From 3d0ad09412ffe00c9afa201d01effdb6023d09b4 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Thu, 30 Oct 2014 18:27:12 +0000 Subject: [PATCH 1/2] drivers/net: Disable UFO through virtio IPv6 does not allow fragmentation by routers, so there is no fragmentation ID in the fixed header. UFO for IPv6 requires the ID to be passed separately, but there is no provision for this in the virtio net protocol. Until recently our software implementation of UFO/IPv6 generated a new ID, but this was a bug. Now we will use ID=0 for any UFO/IPv6 packet passed through a tap, which is even worse. Unfortunately there is no distinction between UFO/IPv4 and v6 features, so disable UFO on taps and virtio_net completely until we have a proper solution. We cannot depend on VM managers respecting the tap feature flags, so keep accepting UFO packets but log a warning the first time we do this. Signed-off-by: Ben Hutchings Fixes: 916e4cf46d02 ("ipv6: reuse ip6_frag_id from ip6_ufo_append_data") Signed-off-by: David S. Miller --- drivers/net/macvtap.c | 13 +++++-------- drivers/net/tun.c | 19 +++++++++++-------- drivers/net/virtio_net.c | 24 ++++++++++++++---------- 3 files changed, 30 insertions(+), 26 deletions(-) diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 65e2892342bd..2aeaa61ece09 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -65,7 +65,7 @@ static struct cdev macvtap_cdev; static const struct proto_ops macvtap_socket_ops; #define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \ - NETIF_F_TSO6 | NETIF_F_UFO) + NETIF_F_TSO6) #define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO) #define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG) @@ -569,6 +569,8 @@ static int macvtap_skb_from_vnet_hdr(struct sk_buff *skb, gso_type = SKB_GSO_TCPV6; break; case VIRTIO_NET_HDR_GSO_UDP: + pr_warn_once("macvtap: %s: using disabled UFO feature; please fix this program\n", + current->comm); gso_type = SKB_GSO_UDP; break; default: @@ -614,8 +616,6 @@ static void macvtap_skb_to_vnet_hdr(const struct sk_buff *skb, vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; else if (sinfo->gso_type & SKB_GSO_TCPV6) vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; - else if (sinfo->gso_type & SKB_GSO_UDP) - vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP; else BUG(); if (sinfo->gso_type & SKB_GSO_TCP_ECN) @@ -950,9 +950,6 @@ static int set_offload(struct macvtap_queue *q, unsigned long arg) if (arg & TUN_F_TSO6) feature_mask |= NETIF_F_TSO6; } - - if (arg & TUN_F_UFO) - feature_mask |= NETIF_F_UFO; } /* tun/tap driver inverts the usage for TSO offloads, where @@ -963,7 +960,7 @@ static int set_offload(struct macvtap_queue *q, unsigned long arg) * When user space turns off TSO, we turn off GSO/LRO so that * user-space will not receive TSO frames. */ - if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO)) + if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6)) features |= RX_OFFLOADS; else features &= ~RX_OFFLOADS; @@ -1064,7 +1061,7 @@ static long macvtap_ioctl(struct file *file, unsigned int cmd, case TUNSETOFFLOAD: /* let the user check for future flags */ if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 | - TUN_F_TSO_ECN | TUN_F_UFO)) + TUN_F_TSO_ECN)) return -EINVAL; rtnl_lock(); diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 186ce541c657..280d3d2a9792 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -174,7 +174,7 @@ struct tun_struct { struct net_device *dev; netdev_features_t set_features; #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ - NETIF_F_TSO6|NETIF_F_UFO) + NETIF_F_TSO6) int vnet_hdr_sz; int sndbuf; @@ -1149,8 +1149,18 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; break; case VIRTIO_NET_HDR_GSO_UDP: + { + static bool warned; + + if (!warned) { + warned = true; + netdev_warn(tun->dev, + "%s: using disabled UFO feature; please fix this program\n", + current->comm); + } skb_shinfo(skb)->gso_type = SKB_GSO_UDP; break; + } default: tun->dev->stats.rx_frame_errors++; kfree_skb(skb); @@ -1251,8 +1261,6 @@ static ssize_t tun_put_user(struct tun_struct *tun, gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; else if (sinfo->gso_type & SKB_GSO_TCPV6) gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; - else if (sinfo->gso_type & SKB_GSO_UDP) - gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; else { pr_err("unexpected GSO type: " "0x%x, gso_size %d, hdr_len %d\n", @@ -1762,11 +1770,6 @@ static int set_offload(struct tun_struct *tun, unsigned long arg) features |= NETIF_F_TSO6; arg &= ~(TUN_F_TSO4|TUN_F_TSO6); } - - if (arg & TUN_F_UFO) { - features |= NETIF_F_UFO; - arg &= ~TUN_F_UFO; - } } /* This gives the user a way to test for new features in future by diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index d75256bd1a6a..ec2a8b41ed41 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -491,8 +491,17 @@ static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len) skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; break; case VIRTIO_NET_HDR_GSO_UDP: + { + static bool warned; + + if (!warned) { + warned = true; + netdev_warn(dev, + "host using disabled UFO feature; please fix it\n"); + } skb_shinfo(skb)->gso_type = SKB_GSO_UDP; break; + } case VIRTIO_NET_HDR_GSO_TCPV6: skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; break; @@ -881,8 +890,6 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; - else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP) - hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP; else BUG(); if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN) @@ -1705,7 +1712,7 @@ static int virtnet_probe(struct virtio_device *vdev) dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST; if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) { - dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO + dev->hw_features |= NETIF_F_TSO | NETIF_F_TSO_ECN | NETIF_F_TSO6; } /* Individual feature bits: what can host handle? */ @@ -1715,11 +1722,9 @@ static int virtnet_probe(struct virtio_device *vdev) dev->hw_features |= NETIF_F_TSO6; if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN)) dev->hw_features |= NETIF_F_TSO_ECN; - if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO)) - dev->hw_features |= NETIF_F_UFO; if (gso) - dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO); + dev->features |= dev->hw_features & NETIF_F_ALL_TSO; /* (!csum && gso) case will be fixed by register_netdev() */ } if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_CSUM)) @@ -1757,8 +1762,7 @@ static int virtnet_probe(struct virtio_device *vdev) /* If we can receive ANY GSO packets, we must allocate large ones. */ if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) || - virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN) || - virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UFO)) + virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN)) vi->big_packets = true; if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF)) @@ -1952,9 +1956,9 @@ static struct virtio_device_id id_table[] = { static unsigned int features[] = { VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM, VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC, - VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6, + VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_TSO6, VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6, - VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO, + VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ, VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN, VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, From 5188cd44c55db3e92cd9e77a40b5baa7ed4340f7 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Thu, 30 Oct 2014 18:27:17 +0000 Subject: [PATCH 2/2] drivers/net, ipv6: Select IPv6 fragment idents for virtio UFO packets UFO is now disabled on all drivers that work with virtio net headers, but userland may try to send UFO/IPv6 packets anyway. Instead of sending with ID=0, we should select identifiers on their behalf (as we used to). Signed-off-by: Ben Hutchings Fixes: 916e4cf46d02 ("ipv6: reuse ip6_frag_id from ip6_ufo_append_data") Signed-off-by: David S. Miller --- drivers/net/macvtap.c | 3 +++ drivers/net/tun.c | 6 +++++- include/net/ipv6.h | 2 ++ net/ipv6/output_core.c | 34 ++++++++++++++++++++++++++++++++++ 4 files changed, 44 insertions(+), 1 deletion(-) diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 2aeaa61ece09..6f226de655a4 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -16,6 +16,7 @@ #include #include +#include #include #include #include @@ -572,6 +573,8 @@ static int macvtap_skb_from_vnet_hdr(struct sk_buff *skb, pr_warn_once("macvtap: %s: using disabled UFO feature; please fix this program\n", current->comm); gso_type = SKB_GSO_UDP; + if (skb->protocol == htons(ETH_P_IPV6)) + ipv6_proxy_select_ident(skb); break; default: return -EINVAL; diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 280d3d2a9792..7302398f0b1f 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -65,6 +65,7 @@ #include #include #include +#include #include #include #include @@ -1139,6 +1140,8 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, break; } + skb_reset_network_header(skb); + if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { pr_debug("GSO!\n"); switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { @@ -1159,6 +1162,8 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, current->comm); } skb_shinfo(skb)->gso_type = SKB_GSO_UDP; + if (skb->protocol == htons(ETH_P_IPV6)) + ipv6_proxy_select_ident(skb); break; } default: @@ -1189,7 +1194,6 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; } - skb_reset_network_header(skb); skb_probe_transport_header(skb, 0); rxhash = skb_get_hash(skb); diff --git a/include/net/ipv6.h b/include/net/ipv6.h index 97f472012438..4292929392b0 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -671,6 +671,8 @@ static inline int ipv6_addr_diff(const struct in6_addr *a1, const struct in6_add return __ipv6_addr_diff(a1, a2, sizeof(struct in6_addr)); } +void ipv6_proxy_select_ident(struct sk_buff *skb); + int ip6_dst_hoplimit(struct dst_entry *dst); static inline int ip6_sk_dst_hoplimit(struct ipv6_pinfo *np, struct flowi6 *fl6, diff --git a/net/ipv6/output_core.c b/net/ipv6/output_core.c index fc24c390af05..97f41a3e68d9 100644 --- a/net/ipv6/output_core.c +++ b/net/ipv6/output_core.c @@ -3,11 +3,45 @@ * not configured or static. These functions are needed by GSO/GRO implementation. */ #include +#include #include #include #include #include +/* This function exists only for tap drivers that must support broken + * clients requesting UFO without specifying an IPv6 fragment ID. + * + * This is similar to ipv6_select_ident() but we use an independent hash + * seed to limit information leakage. + * + * The network header must be set before calling this. + */ +void ipv6_proxy_select_ident(struct sk_buff *skb) +{ + static u32 ip6_proxy_idents_hashrnd __read_mostly; + struct in6_addr buf[2]; + struct in6_addr *addrs; + u32 hash, id; + + addrs = skb_header_pointer(skb, + skb_network_offset(skb) + + offsetof(struct ipv6hdr, saddr), + sizeof(buf), buf); + if (!addrs) + return; + + net_get_random_once(&ip6_proxy_idents_hashrnd, + sizeof(ip6_proxy_idents_hashrnd)); + + hash = __ipv6_addr_jhash(&addrs[1], ip6_proxy_idents_hashrnd); + hash = __ipv6_addr_jhash(&addrs[0], hash); + + id = ip_idents_reserve(hash, 1); + skb_shinfo(skb)->ip6_frag_id = htonl(id); +} +EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident); + int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr) { u16 offset = sizeof(struct ipv6hdr);