From 2051f11fb86b0056fec440fe7e9fa8370d60a5c6 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Sun, 23 Mar 2008 22:21:28 -0700 Subject: [PATCH] [TCP]: Shrink syncookie_secret by 8 byte. the first u32 copied from syncookie_secret is overwritten by the minute-counter four lines below. After adjusting the destination address, the size of syncookie_secret can be reduced accordingly. AFAICS, the only other user of syncookie_secret[] is the ipv6 syncookie support. Because ipv6 syncookies only grab 44 bytes from syncookie_secret[], this shouldn't affect them in any way. With fixes from Glenn Griffin. Signed-off-by: Florian Westphal Acked-by: Glenn Griffin Signed-off-by: David S. Miller --- include/net/tcp.h | 2 +- net/ipv4/syncookies.c | 4 ++-- net/ipv6/syncookies.c | 2 +- 3 files changed, 4 insertions(+), 4 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 67cc3956d29c..723b36851dde 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -436,7 +436,7 @@ extern int tcp_disconnect(struct sock *sk, int flags); extern void tcp_unhash(struct sock *sk); /* From syncookies.c */ -extern __u32 syncookie_secret[2][16-3+SHA_DIGEST_WORDS]; +extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS]; extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, struct ip_options *opt); extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index 4704f27f6c0b..abc752d45cf7 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -21,7 +21,7 @@ extern int sysctl_tcp_syncookies; -__u32 syncookie_secret[2][16-3+SHA_DIGEST_WORDS]; +__u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS]; EXPORT_SYMBOL(syncookie_secret); static __init int init_syncookies(void) @@ -41,7 +41,7 @@ static u32 cookie_hash(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport, { __u32 *tmp = __get_cpu_var(cookie_scratch); - memcpy(tmp + 3, syncookie_secret[c], sizeof(syncookie_secret[c])); + memcpy(tmp + 4, syncookie_secret[c], sizeof(syncookie_secret[c])); tmp[0] = (__force u32)saddr; tmp[1] = (__force u32)daddr; tmp[2] = ((__force u32)sport << 16) + (__force u32)dport; diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c index 827c5aa7524c..3a622e7abc02 100644 --- a/net/ipv6/syncookies.c +++ b/net/ipv6/syncookies.c @@ -22,7 +22,7 @@ #include extern int sysctl_tcp_syncookies; -extern __u32 syncookie_secret[2][16-3+SHA_DIGEST_WORDS]; +extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS]; #define COOKIEBITS 24 /* Upper bits store count */ #define COOKIEMASK (((__u32)1 << COOKIEBITS) - 1) -- 2.20.1