mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-28 11:18:45 +07:00
9274124f02
Syzkaller again found a path to a kernel crash through bad gso input:
a packet with transport header extending beyond skb_headlen(skb).
Tighten validation at kernel entry:
- Verify that the transport header lies within the linear section.
To avoid pulling linux/tcp.h, verify just sizeof tcphdr.
tcp_gso_segment will call pskb_may_pull (th->doff * 4) before use.
- Match the gso_type against the ip_proto found by the flow dissector.
Fixes: bfd5f4a3d6 ("packet: Add GSO/csum offload support.")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
159 lines
4.2 KiB
C
159 lines
4.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _LINUX_VIRTIO_NET_H
|
|
#define _LINUX_VIRTIO_NET_H
|
|
|
|
#include <linux/if_vlan.h>
|
|
#include <uapi/linux/tcp.h>
|
|
#include <uapi/linux/udp.h>
|
|
#include <uapi/linux/virtio_net.h>
|
|
|
|
static inline int virtio_net_hdr_set_proto(struct sk_buff *skb,
|
|
const struct virtio_net_hdr *hdr)
|
|
{
|
|
switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
|
|
case VIRTIO_NET_HDR_GSO_TCPV4:
|
|
case VIRTIO_NET_HDR_GSO_UDP:
|
|
skb->protocol = cpu_to_be16(ETH_P_IP);
|
|
break;
|
|
case VIRTIO_NET_HDR_GSO_TCPV6:
|
|
skb->protocol = cpu_to_be16(ETH_P_IPV6);
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
|
|
const struct virtio_net_hdr *hdr,
|
|
bool little_endian)
|
|
{
|
|
unsigned int gso_type = 0;
|
|
unsigned int thlen = 0;
|
|
unsigned int ip_proto;
|
|
|
|
if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
|
|
switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
|
|
case VIRTIO_NET_HDR_GSO_TCPV4:
|
|
gso_type = SKB_GSO_TCPV4;
|
|
ip_proto = IPPROTO_TCP;
|
|
thlen = sizeof(struct tcphdr);
|
|
break;
|
|
case VIRTIO_NET_HDR_GSO_TCPV6:
|
|
gso_type = SKB_GSO_TCPV6;
|
|
ip_proto = IPPROTO_TCP;
|
|
thlen = sizeof(struct tcphdr);
|
|
break;
|
|
case VIRTIO_NET_HDR_GSO_UDP:
|
|
gso_type = SKB_GSO_UDP;
|
|
ip_proto = IPPROTO_UDP;
|
|
thlen = sizeof(struct udphdr);
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
|
|
gso_type |= SKB_GSO_TCP_ECN;
|
|
|
|
if (hdr->gso_size == 0)
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
|
|
u16 start = __virtio16_to_cpu(little_endian, hdr->csum_start);
|
|
u16 off = __virtio16_to_cpu(little_endian, hdr->csum_offset);
|
|
|
|
if (!skb_partial_csum_set(skb, start, off))
|
|
return -EINVAL;
|
|
|
|
if (skb_transport_offset(skb) + thlen > skb_headlen(skb))
|
|
return -EINVAL;
|
|
} else {
|
|
/* gso packets without NEEDS_CSUM do not set transport_offset.
|
|
* probe and drop if does not match one of the above types.
|
|
*/
|
|
if (gso_type && skb->network_header) {
|
|
struct flow_keys_basic keys;
|
|
|
|
if (!skb->protocol)
|
|
virtio_net_hdr_set_proto(skb, hdr);
|
|
retry:
|
|
if (!skb_flow_dissect_flow_keys_basic(NULL, skb, &keys,
|
|
NULL, 0, 0, 0,
|
|
0)) {
|
|
/* UFO does not specify ipv4 or 6: try both */
|
|
if (gso_type & SKB_GSO_UDP &&
|
|
skb->protocol == htons(ETH_P_IP)) {
|
|
skb->protocol = htons(ETH_P_IPV6);
|
|
goto retry;
|
|
}
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (keys.control.thoff + thlen > skb_headlen(skb) ||
|
|
keys.basic.ip_proto != ip_proto)
|
|
return -EINVAL;
|
|
|
|
skb_set_transport_header(skb, keys.control.thoff);
|
|
}
|
|
}
|
|
|
|
if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
|
|
u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size);
|
|
|
|
skb_shinfo(skb)->gso_size = gso_size;
|
|
skb_shinfo(skb)->gso_type = gso_type;
|
|
|
|
/* Header must be checked, and gso_segs computed. */
|
|
skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
|
|
skb_shinfo(skb)->gso_segs = 0;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
|
|
struct virtio_net_hdr *hdr,
|
|
bool little_endian,
|
|
bool has_data_valid,
|
|
int vlan_hlen)
|
|
{
|
|
memset(hdr, 0, sizeof(*hdr)); /* no info leak */
|
|
|
|
if (skb_is_gso(skb)) {
|
|
struct skb_shared_info *sinfo = skb_shinfo(skb);
|
|
|
|
/* This is a hint as to how much should be linear. */
|
|
hdr->hdr_len = __cpu_to_virtio16(little_endian,
|
|
skb_headlen(skb));
|
|
hdr->gso_size = __cpu_to_virtio16(little_endian,
|
|
sinfo->gso_size);
|
|
if (sinfo->gso_type & SKB_GSO_TCPV4)
|
|
hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
|
|
else if (sinfo->gso_type & SKB_GSO_TCPV6)
|
|
hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
|
|
else
|
|
return -EINVAL;
|
|
if (sinfo->gso_type & SKB_GSO_TCP_ECN)
|
|
hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
|
|
} else
|
|
hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
|
|
|
|
if (skb->ip_summed == CHECKSUM_PARTIAL) {
|
|
hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
|
|
hdr->csum_start = __cpu_to_virtio16(little_endian,
|
|
skb_checksum_start_offset(skb) + vlan_hlen);
|
|
hdr->csum_offset = __cpu_to_virtio16(little_endian,
|
|
skb->csum_offset);
|
|
} else if (has_data_valid &&
|
|
skb->ip_summed == CHECKSUM_UNNECESSARY) {
|
|
hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
|
|
} /* else everything is zero */
|
|
|
|
return 0;
|
|
}
|
|
|
|
#endif /* _LINUX_VIRTIO_NET_H */
|