[PATCH 5.10 04/43] ipvs: reload ip header after head reallocation

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

5.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Florian Westphal <fw@strlen.de>

commit a2f57827bf7c695b8c72dc4511cae8e86582369d upstream.

__ip_vs_get_out_rt() calls skb_ensure_writable() which may
reallocate skb->head.

Fixes: 8d8e20e2d7bb ("ipvs: Decrement ttl")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-sonnet-4-6
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
[Denis Arefev: adapted for 5.10/6.1: keep EnterFunction/LeaveFunction
instrumentation]
Signed-off-by: Denis Arefev <arefev@swemel.ru>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/netfilter/ipvs/ip_vs_xmit.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
index 9e199f00eea73..40a1d31b4054f 100644
--- a/net/netfilter/ipvs/ip_vs_xmit.c
+++ b/net/netfilter/ipvs/ip_vs_xmit.c
@@ -718,15 +718,13 @@ int
 ip_vs_bypass_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 		  struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
 {
-	struct iphdr  *iph = ip_hdr(skb);
-
 	EnterFunction(10);
 
-	if (__ip_vs_get_out_rt(cp->ipvs, cp->af, skb, NULL, iph->daddr,
+	if (__ip_vs_get_out_rt(cp->ipvs, cp->af, skb, NULL, ip_hdr(skb)->daddr,
 			       IP_VS_RT_MODE_NON_LOCAL, NULL, ipvsh) < 0)
 		goto tx_error;
 
-	ip_send_check(iph);
+	ip_send_check(ip_hdr(skb));
 
 	/* Another hack: avoid icmp_send in ip_fragment */
 	skb->ignore_df = 1;
-- 
2.53.0