crypto/x509: does not implement other hash algorithms then SHA1WithRSA

[gopherbot]

by jdnurmi:

crypto/x509 does not actually use any algorithms but SHA1WithRSA, and any attempt to
create or validate one will fail.

I've attached a patch that expands its capabilities to include RSA+MD5,SHA256,384 &
512.

It is a breaking patch, in that anyone using CreateCertificate without having specified
SignatureAlgorithm will get an error.

It's a rough patch that just implements that bare functionality (and test fixes).  I am
completely open to fixing this for style or functionality as needed, or you can just run
with it;  I have verified go can verify its own generated certs, and that openSSL can
parse them -- though I've not done extensive validation tests.

I'm also by no means a crypto expert, but the places I needed to patch seemed pretty
straight forward.

Attachments:

1. x509-patch.1 (4480 bytes)

[gopherbot]

Comment 1 by jdnurmi:

The bored might also want a DSA patch

[gopherbot]

Comment 2 by jdnurmi:

One last note for you;  Utilizing:
grep -v --  '-----' /etc/ssl/certs/Equifax_Secure_CA.pem | base64 -d | dumpasn1 -
and 
dumpasn1 - < go-generated.der
I noticed some potential ASN.1 rendering errors relating to (I think) the boolean type. 
I don't know enough about ASN.1 to know what the error is, but I don't see anything
obvious since the rest of the object seems to dump fine.
I don't see similar ASN.1 errors in any other certs I tested in the standard
ca-certificates bundle, so my inclination is to say this should be examined more closely
and fixed.

[rsc]

Comment 3:

Thanks for the patch.  Could you please send it in using
the code review tools as described at
http://golang.org/doc/contribute.html ?
That makes it easier for us to comment and
eventually apply it.  In the change list description
you can end with the line
Fixes issue #988.
and when it is submitted it will close this issue.
Thanks very much.
Russ

Owner changed to r...@golang.org.

Status changed to Started.

[rsc]

Comment 4:

Status changed to WaitingForReply.

[rsc]

Comment 5:

jdnurmi:  Are you interested in sending this code via the code review process?
See http://golang.org/doc/contribute.html.  We need to do it that way for
our records and also to get your name in the commit log.
Thanks.

[rsc]

Comment 6:

Status changed to TimedOut.