diff options
Diffstat (limited to 'net/core/secure_seq.c')
| -rw-r--r-- | net/core/secure_seq.c | 235 |
1 files changed, 104 insertions, 131 deletions
diff --git a/net/core/secure_seq.c b/net/core/secure_seq.c index 6a2f13cee86a..9a3965680451 100644 --- a/net/core/secure_seq.c +++ b/net/core/secure_seq.c @@ -1,21 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + #include <linux/kernel.h> #include <linux/init.h> -#include <linux/cryptohash.h> #include <linux/module.h> #include <linux/cache.h> #include <linux/random.h> #include <linux/hrtimer.h> #include <linux/ktime.h> #include <linux/string.h> - +#include <linux/net.h> +#include <linux/siphash.h> #include <net/secure_seq.h> -static u32 net_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned; +#if IS_ENABLED(CONFIG_IPV6) || IS_ENABLED(CONFIG_INET) +#include <linux/in6.h> +#include <net/tcp.h> + +static siphash_aligned_key_t net_secret; +static siphash_aligned_key_t ts_secret; + +#define EPHEMERAL_PORT_SHUFFLE_PERIOD (10 * HZ) + +static __always_inline void net_secret_init(void) +{ + net_get_random_once(&net_secret, sizeof(net_secret)); +} -void net_secret_init(void) +static __always_inline void ts_secret_init(void) { - get_random_bytes(net_secret, sizeof(net_secret)); + net_get_random_once(&ts_secret, sizeof(ts_secret)); } +#endif #ifdef CONFIG_INET static u32 seq_scale(u32 seq) @@ -30,156 +48,111 @@ static u32 seq_scale(u32 seq) * overlaps less than one time per MSL (2 minutes). * Choosing a clock of 64 ns period is OK. (period of 274 s) */ - return seq + (ktime_to_ns(ktime_get_real()) >> 6); + return seq + (ktime_get_real_ns() >> 6); } #endif #if IS_ENABLED(CONFIG_IPV6) -__u32 secure_tcpv6_sequence_number(const __be32 *saddr, const __be32 *daddr, - __be16 sport, __be16 dport) +u32 secure_tcpv6_ts_off(const struct net *net, + const __be32 *saddr, const __be32 *daddr) { - u32 secret[MD5_MESSAGE_BYTES / 4]; - u32 hash[MD5_DIGEST_WORDS]; - u32 i; - - 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); + const struct { + struct in6_addr saddr; + struct in6_addr daddr; + } __aligned(SIPHASH_ALIGNMENT) combined = { + .saddr = *(struct in6_addr *)saddr, + .daddr = *(struct in6_addr *)daddr, + }; + + if (READ_ONCE(net->ipv4.sysctl_tcp_timestamps) != 1) + return 0; + + ts_secret_init(); + return siphash(&combined, offsetofend(typeof(combined), daddr), + &ts_secret); +} +EXPORT_IPV6_MOD(secure_tcpv6_ts_off); - return seq_scale(hash[0]); +u32 secure_tcpv6_seq(const __be32 *saddr, const __be32 *daddr, + __be16 sport, __be16 dport) +{ + 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 + }; + u32 hash; + + net_secret_init(); + hash = siphash(&combined, offsetofend(typeof(combined), dport), + &net_secret); + return seq_scale(hash); } -EXPORT_SYMBOL(secure_tcpv6_sequence_number); +EXPORT_SYMBOL(secure_tcpv6_seq); -u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr, +u64 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; - - 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]; + const struct { + struct in6_addr saddr; + struct in6_addr daddr; + unsigned int timeseed; + __be16 dport; + } __aligned(SIPHASH_ALIGNMENT) combined = { + .saddr = *(struct in6_addr *)saddr, + .daddr = *(struct in6_addr *)daddr, + .timeseed = jiffies / EPHEMERAL_PORT_SHUFFLE_PERIOD, + .dport = dport, + }; + net_secret_init(); + return siphash(&combined, offsetofend(typeof(combined), dport), + &net_secret); } EXPORT_SYMBOL(secure_ipv6_port_ephemeral); #endif #ifdef CONFIG_INET -__u32 secure_ip_id(__be32 daddr) -{ - u32 hash[MD5_DIGEST_WORDS]; - - hash[0] = (__force __u32) daddr; - hash[1] = net_secret[13]; - hash[2] = net_secret[14]; - hash[3] = net_secret[15]; - - md5_transform(hash, net_secret); - - return hash[0]; -} - -__u32 secure_ipv6_id(const __be32 daddr[4]) +u32 secure_tcp_ts_off(const struct net *net, __be32 saddr, __be32 daddr) { - __u32 hash[4]; - - memcpy(hash, daddr, 16); - md5_transform(hash, net_secret); + if (READ_ONCE(net->ipv4.sysctl_tcp_timestamps) != 1) + return 0; - return hash[0]; + ts_secret_init(); + return siphash_2u32((__force u32)saddr, (__force u32)daddr, + &ts_secret); } -__u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr, - __be16 sport, __be16 dport) +/* secure_tcp_seq_and_tsoff(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_seq(__be32 saddr, __be32 daddr, + __be16 sport, __be16 dport) { - u32 hash[MD5_DIGEST_WORDS]; - - hash[0] = (__force u32)saddr; - hash[1] = (__force u32)daddr; - hash[2] = ((__force u16)sport << 16) + (__force u16)dport; - hash[3] = net_secret[15]; + u32 hash; - md5_transform(hash, net_secret); - - return seq_scale(hash[0]); + net_secret_init(); + hash = siphash_3u32((__force u32)saddr, (__force u32)daddr, + (__force u32)sport << 16 | (__force u32)dport, + &net_secret); + return seq_scale(hash); } +EXPORT_SYMBOL_GPL(secure_tcp_seq); -u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport) +u64 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport) { - u32 hash[MD5_DIGEST_WORDS]; - - 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]; + net_secret_init(); + return siphash_4u32((__force u32)saddr, (__force u32)daddr, + (__force u16)dport, + jiffies / EPHEMERAL_PORT_SHUFFLE_PERIOD, + &net_secret); } EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral); #endif - -#if IS_ENABLED(CONFIG_IP_DCCP) -u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr, - __be16 sport, __be16 dport) -{ - u32 hash[MD5_DIGEST_WORDS]; - u64 seq; - - 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 += ktime_to_ns(ktime_get_real()); - seq &= (1ull << 48) - 1; - - return seq; -} -EXPORT_SYMBOL(secure_dccp_sequence_number); - -#if IS_ENABLED(CONFIG_IPV6) -u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr, - __be16 sport, __be16 dport) -{ - u32 secret[MD5_MESSAGE_BYTES / 4]; - u32 hash[MD5_DIGEST_WORDS]; - u64 seq; - u32 i; - - memcpy(hash, saddr, 16); - for (i = 0; i < 4; i++) - secret[i] = net_secret[i] + 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 += ktime_to_ns(ktime_get_real()); - seq &= (1ull << 48) - 1; - - return seq; -} -EXPORT_SYMBOL(secure_dccpv6_sequence_number); -#endif -#endif |