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1eb2cded45
Simon reported that ndo_change_mtu() methods were never
updated to use WRITE_ONCE(dev->mtu, new_mtu) as hinted
in commit 501a90c945 ("inet: protect against too small
mtu values.")
We read dev->mtu without holding RTNL in many places,
with READ_ONCE() annotations.
It is time to take care of ndo_change_mtu() methods
to use corresponding WRITE_ONCE()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Simon Horman <horms@kernel.org>
Closes: https://lore.kernel.org/netdev/20240505144608.GB67882@kernel.org/
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Acked-by: Shannon Nelson <shannon.nelson@amd.com>
Link: https://lore.kernel.org/r/20240506102812.3025432-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
123 lines
2.7 KiB
C
123 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/ethtool.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/if_arp.h>
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#include <net/rtnetlink.h>
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#include <net/sock.h>
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#include <net/af_vsock.h>
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#include <uapi/linux/vsockmon.h>
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#include <linux/virtio_vsock.h>
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/* Virtio transport max packet size plus header */
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#define DEFAULT_MTU (VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + \
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sizeof(struct af_vsockmon_hdr))
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struct vsockmon {
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struct vsock_tap vt;
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};
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static int vsockmon_open(struct net_device *dev)
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{
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struct vsockmon *vsockmon = netdev_priv(dev);
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vsockmon->vt.dev = dev;
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vsockmon->vt.module = THIS_MODULE;
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return vsock_add_tap(&vsockmon->vt);
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}
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static int vsockmon_close(struct net_device *dev)
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{
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struct vsockmon *vsockmon = netdev_priv(dev);
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return vsock_remove_tap(&vsockmon->vt);
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}
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static netdev_tx_t vsockmon_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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dev_lstats_add(dev, skb->len);
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dev_kfree_skb(skb);
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return NETDEV_TX_OK;
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}
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static void
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vsockmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
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{
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dev_lstats_read(dev, &stats->rx_packets, &stats->rx_bytes);
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}
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static int vsockmon_is_valid_mtu(int new_mtu)
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{
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return new_mtu >= (int)sizeof(struct af_vsockmon_hdr);
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}
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static int vsockmon_change_mtu(struct net_device *dev, int new_mtu)
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{
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if (!vsockmon_is_valid_mtu(new_mtu))
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return -EINVAL;
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WRITE_ONCE(dev->mtu, new_mtu);
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return 0;
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}
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static const struct net_device_ops vsockmon_ops = {
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.ndo_open = vsockmon_open,
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.ndo_stop = vsockmon_close,
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.ndo_start_xmit = vsockmon_xmit,
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.ndo_get_stats64 = vsockmon_get_stats64,
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.ndo_change_mtu = vsockmon_change_mtu,
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};
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static u32 always_on(struct net_device *dev)
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{
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return 1;
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}
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static const struct ethtool_ops vsockmon_ethtool_ops = {
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.get_link = always_on,
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};
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static void vsockmon_setup(struct net_device *dev)
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{
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dev->type = ARPHRD_VSOCKMON;
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dev->priv_flags |= IFF_NO_QUEUE;
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dev->netdev_ops = &vsockmon_ops;
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dev->ethtool_ops = &vsockmon_ethtool_ops;
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dev->needs_free_netdev = true;
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dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
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NETIF_F_HIGHDMA | NETIF_F_LLTX;
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dev->flags = IFF_NOARP;
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dev->mtu = DEFAULT_MTU;
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dev->pcpu_stat_type = NETDEV_PCPU_STAT_LSTATS;
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}
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static struct rtnl_link_ops vsockmon_link_ops __read_mostly = {
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.kind = "vsockmon",
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.priv_size = sizeof(struct vsockmon),
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.setup = vsockmon_setup,
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};
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static __init int vsockmon_register(void)
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{
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return rtnl_link_register(&vsockmon_link_ops);
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}
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static __exit void vsockmon_unregister(void)
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{
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rtnl_link_unregister(&vsockmon_link_ops);
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}
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module_init(vsockmon_register);
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module_exit(vsockmon_unregister);
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR("Gerard Garcia <ggarcia@deic.uab.cat>");
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MODULE_DESCRIPTION("Vsock monitoring device. Based on nlmon device.");
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MODULE_ALIAS_RTNL_LINK("vsockmon");
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