Revision 9c1c2b35f1d94de8325344c2777d7ee67492db3b authored by Jeff Layton on 03 April 2019, 17:16:01 UTC, committed by Ilya Dryomov on 21 January 2020, 18:02:37 UTC
Currently, we just assume that it will stick around by virtue of the submitter's reference, but later patches will allow the syscall to return early and we can't rely on that reference at that point. While I'm not aware of any reports of it, Xiubo pointed out that this may fix a use-after-free. If the wait for a reply times out or is canceled via signal, and then the reply comes in after the syscall returns, the client can end up trying to access r_parent without a reference. Take an extra reference to the inode when setting r_parent and release it when releasing the request. Cc: stable@vger.kernel.org Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: "Yan, Zheng" <zyan@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
1 parent def9d27
br_arp_nd_proxy.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Handle bridge arp/nd proxy/suppress
*
* Copyright (C) 2017 Cumulus Networks
* Copyright (c) 2017 Roopa Prabhu <roopa@cumulusnetworks.com>
*
* Authors:
* Roopa Prabhu <roopa@cumulusnetworks.com>
*/
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/neighbour.h>
#include <net/arp.h>
#include <linux/if_vlan.h>
#include <linux/inetdevice.h>
#include <net/addrconf.h>
#include <net/ipv6_stubs.h>
#if IS_ENABLED(CONFIG_IPV6)
#include <net/ip6_checksum.h>
#endif
#include "br_private.h"
void br_recalculate_neigh_suppress_enabled(struct net_bridge *br)
{
struct net_bridge_port *p;
bool neigh_suppress = false;
list_for_each_entry(p, &br->port_list, list) {
if (p->flags & BR_NEIGH_SUPPRESS) {
neigh_suppress = true;
break;
}
}
br_opt_toggle(br, BROPT_NEIGH_SUPPRESS_ENABLED, neigh_suppress);
}
#if IS_ENABLED(CONFIG_INET)
static void br_arp_send(struct net_bridge *br, struct net_bridge_port *p,
struct net_device *dev, __be32 dest_ip, __be32 src_ip,
const unsigned char *dest_hw,
const unsigned char *src_hw,
const unsigned char *target_hw,
__be16 vlan_proto, u16 vlan_tci)
{
struct net_bridge_vlan_group *vg;
struct sk_buff *skb;
u16 pvid;
netdev_dbg(dev, "arp send dev %s dst %pI4 dst_hw %pM src %pI4 src_hw %pM\n",
dev->name, &dest_ip, dest_hw, &src_ip, src_hw);
if (!vlan_tci) {
arp_send(ARPOP_REPLY, ETH_P_ARP, dest_ip, dev, src_ip,
dest_hw, src_hw, target_hw);
return;
}
skb = arp_create(ARPOP_REPLY, ETH_P_ARP, dest_ip, dev, src_ip,
dest_hw, src_hw, target_hw);
if (!skb)
return;
if (p)
vg = nbp_vlan_group_rcu(p);
else
vg = br_vlan_group_rcu(br);
pvid = br_get_pvid(vg);
if (pvid == (vlan_tci & VLAN_VID_MASK))
vlan_tci = 0;
if (vlan_tci)
__vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
if (p) {
arp_xmit(skb);
} else {
skb_reset_mac_header(skb);
__skb_pull(skb, skb_network_offset(skb));
skb->ip_summed = CHECKSUM_UNNECESSARY;
skb->pkt_type = PACKET_HOST;
netif_rx_ni(skb);
}
}
static int br_chk_addr_ip(struct net_device *dev, void *data)
{
__be32 ip = *(__be32 *)data;
struct in_device *in_dev;
__be32 addr = 0;
in_dev = __in_dev_get_rcu(dev);
if (in_dev)
addr = inet_confirm_addr(dev_net(dev), in_dev, 0, ip,
RT_SCOPE_HOST);
if (addr == ip)
return 1;
return 0;
}
static bool br_is_local_ip(struct net_device *dev, __be32 ip)
{
if (br_chk_addr_ip(dev, &ip))
return true;
/* check if ip is configured on upper dev */
if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip, &ip))
return true;
return false;
}
void br_do_proxy_suppress_arp(struct sk_buff *skb, struct net_bridge *br,
u16 vid, struct net_bridge_port *p)
{
struct net_device *dev = br->dev;
struct net_device *vlandev = dev;
struct neighbour *n;
struct arphdr *parp;
u8 *arpptr, *sha;
__be32 sip, tip;
BR_INPUT_SKB_CB(skb)->proxyarp_replied = 0;
if ((dev->flags & IFF_NOARP) ||
!pskb_may_pull(skb, arp_hdr_len(dev)))
return;
parp = arp_hdr(skb);
if (parp->ar_pro != htons(ETH_P_IP) ||
parp->ar_hln != dev->addr_len ||
parp->ar_pln != 4)
return;
arpptr = (u8 *)parp + sizeof(struct arphdr);
sha = arpptr;
arpptr += dev->addr_len; /* sha */
memcpy(&sip, arpptr, sizeof(sip));
arpptr += sizeof(sip);
arpptr += dev->addr_len; /* tha */
memcpy(&tip, arpptr, sizeof(tip));
if (ipv4_is_loopback(tip) ||
ipv4_is_multicast(tip))
return;
if (br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED)) {
if (p && (p->flags & BR_NEIGH_SUPPRESS))
return;
if (ipv4_is_zeronet(sip) || sip == tip) {
/* prevent flooding to neigh suppress ports */
BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
return;
}
}
if (parp->ar_op != htons(ARPOP_REQUEST))
return;
if (vid != 0) {
vlandev = __vlan_find_dev_deep_rcu(br->dev, skb->vlan_proto,
vid);
if (!vlandev)
return;
}
if (br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED) &&
br_is_local_ip(vlandev, tip)) {
/* its our local ip, so don't proxy reply
* and don't forward to neigh suppress ports
*/
BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
return;
}
n = neigh_lookup(&arp_tbl, &tip, vlandev);
if (n) {
struct net_bridge_fdb_entry *f;
if (!(n->nud_state & NUD_VALID)) {
neigh_release(n);
return;
}
f = br_fdb_find_rcu(br, n->ha, vid);
if (f) {
bool replied = false;
if ((p && (p->flags & BR_PROXYARP)) ||
(f->dst && (f->dst->flags & (BR_PROXYARP_WIFI |
BR_NEIGH_SUPPRESS)))) {
if (!vid)
br_arp_send(br, p, skb->dev, sip, tip,
sha, n->ha, sha, 0, 0);
else
br_arp_send(br, p, skb->dev, sip, tip,
sha, n->ha, sha,
skb->vlan_proto,
skb_vlan_tag_get(skb));
replied = true;
}
/* If we have replied or as long as we know the
* mac, indicate to arp replied
*/
if (replied ||
br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED))
BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
}
neigh_release(n);
}
}
#endif
#if IS_ENABLED(CONFIG_IPV6)
struct nd_msg *br_is_nd_neigh_msg(struct sk_buff *skb, struct nd_msg *msg)
{
struct nd_msg *m;
m = skb_header_pointer(skb, skb_network_offset(skb) +
sizeof(struct ipv6hdr), sizeof(*msg), msg);
if (!m)
return NULL;
if (m->icmph.icmp6_code != 0 ||
(m->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION &&
m->icmph.icmp6_type != NDISC_NEIGHBOUR_ADVERTISEMENT))
return NULL;
return m;
}
static void br_nd_send(struct net_bridge *br, struct net_bridge_port *p,
struct sk_buff *request, struct neighbour *n,
__be16 vlan_proto, u16 vlan_tci, struct nd_msg *ns)
{
struct net_device *dev = request->dev;
struct net_bridge_vlan_group *vg;
struct sk_buff *reply;
struct nd_msg *na;
struct ipv6hdr *pip6;
int na_olen = 8; /* opt hdr + ETH_ALEN for target */
int ns_olen;
int i, len;
u8 *daddr;
u16 pvid;
if (!dev)
return;
len = LL_RESERVED_SPACE(dev) + sizeof(struct ipv6hdr) +
sizeof(*na) + na_olen + dev->needed_tailroom;
reply = alloc_skb(len, GFP_ATOMIC);
if (!reply)
return;
reply->protocol = htons(ETH_P_IPV6);
reply->dev = dev;
skb_reserve(reply, LL_RESERVED_SPACE(dev));
skb_push(reply, sizeof(struct ethhdr));
skb_set_mac_header(reply, 0);
daddr = eth_hdr(request)->h_source;
/* Do we need option processing ? */
ns_olen = request->len - (skb_network_offset(request) +
sizeof(struct ipv6hdr)) - sizeof(*ns);
for (i = 0; i < ns_olen - 1; i += (ns->opt[i + 1] << 3)) {
if (ns->opt[i] == ND_OPT_SOURCE_LL_ADDR) {
daddr = ns->opt + i + sizeof(struct nd_opt_hdr);
break;
}
}
/* Ethernet header */
ether_addr_copy(eth_hdr(reply)->h_dest, daddr);
ether_addr_copy(eth_hdr(reply)->h_source, n->ha);
eth_hdr(reply)->h_proto = htons(ETH_P_IPV6);
reply->protocol = htons(ETH_P_IPV6);
skb_pull(reply, sizeof(struct ethhdr));
skb_set_network_header(reply, 0);
skb_put(reply, sizeof(struct ipv6hdr));
/* IPv6 header */
pip6 = ipv6_hdr(reply);
memset(pip6, 0, sizeof(struct ipv6hdr));
pip6->version = 6;
pip6->priority = ipv6_hdr(request)->priority;
pip6->nexthdr = IPPROTO_ICMPV6;
pip6->hop_limit = 255;
pip6->daddr = ipv6_hdr(request)->saddr;
pip6->saddr = *(struct in6_addr *)n->primary_key;
skb_pull(reply, sizeof(struct ipv6hdr));
skb_set_transport_header(reply, 0);
na = (struct nd_msg *)skb_put(reply, sizeof(*na) + na_olen);
/* Neighbor Advertisement */
memset(na, 0, sizeof(*na) + na_olen);
na->icmph.icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT;
na->icmph.icmp6_router = (n->flags & NTF_ROUTER) ? 1 : 0;
na->icmph.icmp6_override = 1;
na->icmph.icmp6_solicited = 1;
na->target = ns->target;
ether_addr_copy(&na->opt[2], n->ha);
na->opt[0] = ND_OPT_TARGET_LL_ADDR;
na->opt[1] = na_olen >> 3;
na->icmph.icmp6_cksum = csum_ipv6_magic(&pip6->saddr,
&pip6->daddr,
sizeof(*na) + na_olen,
IPPROTO_ICMPV6,
csum_partial(na, sizeof(*na) + na_olen, 0));
pip6->payload_len = htons(sizeof(*na) + na_olen);
skb_push(reply, sizeof(struct ipv6hdr));
skb_push(reply, sizeof(struct ethhdr));
reply->ip_summed = CHECKSUM_UNNECESSARY;
if (p)
vg = nbp_vlan_group_rcu(p);
else
vg = br_vlan_group_rcu(br);
pvid = br_get_pvid(vg);
if (pvid == (vlan_tci & VLAN_VID_MASK))
vlan_tci = 0;
if (vlan_tci)
__vlan_hwaccel_put_tag(reply, vlan_proto, vlan_tci);
netdev_dbg(dev, "nd send dev %s dst %pI6 dst_hw %pM src %pI6 src_hw %pM\n",
dev->name, &pip6->daddr, daddr, &pip6->saddr, n->ha);
if (p) {
dev_queue_xmit(reply);
} else {
skb_reset_mac_header(reply);
__skb_pull(reply, skb_network_offset(reply));
reply->ip_summed = CHECKSUM_UNNECESSARY;
reply->pkt_type = PACKET_HOST;
netif_rx_ni(reply);
}
}
static int br_chk_addr_ip6(struct net_device *dev, void *data)
{
struct in6_addr *addr = (struct in6_addr *)data;
if (ipv6_chk_addr(dev_net(dev), addr, dev, 0))
return 1;
return 0;
}
static bool br_is_local_ip6(struct net_device *dev, struct in6_addr *addr)
{
if (br_chk_addr_ip6(dev, addr))
return true;
/* check if ip is configured on upper dev */
if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip6, addr))
return true;
return false;
}
void br_do_suppress_nd(struct sk_buff *skb, struct net_bridge *br,
u16 vid, struct net_bridge_port *p, struct nd_msg *msg)
{
struct net_device *dev = br->dev;
struct net_device *vlandev = NULL;
struct in6_addr *saddr, *daddr;
struct ipv6hdr *iphdr;
struct neighbour *n;
BR_INPUT_SKB_CB(skb)->proxyarp_replied = 0;
if (p && (p->flags & BR_NEIGH_SUPPRESS))
return;
if (msg->icmph.icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT &&
!msg->icmph.icmp6_solicited) {
/* prevent flooding to neigh suppress ports */
BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
return;
}
if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
return;
iphdr = ipv6_hdr(skb);
saddr = &iphdr->saddr;
daddr = &iphdr->daddr;
if (ipv6_addr_any(saddr) || !ipv6_addr_cmp(saddr, daddr)) {
/* prevent flooding to neigh suppress ports */
BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
return;
}
if (vid != 0) {
/* build neigh table lookup on the vlan device */
vlandev = __vlan_find_dev_deep_rcu(br->dev, skb->vlan_proto,
vid);
if (!vlandev)
return;
} else {
vlandev = dev;
}
if (br_is_local_ip6(vlandev, &msg->target)) {
/* its our own ip, so don't proxy reply
* and don't forward to arp suppress ports
*/
BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
return;
}
n = neigh_lookup(ipv6_stub->nd_tbl, &msg->target, vlandev);
if (n) {
struct net_bridge_fdb_entry *f;
if (!(n->nud_state & NUD_VALID)) {
neigh_release(n);
return;
}
f = br_fdb_find_rcu(br, n->ha, vid);
if (f) {
bool replied = false;
if (f->dst && (f->dst->flags & BR_NEIGH_SUPPRESS)) {
if (vid != 0)
br_nd_send(br, p, skb, n,
skb->vlan_proto,
skb_vlan_tag_get(skb), msg);
else
br_nd_send(br, p, skb, n, 0, 0, msg);
replied = true;
}
/* If we have replied or as long as we know the
* mac, indicate to NEIGH_SUPPRESS ports that we
* have replied
*/
if (replied ||
br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED))
BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
}
neigh_release(n);
}
}
#endif
Computing file changes ...
