[whatwg] Spec comments, sections 1-2
ian at hixie.ch
Wed Jul 29 01:39:05 PDT 2009
On Wed, 15 Jul 2009, Aryeh Gregor wrote:
> In 220.127.116.11:
> "If position is not past the end of input, return to the top of the
> step labeled loop in the overall algorithm (that's the step within
> which these substeps find themselves)."
> Why not just "go to step 9"?
Which part specifically are you saying should be changed? I'm not sure I
> In any event this is inconsistent with
> 18.104.22.168, which says
> "If position is not past the end of input, return to the top of step 9
> in the overall algorithm (that's the step within which these substeps
> find themselves)."
I guess I didn't screw that one up yet. :-) I originally wrote algorithms
using numeric step jumps, then when editing them I broke a bunch of jumps
(adding steps but not updating numbers), and so whenever I edit an
algorithm now, I make it symbolic rather than numeric.
> Either both should say "the top of step 9" or both should say "the top
> of the step labeled loop".
There is value in not changing them unless they are actually broken --
when I edit the spec, there's always a risk I'll break something.
> I don't see the value in the whole "in the overall algorithm . . ."
> part, since in context there's no ambiguity with just giving the number.
For now -- what if I later add a dozen more substeps?
> "If sign is "positive", return value, otherwise return 0-value."
> I initially read "0-value" as a single word, like "p-value" or
> whatever. Perhaps it should have spaces to make it more immediately
> obvious that it's subtraction ("0 - value").
I've rephrased this.
> In 2.6.2:
> The specification says that user agents may serve HTTPS content as
> though it were unencrypted. For instance, an example states: "If a user
> connects to a server with a self-signed certificate, the user agent
> could allow the connection but just act as if there had been no
> encryption." If this is done, however, man-in-the-middle attacks become
> trivial, unless the user is expected to notice the lack of encryption
> For instance, suppose a user navigates to PayPal and bookmarks it.
> PayPal is configured so if you try using HTTP (e.g., typing "paypal.com"
> in the URL bar), it will redirect to HTTPS. Therefore the user will
> bookmark a URL such as https://www.paypal.com/. Now suppose the user
> later attempts to access this site from the bookmark with a MITM present
> (e.g., a free wireless router placed in a public place by a malicious
> The router can intercept the HTTPS request, make its own identical HTTPS
> request, and return the results to the original HTTPS request, but
> signed with its own key instead of the original. If the user agent
> behaves as described in the example, the only way for the user to notice
> this is to notice that the URL bar looks different, or whatever visual
> cue the browser uses. If the user agent raises a prominent scary
> warning or even makes it difficult for the user to continue, on the
> other hand, there's no way for the attacker to prevent this, AFAIK.
> The section should prohibit user agents from displaying self-signed
> pages without at least giving a warning. Or, at a minimum, it should
> strongly discourage it. Currently it seems to indicate that this
> behavior is acceptable. As far as I know, existing browsers all present
> scary warnings for self-signed pages (probably so scary as to be
> misleading, in fact, but that's a separate issue).
I've required UAs to catch this case and added this example.
> In 2.7:
> "User agents must at a minimum support the UTF-8 and Windows-1252
> encodings, but may support more.
> "It is not unusual for Web browsers to support dozens if not upwards
> of a hundred distinct character encodings."
> Why aren't the most important ones listed as requirements?
They are. UTF-8 and 1252 are the most important ones.
> This seems to be contrary to the usual HTML 5 philosophy of mandating
> (or at least precisely specifying) existing behavior that's required for
Which others are needed for compatibility?
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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