From f9242b6b28d61295f2bf7e8adfb1060b382e5381 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Tue, 19 Jun 2012 18:56:21 -0700 Subject: [PATCH] inet: Sanitize inet{,6} protocol demux. Don't pretend that inet_protos[] and inet6_protos[] are hashes, thay are just a straight arrays. Remove all unnecessary hash masking. Document MAX_INET_PROTOS. Use RAW_HTABLE_SIZE when appropriate. Reported-by: Ben Hutchings Signed-off-by: David S. Miller --- include/net/protocol.h | 7 +++++-- net/ipv4/af_inet.c | 26 ++++++++++++-------------- net/ipv4/icmp.c | 9 ++++----- net/ipv4/ip_input.c | 5 ++--- net/ipv4/protocol.c | 8 +++----- net/ipv6/icmp.c | 7 ++----- net/ipv6/ip6_input.c | 9 +++------ net/ipv6/protocol.c | 8 +++----- net/ipv6/raw.c | 4 ++-- 9 files changed, 36 insertions(+), 47 deletions(-) diff --git a/include/net/protocol.h b/include/net/protocol.h index 875f4895b033..a1b1b530c338 100644 --- a/include/net/protocol.h +++ b/include/net/protocol.h @@ -29,8 +29,11 @@ #include #endif -#define MAX_INET_PROTOS 256 /* Must be a power of 2 */ - +/* This is one larger than the largest protocol value that can be + * found in an ipv4 or ipv6 header. Since in both cases the protocol + * value is presented in a __u8, this is defined to be 256. + */ +#define MAX_INET_PROTOS 256 /* This is used to register protocols. */ struct net_protocol { diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index e4e8e00a2c91..85a3b1763136 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -242,20 +242,18 @@ void build_ehash_secret(void) } EXPORT_SYMBOL(build_ehash_secret); -static inline int inet_netns_ok(struct net *net, int protocol) +static inline int inet_netns_ok(struct net *net, __u8 protocol) { - int hash; const struct net_protocol *ipprot; if (net_eq(net, &init_net)) return 1; - hash = protocol & (MAX_INET_PROTOS - 1); - ipprot = rcu_dereference(inet_protos[hash]); - - if (ipprot == NULL) + ipprot = rcu_dereference(inet_protos[protocol]); + if (ipprot == NULL) { /* raw IP is OK */ return 1; + } return ipprot->netns_ok; } @@ -1216,8 +1214,8 @@ EXPORT_SYMBOL(inet_sk_rebuild_header); static int inet_gso_send_check(struct sk_buff *skb) { - const struct iphdr *iph; const struct net_protocol *ops; + const struct iphdr *iph; int proto; int ihl; int err = -EINVAL; @@ -1236,7 +1234,7 @@ static int inet_gso_send_check(struct sk_buff *skb) __skb_pull(skb, ihl); skb_reset_transport_header(skb); iph = ip_hdr(skb); - proto = iph->protocol & (MAX_INET_PROTOS - 1); + proto = iph->protocol; err = -EPROTONOSUPPORT; rcu_read_lock(); @@ -1253,8 +1251,8 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, netdev_features_t features) { struct sk_buff *segs = ERR_PTR(-EINVAL); - struct iphdr *iph; const struct net_protocol *ops; + struct iphdr *iph; int proto; int ihl; int id; @@ -1286,7 +1284,7 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, skb_reset_transport_header(skb); iph = ip_hdr(skb); id = ntohs(iph->id); - proto = iph->protocol & (MAX_INET_PROTOS - 1); + proto = iph->protocol; segs = ERR_PTR(-EPROTONOSUPPORT); rcu_read_lock(); @@ -1340,7 +1338,7 @@ static struct sk_buff **inet_gro_receive(struct sk_buff **head, goto out; } - proto = iph->protocol & (MAX_INET_PROTOS - 1); + proto = iph->protocol; rcu_read_lock(); ops = rcu_dereference(inet_protos[proto]); @@ -1398,11 +1396,11 @@ out: static int inet_gro_complete(struct sk_buff *skb) { - const struct net_protocol *ops; + __be16 newlen = htons(skb->len - skb_network_offset(skb)); struct iphdr *iph = ip_hdr(skb); - int proto = iph->protocol & (MAX_INET_PROTOS - 1); + const struct net_protocol *ops; + int proto = iph->protocol; int err = -ENOSYS; - __be16 newlen = htons(skb->len - skb_network_offset(skb)); csum_replace2(&iph->check, iph->tot_len, newlen); iph->tot_len = newlen; diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index e1caa1abe5d1..49a74cc79dc8 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -637,12 +637,12 @@ EXPORT_SYMBOL(icmp_send); static void icmp_unreach(struct sk_buff *skb) { + const struct net_protocol *ipprot; const struct iphdr *iph; struct icmphdr *icmph; - int hash, protocol; - const struct net_protocol *ipprot; - u32 info = 0; struct net *net; + u32 info = 0; + int protocol; net = dev_net(skb_dst(skb)->dev); @@ -731,9 +731,8 @@ static void icmp_unreach(struct sk_buff *skb) */ raw_icmp_error(skb, protocol, info); - hash = protocol & (MAX_INET_PROTOS - 1); rcu_read_lock(); - ipprot = rcu_dereference(inet_protos[hash]); + ipprot = rcu_dereference(inet_protos[protocol]); if (ipprot && ipprot->err_handler) ipprot->err_handler(skb, info); rcu_read_unlock(); diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c index 8590144ca330..c4fe1d271131 100644 --- a/net/ipv4/ip_input.c +++ b/net/ipv4/ip_input.c @@ -198,14 +198,13 @@ static int ip_local_deliver_finish(struct sk_buff *skb) rcu_read_lock(); { int protocol = ip_hdr(skb)->protocol; - int hash, raw; const struct net_protocol *ipprot; + int raw; resubmit: raw = raw_local_deliver(skb, protocol); - hash = protocol & (MAX_INET_PROTOS - 1); - ipprot = rcu_dereference(inet_protos[hash]); + ipprot = rcu_dereference(inet_protos[protocol]); if (ipprot != NULL) { int ret; diff --git a/net/ipv4/protocol.c b/net/ipv4/protocol.c index 9ae5c01cd0b2..8918eff1426d 100644 --- a/net/ipv4/protocol.c +++ b/net/ipv4/protocol.c @@ -36,9 +36,7 @@ const struct net_protocol __rcu *inet_protos[MAX_INET_PROTOS] __read_mostly; int inet_add_protocol(const struct net_protocol *prot, unsigned char protocol) { - int hash = protocol & (MAX_INET_PROTOS - 1); - - return !cmpxchg((const struct net_protocol **)&inet_protos[hash], + return !cmpxchg((const struct net_protocol **)&inet_protos[protocol], NULL, prot) ? 0 : -1; } EXPORT_SYMBOL(inet_add_protocol); @@ -49,9 +47,9 @@ EXPORT_SYMBOL(inet_add_protocol); int inet_del_protocol(const struct net_protocol *prot, unsigned char protocol) { - int ret, hash = protocol & (MAX_INET_PROTOS - 1); + int ret; - ret = (cmpxchg((const struct net_protocol **)&inet_protos[hash], + ret = (cmpxchg((const struct net_protocol **)&inet_protos[protocol], prot, NULL) == prot) ? 0 : -1; synchronize_net(); diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index 5247d5c211f9..c7da1422cbde 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -600,9 +600,8 @@ static void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) { const struct inet6_protocol *ipprot; int inner_offset; - int hash; - u8 nexthdr; __be16 frag_off; + u8 nexthdr; if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) return; @@ -629,10 +628,8 @@ static void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) --ANK (980726) */ - hash = nexthdr & (MAX_INET_PROTOS - 1); - rcu_read_lock(); - ipprot = rcu_dereference(inet6_protos[hash]); + ipprot = rcu_dereference(inet6_protos[nexthdr]); if (ipprot && ipprot->err_handler) ipprot->err_handler(skb, NULL, type, code, inner_offset, info); rcu_read_unlock(); diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c index 21a15dfe4a9e..5ab923e51af3 100644 --- a/net/ipv6/ip6_input.c +++ b/net/ipv6/ip6_input.c @@ -168,13 +168,12 @@ drop: static int ip6_input_finish(struct sk_buff *skb) { + struct net *net = dev_net(skb_dst(skb)->dev); const struct inet6_protocol *ipprot; + struct inet6_dev *idev; unsigned int nhoff; int nexthdr; bool raw; - u8 hash; - struct inet6_dev *idev; - struct net *net = dev_net(skb_dst(skb)->dev); /* * Parse extension headers @@ -189,9 +188,7 @@ resubmit: nexthdr = skb_network_header(skb)[nhoff]; raw = raw6_local_deliver(skb, nexthdr); - - hash = nexthdr & (MAX_INET_PROTOS - 1); - if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) { + if ((ipprot = rcu_dereference(inet6_protos[nexthdr])) != NULL) { int ret; if (ipprot->flags & INET6_PROTO_FINAL) { diff --git a/net/ipv6/protocol.c b/net/ipv6/protocol.c index 9a7978fdc02a..053082dfc93e 100644 --- a/net/ipv6/protocol.c +++ b/net/ipv6/protocol.c @@ -29,9 +29,7 @@ const struct inet6_protocol __rcu *inet6_protos[MAX_INET_PROTOS] __read_mostly; int inet6_add_protocol(const struct inet6_protocol *prot, unsigned char protocol) { - int hash = protocol & (MAX_INET_PROTOS - 1); - - return !cmpxchg((const struct inet6_protocol **)&inet6_protos[hash], + return !cmpxchg((const struct inet6_protocol **)&inet6_protos[protocol], NULL, prot) ? 0 : -1; } EXPORT_SYMBOL(inet6_add_protocol); @@ -42,9 +40,9 @@ EXPORT_SYMBOL(inet6_add_protocol); int inet6_del_protocol(const struct inet6_protocol *prot, unsigned char protocol) { - int ret, hash = protocol & (MAX_INET_PROTOS - 1); + int ret; - ret = (cmpxchg((const struct inet6_protocol **)&inet6_protos[hash], + ret = (cmpxchg((const struct inet6_protocol **)&inet6_protos[protocol], prot, NULL) == prot) ? 0 : -1; synchronize_net(); diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c index 43b0042f15f4..b5c1dcb27737 100644 --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -165,7 +165,7 @@ static bool ipv6_raw_deliver(struct sk_buff *skb, int nexthdr) saddr = &ipv6_hdr(skb)->saddr; daddr = saddr + 1; - hash = nexthdr & (MAX_INET_PROTOS - 1); + hash = nexthdr & (RAW_HTABLE_SIZE - 1); read_lock(&raw_v6_hashinfo.lock); sk = sk_head(&raw_v6_hashinfo.ht[hash]); @@ -229,7 +229,7 @@ bool raw6_local_deliver(struct sk_buff *skb, int nexthdr) { struct sock *raw_sk; - raw_sk = sk_head(&raw_v6_hashinfo.ht[nexthdr & (MAX_INET_PROTOS - 1)]); + raw_sk = sk_head(&raw_v6_hashinfo.ht[nexthdr & (RAW_HTABLE_SIZE - 1)]); if (raw_sk && !ipv6_raw_deliver(skb, nexthdr)) raw_sk = NULL; -- 2.20.1