This swaps out url_format_string from all of our APIs and replaces it
with url_template. Note that the documentation changes in the following
commits will be squashed with this commit.
We change the "url_format" key to "url_template" for the
realm_linkifiers events in event_schema, along with updating
LinkifierDict. "url_template" is the name chosen to normalize
mixed usages of "url_format_string" and "url_format" throughout
the backend.
The markdown processor is updated to stop handling the format string
interpolation and delegate the task template expansion to the uri_template
library instead.
This change affects many test cases. We mostly just replace "%(name)s"
with "{name}", "url_format_string" with "url_template" to make sure that
they still pass. There are some test cases dedicated for testing "%"
escaping, which aren't relevant anymore and are subject to removal.
But for now we keep most of them as-is, and make sure that "%" is always
escaped since we do not use it for variable substitution any more.
Since url_format_string is not populated anymore, a migration is created
to remove this field entirely, and make url_template non-nullable since
we will always populate it. Note that it is possible to have
url_template being null after migration 0422 and before 0424, but
in practice, url_template will not be None after backfilling and the
backend now is always setting url_template.
With the removal of url_format_string, RealmFilter model will now be cleaned
with URL template checks, and the old checks for escapes are removed.
We also modified RealmFilter.clean to skip the validation when the
url_template is invalid. This avoids raising mulitple ValidationError's
when calling full_clean on a linkifier. But we might eventually want to
have a more centric approach to data validation instead of having
the same validation in both the clean method and the validator.
Fixes#23124.
Signed-off-by: Zixuan James Li <p359101898@gmail.com>
Supporting URL percent-encoded bytes is possible using `%%20`, but this
is not necessarily very understandable to end-users, even those that
understand percent encoding.
Allow `%20` in linkifier URL format strings, and transform them into
`%%20` in the pattern just before they are applied in markdown
translation. Care must be taken here, such that already-escaped `%`s
are not escaped an extra time.
We do this before rendering, and not before storage, as
a simplification; the JS-side linkifier at present only understands
`%(foo)s` and thus needs no changes, and to avoid an un-escaping pass
before showing in the admin UI.
User-supplied custom realm filter has had some sort of regex-based
validation of the format URL since their introduction in
d7e1e4a2c0 -- and this has always been
in addition to the URLValidator. The URLValidator is the one which
does the security-relevant work of validating that the schema is
reasonable, and that the overall shape of the URL is well-formed. The
regex has served primarily to arbitrary limit the characters that can
appear in the URL, in the mistaken name of safety.
Adjust the regex, such that its only purpose is to verify that the
usages of `%` characters in the URL are reasonable, and leave the URL
validation to the URLValidator, which can do a far better job. This
includes broadening the support to include `%%` as an escape
character; this is likely such a niche case as to be unnecessary, but
costs little.
Fixes#16013.
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 now validate the linkifier urls and patterns together, and add
the following additional checks:
1. All groups in the pattern must be used in the URL format string.
2. All groups in the URL format string must be declared in the pattern.
Linkifier pattern is now validated inside the `clean` method.
`filter_pattern_validator` is moved from `clean_fields` to `clean`
method as a safe check. As a result of this, a Puppeteer test case
is updated.
NOTE: The changes here are IN ADDITION to the existing validations.
Fixes#16482.
Co-authored-by: akshatdalton <akshat.dak@students.iiit.ac.in>
This commit adds an API to `zproject/urls.py` to edit/update
the realm linkifier. Its helper function to update the
database is added in `zerver/lib/actions.py`.
`zulip.yaml` is documented accordingly as well, clearly
stating that this API updates one linkifier at a time.
The tests are added for the API and helper function which
updates the realm linkifier.
Fixes#10830.
Use backend-endpoint function instead of helper function in
`test_realm_linkifiers.py` so that tests are more end-to-end.
The removed helper function: `do_add_linkifier` is tested in
`zerver/tests/test_events.py`.
Linkifier error message: `Filter not found` is
updated to `Linkifier not found.`.
Similarly, `filter_id` description is updated to:
`The ID of the linkifier that you want to remove.`,
renamed the term `filter` with `linkifier`, in `zulip.yaml`.
* This introduces a new event type `realm_linkifiers` and
a new key for the initial data fetch of the same name.
Newer clients will be expected to use these.
* Backwards compatibility is ensured by changing neither
the current event nor the /register key. The data which
these hold is the same as before, but internally, it is
generated by processing the `realm_linkifiers` data.
We send both the old and the new event types to clients
whenever the linkifiers are changed.
Older clients will simply ignore the new event type, and
vice versa.
* The `realm/filters:GET` endpoint (which returns tuples)
is currently used by none of the official Zulip clients.
This commit replaces it with `realm/linkifiers:GET` which
returns data in the new dictionary format.
TODO: Update the `get_realm_filters` method in the API
bindings, to hit this new URL instead of the old one.
* This also updates the webapp frontend to use the newer
events and keys.
This is a prep change to eventually completely
replace the term "filter" with "linkifier" in
the codebase.
This only renames files. Code changes will be
done in further commits.
Zixuan James Li
AcKindle3
Alex Vandiver
Rohitt Vashishtha
Abhijeet Prasad Bodas
akshatdalton