From 706ba48665844b859fcf0bd9526ec5da28b915da Mon Sep 17 00:00:00 2001 From: Xiao Wang Date: Mon, 21 Jun 2021 16:21:04 +0800 Subject: [PATCH] vhost: check header for legacy dequeue offload When parsing the virtio net header and packet header for dequeue offload, we need to perform sanity check on the packet header to ensure: - No out-of-boundary memory access. - The packet header and virtio_net header are valid and aligned. Fixes: d0cf91303d73 ("vhost: add Tx offload capabilities") Cc: stable@dpdk.org Signed-off-by: Xiao Wang Reviewed-by: Maxime Coquelin --- lib/vhost/virtio_net.c | 117 +++++++++++++++++++++++++++++++---------- 1 file changed, 89 insertions(+), 28 deletions(-) diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c index b93482587c..aa30d147b6 100644 --- a/lib/vhost/virtio_net.c +++ b/lib/vhost/virtio_net.c @@ -2259,14 +2259,17 @@ virtio_net_with_host_offload(struct virtio_net *dev) return false; } -static void -parse_ethernet(struct rte_mbuf *m, uint16_t *l4_proto, void **l4_hdr) +static int +parse_headers(struct rte_mbuf *m, uint8_t *l4_proto) { struct rte_ipv4_hdr *ipv4_hdr; struct rte_ipv6_hdr *ipv6_hdr; - void *l3_hdr = NULL; struct rte_ether_hdr *eth_hdr; uint16_t ethertype; + uint16_t data_len = rte_pktmbuf_data_len(m); + + if (data_len < sizeof(struct rte_ether_hdr)) + return -EINVAL; eth_hdr = rte_pktmbuf_mtod(m, struct rte_ether_hdr *); @@ -2274,6 +2277,10 @@ parse_ethernet(struct rte_mbuf *m, uint16_t *l4_proto, void **l4_hdr) ethertype = rte_be_to_cpu_16(eth_hdr->ether_type); if (ethertype == RTE_ETHER_TYPE_VLAN) { + if (data_len < sizeof(struct rte_ether_hdr) + + sizeof(struct rte_vlan_hdr)) + goto error; + struct rte_vlan_hdr *vlan_hdr = (struct rte_vlan_hdr *)(eth_hdr + 1); @@ -2281,70 +2288,118 @@ parse_ethernet(struct rte_mbuf *m, uint16_t *l4_proto, void **l4_hdr) ethertype = rte_be_to_cpu_16(vlan_hdr->eth_proto); } - l3_hdr = (char *)eth_hdr + m->l2_len; - switch (ethertype) { case RTE_ETHER_TYPE_IPV4: - ipv4_hdr = l3_hdr; - *l4_proto = ipv4_hdr->next_proto_id; + if (data_len < m->l2_len + sizeof(struct rte_ipv4_hdr)) + goto error; + ipv4_hdr = rte_pktmbuf_mtod_offset(m, struct rte_ipv4_hdr *, + m->l2_len); m->l3_len = rte_ipv4_hdr_len(ipv4_hdr); - *l4_hdr = (char *)l3_hdr + m->l3_len; + if (data_len < m->l2_len + m->l3_len) + goto error; m->ol_flags |= PKT_TX_IPV4; + *l4_proto = ipv4_hdr->next_proto_id; break; case RTE_ETHER_TYPE_IPV6: - ipv6_hdr = l3_hdr; - *l4_proto = ipv6_hdr->proto; + if (data_len < m->l2_len + sizeof(struct rte_ipv6_hdr)) + goto error; + ipv6_hdr = rte_pktmbuf_mtod_offset(m, struct rte_ipv6_hdr *, + m->l2_len); m->l3_len = sizeof(struct rte_ipv6_hdr); - *l4_hdr = (char *)l3_hdr + m->l3_len; m->ol_flags |= PKT_TX_IPV6; + *l4_proto = ipv6_hdr->proto; break; default: - m->l3_len = 0; - *l4_proto = 0; - *l4_hdr = NULL; + /* a valid L3 header is needed for further L4 parsing */ + goto error; + } + + /* both CSUM and GSO need a valid L4 header */ + switch (*l4_proto) { + case IPPROTO_TCP: + if (data_len < m->l2_len + m->l3_len + + sizeof(struct rte_tcp_hdr)) + goto error; + break; + case IPPROTO_UDP: + if (data_len < m->l2_len + m->l3_len + + sizeof(struct rte_udp_hdr)) + goto error; break; + case IPPROTO_SCTP: + if (data_len < m->l2_len + m->l3_len + + sizeof(struct rte_sctp_hdr)) + goto error; + break; + default: + goto error; } + + return 0; + +error: + m->l2_len = 0; + m->l3_len = 0; + m->ol_flags = 0; + return -EINVAL; } static __rte_always_inline void vhost_dequeue_offload_legacy(struct virtio_net_hdr *hdr, struct rte_mbuf *m) { - uint16_t l4_proto = 0; - void *l4_hdr = NULL; + uint8_t l4_proto = 0; struct rte_tcp_hdr *tcp_hdr = NULL; + uint16_t tcp_len; + uint16_t data_len = rte_pktmbuf_data_len(m); + + if (parse_headers(m, &l4_proto) < 0) + return; - parse_ethernet(m, &l4_proto, &l4_hdr); if (hdr->flags == VIRTIO_NET_HDR_F_NEEDS_CSUM) { if (hdr->csum_start == (m->l2_len + m->l3_len)) { switch (hdr->csum_offset) { case (offsetof(struct rte_tcp_hdr, cksum)): - if (l4_proto == IPPROTO_TCP) - m->ol_flags |= PKT_TX_TCP_CKSUM; + if (l4_proto != IPPROTO_TCP) + goto error; + m->ol_flags |= PKT_TX_TCP_CKSUM; break; case (offsetof(struct rte_udp_hdr, dgram_cksum)): - if (l4_proto == IPPROTO_UDP) - m->ol_flags |= PKT_TX_UDP_CKSUM; + if (l4_proto != IPPROTO_UDP) + goto error; + m->ol_flags |= PKT_TX_UDP_CKSUM; break; case (offsetof(struct rte_sctp_hdr, cksum)): - if (l4_proto == IPPROTO_SCTP) - m->ol_flags |= PKT_TX_SCTP_CKSUM; + if (l4_proto != IPPROTO_SCTP) + goto error; + m->ol_flags |= PKT_TX_SCTP_CKSUM; break; default: - break; + goto error; } + } else { + goto error; } } - if (l4_hdr && hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { + if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { case VIRTIO_NET_HDR_GSO_TCPV4: case VIRTIO_NET_HDR_GSO_TCPV6: - tcp_hdr = l4_hdr; + if (l4_proto != IPPROTO_TCP) + goto error; + tcp_hdr = rte_pktmbuf_mtod_offset(m, + struct rte_tcp_hdr *, + m->l2_len + m->l3_len); + tcp_len = (tcp_hdr->data_off & 0xf0) >> 2; + if (data_len < m->l2_len + m->l3_len + tcp_len) + goto error; m->ol_flags |= PKT_TX_TCP_SEG; m->tso_segsz = hdr->gso_size; - m->l4_len = (tcp_hdr->data_off & 0xf0) >> 2; + m->l4_len = tcp_len; break; case VIRTIO_NET_HDR_GSO_UDP: + if (l4_proto != IPPROTO_UDP) + goto error; m->ol_flags |= PKT_TX_UDP_SEG; m->tso_segsz = hdr->gso_size; m->l4_len = sizeof(struct rte_udp_hdr); @@ -2352,9 +2407,15 @@ vhost_dequeue_offload_legacy(struct virtio_net_hdr *hdr, struct rte_mbuf *m) default: VHOST_LOG_DATA(WARNING, "unsupported gso type %u.\n", hdr->gso_type); - break; + goto error; } } + return; + +error: + m->l2_len = 0; + m->l3_len = 0; + m->ol_flags = 0; } static __rte_always_inline void -- 2.20.1