code review 48580043: crypto/tls: support renegotiation extension.

crypto/tls: support renegotiation extension.

The renegotiation extension was introduced[1] due to an attack by Ray in
which a client's handshake was spliced into a connection that was
renegotiating, thus giving an attacker the ability to inject an
arbitary prefix into the connection.

Go has never supported renegotiation as a server and so this attack
doesn't apply. As a client, it's possible that at some point in the
future the population of servers will be sufficiently updated that
it'll be possible to reject connections where the server hasn't
demonstrated that it has been updated to address this problem.

We're not at that point yet, but it's good for Go servers to support
the extension so that it might be possible to do in the future.

[1] https://tools.ietf.org/search/rfc5746

[agl1, 2014-01-07 23:13:25]

Hello golang-dev@googlegroups.com (cc: golang-codereviews@googlegroups.com),

I'd like you to review this change to
https://code.google.com/p/go/

[gobot, 2014-01-07 23:16:48]

Replacing golang-dev with golang-codereviews.

To the author of this CL: 

If you are using 'hg mail -r golang-dev' to mail the CL, use simply 'hg mail'
instead.

If you did not name golang-dev explicitly and it was still added to the CL,
it means your working copy of the repo has a stale codereview.cfg
(or lib/codereview/codereview.cfg).
Please run 'hg sync' to update your client to the most recent codereview.cfg.
If the most recent codereview.cfg has defaultcc set to golang-dev instead of
golang-codereviews, please send a CL correcting it.

Thanks very much.

[mikio, 2014-01-09 10:56:28]

LGTM

You can refer to RFC 5746 in the CL description but people who want to have a
look at TLS code already know that, hm, never mind.

[agl1, 2014-01-09 18:37:43]

Thanks. Have added an RFC reference to the description.

[agl1, 2014-01-09 18:38:19]

*** Submitted as https://code.google.com/p/go/source/detail?r=f1e918132139 ***

crypto/tls: support renegotiation extension.

The renegotiation extension was introduced[1] due to an attack by Ray in
which a client's handshake was spliced into a connection that was
renegotiating, thus giving an attacker the ability to inject an
arbitary prefix into the connection.

Go has never supported renegotiation as a server and so this attack
doesn't apply. As a client, it's possible that at some point in the
future the population of servers will be sufficiently updated that
it'll be possible to reject connections where the server hasn't
demonstrated that it has been updated to address this problem.

We're not at that point yet, but it's good for Go servers to support
the extension so that it might be possible to do in the future.

[1] https://tools.ietf.org/search/rfc5746

R=golang-codereviews, mikioh.mikioh
CC=golang-codereviews
https://codereview.appspot.com/48580043