[PATCH 4.9 101/103] net/mlx5e: Use flow keys dissector to parse packets for ARFS

Greg Kroah-Hartman
2019-08-22T17:36:57Z

From: Maxim Mikityanskiy <maximmi@mellanox.com>

[ Upstream commit 405b93eb764367a670e729da18e54dc42db32620 ]

The current ARFS code relies on certain fields to be set in the SKB
(e.g. transport_header) and extracts IP addresses and ports by custom
code that parses the packet. The necessary SKB fields, however, are not
always set at that point, which leads to an out-of-bounds access. Use
skb_flow_dissect_flow_keys() to get the necessary information reliably,
fix the out-of-bounds access and reuse the code.

Fixes: 18c908e477dc ("net/mlx5e: Add accelerated RFS support")
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/mellanox/mlx5/core/en_arfs.c | 97 +++++++---------------
1 file changed, 34 insertions(+), 63 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_arfs.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_arfs.c
@@ -441,12 +441,6 @@ arfs_hash_bucket(struct arfs_table *arfs
return &arfs_t->rules_hash[bucket_idx];
}

-static u8 arfs_get_ip_proto(const struct sk_buff *skb)
-{
- return (skb->protocol == htons(ETH_P_IP)) ?
- ip_hdr(skb)->protocol : ipv6_hdr(skb)->nexthdr;
-}
-
static struct arfs_table *arfs_get_table(struct mlx5e_arfs_tables *arfs,
u8 ip_proto, __be16 etype)
{
@@ -605,31 +599,9 @@ out:
arfs_may_expire_flow(priv);
}

-/* return L4 destination port from ip4/6 packets */
-static __be16 arfs_get_dst_port(const struct sk_buff *skb)
-{
- char *transport_header;
-
- transport_header = skb_transport_header(skb);
- if (arfs_get_ip_proto(skb) == IPPROTO_TCP)
- return ((struct tcphdr *)transport_header)->dest;
- return ((struct udphdr *)transport_header)->dest;
-}
-
-/* return L4 source port from ip4/6 packets */
-static __be16 arfs_get_src_port(const struct sk_buff *skb)
-{
- char *transport_header;
-
- transport_header = skb_transport_header(skb);
- if (arfs_get_ip_proto(skb) == IPPROTO_TCP)
- return ((struct tcphdr *)transport_header)->source;
- return ((struct udphdr *)transport_header)->source;
-}
-
static struct arfs_rule *arfs_alloc_rule(struct mlx5e_priv *priv,
struct arfs_table *arfs_t,
- const struct sk_buff *skb,
+ const struct flow_keys *fk,
u16 rxq, u32 flow_id)
{
struct arfs_rule *rule;
@@ -644,19 +616,19 @@ static struct arfs_rule *arfs_alloc_rule
INIT_WORK(&rule->arfs_work, arfs_handle_work);

tuple = &rule->tuple;
- tuple->etype = skb->protocol;
+ tuple->etype = fk->basic.n_proto;
+ tuple->ip_proto = fk->basic.ip_proto;
if (tuple->etype == htons(ETH_P_IP)) {
- tuple->src_ipv4 = ip_hdr(skb)->saddr;
- tuple->dst_ipv4 = ip_hdr(skb)->daddr;
+ tuple->src_ipv4 = fk->addrs.v4addrs.src;
+ tuple->dst_ipv4 = fk->addrs.v4addrs.dst;
} else {
- memcpy(&tuple->src_ipv6, &ipv6_hdr(skb)->saddr,
+ memcpy(&tuple->src_ipv6, &fk->addrs.v6addrs.src,
sizeof(struct in6_addr));
- memcpy(&tuple->dst_ipv6, &ipv6_hdr(skb)->daddr,
+ memcpy(&tuple->dst_ipv6, &fk->addrs.v6addrs.dst,
sizeof(struct in6_addr));
}
- tuple->ip_proto = arfs_get_ip_proto(skb);
- tuple->src_port = arfs_get_src_port(skb);
- tuple->dst_port = arfs_get_dst_port(skb);
+ tuple->src_port = fk->ports.src;
+ tuple->dst_port = fk->ports.dst;

rule->flow_id = flow_id;
rule->filter_id = priv->fs.arfs.last_filter_id++ % RPS_NO_FILTER;
@@ -667,37 +639,33 @@ static struct arfs_rule *arfs_alloc_rule
return rule;
}

-static bool arfs_cmp_ips(struct arfs_tuple *tuple,
- const struct sk_buff *skb)
+static bool arfs_cmp(const struct arfs_tuple *tuple, const struct flow_keys *fk)
{
- if (tuple->etype == htons(ETH_P_IP) &&
- tuple->src_ipv4 == ip_hdr(skb)->saddr &&
- tuple->dst_ipv4 == ip_hdr(skb)->daddr)
- return true;
- if (tuple->etype == htons(ETH_P_IPV6) &&
- (!memcmp(&tuple->src_ipv6, &ipv6_hdr(skb)->saddr,
- sizeof(struct in6_addr))) &&
- (!memcmp(&tuple->dst_ipv6, &ipv6_hdr(skb)->daddr,
- sizeof(struct in6_addr))))
- return true;
+ if (tuple->src_port != fk->ports.src || tuple->dst_port != fk->ports.dst)
+ return false;
+ if (tuple->etype != fk->basic.n_proto)
+ return false;
+ if (tuple->etype == htons(ETH_P_IP))
+ return tuple->src_ipv4 == fk->addrs.v4addrs.src &&
+ tuple->dst_ipv4 == fk->addrs.v4addrs.dst;
+ if (tuple->etype == htons(ETH_P_IPV6))
+ return !memcmp(&tuple->src_ipv6, &fk->addrs.v6addrs.src,
+ sizeof(struct in6_addr)) &&
+ !memcmp(&tuple->dst_ipv6, &fk->addrs.v6addrs.dst,
+ sizeof(struct in6_addr));
return false;
}

static struct arfs_rule *arfs_find_rule(struct arfs_table *arfs_t,
- const struct sk_buff *skb)
+ const struct flow_keys *fk)
{
struct arfs_rule *arfs_rule;
struct hlist_head *head;
- __be16 src_port = arfs_get_src_port(skb);
- __be16 dst_port = arfs_get_dst_port(skb);

- head = arfs_hash_bucket(arfs_t, src_port, dst_port);
+ head = arfs_hash_bucket(arfs_t, fk->ports.src, fk->ports.dst);
hlist_for_each_entry(arfs_rule, head, hlist) {
- if (arfs_rule->tuple.src_port == src_port &&
- arfs_rule->tuple.dst_port == dst_port &&
- arfs_cmp_ips(&arfs_rule->tuple, skb)) {
+ if (arfs_cmp(&arfs_rule->tuple, fk))
return arfs_rule;
- }
}

return NULL;
@@ -710,20 +678,24 @@ int mlx5e_rx_flow_steer(struct net_devic
struct mlx5e_arfs_tables *arfs = &priv->fs.arfs;
struct arfs_table *arfs_t;
struct arfs_rule *arfs_rule;
+ struct flow_keys fk;
+
+ if (!skb_flow_dissect_flow_keys(skb, &fk, 0))
+ return -EPROTONOSUPPORT;

- if (skb->protocol != htons(ETH_P_IP) &&
- skb->protocol != htons(ETH_P_IPV6))
+ if (fk.basic.n_proto != htons(ETH_P_IP) &&
+ fk.basic.n_proto != htons(ETH_P_IPV6))
return -EPROTONOSUPPORT;

if (skb->encapsulation)
return -EPROTONOSUPPORT;

- arfs_t = arfs_get_table(arfs, arfs_get_ip_proto(skb), skb->protocol);
+ arfs_t = arfs_get_table(arfs, fk.basic.ip_proto, fk.basic.n_proto);
if (!arfs_t)
return -EPROTONOSUPPORT;

spin_lock_bh(&arfs->arfs_lock);
- arfs_rule = arfs_find_rule(arfs_t, skb);
+ arfs_rule = arfs_find_rule(arfs_t, &fk);
if (arfs_rule) {
if (arfs_rule->rxq == rxq_index) {
spin_unlock_bh(&arfs->arfs_lock);
@@ -731,8 +703,7 @@ int mlx5e_rx_flow_steer(struct net_devic
}
arfs_rule->rxq = rxq_index;
} else {
- arfs_rule = arfs_alloc_rule(priv, arfs_t, skb,
- rxq_index, flow_id);
+ arfs_rule = arfs_alloc_rule(priv, arfs_t, &fk, rxq_index, flow_id);
if (!arfs_rule) {
spin_unlock_bh(&arfs->arfs_lock);
return -ENOMEM;