crypto/tls: keysFromMasterSecret() takes len(clientRandom), but should be server

[RalphCorderoy]

Hi @agl,

keysFromMasterSecret() in crypto/tls/prf.go does

copy(seed[0:len(clientRandom)], serverRandom)
copy(seed[len(serverRandom):], clientRandom)

The first len() should be of serverRandom, not clientRandom. It looks like a copy-and-paste error from the previous masterFromPreMasterSecret(). (They're the same length AFAIK, so no fault occurs.)

But I think both functions could have the first copy() be copy(seed, ...) as used elsewhere in prf.go.

[RalphCorderoy]

See https://go-review.googlesource.com/16697

[gopherbot]

CL https://golang.org/cl/16697 mentions this issue.