diff options
Diffstat (limited to 'net/core/secure_seq.c')
| -rw-r--r-- | net/core/secure_seq.c | 147 |
1 files changed, 65 insertions, 82 deletions
diff --git a/net/core/secure_seq.c b/net/core/secure_seq.c index 88a8e429fc3e..758f140b6bed 100644 --- a/net/core/secure_seq.c +++ b/net/core/secure_seq.c @@ -1,3 +1,7 @@ +/* + * Copyright (C) 2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + #include <linux/kernel.h> #include <linux/init.h> #include <linux/cryptohash.h> @@ -8,18 +12,18 @@ #include <linux/ktime.h> #include <linux/string.h> #include <linux/net.h> - +#include <linux/siphash.h> #include <net/secure_seq.h> #if IS_ENABLED(CONFIG_IPV6) || IS_ENABLED(CONFIG_INET) +#include <linux/in6.h> #include <net/tcp.h> -#define NET_SECRET_SIZE (MD5_MESSAGE_BYTES / 4) -static u32 net_secret[NET_SECRET_SIZE] ____cacheline_aligned; +static siphash_key_t net_secret __read_mostly; static __always_inline void net_secret_init(void) { - net_get_random_once(net_secret, sizeof(net_secret)); + net_get_random_once(&net_secret, sizeof(net_secret)); } #endif @@ -44,80 +48,70 @@ static u32 seq_scale(u32 seq) u32 secure_tcpv6_sequence_number(const __be32 *saddr, const __be32 *daddr, __be16 sport, __be16 dport, u32 *tsoff) { - u32 secret[MD5_MESSAGE_BYTES / 4]; - u32 hash[MD5_DIGEST_WORDS]; - u32 i; - + const struct { + struct in6_addr saddr; + struct in6_addr daddr; + __be16 sport; + __be16 dport; + } __aligned(SIPHASH_ALIGNMENT) combined = { + .saddr = *(struct in6_addr *)saddr, + .daddr = *(struct in6_addr *)daddr, + .sport = sport, + .dport = dport + }; + u64 hash; net_secret_init(); - memcpy(hash, saddr, 16); - for (i = 0; i < 4; i++) - secret[i] = net_secret[i] + (__force u32)daddr[i]; - secret[4] = net_secret[4] + - (((__force u16)sport << 16) + (__force u16)dport); - for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++) - secret[i] = net_secret[i]; - - md5_transform(hash, secret); - - *tsoff = sysctl_tcp_timestamps == 1 ? hash[1] : 0; - return seq_scale(hash[0]); + hash = siphash(&combined, offsetofend(typeof(combined), dport), + &net_secret); + *tsoff = sysctl_tcp_timestamps == 1 ? (hash >> 32) : 0; + return seq_scale(hash); } EXPORT_SYMBOL(secure_tcpv6_sequence_number); u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr, __be16 dport) { - u32 secret[MD5_MESSAGE_BYTES / 4]; - u32 hash[MD5_DIGEST_WORDS]; - u32 i; - + const struct { + struct in6_addr saddr; + struct in6_addr daddr; + __be16 dport; + } __aligned(SIPHASH_ALIGNMENT) combined = { + .saddr = *(struct in6_addr *)saddr, + .daddr = *(struct in6_addr *)daddr, + .dport = dport + }; net_secret_init(); - memcpy(hash, saddr, 16); - for (i = 0; i < 4; i++) - secret[i] = net_secret[i] + (__force u32) daddr[i]; - secret[4] = net_secret[4] + (__force u32)dport; - for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++) - secret[i] = net_secret[i]; - - md5_transform(hash, secret); - - return hash[0]; + return siphash(&combined, offsetofend(typeof(combined), dport), + &net_secret); } EXPORT_SYMBOL(secure_ipv6_port_ephemeral); #endif #ifdef CONFIG_INET +/* secure_tcp_sequence_number(a, b, 0, d) == secure_ipv4_port_ephemeral(a, b, d), + * but fortunately, `sport' cannot be 0 in any circumstances. If this changes, + * it would be easy enough to have the former function use siphash_4u32, passing + * the arguments as separate u32. + */ + u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport, u32 *tsoff) { - u32 hash[MD5_DIGEST_WORDS]; - + u64 hash; net_secret_init(); - hash[0] = (__force u32)saddr; - hash[1] = (__force u32)daddr; - hash[2] = ((__force u16)sport << 16) + (__force u16)dport; - hash[3] = net_secret[15]; - - md5_transform(hash, net_secret); - - *tsoff = sysctl_tcp_timestamps == 1 ? hash[1] : 0; - return seq_scale(hash[0]); + hash = siphash_3u32((__force u32)saddr, (__force u32)daddr, + (__force u32)sport << 16 | (__force u32)dport, + &net_secret); + *tsoff = sysctl_tcp_timestamps == 1 ? (hash >> 32) : 0; + return seq_scale(hash); } u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport) { - u32 hash[MD5_DIGEST_WORDS]; - net_secret_init(); - hash[0] = (__force u32)saddr; - hash[1] = (__force u32)daddr; - hash[2] = (__force u32)dport ^ net_secret[14]; - hash[3] = net_secret[15]; - - md5_transform(hash, net_secret); - - return hash[0]; + return siphash_3u32((__force u32)saddr, (__force u32)daddr, + (__force u16)dport, &net_secret); } EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral); #endif @@ -126,21 +120,13 @@ EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral); u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport) { - u32 hash[MD5_DIGEST_WORDS]; u64 seq; - net_secret_init(); - hash[0] = (__force u32)saddr; - hash[1] = (__force u32)daddr; - hash[2] = ((__force u16)sport << 16) + (__force u16)dport; - hash[3] = net_secret[15]; - - md5_transform(hash, net_secret); - - seq = hash[0] | (((u64)hash[1]) << 32); + seq = siphash_3u32((__force u32)saddr, (__force u32)daddr, + (__force u32)sport << 16 | (__force u32)dport, + &net_secret); seq += ktime_get_real_ns(); seq &= (1ull << 48) - 1; - return seq; } EXPORT_SYMBOL(secure_dccp_sequence_number); @@ -149,26 +135,23 @@ EXPORT_SYMBOL(secure_dccp_sequence_number); u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr, __be16 sport, __be16 dport) { - u32 secret[MD5_MESSAGE_BYTES / 4]; - u32 hash[MD5_DIGEST_WORDS]; + const struct { + struct in6_addr saddr; + struct in6_addr daddr; + __be16 sport; + __be16 dport; + } __aligned(SIPHASH_ALIGNMENT) combined = { + .saddr = *(struct in6_addr *)saddr, + .daddr = *(struct in6_addr *)daddr, + .sport = sport, + .dport = dport + }; u64 seq; - u32 i; - net_secret_init(); - memcpy(hash, saddr, 16); - for (i = 0; i < 4; i++) - secret[i] = net_secret[i] + (__force u32)daddr[i]; - secret[4] = net_secret[4] + - (((__force u16)sport << 16) + (__force u16)dport); - for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++) - secret[i] = net_secret[i]; - - md5_transform(hash, secret); - - seq = hash[0] | (((u64)hash[1]) << 32); + seq = siphash(&combined, offsetofend(typeof(combined), dport), + &net_secret); seq += ktime_get_real_ns(); seq &= (1ull << 48) - 1; - return seq; } EXPORT_SYMBOL(secure_dccpv6_sequence_number); |