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7c6d2ecbda
Recent change in virtio_net_hdr_to_skb() broke some packetdrill tests.
When --mss=XXX option is set, packetdrill always provide gso_type & gso_size
for its inbound packets, regardless of packet size.
if (packet->tcp && packet->mss) {
if (packet->ipv4)
gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
else
gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
gso.gso_size = packet->mss;
}
Since many other programs could do the same, relax virtio_net_hdr_to_skb()
to no longer return an error, but instead ignore gso settings.
This keeps Willem intent to make sure no malicious packet could
reach gso stack.
Note that TCP stack has a special logic in tcp_set_skb_tso_segs()
to clear gso_size for small packets.
Fixes: 6dd912f826 ("net: check untrusted gso_size at kernel entry")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
169 lines
4.4 KiB
C
169 lines
4.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_VIRTIO_NET_H
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#define _LINUX_VIRTIO_NET_H
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#include <linux/if_vlan.h>
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#include <uapi/linux/tcp.h>
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#include <uapi/linux/udp.h>
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#include <uapi/linux/virtio_net.h>
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static inline int virtio_net_hdr_set_proto(struct sk_buff *skb,
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const struct virtio_net_hdr *hdr)
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{
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switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
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case VIRTIO_NET_HDR_GSO_TCPV4:
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case VIRTIO_NET_HDR_GSO_UDP:
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skb->protocol = cpu_to_be16(ETH_P_IP);
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break;
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case VIRTIO_NET_HDR_GSO_TCPV6:
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skb->protocol = cpu_to_be16(ETH_P_IPV6);
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
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const struct virtio_net_hdr *hdr,
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bool little_endian)
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{
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unsigned int gso_type = 0;
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unsigned int thlen = 0;
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unsigned int p_off = 0;
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unsigned int ip_proto;
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if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
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switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
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case VIRTIO_NET_HDR_GSO_TCPV4:
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gso_type = SKB_GSO_TCPV4;
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ip_proto = IPPROTO_TCP;
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thlen = sizeof(struct tcphdr);
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break;
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case VIRTIO_NET_HDR_GSO_TCPV6:
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gso_type = SKB_GSO_TCPV6;
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ip_proto = IPPROTO_TCP;
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thlen = sizeof(struct tcphdr);
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break;
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case VIRTIO_NET_HDR_GSO_UDP:
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gso_type = SKB_GSO_UDP;
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ip_proto = IPPROTO_UDP;
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thlen = sizeof(struct udphdr);
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break;
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default:
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return -EINVAL;
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}
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if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
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gso_type |= SKB_GSO_TCP_ECN;
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if (hdr->gso_size == 0)
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return -EINVAL;
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}
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if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
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u16 start = __virtio16_to_cpu(little_endian, hdr->csum_start);
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u16 off = __virtio16_to_cpu(little_endian, hdr->csum_offset);
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if (!skb_partial_csum_set(skb, start, off))
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return -EINVAL;
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p_off = skb_transport_offset(skb) + thlen;
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if (p_off > skb_headlen(skb))
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return -EINVAL;
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} else {
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/* gso packets without NEEDS_CSUM do not set transport_offset.
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* probe and drop if does not match one of the above types.
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*/
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if (gso_type && skb->network_header) {
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struct flow_keys_basic keys;
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if (!skb->protocol)
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virtio_net_hdr_set_proto(skb, hdr);
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retry:
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if (!skb_flow_dissect_flow_keys_basic(NULL, skb, &keys,
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NULL, 0, 0, 0,
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0)) {
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/* UFO does not specify ipv4 or 6: try both */
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if (gso_type & SKB_GSO_UDP &&
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skb->protocol == htons(ETH_P_IP)) {
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skb->protocol = htons(ETH_P_IPV6);
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goto retry;
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}
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return -EINVAL;
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}
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p_off = keys.control.thoff + thlen;
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if (p_off > skb_headlen(skb) ||
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keys.basic.ip_proto != ip_proto)
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return -EINVAL;
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skb_set_transport_header(skb, keys.control.thoff);
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} else if (gso_type) {
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p_off = thlen;
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if (p_off > skb_headlen(skb))
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return -EINVAL;
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}
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}
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if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
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u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size);
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struct skb_shared_info *shinfo = skb_shinfo(skb);
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/* Too small packets are not really GSO ones. */
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if (skb->len - p_off > gso_size) {
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shinfo->gso_size = gso_size;
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shinfo->gso_type = gso_type;
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/* Header must be checked, and gso_segs computed. */
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shinfo->gso_type |= SKB_GSO_DODGY;
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shinfo->gso_segs = 0;
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}
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}
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return 0;
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}
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static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
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struct virtio_net_hdr *hdr,
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bool little_endian,
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bool has_data_valid,
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int vlan_hlen)
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{
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memset(hdr, 0, sizeof(*hdr)); /* no info leak */
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if (skb_is_gso(skb)) {
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struct skb_shared_info *sinfo = skb_shinfo(skb);
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/* This is a hint as to how much should be linear. */
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hdr->hdr_len = __cpu_to_virtio16(little_endian,
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skb_headlen(skb));
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hdr->gso_size = __cpu_to_virtio16(little_endian,
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sinfo->gso_size);
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if (sinfo->gso_type & SKB_GSO_TCPV4)
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hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
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else if (sinfo->gso_type & SKB_GSO_TCPV6)
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hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
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else
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return -EINVAL;
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if (sinfo->gso_type & SKB_GSO_TCP_ECN)
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hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
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} else
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hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
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if (skb->ip_summed == CHECKSUM_PARTIAL) {
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hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
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hdr->csum_start = __cpu_to_virtio16(little_endian,
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skb_checksum_start_offset(skb) + vlan_hlen);
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hdr->csum_offset = __cpu_to_virtio16(little_endian,
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skb->csum_offset);
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} else if (has_data_valid &&
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skb->ip_summed == CHECKSUM_UNNECESSARY) {
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hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
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} /* else everything is zero */
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return 0;
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}
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#endif /* _LINUX_VIRTIO_NET_H */
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