linuxmsm/laptops-kernel
0
0
Fork 0
mirror of https://github.com/linux-msm/laptops-kernel.git synced 2026-08-13 14:19:53 -07:00
Code Issues Packages Projects Releases Wiki Activity

ipv4: snapshot dst.dev in ip_rt_send_redirect() and ip_rt_get_source()

Browse Source 
rt_flush_dev() can replace rt->dst.dev with blackhole_netdev while RCU
readers are running.  ip_rt_send_redirect() and ip_rt_get_source() both
read rt->dst.dev more than once and use the results in one operation.

If rt->dst.dev changes between those reads, the operation can use values
from two devices.  For example, ip_rt_send_redirect() can use in_dev from
the old device and the L3 master ifindex from blackhole_netdev.

Read rt->dst.dev once in these two functions and use the snapshot for the
later device accesses.

Signed-off-by: Xuanqiang Luo <luoxuanqiang@kylinos.cn>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260708060537.17188-3-xuanqiang.luo@linux.dev
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Xuanqiang Luo
2026-07-21 11:45:53 +02:00
committed by Paolo Abeni
parent 1469773b24
commit 7804eaa057
1 changed files with 18 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files
net/ipv4/route.c
+18 -13
View File
@@ -874,21 +874,23 @@ void ip_rt_send_redirect(struct sk_buff *skb)
{ {
struct rtable *rt = skb_rtable(skb); struct rtable *rt = skb_rtable(skb);
struct in_device *in_dev; struct in_device *in_dev;
struct net_device *dev;
struct inet_peer *peer; struct inet_peer *peer;
struct net *net;
int log_martians; int log_martians;
struct net *net;
int vif; int vif;
rcu_read_lock(); rcu_read_lock();
in_dev = __in_dev_get_rcu(rt->dst.dev); dev = dst_dev_rcu(&rt->dst);
in_dev = __in_dev_get_rcu(dev);
if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
rcu_read_unlock(); rcu_read_unlock();
return; return;
} }
log_martians = IN_DEV_LOG_MARTIANS(in_dev); log_martians = IN_DEV_LOG_MARTIANS(in_dev);
vif = l3mdev_master_ifindex_rcu(rt->dst.dev); vif = l3mdev_master_ifindex_rcu(dev);
net = dev_net(rt->dst.dev); net = dev_net_rcu(dev);
peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif); peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif);
if (!peer) { if (!peer) {
rcu_read_unlock(); rcu_read_unlock();
@@ -1287,29 +1289,32 @@ void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
{ {
__be32 src; __be32 src;
if (rt_is_output_route(rt)) rcu_read_lock();
if (rt_is_output_route(rt)) {
src = ip_hdr(skb)->saddr; src = ip_hdr(skb)->saddr;
else { } else {
struct fib_result res; struct net_device *dev = dst_dev_rcu(&rt->dst);
struct net *net = dev_net_rcu(dev);
struct iphdr *iph = ip_hdr(skb); struct iphdr *iph = ip_hdr(skb);
struct fib_result res;
struct flowi4 fl4 = { struct flowi4 fl4 = {
.daddr = iph->daddr, .daddr = iph->daddr,
.saddr = iph->saddr, .saddr = iph->saddr,
.flowi4_dscp = ip4h_dscp(iph), .flowi4_dscp = ip4h_dscp(iph),
.flowi4_oif = rt->dst.dev->ifindex, .flowi4_oif = dev->ifindex,
.flowi4_iif = skb->dev->ifindex, .flowi4_iif = skb->dev->ifindex,
.flowi4_mark = skb->mark, .flowi4_mark = skb->mark,
}; };
rcu_read_lock(); if (fib_lookup(net, &fl4, &res, 0) == 0)
if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0) src = fib_result_prefsrc(net, &res);
src = fib_result_prefsrc(dev_net(rt->dst.dev), &res);
else else
src = inet_select_addr(rt->dst.dev, src = inet_select_addr(dev,
rt_nexthop(rt, iph->daddr), rt_nexthop(rt, iph->daddr),
RT_SCOPE_UNIVERSE); RT_SCOPE_UNIVERSE);
rcu_read_unlock();
} }
rcu_read_unlock();
memcpy(addr, &src, 4); memcpy(addr, &src, 4);
} }