (originally intended by the question)</p> <ul> <li><p>don't let the file data reach PHP directly → <a href="https://stackoverflow.com/questions/5701508/storing-php-php-fpm-apaches-temporary-from-upload-files-in-ram-rather-than-the/5878263#5878263">reverse-proxy</a> (<em>Cal</em>)</p></li> <li><p>disable PHP writing to the filesystem → <a href="https://stackoverflow.com/questions/5701508/storing-php-php-fpm-apaches-temporary-from-upload-files-in-ram-rather-than-the/5867691#5867691">see PHP bug link in this answer</a> (<em>Stephan B</em>) or <a href="https://stackoverflow.com/questions/5701508/storing-php-php-fpm-apaches-temporary-from-upload-files-in-ram-rather-than-the/5877346#5877346">run PHP in CGI mode</a> (<em>Phil Lello</em>)</p></li> <li><p>write-only files → <a href="https://stackoverflow.com/questions/5701508/storing-php-php-fpm-apaches-temporary-from-upload-files-in-ram-rather-than-the/5904618#5904618"><code>/dev/null</code> filesystem</a> (<em>Phil Lello</em>) (this is useful if you have access to the data as a stream <em>additionally</em> but cannot turn off the file-writing functionality that runs in parallel; whether PHP allows this is unclear)</p></li> </ul></li> </ul> <h3>Re: your files, post-upload</h3> <ul> <li>storing in database instead of disc → <a href="https://stackoverflow.com/questions/5701508/storing-php-php-fpm-apaches-temporary-from-upload-files-in-ram-rather-than-the/5862044#5862044">file encryption in a database HowTo</a> (<em>Rook</em>)</li> </ul>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload