The `TruncateHTMLParser` used `deque.remove()` to remove tags from the
stack when processing end tags. With crafted input containing many
unmatched end tags, this caused repeated full scans of the tag stack,
leading to quadratic time complexity.
The fix uses LIFO semantics, only removing a tag from the stack when it
matches the most recently opened tag. This avoids linear scans for
unmatched end tags and reduces complexity to linear time.
Refs #30686 and 6ee37ada32.
Thanks Seokchan Yoon for the report, and Jake Howard and Jacob Walls for
reviews.
Moved nonce generation in ``django.utils.csp.LazyNonce`` to a function
to avoid infinite recursion in ``SimpleLazyObject.__repr__`` for
unevaluated instances.
Co-authored-by: Natalia <124304+nessita@users.noreply.github.com>
This partially reverts commit 9aabe7eae3.
The simplification of parse_header_parameters using stdlib's Message
is reverted due to a performance regression. The check for the header
maximum length remains in place, per Security Team guidance.
Thanks to David Smith for reporting the regression, and Jacob Walls for
the review.
Introduced `{% partialdef %}` and `{% partial %}` template tags to
define and render reusable named fragments within a template file.
Partials can also be accessed using the `template_name#partial_name`
syntax via `get_template()`, `render()`, `{% include %}`, and other
template-loading tools.
Adjusted `get_template()` behavior to support partial resolution, with
appropriate error handling for invalid names and edge cases. Introduced
`PartialTemplate` to encapsulate partial rendering behavior.
Includes tests and internal refactors to support partial context
binding, exception reporting, and tag validation.
Co-authored-by: Carlton Gibson <carlton@noumenal.es>
Co-authored-by: Natalia <124304+nessita@users.noreply.github.com>
Co-authored-by: Nick Pope <nick@nickpope.me.uk>
This initial work adds a pair of settings to configure specific CSP
directives for enforcing or reporting policy violations, a new
`django.middleware.csp.ContentSecurityPolicyMiddleware` to apply the
appropriate headers to responses, and a context processor to support CSP
nonces in templates for safely inlining assets.
Relevant documentation has been added for the 6.0 release notes,
security overview, a new how-to page, and a dedicated reference section.
Thanks to the multiple reviewers for their precise and valuable feedback.
Co-authored-by: Natalia <124304+nessita@users.noreply.github.com>
Thanks to Elias Myllymäki for the report, and Shai Berger and Jake
Howard for the reviews.
Co-authored-by: Natalia <124304+nessita@users.noreply.github.com>
The `parse_header_parameters` function historically used Python's `cgi`
module (now deprecated). In 34e2148fc7,
the logic was inlined to work around this deprecation ( #33173). Later,
in d4d5427571, the header parsing logic
was further cleaned up to align with `multipartparser.py` (#33697).
This change takes it a step further by replacing the copied `cgi` logic with
Python's `email.message.Message` API for a more robust and maintainable header
parsing implementation.
Thanks to Raphael Gaschignard for testing, and to Adam Johnson and Shai
Berger for reviews.
Co-authored-by: Ben Cail <bcail@crossway.org>
Co-authored-by: Natalia <124304+nessita@users.noreply.github.com>
Removed obsolete and potentially problematic IDNA 2003 ("punycode")
encoding of international domain names in smart_urlquote() and Urlizer,
which are used (only) by AdminURLFieldWidget and the urlize/urlizetrunc
template filters. Changed to use percent-encoded UTF-8, which defers
IDNA details to the browser (like other URLs rendered by Django).
Thanks Saravana Kumar for the report, and Sarah Boyce and Mariusz
Felisiak for the reviews.
Co-authored-by: Natalia <124304+nessita@users.noreply.github.com>
To use the simple `filename="..."` form, the value must conform to the
official grammar from RFC6266[^1]:
filename-parm = "filename" "=" value
value = <value, defined in [RFC2616], Section 3.6>
; token | quoted-string
The `quoted-string` definition comes from RFC 9110[^2]:
```
quoted-string = DQUOTE *( qdtext / quoted-pair ) DQUOTE
qdtext = HTAB / SP / %x21 / %x23-5B / %x5D-7E / obs-text
The backslash octet ("\") can be used as a single-octet quoting
mechanism within quoted-string and comment constructs. Recipients that
process the value of a quoted-string MUST handle a quoted-pair as if
it were replaced by the octet following the backslash.
quoted-pair = "\" ( HTAB / SP / VCHAR / obs-text )
A sender SHOULD NOT generate a quoted-pair in a quoted-string except
where necessary to quote DQUOTE and backslash octets occurring within
that string.
```
That is, quoted strings are able to express horizontal tabs, space
characters, and everything in the range from 0x21 to 0x7e, expect for
0x22 (`"`) and 0x5C (`\`), which can still be expressed but must be
escaped with their own `\`.
We ignore the case of `obs-text`, which is defined as the range
0x80-0xFF, since its presence is there for permissive parsing of
accidental high-bit characters, and it should not be generated by
conforming implementations.
Transform this character range into a regex and apply it in addition
to the "is ASCII" check. This ensures that all simple filenames are
expressed in the simple format, and that all filenames with newlines
and other control characters are properly expressed with the
percent-encoded `filename*=...`form.
[^1]: https://datatracker.ietf.org/doc/html/rfc6266#section-4.1
[^2]: https://datatracker.ietf.org/doc/html/rfc9110#name-quoted-strings
Urlizer was not properly encoding email addresses containing punctuation
in generated mailto links. Per RFC 6068, fixed by percent encoding
(urllib.parse.quote) the local and domain address parts.
Over the years we've had multiple instances of hit and misses when
emitting warnings: either setting the wrong stacklevel or not setting
it at all.
This work adds assertions for the existing warnings that were declaring
the correct stacklevel, but were lacking tests for it.
