9adfb308c1
We currently store the file descriptor used during the main outgoing channel creation to use it again when creating the multifd channels. Since this fd is used for the first iochannel, there's risk that the QIOChannel gets freed and the fd closed while outgoing_args.fd still has it available. This could lead to an fd-reuse bug. Duplicate the outgoing_args fd to avoid this issue. Suggested-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Link: https://lore.kernel.org/r/20240315032040.7974-3-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
124 lines
3.0 KiB
C
124 lines
3.0 KiB
C
/*
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* QEMU live migration via generic fd
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*
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* Copyright Red Hat, Inc. 2009-2016
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*
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* Authors:
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* Chris Lalancette <clalance@redhat.com>
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* Daniel P. Berrange <berrange@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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* Contributions after 2012-01-13 are licensed under the terms of the
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* GNU GPL, version 2 or (at your option) any later version.
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*/
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#include "qemu/osdep.h"
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#include "qapi/error.h"
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#include "channel.h"
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#include "fd.h"
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#include "file.h"
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#include "migration.h"
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#include "monitor/monitor.h"
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#include "io/channel-file.h"
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#include "io/channel-socket.h"
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#include "io/channel-util.h"
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#include "options.h"
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#include "trace.h"
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static struct FdOutgoingArgs {
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int fd;
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} outgoing_args;
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int fd_args_get_fd(void)
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{
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return outgoing_args.fd;
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}
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void fd_cleanup_outgoing_migration(void)
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{
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if (outgoing_args.fd > 0) {
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close(outgoing_args.fd);
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outgoing_args.fd = -1;
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}
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}
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void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **errp)
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{
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QIOChannel *ioc;
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int fd = monitor_get_fd(monitor_cur(), fdname, errp);
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int newfd;
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if (fd == -1) {
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return;
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}
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trace_migration_fd_outgoing(fd);
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ioc = qio_channel_new_fd(fd, errp);
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if (!ioc) {
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close(fd);
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return;
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}
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/*
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* This is dup()ed just to avoid referencing an fd that might
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* be already closed by the iochannel.
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*/
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newfd = dup(fd);
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if (newfd == -1) {
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error_setg_errno(errp, errno, "Could not dup FD %d", fd);
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object_unref(ioc);
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return;
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}
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outgoing_args.fd = newfd;
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qio_channel_set_name(ioc, "migration-fd-outgoing");
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migration_channel_connect(s, ioc, NULL, NULL);
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object_unref(OBJECT(ioc));
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}
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static gboolean fd_accept_incoming_migration(QIOChannel *ioc,
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GIOCondition condition,
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gpointer opaque)
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{
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migration_channel_process_incoming(ioc);
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object_unref(OBJECT(ioc));
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return G_SOURCE_REMOVE;
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}
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void fd_start_incoming_migration(const char *fdname, Error **errp)
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{
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QIOChannel *ioc;
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int fd = monitor_fd_param(monitor_cur(), fdname, errp);
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if (fd == -1) {
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return;
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}
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trace_migration_fd_incoming(fd);
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ioc = qio_channel_new_fd(fd, errp);
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if (!ioc) {
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close(fd);
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return;
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}
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if (migrate_multifd()) {
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if (fd_is_socket(fd)) {
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error_setg(errp,
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"Multifd migration to a socket FD is not supported");
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object_unref(ioc);
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return;
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}
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file_create_incoming_channels(ioc, errp);
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} else {
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qio_channel_set_name(ioc, "migration-fd-incoming");
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qio_channel_add_watch_full(ioc, G_IO_IN,
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fd_accept_incoming_migration,
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NULL, NULL,
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g_main_context_get_thread_default());
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}
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}
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