Store and check previously denied CSRs

[rolandshoemaker]

Fix for #101, I plan to add RA tests tomorrow.

[coveralls]

Coverage decreased (-0.09%) to 47.91% when pulling a2b3461 on rolandshoemaker:deny-store into fdc1825 on letsencrypt:master.

[coveralls]

Coverage decreased (-0.94%) to 47.05% when pulling 0718250 on rolandshoemaker:deny-store into fdc1825 on letsencrypt:master.

[jsha]

I think storing whole CSRs is the wrong approach. I think we to store a list of DNS names, possibly with some extra metadata. Otherwise you could avoid the list by changing some unimportant part of the CSR.

Also one thing I didn't notice until re-reading the relevant CPS part is that this denied list is only necessary for revocations or denials "due to suspected phishing or other fraud." So we still need the table, but it can be pretty small.

[coveralls]

Coverage decreased (-1.07%) to 46.92% when pulling 07e6f10 on rolandshoemaker:deny-store into fdc1825 on letsencrypt:master.

[rolandshoemaker]

Ready for re-review. Not too sure about my method for passing a bool in rpc-wrappers.go so thoughts on that would be appreciated.

[jcjones]

@rolandshoemaker I don't think there's anything in golang you can do to make that cleaner, except to marshal to/from JSON.

I'm fine with it as-is, or we can write a tiny marshalBool unmarshalBool function pair to be cleaner.

[jcjones]

Oh, and LGTM, ready to commit when you are @rolandshoemaker

[rolandshoemaker]

If we start passing more bools via RPC it'll make sense to write a function pair but for now i'm okay leaving it as-is...

[jcjones]

Build failures merged to master:

wfe/web-front-end_test.go:105: cannot use MockSA literal (type *MockSA) as type core.StorageGetter in assignment:
    *MockSA does not implement core.StorageGetter (missing AlreadyDeniedCSR method)
wfe/web-front-end_test.go:270: cannot use MockSA literal (type *MockSA) as type core.StorageGetter in assignment:
    *MockSA does not implement core.StorageGetter (missing AlreadyDeniedCSR method)
wfe/web-front-end_test.go:331: cannot use MockSA literal (type *MockSA) as type core.StorageGetter in assignment:
    *MockSA does not implement core.StorageGetter (missing AlreadyDeniedCSR method)
wfe/web-front-end_test.go:420: cannot use MockSA literal (type *MockSA) as type core.StorageGetter in assignment:
    *MockSA does not implement core.StorageGetter (missing AlreadyDeniedCSR method)