Merge remote-tracking branch 'remotes/berrange/tags/qcrypto-next-pull-request' into staging

# gpg: Signature made Fri 06 Apr 2018 14:29:10 BST
# gpg:                using RSA key BE86EBB415104FDF
# gpg: Good signature from "Daniel P. Berrange <dan@berrange.com>"
# gpg:                 aka "Daniel P. Berrange <berrange@redhat.com>"
# Primary key fingerprint: DAF3 A6FD B26B 6291 2D0E  8E3F BE86 EBB4 1510 4FDF

* remotes/berrange/tags/qcrypto-next-pull-request:
  crypto: ensure we use a predictable TLS priority setting
  docs: Document -object tls-creds-x509 priority=xxx
  docs: update information for TLS certificate management
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

qemu-options.hx

@@ -4112,7 +4112,7 @@ expensive operation that consumes random pool entropy, so it is
 recommended that a persistent set of parameters be generated
 upfront and saved.
 
-@item -object tls-creds-x509,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/cred/dir},verify-peer=@var{on|off},passwordid=@var{id}
+@item -object tls-creds-x509,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/cred/dir},priority=@var{priority},verify-peer=@var{on|off},passwordid=@var{id}
 
 Creates a TLS anonymous credentials object, which can be used to provide
 TLS support on network backends. The @option{id} parameter is a unique
@@ -4145,6 +4145,15 @@ version by providing the @var{passwordid} parameter. This provides
 the ID of a previously created @code{secret} object containing the
 password for decryption.
 
+The @var{priority} parameter allows to override the global default
+priority used by gnutls. This can be useful if the system administrator
+needs to use a weaker set of crypto priorities for QEMU without
+potentially forcing the weakness onto all applications. Or conversely
+if one wants wants a stronger default for QEMU than for all other
+applications, they can do this through this parameter. Its format is
+a gnutls priority string as described at
+@url{https://gnutls.org/manual/html_node/Priority-Strings.html}.
+
 @item -object filter-buffer,id=@var{id},netdev=@var{netdevid},interval=@var{t}[,queue=@var{all|rx|tx}][,status=@var{on|off}]
 
 Interval @var{t} can't be 0, this filter batches the packet delivery: all

tests/test-crypto-tlssession.c

@@ -75,6 +75,7 @@ static QCryptoTLSCreds *test_tls_creds_create(QCryptoTLSCredsEndpoint endpoint,
                      "server" : "client"),
         "dir", certdir,
         "verify-peer", "yes",
+        "priority", "NORMAL",
         /* We skip initial sanity checks here because we
          * want to make sure that problems are being
          * detected at the TLS session validation stage,

tests/test-io-channel-tls.c

@@ -78,6 +78,7 @@ static QCryptoTLSCreds *test_tls_creds_create(QCryptoTLSCredsEndpoint endpoint,
                      "server" : "client"),
         "dir", certdir,
         "verify-peer", "yes",
+        "priority", "NORMAL",
         /* We skip initial sanity checks here because we
          * want to make sure that problems are being
          * detected at the TLS session validation stage,