There are cases where a user can copy image markdown from a public
post (such as via the discourse-templates plugin) into a PM which
is then sent via an email. Since a PM is a secure context (via the
.with_secure_uploads? check on Post), the image will get a secure
URL in the PM post even though the backing upload is not secure.
This fixes the bug in that case where the image would be stripped
from the email (since it had a /secure-uploads/ URL) but not re-attached
further down the line using the secure_uploads_allow_embed_images_in_emails
setting because the upload itself was not secure.
The flow in Email::Sender for doing this is still not ideal, but
there are chicken and egg problems around when to strip the images,
how to fit in with other attachments and email size limits, and
when to apply the images inline via Email::Styles. It's convoluted,
but at least this fixes the Template use case for now.
This adds a new secure_uploads_pm_only site setting. When secure_uploads
is true with this setting, only uploads created in PMs will be marked
secure; no uploads in secure categories will be marked as secure, and
the login_required site setting has no bearing on upload security
either.
This is meant to be a stopgap solution to prevent secure uploads
in a single place (private messages) for sensitive admin data exports.
Ideally we would want a more comprehensive way of saying that certain
upload types get secured which is a hybrid/mixed mode secure uploads,
but for now this will do the trick.
16 bit images were not returning the correct dominant color due truncation
The routine expected an 8bit color eg: #FFAA00, but ended up getting a 16bit one eg: #FFFAAA000. This caused a truncation, which leads to wildly off colors.
The previous fix in e83d35d6 was incorrect, and the stub in the test was never actually hit. This commit moves the error handling to the right place and updates the specs to ensure the stub is always used.
These errors tend to indicate that the upload is missing on the remote store. This is bad, but we don't want it to block the dominant-color calculation process. This commit catches errors when there is an HTTP error, and fixes the `base_store.rb` implementation when `FileHelper.download` returns nil.
This commit renames all secure_media related settings to secure_uploads_* along with the associated functionality.
This is being done because "media" does not really cover it, we aren't just doing this for images and videos etc. but for all uploads in the site.
Additionally, in future we want to secure more types of uploads, and enable a kind of "mixed mode" where some uploads are secure and some are not, so keeping media in the name is just confusing.
This also keeps compatibility with the `secure-media-uploads` path, and changes new
secure URLs to be `secure-uploads`.
Deprecated settings:
* secure_media -> secure_uploads
* secure_media_allow_embed_images_in_emails -> secure_uploads_allow_embed_images_in_emails
* secure_media_max_email_embed_image_size_kb -> secure_uploads_max_email_embed_image_size_kb
The `add_column` `limit` parameter has no effect on a postgres `text` column. Instead we can perform the check in ActiveRecord.
We never expect this condition to be hit - users cannot control this value. It's just a safety net.
We previously had a system which would generate a 10x10px preview of images and add their URLs in a data-small-upload attribute. The client would then use that as the background-image of the `<img>` element. This works reasonably well on fast connections, but on slower connections it can take a few seconds for the placeholders to appear. The act of loading the placeholders can also break or delay the loading of the 'real' images.
This commit replaces the placeholder logic with a new approach. Instead of a 10x10px preview, we use imagemagick to calculate the average color of an image and store it in the database. The hex color value then added as a `data-dominant-color` attribute on the `<img>` element, and the client can use this as a `background-color` on the element while the real image is loading. That means no extra HTTP request is required, and so the placeholder color can appear instantly.
Dominant color will be calculated:
1. When a new upload is created
2. During a post rebake, if the dominant color is missing from an upload, it will be calculated and stored
3. Every 15 minutes, 25 old upload records are fetched and their dominant color calculated and stored. (part of the existing PeriodicalUpdates job)
Existing posts will continue to use the old 10x10px placeholder system until they are next rebaked
normalized_encode in addressable has a number of issues, including https://github.com/sporkmonger/addressable/issues/472
To temporaily work around those issues for the majority of cases, we try parsing with `::URI`. If that fails (e.g. due to non-ascii characters) then we will fall back to addressable.
Hopefully we can simplify this back to `Addressable::URI.normalized_encode` in the future.
This commit also adds support for unicode domain names and emoji domain names with escape_uri.
This removes an unneeded hack checking for pre-signed urls, which are now handled by the general case due to starting off valid and only being minimally normalized. Previous test case continues to pass.
UrlHelper.s3_presigned_url? which was somewhat wide was removed.
We do not zero-pad our base62 short URLs, so there is no guarantee that the length is 27. Instead, let's greedily match all consecutive base62 characters and look for a matching upload.
This reverts bd32656157 and 36f5d5eada.
This table holds associations between uploads and other models. This can be used to prevent removing uploads that are still in use.
* DEV: Create upload_references
* DEV: Use UploadReference instead of PostUpload
* DEV: Use UploadReference for SiteSetting
* DEV: Use UploadReference for Badge
* DEV: Use UploadReference for Category
* DEV: Use UploadReference for CustomEmoji
* DEV: Use UploadReference for Group
* DEV: Use UploadReference for ThemeField
* DEV: Use UploadReference for ThemeSetting
* DEV: Use UploadReference for User
* DEV: Use UploadReference for UserAvatar
* DEV: Use UploadReference for UserExport
* DEV: Use UploadReference for UserProfile
* DEV: Add method to extract uploads from raw text
* DEV: Use UploadReference for Draft
* DEV: Use UploadReference for ReviewableQueuedPost
* DEV: Use UploadReference for UserProfile's bio_raw
* DEV: Do not copy user uploads to upload references
* DEV: Copy post uploads again after deploy
* DEV: Use created_at and updated_at from uploads table
* FIX: Check if upload site setting is empty
* DEV: Copy user uploads to upload references
* DEV: Make upload extraction less strict
When changing upload security using `Upload#update_secure_status`,
we may not have the context of how an upload is being created, because
this code path can be run through scheduled jobs. When calling
update_secure_status, the normal ActiveRecord validations are run,
and ours include validating extensions. In some cases the upload
is created in an automated way, such as user export zips, and the
security is applied later, with the extension prohibited from
use when normally uploading.
This caused the upload to fail validation on `update_secure_status`,
causing the security change to silently fail. This fixes the issue
by skipping the file extension validation when the upload security
is being changed.
Due to default CSP web workers instantiated from CDN based assets are still
treated as "same-origin" meaning that we had no way of safely instansiating
a web worker from a theme.
This limits the theme system and adds the arbitrary restriction that WASM
based components can not be safely used.
To resolve this limitation all js assets in about.json are also cached on
local domain.
{
"name": "Header Icons",
"assets" : {
"worker" : "assets/worker.js"
}
}
This can then be referenced in JS via:
settings.theme_uploads_local.worker
local_js_assets are unconditionally served from the site directly and
bypass the entire CDN, using the pre-existing JavascriptCache
Previous to this change this code was completely dormant on sites which
used s3 based uploads, this reuses the very well tested and cached asset
system on s3 based sites.
Note, when creating local_js_assets it is highly recommended to keep the
assets lean and keep all the heavy working in CDN based assets. For example
wasm files can still live on the CDN but the lean worker that loads it can
live on local.
This change unlocks wasm in theme components, so wasm is now also allowed
in `theme_authorized_extensions`
* more usages of upload.content
* add a specific test for upload.content
* Adjust logic to ensure that after upgrades we still get a cached local js
on save
It's very easy to forget to add `require 'rails_helper'` at the top of every core/plugin spec file, and omissions can cause some very confusing/sporadic errors.
By setting this flag in `.rspec`, we can remove the need for `require 'rails_helper'` entirely.
When secure media is enabled or when upload secure status
is updated, we also try and update the upload ACL. However
if the object storage provider does not implement this we
get an Aws::S3::Errors::NotImplemented error. This PR handles
this error so the update_secure_status method does not error
out and still returns whether the secure status changed.
Discourse shouldn't dynamically calculate the path of uploads and optimized images after a file has been stored on disk or S3. Otherwise it might calculate the wrong path if the SHA1 or extension stored in the database doesn't match the actual file path.
This PR adds security_last_changed_at and security_last_changed_reason to uploads. This has been done to make it easier to track down why an upload's secure column has changed and when. This necessitated a refactor of the UploadSecurity class to provide reasons why the upload security would have changed.
As well as this, a source is now provided from the location which called for the upload's security status to be updated as they are several (e.g. post creator, topic security updater, rake tasks, manual change).
Upload.secure_media_url? raised an exceptions when the URL was invalid,
which was a issue in some situations where secure media URLs must be
removed.
For example, sending digests used PrettyText.strip_secure_media,
which used Upload.secure_media_url? to replace secure media with
placeholders. If the URL was invalid, then an exception would be raised
and left unhandled.
Now instead in UrlHelper.rails_route_from_url we return nil if there is something wrong with the URL.
Co-authored-by: Bianca Nenciu <nenciu.bianca@gmail.com>
Extracted commonly used spec helpers into spec/support/uploads_helpers.rb, removed unused stubs and let definitions. Makes it easier to write new S3-related specs without copy and pasting setup steps from other specs.
There is an fk to user_profile that can make destroying uploads fail
if they happen to be set as user profile.
This ensures we clear this information when destroying uploads.
There are more relationships, but this makes some more progress.
* When copying the markdown for an image between posts, we were not adding the srcset and data-small-image attributes which are done by calling optimize_image! in cooked post processor
* Refactored the code which was confusing in its current state (the consider_for_reuse method was super confusing) and fixed the issue
If the “secure media” site setting is enabled then ALL files uploaded to Discourse (images, video, audio, pdf, txt, zip etc. etc.) will follow the secure media rules. The “prevent anons from downloading files” setting will no longer have any bearing on upload security. Basically, the feature will more appropriately be called “secure uploads” instead of “secure media”.
This is being done because there are communities out there that would like all attachments and media to be secure based on category rules but still allow anonymous users to download attachments in public places, which is not possible in the current arrangement.
* Attachments (non media files) were being marked as secure if just
SiteSetting.prevent_anons_from_downloading_files was enabled. this
was not correct as nothing should be marked as actually "secure" in
the DB without that site setting enabled
* Also add a proper standalone spec file for the upload security class
Further on from my earlier PR #8973 also reject upload as secure if its origin URL contains images/emoji. We still check Emoji.all first to try and be canonical.
This may be a little heavy handed (e.g. if an external URL followed this same path it would be a false positive), but there are a lot of emoji aliases where the actual Emoji url is something, but you can have another image that should not be secure that that thing is an alias for. For example slight_smile.png does not show up in Emoji.all BUT slightly_smiling_face does, and it aliases slight_smile e.g. /images/emoji/twitter/slight_smile.png?v=9 and /images/emoji/twitter/slightly_smiling_face.png?v=9 are equivalent.
Sometimes PullHotlinkedImages pulls down a site emoji and creates a new upload record for it. In the cases where these happen the upload is not created via the normal path that custom emoji follows, so we need to check in UploadSecurity whether the origin of the upload is based on a regular site emoji. If it is we never want to mark it as secure (we don't want emoji not accessible from other posts because of secure media).
This only became apparent because the uploads:ensure_correct_acl rake task uses UploadSecurity to check whether an upload should be secure, which would have marked a whole bunch of regular-old-emojis as secure.
* Because custom emoji count as post "uploads" we were
marking them as secure when updating the secure status for post uploads.
* We were also giving them an access control post id, which meant
broken image previews from 403 errors in the admin custom emoji list.
* We now check if an upload is used as a custom emoji and do not
assign the access control post + never mark as secure.
Basically, say you had already downloaded a certain image from a certain URL
using pull_hotlinked_images and the onebox. The upload would be stored
by its sha as an upload record. Whenever you linked to the same URL again
in a post (e.g. in our case an og:image on review.discourse) we would
would reuse the original upload record because of the sha1.
However when you turned on secure media this could cause problems as
the first post that uses that upload after secure media is enabled
will set the access control post for the upload to the new post.
Then if the post is deleted every single onebox/link to that same image
URL will fail forever with 403 as the secure-media-uploads URL fails
if the access control post has been deleted.
To fix this when cooking posts and pulling hotlinked images, we only
allow using an original upload by URL if its access control post
matches the current post, and if the original_sha1 is filled in,
meaning it was uploaded AFTER secure media was enabled. otherwise
we just redownload the media again to be safe, as the URL will always
be new then.
### General Changes and Duplication
* We now consider a post `with_secure_media?` if it is in a read-restricted category.
* When uploading we now set an upload's secure status straight away.
* When uploading if `SiteSetting.secure_media` is enabled, we do not check to see if the upload already exists using the `sha1` digest of the upload. The `sha1` column of the upload is filled with a `SecureRandom.hex(20)` value which is the same length as `Upload::SHA1_LENGTH`. The `original_sha1` column is filled with the _real_ sha1 digest of the file.
* Whether an upload `should_be_secure?` is now determined by whether the `access_control_post` is `with_secure_media?` (if there is no access control post then we leave the secure status as is).
* When serializing the upload, we now cook the URL if the upload is secure. This is so it shows up correctly in the composer preview, because we set secure status on upload.
### Viewing Secure Media
* The secure-media-upload URL will take the post that the upload is attached to into account via `Guardian.can_see?` for access permissions
* If there is no `access_control_post` then we just deliver the media. This should be a rare occurrance and shouldn't cause issues as the `access_control_post` is set when `link_post_uploads` is called via `CookedPostProcessor`
### Removed
We no longer do any of these because we do not reuse uploads by sha1 if secure media is enabled.
* We no longer have a way to prevent cross-posting of a secure upload from a private context to a public context.
* We no longer have to set `secure: false` for uploads when uploading for a theme component.
When uploading a file to a theme component, and that file is existing and has already been marked as secure, we now automatically mark the file as secure: false, change the ACL, and log the action as the user (also rebake the posts for the upload)
This PR introduces a new secure media setting. When enabled, it prevent unathorized access to media uploads (files of type image, video and audio). When the `login_required` setting is enabled, then all media uploads will be protected from unauthorized (anonymous) access. When `login_required`is disabled, only media in private messages will be protected from unauthorized access.
A few notes:
- the `prevent_anons_from_downloading_files` setting no longer applies to audio and video uploads
- the `secure_media` setting can only be enabled if S3 uploads are already enabled and configured
- upload records have a new column, `secure`, which is a boolean `true/false` of the upload's secure status
- when creating a public post with an upload that has already been uploaded and is marked as secure, the post creator will raise an error
- when enabling or disabling the setting on a site with existing uploads, the rake task `uploads:ensure_correct_acl` should be used to update all uploads' secure status and their ACL on S3
