crypto: propagate Error object on premature termination

The way that premature termination was handled in TLS connections was
changed to handle an ordering problem during graceful shutdown in the
migration code.

Unfortunately one of the codepaths returned -1 to indicate an error
condition, but failed to set the 'errp' parameter.

This broke error handling in the qio_channel_tls_handshake function,
as the QTask callback would no longer see that an error was raised.
As a result, the client will go on to try to use the already closed
TLS connection, resulting in misleading errors.

This was evidenced in the I/O test 233 which showed changes such as

-qemu-nbd: Certificate does not match the hostname localhost
+qemu-nbd: Failed to read initial magic: Unable to read from socket: Connection reset by peer

Fixes: 7e0c22d585581b8083ffdeb332ea497218665daf
Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

diff --git a/crypto/tlssession.c b/crypto/tlssession.c
index ac38c2121dbd38eeeeae03a06034b3230ed584fc..8c0bf457ad7d1ed6eda0bceb70d3d208f6ec51f5 100644 (file)
--- a/crypto/tlssession.c
+++ b/crypto/tlssession.c
@@ -569,8 +569,6 @@ qcrypto_tls_session_read(QCryptoTLSSession *session,
     if (ret < 0) {
         if (ret == GNUTLS_E_AGAIN) {
             return QCRYPTO_TLS_SESSION_ERR_BLOCK;
-        } else if (ret == GNUTLS_E_PREMATURE_TERMINATION) {
-            return QCRYPTO_TLS_SESSION_PREMATURE_TERMINATION;
         } else {
             if (session->rerr) {
                 error_propagate(errp, session->rerr);
@@ -580,7 +578,11 @@ qcrypto_tls_session_read(QCryptoTLSSession *session,
                            "Cannot read from TLS channel: %s",
                            gnutls_strerror(ret));
             }
-            return -1;
+            if (ret == GNUTLS_E_PREMATURE_TERMINATION) {
+                return QCRYPTO_TLS_SESSION_PREMATURE_TERMINATION;
+            } else {
+                return -1;
+            }
         }
     }
 

diff --git a/io/channel-tls.c b/io/channel-tls.c
index 1fbed4be0c670a72dd0ba14381671e0be7610447..70fad38d18c828b8e78d310f97132f039b704f3b 100644 (file)
--- a/io/channel-tls.c
+++ b/io/channel-tls.c
@@ -368,6 +368,7 @@ static ssize_t qio_channel_tls_readv(QIOChannel *ioc,
                                      int flags,
                                      Error **errp)
 {
+    ERRP_GUARD();
     QIOChannelTLS *tioc = QIO_CHANNEL_TLS(ioc);
     size_t i;
     ssize_t got = 0;
@@ -384,13 +385,13 @@ static ssize_t qio_channel_tls_readv(QIOChannel *ioc,
             } else {
                 return QIO_CHANNEL_ERR_BLOCK;
             }
-        } else if (ret == QCRYPTO_TLS_SESSION_PREMATURE_TERMINATION) {
-            if (qio_channel_tls_allow_premature_termination(tioc, flags)) {
-                ret = 0;
-            } else {
-                return -1;
-            }
         } else if (ret < 0) {
+            if (ret == QCRYPTO_TLS_SESSION_PREMATURE_TERMINATION &&
+                qio_channel_tls_allow_premature_termination(tioc, flags)) {
+                error_free(*errp);
+                *errp = NULL;
+                return got;
+            }
             return -1;
         }
         got += ret;