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.
This fixes the issue where 'None' would appear in the rendered
html in case of a missing tab display_name. Now,
'test-help-documentation' will fail in case of any tab display_name
being missing.
In case of a tab_section with no tabs, currently a single tab with
the name 'null_tab' gets added. Added the display name 'None' for
'null_tab', to keep in line with the existing behaviour.
Fixes#19822
Recently, we discovered that our settings_tab/relative Markdown
directives didn't work when they were in a macro that was included
in another Markdown file. Note that without this commit, the
/help/create-your-organization-profile page is broken. This commit
changes the respective priorities of these two extensions such that
these directives are rendered *after* the macro is included in
another file.
Thanks to Alya Abbott for reporting this bug!
All of our custom Markdown extensions have priorities that govern
the order in which the preprocessors will be run. It is more
convenient to have these all in one file so that you can easily
discern the order at first glance.
Thanks to Alya Abbott for reporting the bug that led to this
refactoring!
This check was copied from upstream python-markdown's "safe mode"
before they removed that feature. The upstream history is that they
introduced this check in
2db5d1c8e4,
which was not a complete security check, and then added the
immediately following check (with an allowlist of schemes) in
0b4ffbb60e.
Their first, incomplete check provides no security benefit and makes
the code hard to reason about, so we remove it.
This adds the X-Smokescreen-Role header to proxy connections, to track
usage from various codepaths, and enforces a timeout. Timeouts were
kept consistent with their previous values, or set to 5s if they had
none previously.
This commits removes some unnecessary checks for `self.md.zulip_message`,
which were put there historically, as earlier we used to add the additional
properties like mentions_user_ids, alert_words, etc. to Message dict
only. These were later moved to MessageRenderingResult class in commit
75cea329b but the checks weren't removed.
This is important because while rendering the messages imported from
other chat tools (like Rocket.Chat), the Message dict is not passed to
the markdown, due to which the checks for `self.md.zerver_message` fails
and hence, things like user mentions, stream/topic mentions are not
rendered in the imported messages properly.
These changes are all independent of each other; I just didn’t feel
like making dozens of commits for them.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
This way we can stop reading as soon as we get to the body. Also,
send an Accept header, check that the request was actually successful,
use lxml.etree.iterparse instead of a broken hand-rolled state
machine, and support XHTML, all for negative 28 lines of code.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
This reverts commit 1965584eec.
This syntax has a bad interaction with table syntax and needs to be
rethought.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
This is more efficient than get_lexer_by_name, since we don’t need to
instantiate the class just to get its name.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
The absence of __init__.py was preventing mypy from following any of
the zerver.openapi imports. These errors were being silenced by
ignore_missing_imports.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
As we have changed the tab selector above from "Settings" to "Personal
settings", we can simply change "Your bots" to "Bots" as "Bots" is
clear enough given the personal settings context.
We also need to update the API documentation for bots accordingly.
This commit fixes the documentation of settings as we have
replaced "Your account" section into two new sections -
"Profile" and "Account & privacy".
This commit also fixes a comment in the test for settings
documentation in test_middleware.py.
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
Currently, the message that no parameters are accepted by
the endpoint is displayed if there are no parameters in
OpenAPI data, but it is possible that information is
encoded in x-parameter-description (example in upload-file
endpoint), and we want to display that information rather
than the message.
Added an if condition to check the same.
The headings for return values were currently hardcoded
in cases where they occur, but they can be rendered directly
in the markdown extension if the return values exist.
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>
Alya Abbott
Alex Vandiver
Pradyumna Sinha
Kevin Scott
Eeshan Garg
Mateusz Mandera
Tim Abbott
rht
Anders Kaseorg
Priyansh Garg
Ganesh Pawar
akshatdalton
sahil839
PIG208
Suyash Vardhan Mathur
Wesley Aptekar-Cassels