Re: [PATCH v4 07/33] io: tls: Allow terminating the TLS session gracefully with EOF

[Maciej S. Szmigiero]

On 4.02.2025 16:15, Daniel P. Berrangé wrote:

On Thu, Jan 30, 2025 at 11:08:28AM +0100, Maciej S. Szmigiero wrote:

From: "Maciej S. Szmigiero" <maciej.szmigi...@oracle.com>

Currently, hitting EOF on receive without sender terminating the TLS
session properly causes the TLS channel to return an error (unless
the channel was already shut down for read).

Add an optional setting whether we instead just return EOF in that
case.

This possibility will be soon used by the migration multifd code.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigi...@oracle.com>
---
  include/io/channel-tls.h | 11 +++++++++++
  io/channel-tls.c         |  6 ++++++
  2 files changed, 17 insertions(+)

diff --git a/include/io/channel-tls.h b/include/io/channel-tls.h
index 26c67f17e2d3..8552c0d0266e 100644
--- a/include/io/channel-tls.h
+++ b/include/io/channel-tls.h
@@ -49,6 +49,7 @@ struct QIOChannelTLS {
      QCryptoTLSSession *session;
      QIOChannelShutdown shutdown;
      guint hs_ioc_tag;
+    bool premature_eof_okay;
  };

/**

@@ -143,4 +144,14 @@ void qio_channel_tls_handshake(QIOChannelTLS *ioc,
  QCryptoTLSSession *
  qio_channel_tls_get_session(QIOChannelTLS *ioc);

+/**

+ * qio_channel_tls_set_premature_eof_okay:
+ * @ioc: the TLS channel object
+ *
+ * Sets whether receiving an EOF without terminating the TLS session properly
+ * by used the other side is considered okay or an error (the
+ * default behaviour).
+ */
+void qio_channel_tls_set_premature_eof_okay(QIOChannelTLS *ioc, bool enabled);
+
  #endif /* QIO_CHANNEL_TLS_H */
diff --git a/io/channel-tls.c b/io/channel-tls.c
index aab630e5ae32..1079d6d10de1 100644
--- a/io/channel-tls.c
+++ b/io/channel-tls.c
@@ -147,6 +147,11 @@ qio_channel_tls_new_client(QIOChannel *master,
      return NULL;
  }

+void qio_channel_tls_set_premature_eof_okay(QIOChannelTLS *ioc, bool enabled)

+{
+    ioc->premature_eof_okay = enabled;
+}
+
  struct QIOChannelTLSData {
      QIOTask *task;
      GMainContext *context;
@@ -279,6 +284,7 @@ static ssize_t qio_channel_tls_readv(QIOChannel *ioc,
              tioc->session,
              iov[i].iov_base,
              iov[i].iov_len,
+            tioc->premature_eof_okay ||
              qatomic_load_acquire(&tioc->shutdown) & QIO_CHANNEL_SHUTDOWN_READ,
              errp);
          if (ret == QCRYPTO_TLS_SESSION_ERR_BLOCK) {

IMHO a better way to do this is by defining an new flag for use with
the qio_channel_readv_full() method. That makes the ignoring of
premature shutdown a contextually scoped behaviour rather than a
global behaviour.

Something named like QIO_CHANNEL_READ_FLAG_TLS_EARLY_EOF_OKAY?

With regards,
Daniel

Thanks,
Maciej