Eric Blake <ebl...@redhat.com> writes:
> Gnutls documents that applications that want to distinguish between a
> clean end-of-communication and a malicious client abruptly tearing the
> underlying transport out of under our feet need to use gnutls_bye().
> Our channel code is already set up to allow shutdown requests, but we
> weren't forwarding those to gnutls. To make that work, we first need
> a new entry point that can isolate the rest of our code from the
> gnutls interface.
>
> Signed-off-by: Eric Blake <ebl...@redhat.com>
> ---
> qapi/crypto.json | 15 +++++++++++++++
> include/crypto/tlssession.h | 24 ++++++++++++++++++++++++
> crypto/tlssession.c | 27 +++++++++++++++++++++++++++
> 3 files changed, 66 insertions(+)
>
> diff --git a/qapi/crypto.json b/qapi/crypto.json
> index b2a4cff683ff..1df0f4502885 100644
> --- a/qapi/crypto.json
> +++ b/qapi/crypto.json
> @@ -119,6 +119,21 @@
> 'prefix': 'QCRYPTO_IVGEN_ALG',
> 'data': ['plain', 'plain64', 'essiv']}
>
> +##
> +# @QCryptoShutdownMode:
> +#
> +# The supported modes for requesting shutdown of a crypto
> +# communication channel.
> +#
> +# @shut-wr: No more writes will be sent, but the remote end can still send
> +# data to be read.
> +# @shut-rdwr: No more reads or writes should occur.
> +# Since: 5.1
> +##
> +{ 'enum': 'QCryptoShutdownMode',
> + 'prefix': 'QCRYPTO',
> + 'data': ['shut-wr', 'shut-rdwr']}
> +
> ##
> # @QCryptoBlockFormat:
> #
> diff --git a/include/crypto/tlssession.h b/include/crypto/tlssession.h
> index 15b9cef086cc..10c670e3b6a2 100644
> --- a/include/crypto/tlssession.h
> +++ b/include/crypto/tlssession.h
> @@ -321,4 +321,28 @@ int qcrypto_tls_session_get_key_size(QCryptoTLSSession
> *sess,
> */
> char *qcrypto_tls_session_get_peer_name(QCryptoTLSSession *sess);
>
> +/**
> + * qcrypto_tls_shutdown:
> + * @sess: the TLS session object
> + * @how: the desired shutdown mode
> + *
> + * Prepare to terminate the session. If @how is QCRYPTO_SHUT_WR, this
> + * side will no longer write data, but should still process reads
> + * until EOF; if @how is QCRYPTO_SHUT_RDWR, then the entire session
> + * should shut down. Use of this function is optional, since closing
> + * the session implies QCRYPTO_SHUT_RDWR. However, using this
> + * function prior to terminating the underlying transport layer makes
> + * it possible for the remote endpoint to distinguish between a
> + * malicious party prematurely terminating the the connection and
> + * normal termination.
> + *
> + * This function should only be used after a successful
> + * qcrypto_tls_session_handshake().
> + *
> + * Returns: 0 for success, or -EAGAIN if more underlying I/O is
> + * required to finish proper session shutdown.
> + */
> +int qcrypto_tls_session_shutdown(QCryptoTLSSession *sess,
> + QCryptoShutdownMode how);
> +
> #endif /* QCRYPTO_TLSSESSION_H */
> diff --git a/crypto/tlssession.c b/crypto/tlssession.c
> index 33203e8ca711..903301189069 100644
> --- a/crypto/tlssession.c
> +++ b/crypto/tlssession.c
> @@ -521,6 +521,33 @@
> qcrypto_tls_session_get_handshake_status(QCryptoTLSSession *session)
> }
>
>
> +int qcrypto_tls_session_shutdown(QCryptoTLSSession *session,
> + QCryptoShutdownMode how)
> +{
> + gnutls_close_request_t mode;
> + int ret;
> +
> + assert(session->handshakeComplete);
Suggest a blank line here.
> + switch (how) {
> + case QCRYPTO_SHUT_WR:
> + mode = GNUTLS_SHUT_WR;
> + break;
> + case QCRYPTO_SHUT_RDWR:
> + mode = GNUTLS_SHUT_RDWR;
> + break;
> + default:
> + abort();
> + }
> +
> + ret = gnutls_bye(session->handle, mode);
> + if (ret == GNUTLS_E_INTERRUPTED ||
> + ret == GNUTLS_E_AGAIN) {
> + return -EAGAIN;
> + }
> + return 0;
> +}
> +
> +
> int
> qcrypto_tls_session_get_key_size(QCryptoTLSSession *session,
> Error **errp)
This is a thin wrapper around gnutls_bye(). I understand this is an
abstraction layer backed by GnuTLS. Not sure abstracting from just one
concrete thing is a good idea, but that's way out of scope here.
In scope: why do you need QCryptoShutdownMode be a QAPI type?
