On 02/01/2012 03:41 PM, Cory Spencer wrote:
Hi Dannon and thanks for the response!
I can see the need to sanitize incoming HTTP request parameters that may have malicious
content. However, I'm unclear as to why this also needs to happen for HTML pages
outputted by the Galaxy tools? If they have been generated with sanitized HTTP request
parameters, is there still a risk of an XSS attack?toolbox
With Galaxy's toolbox
at hand you could generate invalid HTML from plain
text components. A simple example, but consider the following:
Upload one plain text file with the content:
Another one with:
And finally one with:
Taken individually they're meaningless, but run the concatenate datasets
tool to reassemble that into:
Change the type of this dataset to html and there's your attack. If you
tried to upload this, we'd interpret it as malicious HTML and discard
it. As separate datasets, it's impossible to tell. Given Galaxy's
powerful text manipulation tools you could write just about whatever you
wanted using Galaxy itself and get it in the system as a (seemingly)
valid tool-generated dataset. Now, with the outbound sanitation on any
dataset served as "text/html" it doesn't matter and it gets handled
prior to serving.
Another option we discussed would be to trust all tool generated HTML,
disallow changing the datatype of anything *to* html, and so on, but
that approach comes with its own problems.
If anything, would it be possible to make this sort of sanitization controllable via a
configuration file option?
I'm rather hesitant to put in a disable option for a security feature,
though you're more than welcome to pop those two lines out of your
instance. I think the best path forward is probably relaxing the filter
a bit, the initial pass was somewhat draconian. Would relaxing the
filter to allow style content to pass through work for your needs?
On 2012-02-01, at 12:01 PM, Dannon Baker wrote:
> Hi Cory,
> The new call to sanitize_html was introduced to more effectively prevent malicious
content and possible XSS attacks, though I can't think off the top of my head why we
couldn't allow style content. I'll see what I can do about relaxing the filter a
> On 01/30/2012 10:33 PM, Cory Spencer wrote:
>> Hello all -
>> One of the Galaxy tools I've been developing generates HTML output which
I'd styled using a<style>...</style> tag in the HTML header. After
updating to the latest Galaxy release earlier today,
the<html>,<head>...</head>,<style> and<body> tags
started to get stripped from the output, rendering previously CSS styled output rather
>> Delving into things, I noticed a change committed in December that sanitizes the
output for HTML files via a call to "sanitize_html":
>> The added lines 381 -> 383 in the new file appear to be causing this new
>> Is there any option for making this optional? What was the rational behind
stripping out these tags on outputted HTML files?
>> Thanks for any help!
>> Cory Spencer
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and other Galaxy lists, please use the interface at: