parseRSAPrivateKey calls rsa.PrivateKey.Precompute which triggers divide-by-zero panic if either p or q is 1. Sanity check the parsed values by calling rsa.PrivateKey.Validate. Fixes golang/go#11505 Change-Id: Ia6c9eccca0cfa49aaa58716e708c557a788bb204 Reviewed-on: https://go-review.googlesource.com/12356 Reviewed-by: Adam Langley <agl@golang.org>