linux/fs/dlm/netlink.c
Jakub Kicinski 9c5d03d362 genetlink: start to validate reserved header bytes
We had historically not checked that genlmsghdr.reserved
is 0 on input which prevents us from using those precious
bytes in the future.

One use case would be to extend the cmd field, which is
currently just 8 bits wide and 256 is not a lot of commands
for some core families.

To make sure that new families do the right thing by default
put the onus of opting out of validation on existing families.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Paul Moore <paul@paul-moore.com> (NetLabel)
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-08-29 12:47:15 +01:00

140 lines
2.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2007 Red Hat, Inc. All rights reserved.
*/
#include <net/genetlink.h>
#include <linux/dlm.h>
#include <linux/dlm_netlink.h>
#include <linux/gfp.h>
#include "dlm_internal.h"
static uint32_t dlm_nl_seqnum;
static uint32_t listener_nlportid;
static struct genl_family family;
static int prepare_data(u8 cmd, struct sk_buff **skbp, size_t size)
{
struct sk_buff *skb;
void *data;
skb = genlmsg_new(size, GFP_NOFS);
if (!skb)
return -ENOMEM;
/* add the message headers */
data = genlmsg_put(skb, 0, dlm_nl_seqnum++, &family, 0, cmd);
if (!data) {
nlmsg_free(skb);
return -EINVAL;
}
*skbp = skb;
return 0;
}
static struct dlm_lock_data *mk_data(struct sk_buff *skb)
{
struct nlattr *ret;
ret = nla_reserve(skb, DLM_TYPE_LOCK, sizeof(struct dlm_lock_data));
if (!ret)
return NULL;
return nla_data(ret);
}
static int send_data(struct sk_buff *skb)
{
struct genlmsghdr *genlhdr = nlmsg_data((struct nlmsghdr *)skb->data);
void *data = genlmsg_data(genlhdr);
genlmsg_end(skb, data);
return genlmsg_unicast(&init_net, skb, listener_nlportid);
}
static int user_cmd(struct sk_buff *skb, struct genl_info *info)
{
listener_nlportid = info->snd_portid;
printk("user_cmd nlpid %u\n", listener_nlportid);
return 0;
}
static const struct genl_small_ops dlm_nl_ops[] = {
{
.cmd = DLM_CMD_HELLO,
.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
.doit = user_cmd,
},
};
static struct genl_family family __ro_after_init = {
.name = DLM_GENL_NAME,
.version = DLM_GENL_VERSION,
.small_ops = dlm_nl_ops,
.n_small_ops = ARRAY_SIZE(dlm_nl_ops),
.resv_start_op = DLM_CMD_HELLO + 1,
.module = THIS_MODULE,
};
int __init dlm_netlink_init(void)
{
return genl_register_family(&family);
}
void dlm_netlink_exit(void)
{
genl_unregister_family(&family);
}
static void fill_data(struct dlm_lock_data *data, struct dlm_lkb *lkb)
{
struct dlm_rsb *r = lkb->lkb_resource;
memset(data, 0, sizeof(struct dlm_lock_data));
data->version = DLM_LOCK_DATA_VERSION;
data->nodeid = lkb->lkb_nodeid;
data->ownpid = lkb->lkb_ownpid;
data->id = lkb->lkb_id;
data->remid = lkb->lkb_remid;
data->status = lkb->lkb_status;
data->grmode = lkb->lkb_grmode;
data->rqmode = lkb->lkb_rqmode;
if (lkb->lkb_ua)
data->xid = lkb->lkb_ua->xid;
if (r) {
data->lockspace_id = r->res_ls->ls_global_id;
data->resource_namelen = r->res_length;
memcpy(data->resource_name, r->res_name, r->res_length);
}
}
void dlm_timeout_warn(struct dlm_lkb *lkb)
{
struct sk_buff *send_skb;
struct dlm_lock_data *data;
size_t size;
int rv;
size = nla_total_size(sizeof(struct dlm_lock_data)) +
nla_total_size(0); /* why this? */
rv = prepare_data(DLM_CMD_TIMEOUT, &send_skb, size);
if (rv < 0)
return;
data = mk_data(send_skb);
if (!data) {
nlmsg_free(send_skb);
return;
}
fill_data(data, lkb);
send_data(send_skb);
}