6.6-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit 4b8474a0951e605d2a27a2c483da4eb4b8c63760 ]
__icmp_send() must ensure rcu_read_lock() is held, as spotted by Jakub.
Other ICMP uses of dev_net() seem safe, change them to dev_net_rcu() to get LOCKDEP support.
Fixes: dde1bc0e6f86 ("[NETNS]: Add namespace for ICMP replying code.") Closes: https://lore.kernel.org/netdev/20250203153633.46ce0337@kernel.org/ Reported-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Eric Dumazet edumazet@google.com Link: https://patch.msgid.link/20250205155120.1676781-9-edumazet@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv4/icmp.c | 31 +++++++++++++++++-------------- 1 file changed, 17 insertions(+), 14 deletions(-)
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index a6adf6a2ec4b5..a21d32b3ae6c3 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -403,10 +403,10 @@ static void icmp_push_reply(struct sock *sk,
static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) { - struct ipcm_cookie ipc; struct rtable *rt = skb_rtable(skb); - struct net *net = dev_net(rt->dst.dev); + struct net *net = dev_net_rcu(rt->dst.dev); bool apply_ratelimit = false; + struct ipcm_cookie ipc; struct flowi4 fl4; struct sock *sk; struct inet_sock *inet; @@ -609,12 +609,14 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, struct sock *sk;
if (!rt) - goto out; + return; + + rcu_read_lock();
if (rt->dst.dev) - net = dev_net(rt->dst.dev); + net = dev_net_rcu(rt->dst.dev); else if (skb_in->dev) - net = dev_net(skb_in->dev); + net = dev_net_rcu(skb_in->dev); else goto out;
@@ -783,7 +785,8 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, icmp_xmit_unlock(sk); out_bh_enable: local_bh_enable(); -out:; +out: + rcu_read_unlock(); } EXPORT_SYMBOL(__icmp_send);
@@ -832,7 +835,7 @@ static void icmp_socket_deliver(struct sk_buff *skb, u32 info) * avoid additional coding at protocol handlers. */ if (!pskb_may_pull(skb, iph->ihl * 4 + 8)) { - __ICMP_INC_STATS(dev_net(skb->dev), ICMP_MIB_INERRORS); + __ICMP_INC_STATS(dev_net_rcu(skb->dev), ICMP_MIB_INERRORS); return; }
@@ -866,7 +869,7 @@ static enum skb_drop_reason icmp_unreach(struct sk_buff *skb) struct net *net; u32 info = 0;
- net = dev_net(skb_dst(skb)->dev); + net = dev_net_rcu(skb_dst(skb)->dev);
/* * Incomplete header ? @@ -977,7 +980,7 @@ static enum skb_drop_reason icmp_unreach(struct sk_buff *skb) static enum skb_drop_reason icmp_redirect(struct sk_buff *skb) { if (skb->len < sizeof(struct iphdr)) { - __ICMP_INC_STATS(dev_net(skb->dev), ICMP_MIB_INERRORS); + __ICMP_INC_STATS(dev_net_rcu(skb->dev), ICMP_MIB_INERRORS); return SKB_DROP_REASON_PKT_TOO_SMALL; }
@@ -1009,7 +1012,7 @@ static enum skb_drop_reason icmp_echo(struct sk_buff *skb) struct icmp_bxm icmp_param; struct net *net;
- net = dev_net(skb_dst(skb)->dev); + net = dev_net_rcu(skb_dst(skb)->dev); /* should there be an ICMP stat for ignored echos? */ if (READ_ONCE(net->ipv4.sysctl_icmp_echo_ignore_all)) return SKB_NOT_DROPPED_YET; @@ -1038,9 +1041,9 @@ static enum skb_drop_reason icmp_echo(struct sk_buff *skb)
bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) { + struct net *net = dev_net_rcu(skb->dev); struct icmp_ext_hdr *ext_hdr, _ext_hdr; struct icmp_ext_echo_iio *iio, _iio; - struct net *net = dev_net(skb->dev); struct inet6_dev *in6_dev; struct in_device *in_dev; struct net_device *dev; @@ -1179,7 +1182,7 @@ static enum skb_drop_reason icmp_timestamp(struct sk_buff *skb) return SKB_NOT_DROPPED_YET;
out_err: - __ICMP_INC_STATS(dev_net(skb_dst(skb)->dev), ICMP_MIB_INERRORS); + __ICMP_INC_STATS(dev_net_rcu(skb_dst(skb)->dev), ICMP_MIB_INERRORS); return SKB_DROP_REASON_PKT_TOO_SMALL; }
@@ -1196,7 +1199,7 @@ int icmp_rcv(struct sk_buff *skb) { enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED; struct rtable *rt = skb_rtable(skb); - struct net *net = dev_net(rt->dst.dev); + struct net *net = dev_net_rcu(rt->dst.dev); struct icmphdr *icmph;
if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { @@ -1369,9 +1372,9 @@ int icmp_err(struct sk_buff *skb, u32 info) struct iphdr *iph = (struct iphdr *)skb->data; int offset = iph->ihl<<2; struct icmphdr *icmph = (struct icmphdr *)(skb->data + offset); + struct net *net = dev_net_rcu(skb->dev); int type = icmp_hdr(skb)->type; int code = icmp_hdr(skb)->code; - struct net *net = dev_net(skb->dev);
/* * Use ping_err to handle all icmp errors except those