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 >
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