diff options
| -rw-r--r-- | include/linux/siphash.h | 5 | ||||
| -rw-r--r-- | include/net/netns/ipv4.h | 2 | ||||
| -rw-r--r-- | net/ipv4/route.c | 12 | ||||
| -rw-r--r-- | net/ipv6/output_core.c | 30 |
4 files changed, 30 insertions, 19 deletions
diff --git a/include/linux/siphash.h b/include/linux/siphash.h index fa7a6b9cedbf..bf21591a9e5e 100644 --- a/include/linux/siphash.h +++ b/include/linux/siphash.h @@ -21,6 +21,11 @@ typedef struct { u64 key[2]; } siphash_key_t; +static inline bool siphash_key_is_zero(const siphash_key_t *key) +{ + return !(key->key[0] | key->key[1]); +} + u64 __siphash_aligned(const void *data, size_t len, const siphash_key_t *key); #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS u64 __siphash_unaligned(const void *data, size_t len, const siphash_key_t *key); diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h index 104a6669e344..7698460a3dd1 100644 --- a/include/net/netns/ipv4.h +++ b/include/net/netns/ipv4.h @@ -9,6 +9,7 @@ #include <linux/uidgid.h> #include <net/inet_frag.h> #include <linux/rcupdate.h> +#include <linux/siphash.h> struct tcpm_hash_bucket; struct ctl_table_header; @@ -217,5 +218,6 @@ struct netns_ipv4 { unsigned int ipmr_seq; /* protected by rtnl_mutex */ atomic_t rt_genid; + siphash_key_t ip_id_key; }; #endif diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 14c7fdacaa72..f2688fce39e1 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -500,15 +500,17 @@ EXPORT_SYMBOL(ip_idents_reserve); void __ip_select_ident(struct net *net, struct iphdr *iph, int segs) { - static u32 ip_idents_hashrnd __read_mostly; u32 hash, id; - net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd)); + /* Note the following code is not safe, but this is okay. */ + if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key))) + get_random_bytes(&net->ipv4.ip_id_key, + sizeof(net->ipv4.ip_id_key)); - hash = jhash_3words((__force u32)iph->daddr, + hash = siphash_3u32((__force u32)iph->daddr, (__force u32)iph->saddr, - iph->protocol ^ net_hash_mix(net), - ip_idents_hashrnd); + iph->protocol, + &net->ipv4.ip_id_key); id = ip_idents_reserve(hash, segs); iph->id = htons(id); } diff --git a/net/ipv6/output_core.c b/net/ipv6/output_core.c index 4fe7c90962dd..868ae23dbae1 100644 --- a/net/ipv6/output_core.c +++ b/net/ipv6/output_core.c @@ -10,15 +10,25 @@ #include <net/secure_seq.h> #include <linux/netfilter.h> -static u32 __ipv6_select_ident(struct net *net, u32 hashrnd, +static u32 __ipv6_select_ident(struct net *net, const struct in6_addr *dst, const struct in6_addr *src) { + const struct { + struct in6_addr dst; + struct in6_addr src; + } __aligned(SIPHASH_ALIGNMENT) combined = { + .dst = *dst, + .src = *src, + }; u32 hash, id; - hash = __ipv6_addr_jhash(dst, hashrnd); - hash = __ipv6_addr_jhash(src, hash); - hash ^= net_hash_mix(net); + /* Note the following code is not safe, but this is okay. */ + if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key))) + get_random_bytes(&net->ipv4.ip_id_key, + sizeof(net->ipv4.ip_id_key)); + + hash = siphash(&combined, sizeof(combined), &net->ipv4.ip_id_key); /* Treat id of 0 as unset and if we get 0 back from ip_idents_reserve, * set the hight order instead thus minimizing possible future @@ -41,7 +51,6 @@ static u32 __ipv6_select_ident(struct net *net, u32 hashrnd, */ __be32 ipv6_proxy_select_ident(struct net *net, struct sk_buff *skb) { - static u32 ip6_proxy_idents_hashrnd __read_mostly; struct in6_addr buf[2]; struct in6_addr *addrs; u32 id; @@ -53,11 +62,7 @@ __be32 ipv6_proxy_select_ident(struct net *net, struct sk_buff *skb) if (!addrs) return 0; - net_get_random_once(&ip6_proxy_idents_hashrnd, - sizeof(ip6_proxy_idents_hashrnd)); - - id = __ipv6_select_ident(net, ip6_proxy_idents_hashrnd, - &addrs[1], &addrs[0]); + id = __ipv6_select_ident(net, &addrs[1], &addrs[0]); return htonl(id); } EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident); @@ -66,12 +71,9 @@ __be32 ipv6_select_ident(struct net *net, const struct in6_addr *daddr, const struct in6_addr *saddr) { - static u32 ip6_idents_hashrnd __read_mostly; u32 id; - net_get_random_once(&ip6_idents_hashrnd, sizeof(ip6_idents_hashrnd)); - - id = __ipv6_select_ident(net, ip6_idents_hashrnd, daddr, saddr); + id = __ipv6_select_ident(net, daddr, saddr); return htonl(id); } EXPORT_SYMBOL(ipv6_select_ident); |