73f2d6f723
- kvm-linux-aio-add-IO_CMD_FDSYNC-command-support.patch [RHEL-51901] - kvm-nbd-server-Plumb-in-new-args-to-nbd_client_add.patch [RHEL-52599] - kvm-nbd-server-CVE-2024-7409-Cap-default-max-connections.patch [RHEL-52599] - kvm-nbd-server-CVE-2024-7409-Drop-non-negotiating-client.patch [RHEL-52599] - kvm-nbd-server-CVE-2024-7409-Close-stray-clients-at-serv.patch [RHEL-52599] - Resolves: RHEL-51901 (qemu-kvm: linux-aio: add support for IO_CMD_FDSYNC command[RHEL-10]) - Resolves: RHEL-52599 (CVE-2024-7409 qemu-kvm: Denial of Service via Improper Synchronization in QEMU NBD Server During Socket Closure [rhel-10.0])
176 lines
6.5 KiB
Diff
176 lines
6.5 KiB
Diff
From 785893c171d994bbcffe0585953ca0d290f3c27e Mon Sep 17 00:00:00 2001
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From: Eric Blake <eblake@redhat.com>
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Date: Wed, 7 Aug 2024 08:50:01 -0500
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Subject: [PATCH 2/5] nbd/server: Plumb in new args to nbd_client_add()
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Eric Blake <eblake@redhat.com>
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RH-MergeRequest: 263: nbd/server: fix CVE-2024-7409 (qemu crash on nbd-server-stop) [RHEL 10.0]
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RH-Jira: RHEL-52599
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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RH-Commit: [1/4] 68e9f83d467704d3dfbf0a879b2bb4d9a568f81c (redhat/centos-stream/src/qemu-kvm)
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Upcoming patches to fix a CVE need to track an opaque pointer passed
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in by the owner of a client object, as well as request for a time
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limit on how fast negotiation must complete. Prepare for that by
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changing the signature of nbd_client_new() and adding an accessor to
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get at the opaque pointer, although for now the two servers
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(qemu-nbd.c and blockdev-nbd.c) do not change behavior even though
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they pass in a new default timeout value.
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Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
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Signed-off-by: Eric Blake <eblake@redhat.com>
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Message-ID: <20240807174943.771624-11-eblake@redhat.com>
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Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
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[eblake: s/LIMIT/MAX_SECS/ as suggested by Dan]
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Signed-off-by: Eric Blake <eblake@redhat.com>
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(cherry picked from commit fb1c2aaa981e0a2fa6362c9985f1296b74f055ac)
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Jira: https://issues.redhat.com/browse/RHEL-52599
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Signed-off-by: Eric Blake <eblake@redhat.com>
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---
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blockdev-nbd.c | 6 ++++--
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include/block/nbd.h | 11 ++++++++++-
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nbd/server.c | 20 +++++++++++++++++---
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qemu-nbd.c | 4 +++-
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4 files changed, 34 insertions(+), 7 deletions(-)
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diff --git a/blockdev-nbd.c b/blockdev-nbd.c
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index 213012435f..267a1de903 100644
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--- a/blockdev-nbd.c
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+++ b/blockdev-nbd.c
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@@ -64,8 +64,10 @@ static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
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nbd_update_server_watch(nbd_server);
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qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server");
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- nbd_client_new(cioc, nbd_server->tlscreds, nbd_server->tlsauthz,
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- nbd_blockdev_client_closed);
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+ /* TODO - expose handshake timeout as QMP option */
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+ nbd_client_new(cioc, NBD_DEFAULT_HANDSHAKE_MAX_SECS,
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+ nbd_server->tlscreds, nbd_server->tlsauthz,
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+ nbd_blockdev_client_closed, NULL);
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}
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static void nbd_update_server_watch(NBDServerData *s)
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diff --git a/include/block/nbd.h b/include/block/nbd.h
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index 4e7bd6342f..1d4d65922d 100644
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--- a/include/block/nbd.h
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+++ b/include/block/nbd.h
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@@ -33,6 +33,12 @@ typedef struct NBDMetaContexts NBDMetaContexts;
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extern const BlockExportDriver blk_exp_nbd;
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+/*
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+ * NBD_DEFAULT_HANDSHAKE_MAX_SECS: Number of seconds in which client must
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+ * succeed at NBD_OPT_GO before being forcefully dropped as too slow.
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+ */
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+#define NBD_DEFAULT_HANDSHAKE_MAX_SECS 10
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+
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/* Handshake phase structs - this struct is passed on the wire */
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typedef struct NBDOption {
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@@ -403,9 +409,12 @@ AioContext *nbd_export_aio_context(NBDExport *exp);
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NBDExport *nbd_export_find(const char *name);
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void nbd_client_new(QIOChannelSocket *sioc,
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+ uint32_t handshake_max_secs,
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QCryptoTLSCreds *tlscreds,
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const char *tlsauthz,
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- void (*close_fn)(NBDClient *, bool));
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+ void (*close_fn)(NBDClient *, bool),
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+ void *owner);
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+void *nbd_client_owner(NBDClient *client);
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void nbd_client_get(NBDClient *client);
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void nbd_client_put(NBDClient *client);
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diff --git a/nbd/server.c b/nbd/server.c
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index 892797bb11..e50012499f 100644
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--- a/nbd/server.c
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+++ b/nbd/server.c
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@@ -124,12 +124,14 @@ struct NBDMetaContexts {
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struct NBDClient {
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int refcount; /* atomic */
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void (*close_fn)(NBDClient *client, bool negotiated);
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+ void *owner;
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QemuMutex lock;
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NBDExport *exp;
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QCryptoTLSCreds *tlscreds;
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char *tlsauthz;
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+ uint32_t handshake_max_secs;
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QIOChannelSocket *sioc; /* The underlying data channel */
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QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
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@@ -3191,6 +3193,7 @@ static coroutine_fn void nbd_co_client_start(void *opaque)
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qemu_co_mutex_init(&client->send_lock);
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+ /* TODO - utilize client->handshake_max_secs */
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if (nbd_negotiate(client, &local_err)) {
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if (local_err) {
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error_report_err(local_err);
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@@ -3205,14 +3208,17 @@ static coroutine_fn void nbd_co_client_start(void *opaque)
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}
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/*
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- * Create a new client listener using the given channel @sioc.
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+ * Create a new client listener using the given channel @sioc and @owner.
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* Begin servicing it in a coroutine. When the connection closes, call
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- * @close_fn with an indication of whether the client completed negotiation.
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+ * @close_fn with an indication of whether the client completed negotiation
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+ * within @handshake_max_secs seconds (0 for unbounded).
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*/
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void nbd_client_new(QIOChannelSocket *sioc,
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+ uint32_t handshake_max_secs,
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QCryptoTLSCreds *tlscreds,
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const char *tlsauthz,
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- void (*close_fn)(NBDClient *, bool))
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+ void (*close_fn)(NBDClient *, bool),
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+ void *owner)
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{
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NBDClient *client;
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Coroutine *co;
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@@ -3225,13 +3231,21 @@ void nbd_client_new(QIOChannelSocket *sioc,
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object_ref(OBJECT(client->tlscreds));
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}
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client->tlsauthz = g_strdup(tlsauthz);
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+ client->handshake_max_secs = handshake_max_secs;
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client->sioc = sioc;
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qio_channel_set_delay(QIO_CHANNEL(sioc), false);
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object_ref(OBJECT(client->sioc));
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client->ioc = QIO_CHANNEL(sioc);
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object_ref(OBJECT(client->ioc));
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client->close_fn = close_fn;
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+ client->owner = owner;
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co = qemu_coroutine_create(nbd_co_client_start, client);
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qemu_coroutine_enter(co);
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}
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+
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+void *
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+nbd_client_owner(NBDClient *client)
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+{
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+ return client->owner;
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+}
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diff --git a/qemu-nbd.c b/qemu-nbd.c
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index d7b3ccab21..48e2fa5858 100644
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--- a/qemu-nbd.c
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+++ b/qemu-nbd.c
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@@ -390,7 +390,9 @@ static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
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nb_fds++;
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nbd_update_server_watch();
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- nbd_client_new(cioc, tlscreds, tlsauthz, nbd_client_closed);
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+ /* TODO - expose handshake timeout as command line option */
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+ nbd_client_new(cioc, NBD_DEFAULT_HANDSHAKE_MAX_SECS,
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+ tlscreds, tlsauthz, nbd_client_closed, NULL);
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}
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static void nbd_update_server_watch(void)
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--
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2.39.3
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