CSP: Harden hash parsing.

CSP: Harden hash parsing.

Pathalogical cases broke CSP's hash parsing code. This patch adds some
bounds checking to ensure that we don't run off the end of the string
in some edge cases.

BUG=427397
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=184822

[Mike West, 2014-11-03 09:36:43]

mkwst@chromium.org changed reviewers:
+ jww@chromium.org

[Mike West, 2014-11-03 09:36:44]

Joel, mind taking a look at this?

-mike

[jww, 2014-11-03 21:16:55]

lgtm with nit

https://codereview.chromium.org/700463003/diff/20001/Source/core/frame/csp/CS...
File Source/core/frame/csp/CSPSourceList.cpp (right):

https://codereview.chromium.org/700463003/diff/20001/Source/core/frame/csp/CS...
Source/core/frame/csp/CSPSourceList.cpp:303: for (const auto& algorithm :
kSupportedPrefixes) {
nit: Calling this 'algorithm' is confusing given that the member is called
algorithm as well. Maybe rename to something like 'algorithmMap' or 'prefixMap'?

[Mike West, 2014-11-04 07:31:40]

The CQ bit was checked by mkwst@chromium.org

[commit-bot: I haz the power, 2014-11-04 07:32:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/700463003/40001

[commit-bot: I haz the power, 2014-11-04 09:00:49]

Committed patchset #3 (id:40001) as 184822