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| author | Hannes Frederic Sowa <hannes@stressinduktion.org> | 2013-10-19 21:48:56 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-10-19 19:45:35 -0400 |
| commit | b23a002fc6f0c19846ee0382f019429af54a27e9 (patch) | |
| tree | 9cb494a707c4145a8a42f0cf6eb6853e487f06a5 | |
| parent | a48e42920ff38bc90bbf75143fff4555723d4540 (diff) | |
| download | linux-b23a002fc6f0c19846ee0382f019429af54a27e9.tar.gz | |
inet: split syncookie keys for ipv4 and ipv6 and initialize with net_get_random_once
This patch splits the secret key for syncookies for ipv4 and ipv6 and initializes them with net_get_random_once. This change was the reason I did this series. I think the initialization of the syncookie_secret is way to early. Cc: Florian Westphal <fw@strlen.de> Cc: Eric Dumazet <edumazet@google.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/net/tcp.h | 1 | ||||
| -rw-r--r-- | net/ipv4/syncookies.c | 15 | ||||
| -rw-r--r-- | net/ipv6/syncookies.c | 12 |
3 files changed, 14 insertions, 14 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index 372dcccfeed0..f30326f1c92b 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -475,7 +475,6 @@ int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size); void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb); /* From syncookies.c */ -extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS]; int __cookie_v4_check(const struct iphdr *iph, const struct tcphdr *th, u32 cookie); struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index 3b64c59b4109..b95331e6c077 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -25,15 +25,7 @@ extern int sysctl_tcp_syncookies; -__u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS]; -EXPORT_SYMBOL(syncookie_secret); - -static __init int init_syncookies(void) -{ - get_random_bytes(syncookie_secret, sizeof(syncookie_secret)); - return 0; -} -__initcall(init_syncookies); +static u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS]; #define COOKIEBITS 24 /* Upper bits store count */ #define COOKIEMASK (((__u32)1 << COOKIEBITS) - 1) @@ -44,8 +36,11 @@ static DEFINE_PER_CPU(__u32 [16 + 5 + SHA_WORKSPACE_WORDS], static u32 cookie_hash(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport, u32 count, int c) { - __u32 *tmp = __get_cpu_var(ipv4_cookie_scratch); + __u32 *tmp; + + net_get_random_once(syncookie_secret, sizeof(syncookie_secret)); + tmp = __get_cpu_var(ipv4_cookie_scratch); memcpy(tmp + 4, syncookie_secret[c], sizeof(syncookie_secret[c])); tmp[0] = (__force u32)saddr; tmp[1] = (__force u32)daddr; diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c index d04d3f1dd9b7..535a3ad262f1 100644 --- a/net/ipv6/syncookies.c +++ b/net/ipv6/syncookies.c @@ -24,6 +24,8 @@ #define COOKIEBITS 24 /* Upper bits store count */ #define COOKIEMASK (((__u32)1 << COOKIEBITS) - 1) +static u32 syncookie6_secret[2][16-4+SHA_DIGEST_WORDS]; + /* RFC 2460, Section 8.3: * [ipv6 tcp] MSS must be computed as the maximum packet size minus 60 [..] * @@ -61,14 +63,18 @@ static DEFINE_PER_CPU(__u32 [16 + 5 + SHA_WORKSPACE_WORDS], static u32 cookie_hash(const struct in6_addr *saddr, const struct in6_addr *daddr, __be16 sport, __be16 dport, u32 count, int c) { - __u32 *tmp = __get_cpu_var(ipv6_cookie_scratch); + __u32 *tmp; + + net_get_random_once(syncookie6_secret, sizeof(syncookie6_secret)); + + tmp = __get_cpu_var(ipv6_cookie_scratch); /* * we have 320 bits of information to hash, copy in the remaining - * 192 bits required for sha_transform, from the syncookie_secret + * 192 bits required for sha_transform, from the syncookie6_secret * and overwrite the digest with the secret */ - memcpy(tmp + 10, syncookie_secret[c], 44); + memcpy(tmp + 10, syncookie6_secret[c], 44); memcpy(tmp, saddr, 16); memcpy(tmp + 4, daddr, 16); tmp[8] = ((__force u32)sport << 16) + (__force u32)dport; |