I don't understand. Could you show example code? Thanks.
On Wed, Mar 11, 2015 at 12:00 PM, John Lenz <[email protected]> wrote: > > > On Tue, Mar 10, 2015 at 9:10 PM, Mark S. Miller <[email protected]> > wrote: > >> 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. >> > > Can't you do the same by hiding "Error" in the same way that "window" is > hidden? Through a proxy or subclass? > > >> >> >>> >>> >>> .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 >> > > -- Cheers, --MarkM
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