Chuck, Thanks for the feedback, it's good to know others are interested in CSP.
I've created a doc to capture the proposal in a little more detail, and allow for more robust comments: https://docs.google.com/document/d/1sfFs6LB1_giodyR4QwBMQssLKP_UxACZifk-VYVX2T8/edit?usp=sharing In that doc, I've attempted to address the questions/comments both from your email, as well as Michal's earlier response. I'll let all interested parties continue the conversation in the doc. Thanks, Jason On 20 February 2015 at 10:54, Chuck Lantz <cla...@microsoft.com> wrote: > Hey Jason - Glad to see this proposal! A number of us at Microsoft have > been talking along these same lines actually. Windows 10 apps will include > CSP support as the latest version of IE has support so I'd say we're > completely in support of moving Cordova apps down this path. In fact I'd > want to make sure that any CSP related metadata tag injection also applied > to the Windows platform as well. > > A few of thoughts: > > 1. I definitely know there is quite a bit of interest still in being able > to enable hosted (https accessed and controlled by the developer) app > content access Cordova device APIs (which is currently a shortcoming of > Windows 8.0/8.1 apps so we hear about it quite a bit). As a result, we'll > want to be sure Cordova doesn't inhibit this use case at a base level. > That said, having a default CSP policy that restricts hosted in the > template is fine and would promote secure practices since you need to > exercise caution when mixing in any remote content even when you control it > completely. Also agree with inline being high risk. > > 2. Re: Long term, one thing that CSP doesn't cover well is which URIs > should be granted elevated device access. Given hosted content with plugin > device API access is still a scenario we'll need to consider, perhaps we > should consider using the config.xml <access> element to represent URIs > that have device API access (beyond standard browser access). Otherwise we > get into a bit of an "all or nothing" situation as it pertains to hosted > app content which poses a larger security risk if you opt to extend device > API access beyond local content. (It also strikes me this is a general gap > in the web standard as a whole.) > > 3. Eval is actually a bit tougher - I know when we've look at this in the > past it impacted JS frameworks far more than inline did. (Ex: With Angular > you can stop using eval but you take a perf hit which is a bigger deal on > mobile than desktop.) Definitely the most secure practice - but it also > could cause the default template to appear to "not work." If we omit the > "unsafe-eval" directive in the CSP policy in the template we'll want to be > crystal clear on how to alter it. That could be solved with proper > documentation and blog posts though. > > 4. I'd suggest we also consider the new "browser" platform here since > Chrome/Firefox/IE (as of Win 10) have support. Should be "free", but I'm > guessing the metadata tag injection you mention is something we could > probably just do all-up rather than only for specific platforms. > > -Chuck > > -----Original Message----- > From: mmo...@google.com [mailto:mmo...@google.com] On Behalf Of Michal > Mocny > Sent: Thursday, February 19, 2015 2:25 PM > To: dev > Subject: Re: Proposal for CSP support > > Thanks for this clear outline. > > Jason, I know you've been working on the short-term items for a while as > part of your investigation, fixing things as you went -- what is the > current state of CSP support in platforms / plugins? What portion already > has fixes (or PR for them), what work is known but undone, and what hasn't > been investigated much at all? > > -Michal > > On Thu, Feb 19, 2015 at 4:55 PM, Jason Chase <cha...@chromium.org> wrote: > > > I'm interested in full-blown support for CSP (Content Security Policy) > > in Cordova. While we're close to having new and improved whitelist > > functionality, there are gaps in what the whitelist is able to protect > > against. In particular, inline script and eval() are higher risks that > > are not addressed by whitelists. > > > > Many Cordova apps may use only static content, or not include any > > third-party content. However, there are certainly examples of apps > > that need to include user input/third-party content, mixed with the > > app's own HTML content. In some cases, platforms may even restrict > > functionality (see [1]). I think CSP is a compelling answer for these > > scenarios, and for security in general for apps. > > > > Assuming CSP support is valuable, the question is how to implement? > > Support for CSP is not universal across platforms. It is known to be > > supported on Android (KitKat and later), iOS (since 7.1), and Firefox. > > Where supported, it is typically via a HTTP response header, or a META > > tag in the document. > > > > I've done some investigation into feasible approaches. As a result, > > I'm proposing as below. > > > > Long term goal: > > Cordova supports CSP in apps *and* plugins, and is enabled/secure by > > default. Ideally, CSP rules can be configurable and automatically > > applied to all content (i.e. so developers can fall into the pit of > > success) > > > > Achieving this goal will likely require incremental progress over a > > number of releases. At a high level, first make changes so developers > > can manually apply CSP to their apps. Longer term, add support for > > configurability and automatic application of CSP. > > > > Short term plan: > > - Change new app template to contain CSP meta tag with a default, > > secure policy (i.e. no inline script, eval(), only local app content) > > - Remove any blockers to default policy from framework and core plugins. > > This would be a continuation of the work in CB-8210, applied to other > > platforms. For example, this would fix any framework code that relies > > on sending javascript to be executed inline, from the native side > > - Deprecate any framework APIs that allow less secure practices. Many > > already are marked as deprecated (at least on Android) > > - Update docs/samples to include CSP, and clearly state that use of > > inline javascript is deprecated > > > > Long term plan: > > - In a future major release, remove the previously deprecated > > framework APIs > > - Define/implement a configuration model for CSP rules > > - Implement a build/package step to apply configured CSP rules to all > > content as meta tags. Run-time support involves re-writing content, > > and/or intercepting resource requests. The feasibility of > > intercepting requests is highly variable across platforms, at greater > > cost/complexity than build-time. > > > > I'm very interested in any comments on this proposal. This includes > > questions around use cases (missing or otherwise), different > > requirements, technical concerns, .etc. > > > > Thanks, > > Jason > > Google Cordova Team > > > > [1] http://callback.markmail.org/thread/yxmmya2o2lc26tpi > > >
