From: Thomas Lamprecht <t.lamprecht@proxmox.com>
To: Dominik Csapak <d.csapak@proxmox.com>, pmg-devel@lists.proxmox.com
Subject: [pmg-devel] applied: [PATCH pmg-api v2] fix #3734: scrub 'url' from style tags/attributes
Date: Fri, 26 Nov 2021 10:07:08 +0100 [thread overview]
Message-ID: <b71d6b96-2265-4be3-0371-fcb524138e47@proxmox.com> (raw)
In-Reply-To: <20211125141441.1383250-1-d.csapak@proxmox.com>
On 25.11.21 15:14, Dominik Csapak wrote:
> if 'view images' for the quarantine is disabled, it is expected that
> *no* images will be loaded. but in addition to img (src/href/etc.)
> also css can load external images via the 'url' directive
>
> since html scrubber does not parse/iterate over css, we simply remove
> the url+protocol part of those tags/attributes. this technically leaves behind
> invalid css, but the browsers should cope with that.
> (we cannot 'cleanly' remove without much more effort because of quoting)
>
> also we have to scrub the style tags in 'dump_html' since HTML::Scrubber
> does not have a way to modify the *content* of a tag, only the
> attributes...
>
> Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
> ---
> changes from v1:
> * replace url with ___ and protocol:// with _ instead of removing
> * move sub out and use the reference
> * always pass $cid_hash and only use it in the function when
> $view_images is set
> * improve comment to show what 'dump_html' does
>
> @thomas: a note to our off-list discussion regarding url-encoding the
> protocol: you *could* do it, but the browser does not recognize it as
> a protocol and interprets it as a relative url, so we're safe on
> this regard
>
> src/PMG/HTMLMail.pm | 31 +++++++++++++++++++++++++++----
> 1 file changed, 27 insertions(+), 4 deletions(-)
>
>
ok, so I went down the wrong road due to the code-ref passing, ref(\foo) being
SCALAR vs \&foo being CODE tripped up the scrubber.
So after a pair debugging/understanding session with Dominik (thx!) I now:
* appreciate our perl code way more, as Scrubber shows that one can do it way
more cryptic and harder to grasp
* got that the style stuff now works pretty great, I only fixed the undef value
variant for the url remover and passing the code-ref
applied, thanks!
prev parent reply other threads:[~2021-11-26 9:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-25 14:14 [pmg-devel] " Dominik Csapak
2021-11-25 17:26 ` Thomas Lamprecht
2021-11-26 7:28 ` Thomas Lamprecht
2021-11-26 7:51 ` Dominik Csapak
2021-11-26 9:07 ` Thomas Lamprecht [this message]
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