From 9e8d1013b0c38910cbc9e60de74dbe883878469d Mon Sep 17 00:00:00 2001 From: Oleksij Rempel Date: Wed, 16 Apr 2025 18:01:25 +0200 Subject: [PATCH] net: selftests: initialize TCP header and skb payload with zero Zero-initialize TCP header via memset() to avoid garbage values that may affect checksum or behavior during test transmission. Also zero-fill allocated payload and padding regions using memset() after skb_put(), ensuring deterministic content for all outgoing test packets. Fixes: 3e1e58d64c3d ("net: add generic selftest support") Signed-off-by: Oleksij Rempel Cc: stable@vger.kernel.org Reviewed-by: Simon Horman Link: https://patch.msgid.link/20250416160125.2914724-1-o.rempel@pengutronix.de Signed-off-by: Paolo Abeni --- net/core/selftests.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/net/core/selftests.c b/net/core/selftests.c index e99ae983fca9..35f807ea9952 100644 --- a/net/core/selftests.c +++ b/net/core/selftests.c @@ -100,10 +100,10 @@ static struct sk_buff *net_test_get_skb(struct net_device *ndev, ehdr->h_proto = htons(ETH_P_IP); if (attr->tcp) { + memset(thdr, 0, sizeof(*thdr)); thdr->source = htons(attr->sport); thdr->dest = htons(attr->dport); thdr->doff = sizeof(struct tcphdr) / 4; - thdr->check = 0; } else { uhdr->source = htons(attr->sport); uhdr->dest = htons(attr->dport); @@ -144,10 +144,18 @@ static struct sk_buff *net_test_get_skb(struct net_device *ndev, attr->id = net_test_next_id; shdr->id = net_test_next_id++; - if (attr->size) - skb_put(skb, attr->size); - if (attr->max_size && attr->max_size > skb->len) - skb_put(skb, attr->max_size - skb->len); + if (attr->size) { + void *payload = skb_put(skb, attr->size); + + memset(payload, 0, attr->size); + } + + if (attr->max_size && attr->max_size > skb->len) { + size_t pad_len = attr->max_size - skb->len; + void *pad = skb_put(skb, pad_len); + + memset(pad, 0, pad_len); + } skb->csum = 0; skb->ip_summed = CHECKSUM_PARTIAL;