On Tue, Mar 10, 2015 at 9:02 PM, Domenic Denicola <[email protected]> wrote:
> I don’t see how any of this follows. SES can censor/remove/etc. either > the .stack getter or the .getStack function. They are isomorphic. > I can selectively provide or deny a given getStack function to different code in the same realm. > > > .stack already has very close to de-facto standard behavior. > Have you looked at the case analysis I go through in debug.js to parse the variety of stack formats we currently have? > We should be attempting to converge it to a standard, and not leaving it a > non-interoperable mess while adding a second API. > > > > I also don’t see why .stack cannot map backward through different source > maps. Again, a getter and a function are isomorphic in this regard. > In a given realm, there can only be one Error.prototype.stack. But what getStack function is in scope can differ per scope as well as per loader. > > > *From:* Mark S. Miller [mailto:[email protected]] > *Sent:* Wednesday, March 11, 2015 12:12 > *To:* Domenic Denicola > *Cc:* John Lenz; es-discuss; Erik Arvidsson > > *Subject:* Re: Maximally minimal stack trace standardization > > > > No, that makes the std SES API non-conformant to the std API, making > porting more difficult, and making it harder to write code that works in > both environments. > > > > Also, if you make it look like err.stack, then no matter what you stdize, > it will conflict with existing err.stack behavior, since they conflict with > each other. This makes the transition more difficult. If the new std > behavior looks like getStack(err), then it can be rolled out without > creating a transition conflict. > > > > As so often happens, the better security is the better modularity. If you > make it err.stack, then you have to make visible one canonical mapping to > source positions. If you make it getStack(err), then different getStack > functions might map backwards through different sourcemaps. > > > > > > > > On Tue, Mar 10, 2015 at 7:45 PM, Domenic Denicola <[email protected]> wrote: > > Can’t we just have Error.prototype.stack be a getter that SES is allowed > to delete and hide away for its own purposes later? > > > > *From:* es-discuss [mailto:[email protected]] *On Behalf Of *John > Lenz > *Sent:* Wednesday, March 11, 2015 08:35 > *To:* Mark S. Miller > *Cc:* es-discuss; Erik Arvidsson > *Subject:* Re: Maximally minimal stack trace standardization > > > > Ok, as long as we are clear there is an existing information leak on > non-v8 engines. > > > > > > On Tue, Mar 10, 2015 at 1:48 PM, Mark S. Miller <[email protected]> > wrote: > > On Chrome and Opera (v8), < > https://code.google.com/p/google-caja/source/browse/trunk/src/com/google/caja/ses/debug.js> > hides the stack. It is important that we not lose this. > > > > Regarding the rest, as previously discussed, there are enough differences > between browsers that there is no legacy we must codify because of web-wide > agreement. Take a look at the extensive efforts < > https://code.google.com/p/google-caja/source/browse/trunk/src/com/google/caja/ses/debug.js> > makes to parse despite these differences in stack format. As long as we're > standardizing something not compat with web-wide legacy, as we must, we > might as well also fix this security leak in the process. > > > > > > > > > > On Tue, Mar 10, 2015 at 1:24 PM, John Lenz <[email protected]> wrote: > > > > > > On Mon, Mar 9, 2015 at 5:45 PM, Mark S. Miller <[email protected]> wrote: > > On Mon, Mar 9, 2015 at 5:02 PM, John Lenz <[email protected]> wrote: > > > > > > On Mon, Mar 9, 2015 at 12:15 PM, Mark S. Miller <[email protected]> > wrote: > > On Sat, Mar 7, 2015 at 2:55 PM, John Lenz <[email protected]> wrote: > > I wanted to ping this thread and see how we could get "max-min stack > traces" to the next step? > > > > Hi John, the best way to take this to the next step is to read < > https://docs.google.com/document/d/1QbEE0BsO4lvl7NFTn5WXWeiEIBfaVUF7Dk0hpPpPDzU/edit> > and submit a proposal to <https://github.com/tc39/ecma262>. > > > > "If you are a TC39 member representative, just submit a pull request for > your proposal." > > > > Since you are at a member organization, attend and participate actively at > TC39 meetings to advance your proposal through the process. > > > > Please keep in mind that the stack trace information should not be > available simply from the error object by itself, as that is a bad > information leak. > > > > The threads I dug up, simply state what you state here. That there is an > "information leak". Are filename and function names considered sensitive? > In what way? > > > > They reveal details of the callee's computation to the caller that the > callee should have been able to assume were private. See starting at middle > of 2nd paragraph of < > http://combex.com/papers/darpa-review/security-review.html#UniversalScope > >. > > > > > > the depth of the execution stack is visible, which could pose a risk in > certain scenarios: for instance, consider trusted code containing a > recursive function whose level of recursion depends on some sensitive data > (e.g., a secret cryptographic key), and suppose the recursive function is > called with arguments that induce it to hit an error condition and throw an > exception from deep within the recursion. In such a case, the caller might > be able to learn something about the callee’s secrets by catching the > exception, examining the resulting stack trace, and recovering the stack > depth. These scenarios do not occur in the DarpaBrowser, but have been > used in exploits on other systems. Accordingly, though the risk for > DarpaBrowser is small, it should probably be repaired (Fixing this was > determined not to be hard). > > > > > > --David Wagner and E. Dean Tribble, > > "A Security Review of the Combex DarpaBrowser Architecture" > > > > > > Likewise, the risk here -- of only a stack of function names and source > positions -- is small. But it violates the normal privacy assumptions > between caller and callee; and fixing it is again not hard -- via getStack. > > > > > > > > I did not intend to promote a "rich stack inspection API" such as V8 > has. > > > > That's good, but there is one thing I really like about the rich > inspection API that it would be a shame to lose: The user doesn't have to > do their own adhoc parsing of yet another ad hoc textual format. Since this > format contains function names, we would then even need to worry about > maliciously chosen function names, intended to get this stack format > parsing code to misparse. If the stack is a stack of, for example, JSON > strings, then we avoid this hazard. > > > > > > Sure, but I feel like that is independent, I mostly want to codify what > already exists and standardize throw/rethrow behavior. That is why I ask > about the information leak. Error objects already have "stack" properties > on all the major browsers. If "stack" leaks information then they already > do and the rectification should be there. (It makes no sense to add a > "leak-free" API when a "leaky" one already exists). > > > > > > -- > > Cheers, > --MarkM > > > > > > > > -- > > Cheers, > --MarkM > > > > > > > > -- > > Cheers, > --MarkM > -- Cheers, --MarkM
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