We should never ignore failure from nbd_negotiate_send_rep(); if we are unable to write to the client, then it is not worth trying to continue the negotiation. Fortunately, the problem is not too severe - chances are that the errors being ignored here (mainly inability to write the reply to the client) are indications of a closed connection or something similar, which will also affect the next attempt to interact with the client and eventually reach a point where the errors are detected to end the loop.
Signed-off-by: Eric Blake <ebl...@redhat.com> --- nbd/server.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-) diff --git a/nbd/server.c b/nbd/server.c index fb6d3ce..53507c5 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -334,7 +334,10 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, return NULL; } - nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, NBD_OPT_STARTTLS); + if (nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, + NBD_OPT_STARTTLS) < 0) { + return NULL; + } tioc = qio_channel_tls_new_server(ioc, client->tlscreds, @@ -460,8 +463,11 @@ static int nbd_negotiate_options(NBDClient *client) if (nbd_negotiate_drop_sync(client->ioc, length) != length) { return -EIO; } - nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_TLS_REQD, - clientflags); + ret = nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_TLS_REQD, + clientflags); + if (ret < 0) { + return ret; + } break; } } else if (fixedNewstyle) { @@ -485,12 +491,17 @@ static int nbd_negotiate_options(NBDClient *client) } if (client->tlscreds) { TRACE("TLS already enabled"); - nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_INVALID, - clientflags); + ret = nbd_negotiate_send_rep(client->ioc, + NBD_REP_ERR_INVALID, + clientflags); } else { TRACE("TLS not configured"); - nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_POLICY, - clientflags); + ret = nbd_negotiate_send_rep(client->ioc, + NBD_REP_ERR_POLICY, + clientflags); + } + if (ret < 0) { + return ret; } break; default: @@ -498,8 +509,11 @@ static int nbd_negotiate_options(NBDClient *client) if (nbd_negotiate_drop_sync(client->ioc, length) != length) { return -EIO; } - nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_UNSUP, - clientflags); + ret = nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_UNSUP, + clientflags); + if (ret < 0) { + return ret; + } break; } } else { -- 2.5.5