From 3d0ad09412ffe00c9afa201d01effdb6023d09b4 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Thu, 30 Oct 2014 18:27:12 +0000 Subject: 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/tun.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) (limited to 'drivers/net/tun.c') 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 -- cgit v1.2.3 From 5188cd44c55db3e92cd9e77a40b5baa7ed4340f7 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Thu, 30 Oct 2014 18:27:17 +0000 Subject: 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(-) (limited to 'drivers/net/tun.c') 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); -- cgit v1.2.3 From a8f9bfdf982e2b1fb9f094e4de9ab08c57f3d2fd Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Mon, 3 Nov 2014 04:30:13 +0800 Subject: tun: Fix csum_start with VLAN acceleration When VLAN acceleration is in use on the xmit path, we end up setting csum_start to the wrong place. The result is that the whoever ends up doing the checksum setting will corrupt the packet instead of writing the checksum to the expected location, usually this means writing the checksum with an offset of -4. This patch fixes this by adjusting csum_start when VLAN acceleration is detected. Fixes: 6680ec68eff4 ("tuntap: hardware vlan tx support") Cc: stable@vger.kernel.org Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- drivers/net/tun.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) (limited to 'drivers/net/tun.c') diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 7302398f0b1f..57e6bf75a632 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1235,6 +1235,10 @@ static ssize_t tun_put_user(struct tun_struct *tun, struct tun_pi pi = { 0, skb->protocol }; ssize_t total = 0; int vlan_offset = 0, copied; + int vlan_hlen = 0; + + if (vlan_tx_tag_present(skb)) + vlan_hlen = VLAN_HLEN; if (!(tun->flags & TUN_NO_PI)) { if ((len -= sizeof(pi)) < 0) @@ -1284,7 +1288,8 @@ static ssize_t tun_put_user(struct tun_struct *tun, if (skb->ip_summed == CHECKSUM_PARTIAL) { gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; - gso.csum_start = skb_checksum_start_offset(skb); + gso.csum_start = skb_checksum_start_offset(skb) + + vlan_hlen; gso.csum_offset = skb->csum_offset; } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; @@ -1297,10 +1302,9 @@ static ssize_t tun_put_user(struct tun_struct *tun, } copied = total; - total += skb->len; - if (!vlan_tx_tag_present(skb)) { - len = min_t(int, skb->len, len); - } else { + len = min_t(int, skb->len + vlan_hlen, len); + total += skb->len + vlan_hlen; + if (vlan_hlen) { int copy, ret; struct { __be16 h_vlan_proto; @@ -1311,8 +1315,6 @@ static ssize_t tun_put_user(struct tun_struct *tun, veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); - len = min_t(int, skb->len + VLAN_HLEN, len); - total += VLAN_HLEN; copy = min_t(int, vlan_offset, len); ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy); -- cgit v1.2.3 From 2eb783c43e7cf807a45899c10ed556b6dc116625 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Mon, 3 Nov 2014 04:30:14 +0800 Subject: tun: Fix TUN_PKT_STRIP setting We set the flag TUN_PKT_STRIP if the user buffer provided is too small to contain the entire packet plus meta-data. However, this has been broken ever since we added GSO meta-data. VLAN acceleration also has the same problem. This patch fixes this by taking both into account when setting the TUN_PKT_STRIP flag. The fact that this has been broken for six years without anyone realising means that nobody actually uses this flag. Fixes: f43798c27684 ("tun: Allow GSO using virtio_net_hdr") Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- drivers/net/tun.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'drivers/net/tun.c') diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 57e6bf75a632..9dd3746994a4 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1236,15 +1236,19 @@ static ssize_t tun_put_user(struct tun_struct *tun, ssize_t total = 0; int vlan_offset = 0, copied; int vlan_hlen = 0; + int vnet_hdr_sz = 0; if (vlan_tx_tag_present(skb)) vlan_hlen = VLAN_HLEN; + if (tun->flags & TUN_VNET_HDR) + vnet_hdr_sz = tun->vnet_hdr_sz; + if (!(tun->flags & TUN_NO_PI)) { if ((len -= sizeof(pi)) < 0) return -EINVAL; - if (len < skb->len) { + if (len < skb->len + vlan_hlen + vnet_hdr_sz) { /* Packet will be striped */ pi.flags |= TUN_PKT_STRIP; } @@ -1254,9 +1258,9 @@ static ssize_t tun_put_user(struct tun_struct *tun, total += sizeof(pi); } - if (tun->flags & TUN_VNET_HDR) { + if (vnet_hdr_sz) { struct virtio_net_hdr gso = { 0 }; /* no info leak */ - if ((len -= tun->vnet_hdr_sz) < 0) + if ((len -= vnet_hdr_sz) < 0) return -EINVAL; if (skb_is_gso(skb)) { @@ -1298,7 +1302,7 @@ static ssize_t tun_put_user(struct tun_struct *tun, if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total, sizeof(gso)))) return -EFAULT; - total += tun->vnet_hdr_sz; + total += vnet_hdr_sz; } copied = total; -- cgit v1.2.3