Zulip attempts to validate that the regular expressions that admins
enter for linkifiers are well-formatted, and only contain a specific
subset of regex grammar. The process of checking these
properties (via a regex!) can cause denial-of-service via
backtracking.
Furthermore, this validation itself does not prevent the creation of
linkifiers which themselves cause denial-of-service when they are
executed. As the validator accepts literally anything inside of a
`(?P<word>...)` block, any quadratic backtracking expression can be
hidden therein.
Switch user-provided linkifier patterns to be matched in the Markdown
processor by the `re2` library, which is guaranteed constant-time.
This somewhat limits the possible features of the regular
expression (notably, look-head and -behind, and back-references);
however, these features had never been advertised as working in the
context of linkifiers.
A migration removes any existing linkifiers which would not function
under re2, after printing them for posterity during the upgrade; they
are unlikely to be common, and are impossible to fix automatically.
The denial-of-service in the linkifier validator was discovered by
@erik-krogh and @yoff, as GHSL-2021-118.
We do not allow mentioning system user groups for now
because this can lead to circumventing the wildcard
mention restrictions. It will be enabled once we add
a setting to control that.
This is implemented by just ignoring it as one of the
mentioned user group even if the message content
inlcudes the mention syntax for it and the message
is sent normally.
We still keep the for_mention parameter for accessing
user group while sending email and push notifications
as mentioning system user groups will be allowed in
future.
This commit also removes the test for email notifications
for system user groups as we are not allowing mentioning
them.
This commit is only for backend change as we already
exclude the system groups from mention typeaheads and
other UI.
This adds a new class called MessageRenderingResult to contain the
additional properties we added to the Message object (like alert_words)
as well as the rendered content to ensure typesafe reference. No
behavioral change is made except changes in typing.
This is a preparatory change for adding django-stubs to the backend.
Related: #18777
This should help with #17425, where messages with lots of LaTeX are
lost, due to the large expansion factor.
This isn't a total fix for this - large messages with lots of LaTeX
can still end up larger than 1MB, and rendering could timeout, but
this fix should help significantly.
1MB is still small enough that I don't expect we'll run into any DOS
problems - my testing didn't show any problems rendering messages that
contain ~1MB of LaTeX.
This will offer users who are self-hosting to adjust
this value. Moreover, this will help to reduce the
overall time taken to test `test_markdown.py` (since
this can be now overridden with `override_settings`
Django decorator).
This is done as a prep commit for #18641.
?dl=1 causes Dropbox to send Content-Type: application/binary, which
can’t be interpreted by Camo. Use ?raw=1 instead.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Prior to this, we only supported direct mention to
the user groups. This commit extends that support
to silent mention for the user groups.
A related test case is also added.
Fixes: #11711.
A message containing wildcard mention when quoted (which
is turned into a silent mention) or message with silent
wildcard mention notifies the users by sending desktop,
sound, and missed message email notifications. This
is clearly a bug which is fixed by this commit.
Fixes: #18354.
Requesting external images is a privacy risk, so route all external
images through Camo.
Tweaked by tabbott for better test coverage, more comments, and to fix
bugs.
Changed the name of the test-user cordelia from `Cordelia Lear` to
`Cordelia, Lear's daughter`.
This change will enable us to test users with escape characters in
their names.
I also updated the Node, Puppeteer, Backend tests and Fixtures to
support this change.
This logic likely never ran due to a combination of bugs.
* Running `maybe_update_markdown_engines` unconditionally meant that
`if md_engine_key in md_engines` was likely always true.
* Introduced in 65838bb: DEFAULT_MARKDOWN_KEY could never be in
md_engines, so should we have ever reached that code path, we'd have
tried to rebuild all markdown engines every time.
And it also wasn't clearly helpful -- because we fetch all linkifiers
for a realm on every request anyway, we don't really save database
queries by doing a bulk fetch on startup, and doing so would likely
result in a material regression to Zulip's overall startup time that
we were creating markdown engines for large numbers of realms in bulk
during process startup.
This adds the is_user_active with the appropriate code for setting the
value correctly in the future. In the following commit a migration to
backfill the value for existing Subscriptions will be added.
To ensure correct user_profile.is_active handling also in tests, we
replace all direct .is_active mutation with calls to appropriate
functions.
Backend logic for handling user mention was cluttered
because it was handled at two stages first in
get_possible_mentions_info while fetching mention data
based on the messsage and then later in UserMentionPattern
which handles processing of text for mention.
Ideally UserMentionPattern should depend on
get_possible_mentions_info only for data but there was a
shared logic between these two that made it hard to debug
any possible bugs.
Updates in this commit make both of these functions
coherent in terms of logic and also add appropiate
comments to improve readability of these functions.
There was also a hidden bug that if a user A is
mentioned in with @**name|id** then @**invalid|id**
again mentioned A because of the way we handled mentions
earlier. It is solved as a result of this refactor and
appropiate test has been added for this.
This has been tested manually as well as by adding new
test to address missing case.
Extend our markdown system to support mentioning of users
by id also. Following these changes, it would be possible
to mention users with @**|user_id** and silently mention
using @_**|user_id**.
Main intention for extending the mention syntax is to make
it convenient for bots to mention a users using their ids. It
is to be noted that previous syntax are also supported.
Documentation tweaked by tabbott for better readability.
The changes were tested manually in development server, and also
by adding some new backend and frontend tests.
Fixes: #17487.
Modifies `StreamPattern` and `StreamTopicPattern` to inherit
from InlineProcessor instead of Pattern. This change is done
because Pattern stopped checking for matching patterns as soon
as it found a match which was not a valid stream. Due to this
all the subsequent mention failed, even if they were valid.
This bug was only present in backend renderring due to
markdown.inlinepatterns.Pattern.
Due to above changes verbose_compile is no longer used for
precompiling STREAM_LINK_REGEX, STREAM_TOPIC_LINK_REGEX as
adds ^(.*?) and (.*?)$ which cause extra overhead of matching
pattern which is not required. With new InlineProcessor these
extra patterns at beggining and end are not required.
So, StreamPattern and StreamTopicPattern now define their own
__init__ method for precompiling the regex.
Fixes#17535.
These changes were tested locally in dev server and by adding
some new markdown tests to test these.
Modifies `UserGroupMentionPattern` to inherit from InlineProcessor
instead of Pattern. This change is done because Pattern
stopped checking for matching patterns as soon as it found
a match which was not a valid user group. Due to this all
the subsequent user group mention failed, even if they were
valid. This bug was only present in backend renderring due to
markdown.inlinepatterns.Pattern.
This was reported as issue #17535.
These changes were tested locally in dev server and by adding
some new markdown tests to test these.
Modifies `UserMentionPattern` to inherit from InlineProcessor
instead of Pattern. This change is done because Pattern
stopped checking for matching patterns as soon as it found
a match which was not a valid user. Due to this all the
subsequent user mention failed. This bug was only present in
backend renderring due to markdown.inlinepatterns.Pattern.
This was reported as issue #17535.
These changes were tested locally in dev server and by adding
some new markdown tests to test these.
Initally, when writing two or more quotes, having
a blank line in between them, merges those quotes.
This created confusion especially in "quote and reply".
This commit fixes such issues. Now two or more quotes
having a blank line in between them, will not get merged.
This change is correct both for usability and for improving our
compatibility with CommonMark.
Fixes#14379.
Upstream has slightly changed the whitespace around stashes. Take
this opportunity to clean up the extra blank lines we were outputting.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
If multiple filters match the same string, we run into an infinite
loop of converting string into urls. To fix it, we mark the matched
string as atomic after first conversion.
When converting fenced code markdown, we add the language (if specified)
in a data-attribute by tweaking the HTML generated. Doing so, allows the
frontend to make use of this attr to display view-in-playground option
for codeblocks.
We use pygments to get the lexer subclass name and use that instead of
directly using the language in the data-attribute. Doing so, helps us
map different language aliases (like `js` and `javascript`) into a common
variable (like `JavaScript`) - and avoids the client from dealing with
multiple tags corresponding to the same language.
The html structure for a message like this:
``` js
..content..
```
would now be:
<div class="codehilite" data-codehilite-language="JavaScript">
<pre>..content..</pre>
</div>
Tests and fixtures amended.
Alex Vandiver
Sahil Batra
Dinesh
Anders Kaseorg
Mateusz Mandera
PIG208
akshatdalton
Wesley Aptekar-Cassels
Abhijeet Prasad Bodas
Arun Sankar
Tim Abbott
Sumanth V Rao
shanukun
m-e-l-u-h-a-n
Aman Agrawal
palash
Mohit Gupta