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bh=wP8QwwtjVUlBP9tLGAX5MBpAv2s5IjeizLlNwmMNrUc=; b=bbvWaoMdCVpQjPGqC+qhElf67rOZOeFrA1CRw7GuyoJwLWK4QADJ7L3Q85Vj5LelFU2xHl +e0wxh6tV/94IKc3J38e9JeuJ1IjvTlDqjjb+1KLfwZWnPeD7JKZ4LLWgB37SGINFPxm0a wxnBpeDcbfb3exIxg5ung4pnd8AMZZo= X-MC-Unique: -KHFNKwfONOQgq2Rtoe_ow-1 From: Eric Blake To: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, Zhu Yangyang , Vladimir Sementsov-Ogievskiy Subject: [PATCH v4] nbd/server: do not poll within a coroutine context Date: Fri, 5 Apr 2024 12:44:13 -0500 Message-ID: <20240405174523.844181-2-eblake@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1712339186214100003 Content-Type: text/plain; charset="utf-8" From: Zhu Yangyang Coroutines are not supposed to block. Instead, they should yield. The client performs TLS upgrade outside of an AIOContext, during synchronous handshake; this still requires g_main_loop. But the server responds to TLS upgrade inside a coroutine, so a nested g_main_loop is wrong. Since the two callbacks no longer share more than the setting of data.complete and data.error, it's just as easy to use static helpers instead of trying to share a common code path. Fixes: f95910f ("nbd: implement TLS support in the protocol negotiation") Signed-off-by: Zhu Yangyang [eblake: move callbacks to their use point] Signed-off-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy --- v3: https://lists.gnu.org/archive/html/qemu-devel/2024-04/msg00375.html in v4, factor even the struct to the .c files, avoiding a union [Vladimir] nbd/nbd-internal.h | 10 ---------- nbd/client.c | 27 +++++++++++++++++++++++---- nbd/common.c | 11 ----------- nbd/server.c | 29 +++++++++++++++++++++++------ 4 files changed, 46 insertions(+), 31 deletions(-) diff --git a/nbd/nbd-internal.h b/nbd/nbd-internal.h index dfa02f77ee4..91895106a95 100644 --- a/nbd/nbd-internal.h +++ b/nbd/nbd-internal.h @@ -72,16 +72,6 @@ static inline int nbd_write(QIOChannel *ioc, const void = *buffer, size_t size, return qio_channel_write_all(ioc, buffer, size, errp) < 0 ? -EIO : 0; } -struct NBDTLSHandshakeData { - GMainLoop *loop; - bool complete; - Error *error; -}; - - -void nbd_tls_handshake(QIOTask *task, - void *opaque); - int nbd_drop(QIOChannel *ioc, size_t size, Error **errp); #endif diff --git a/nbd/client.c b/nbd/client.c index 29ffc609a4b..c7141d7a098 100644 --- a/nbd/client.c +++ b/nbd/client.c @@ -596,13 +596,31 @@ static int nbd_request_simple_option(QIOChannel *ioc,= int opt, bool strict, return 1; } +/* Callback to learn when QIO TLS upgrade is complete */ +struct NBDTLSClientHandshakeData { + bool complete; + Error *error; + GMainLoop *loop; +}; + +static void nbd_client_tls_handshake(QIOTask *task, void *opaque) +{ + struct NBDTLSClientHandshakeData *data =3D opaque; + + qio_task_propagate_error(task, &data->error); + data->complete =3D true; + if (data->loop) { + g_main_loop_quit(data->loop); + } +} + static QIOChannel *nbd_receive_starttls(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, const char *hostname, Error **errp) { int ret; QIOChannelTLS *tioc; - struct NBDTLSHandshakeData data =3D { 0 }; + struct NBDTLSClientHandshakeData data =3D { 0 }; ret =3D nbd_request_simple_option(ioc, NBD_OPT_STARTTLS, true, errp); if (ret <=3D 0) { @@ -619,18 +637,19 @@ static QIOChannel *nbd_receive_starttls(QIOChannel *i= oc, return NULL; } qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-client-tls"); - data.loop =3D g_main_loop_new(g_main_context_default(), FALSE); trace_nbd_receive_starttls_tls_handshake(); qio_channel_tls_handshake(tioc, - nbd_tls_handshake, + nbd_client_tls_handshake, &data, NULL, NULL); if (!data.complete) { + data.loop =3D g_main_loop_new(g_main_context_default(), FALSE); g_main_loop_run(data.loop); + g_main_loop_unref(data.loop); } - g_main_loop_unref(data.loop); + if (data.error) { error_propagate(errp, data.error); object_unref(OBJECT(tioc)); diff --git a/nbd/common.c b/nbd/common.c index 3247c1d618a..589a748cfe6 100644 --- a/nbd/common.c +++ b/nbd/common.c @@ -47,17 +47,6 @@ int nbd_drop(QIOChannel *ioc, size_t size, Error **errp) } -void nbd_tls_handshake(QIOTask *task, - void *opaque) -{ - struct NBDTLSHandshakeData *data =3D opaque; - - qio_task_propagate_error(task, &data->error); - data->complete =3D true; - g_main_loop_quit(data->loop); -} - - const char *nbd_opt_lookup(uint32_t opt) { switch (opt) { diff --git a/nbd/server.c b/nbd/server.c index c3484cc1ebc..ea13cf0e766 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -748,6 +748,23 @@ static int nbd_negotiate_handle_info(NBDClient *client= , Error **errp) return rc; } +/* Callback to learn when QIO TLS upgrade is complete */ +struct NBDTLSServerHandshakeData { + bool complete; + Error *error; + Coroutine *co; +}; + +static void nbd_server_tls_handshake(QIOTask *task, void *opaque) +{ + struct NBDTLSServerHandshakeData *data =3D opaque; + + qio_task_propagate_error(task, &data->error); + data->complete =3D true; + if (!qemu_coroutine_entered(data->co)) { + aio_co_wake(data->co); + } +} /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the * new channel for all further (now-encrypted) communication. */ @@ -756,7 +773,7 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDCli= ent *client, { QIOChannel *ioc; QIOChannelTLS *tioc; - struct NBDTLSHandshakeData data =3D { 0 }; + struct NBDTLSServerHandshakeData data =3D { 0 }; assert(client->opt =3D=3D NBD_OPT_STARTTLS); @@ -777,17 +794,17 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDC= lient *client, qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); trace_nbd_negotiate_handle_starttls_handshake(); - data.loop =3D g_main_loop_new(g_main_context_default(), FALSE); + data.co =3D qemu_coroutine_self(); qio_channel_tls_handshake(tioc, - nbd_tls_handshake, + nbd_server_tls_handshake, &data, NULL, NULL); - if (!data.complete) { - g_main_loop_run(data.loop); + while (!data.complete) { + qemu_coroutine_yield(); } - g_main_loop_unref(data.loop); + if (data.error) { object_unref(OBJECT(tioc)); error_propagate(errp, data.error); --=20 2.44.0