To import private keys, WebCrypto creates a generic PKCS#11 object with a chosen
key ID with PK11_CreateGenericObject and then looks up that object as a
SECKEYPrivateKey using PK11_FindKeyByKeyID. It turns out that this is only safe
to do as long as the ID is unique. If another SECKEYPrivateKey exists that has
the same key ID (realistically this will only happen if an identical key is
imported again), PK11_FindKeyByKeyID may return the other key. Since
SECKEYPrivateKey objects are unique and not meant to be shared, this causes
problems in that when one key is destroyed, the resources backing the other key
are no longer valid, and any cryptographic operations using that key will fail.
The solution is to use random IDs and check for preexisting keys. NSS doesn't
yet expose an elegant API for this, but this patch implements a workaround.
MozReview-Commit-ID: EvYMZxnBxTv
--HG--
extra : rebase_source : 50408e1af9eb3934b51a0f01e02aa4890e57ed03
