6.15-stable review patch. If anyone has any objections, please let me know.
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From: Jakub Kicinski kuba@kernel.org
[ Upstream commit 8d89661a36dd3bb8c9902cff36dc0c144dce3faf ]
The length in the pseudo header should be the length of the L3 payload AKA the L4 header+payload. The selftest code builds the packet from the lower layers up, so all the headers are pushed already when it constructs L4. We need to subtract the lower layer headers from skb->len.
Fixes: 3e1e58d64c3d ("net: add generic selftest support") Signed-off-by: Jakub Kicinski kuba@kernel.org Reviewed-by: Gerhard Engleder gerhard@engleder-embedded.com Reported-by: Oleksij Rempel o.rempel@pengutronix.de Tested-by: Oleksij Rempel o.rempel@pengutronix.de Reviewed-by: Oleksij Rempel o.rempel@pengutronix.de Link: https://patch.msgid.link/20250624183258.3377740-1-kuba@kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/selftests.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/net/core/selftests.c b/net/core/selftests.c index 35f807ea99523..406faf8e5f3f9 100644 --- a/net/core/selftests.c +++ b/net/core/selftests.c @@ -160,8 +160,9 @@ static struct sk_buff *net_test_get_skb(struct net_device *ndev, skb->csum = 0; skb->ip_summed = CHECKSUM_PARTIAL; if (attr->tcp) { - thdr->check = ~tcp_v4_check(skb->len, ihdr->saddr, - ihdr->daddr, 0); + int l4len = skb->len - skb_transport_offset(skb); + + thdr->check = ~tcp_v4_check(l4len, ihdr->saddr, ihdr->daddr, 0); skb->csum_start = skb_transport_header(skb) - skb->head; skb->csum_offset = offsetof(struct tcphdr, check); } else {