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@@ -1300,345 +1300,14 @@ ctl_table random_table[] = {
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};
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#endif /* CONFIG_SYSCTL */
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-/********************************************************************
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- *
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- * Random functions for networking
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- *
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- ********************************************************************/
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-
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-/*
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- * TCP initial sequence number picking. This uses the random number
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- * generator to pick an initial secret value. This value is hashed
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- * along with the TCP endpoint information to provide a unique
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- * starting point for each pair of TCP endpoints. This defeats
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- * attacks which rely on guessing the initial TCP sequence number.
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- * This algorithm was suggested by Steve Bellovin.
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- *
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- * Using a very strong hash was taking an appreciable amount of the total
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- * TCP connection establishment time, so this is a weaker hash,
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- * compensated for by changing the secret periodically.
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- */
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-
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-/* F, G and H are basic MD4 functions: selection, majority, parity */
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-#define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
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-#define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z)))
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-#define H(x, y, z) ((x) ^ (y) ^ (z))
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-
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-/*
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- * The generic round function. The application is so specific that
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- * we don't bother protecting all the arguments with parens, as is generally
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- * good macro practice, in favor of extra legibility.
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- * Rotation is separate from addition to prevent recomputation
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- */
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-#define ROUND(f, a, b, c, d, x, s) \
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- (a += f(b, c, d) + x, a = (a << s) | (a >> (32 - s)))
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-#define K1 0
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-#define K2 013240474631UL
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-#define K3 015666365641UL
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-
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-#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
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-
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-static __u32 twothirdsMD4Transform(__u32 const buf[4], __u32 const in[12])
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-{
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- __u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3];
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-
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- /* Round 1 */
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- ROUND(F, a, b, c, d, in[ 0] + K1, 3);
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- ROUND(F, d, a, b, c, in[ 1] + K1, 7);
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- ROUND(F, c, d, a, b, in[ 2] + K1, 11);
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- ROUND(F, b, c, d, a, in[ 3] + K1, 19);
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- ROUND(F, a, b, c, d, in[ 4] + K1, 3);
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- ROUND(F, d, a, b, c, in[ 5] + K1, 7);
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- ROUND(F, c, d, a, b, in[ 6] + K1, 11);
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- ROUND(F, b, c, d, a, in[ 7] + K1, 19);
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- ROUND(F, a, b, c, d, in[ 8] + K1, 3);
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- ROUND(F, d, a, b, c, in[ 9] + K1, 7);
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- ROUND(F, c, d, a, b, in[10] + K1, 11);
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- ROUND(F, b, c, d, a, in[11] + K1, 19);
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-
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- /* Round 2 */
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- ROUND(G, a, b, c, d, in[ 1] + K2, 3);
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- ROUND(G, d, a, b, c, in[ 3] + K2, 5);
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- ROUND(G, c, d, a, b, in[ 5] + K2, 9);
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- ROUND(G, b, c, d, a, in[ 7] + K2, 13);
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- ROUND(G, a, b, c, d, in[ 9] + K2, 3);
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- ROUND(G, d, a, b, c, in[11] + K2, 5);
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- ROUND(G, c, d, a, b, in[ 0] + K2, 9);
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- ROUND(G, b, c, d, a, in[ 2] + K2, 13);
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- ROUND(G, a, b, c, d, in[ 4] + K2, 3);
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- ROUND(G, d, a, b, c, in[ 6] + K2, 5);
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- ROUND(G, c, d, a, b, in[ 8] + K2, 9);
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- ROUND(G, b, c, d, a, in[10] + K2, 13);
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-
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- /* Round 3 */
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- ROUND(H, a, b, c, d, in[ 3] + K3, 3);
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- ROUND(H, d, a, b, c, in[ 7] + K3, 9);
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- ROUND(H, c, d, a, b, in[11] + K3, 11);
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- ROUND(H, b, c, d, a, in[ 2] + K3, 15);
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- ROUND(H, a, b, c, d, in[ 6] + K3, 3);
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- ROUND(H, d, a, b, c, in[10] + K3, 9);
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- ROUND(H, c, d, a, b, in[ 1] + K3, 11);
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- ROUND(H, b, c, d, a, in[ 5] + K3, 15);
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- ROUND(H, a, b, c, d, in[ 9] + K3, 3);
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- ROUND(H, d, a, b, c, in[ 0] + K3, 9);
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- ROUND(H, c, d, a, b, in[ 4] + K3, 11);
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- ROUND(H, b, c, d, a, in[ 8] + K3, 15);
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-
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- return buf[1] + b; /* "most hashed" word */
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- /* Alternative: return sum of all words? */
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-}
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-#endif
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-
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-#undef ROUND
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-#undef F
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-#undef G
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-#undef H
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-#undef K1
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-#undef K2
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-#undef K3
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-
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-/* This should not be decreased so low that ISNs wrap too fast. */
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-#define REKEY_INTERVAL (300 * HZ)
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-/*
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- * Bit layout of the tcp sequence numbers (before adding current time):
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- * bit 24-31: increased after every key exchange
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- * bit 0-23: hash(source,dest)
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- *
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- * The implementation is similar to the algorithm described
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- * in the Appendix of RFC 1185, except that
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- * - it uses a 1 MHz clock instead of a 250 kHz clock
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- * - it performs a rekey every 5 minutes, which is equivalent
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- * to a (source,dest) tulple dependent forward jump of the
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- * clock by 0..2^(HASH_BITS+1)
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- *
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- * Thus the average ISN wraparound time is 68 minutes instead of
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- * 4.55 hours.
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- *
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- * SMP cleanup and lock avoidance with poor man's RCU.
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- * Manfred Spraul <manfred@colorfullife.com>
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- *
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- */
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-#define COUNT_BITS 8
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-#define COUNT_MASK ((1 << COUNT_BITS) - 1)
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-#define HASH_BITS 24
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-#define HASH_MASK ((1 << HASH_BITS) - 1)
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+static u32 random_int_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned;
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-static struct keydata {
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- __u32 count; /* already shifted to the final position */
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- __u32 secret[12];
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-} ____cacheline_aligned ip_keydata[2];
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-
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-static unsigned int ip_cnt;
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-
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-static void rekey_seq_generator(struct work_struct *work);
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-
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-static DECLARE_DELAYED_WORK(rekey_work, rekey_seq_generator);
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-
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-/*
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- * Lock avoidance:
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- * The ISN generation runs lockless - it's just a hash over random data.
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- * State changes happen every 5 minutes when the random key is replaced.
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- * Synchronization is performed by having two copies of the hash function
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- * state and rekey_seq_generator always updates the inactive copy.
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- * The copy is then activated by updating ip_cnt.
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- * The implementation breaks down if someone blocks the thread
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- * that processes SYN requests for more than 5 minutes. Should never
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- * happen, and even if that happens only a not perfectly compliant
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- * ISN is generated, nothing fatal.
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- */
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-static void rekey_seq_generator(struct work_struct *work)
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+static int __init random_int_secret_init(void)
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{
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- struct keydata *keyptr = &ip_keydata[1 ^ (ip_cnt & 1)];
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-
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- get_random_bytes(keyptr->secret, sizeof(keyptr->secret));
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- keyptr->count = (ip_cnt & COUNT_MASK) << HASH_BITS;
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- smp_wmb();
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- ip_cnt++;
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- schedule_delayed_work(&rekey_work,
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- round_jiffies_relative(REKEY_INTERVAL));
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-}
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-
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-static inline struct keydata *get_keyptr(void)
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-{
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- struct keydata *keyptr = &ip_keydata[ip_cnt & 1];
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-
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- smp_rmb();
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-
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- return keyptr;
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-}
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-
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-static __init int seqgen_init(void)
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-{
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- rekey_seq_generator(NULL);
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+ get_random_bytes(random_int_secret, sizeof(random_int_secret));
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return 0;
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}
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-late_initcall(seqgen_init);
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-
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-#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
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-__u32 secure_tcpv6_sequence_number(__be32 *saddr, __be32 *daddr,
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- __be16 sport, __be16 dport)
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-{
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- __u32 seq;
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- __u32 hash[12];
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- struct keydata *keyptr = get_keyptr();
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-
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- /* The procedure is the same as for IPv4, but addresses are longer.
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- * Thus we must use twothirdsMD4Transform.
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- */
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-
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- memcpy(hash, saddr, 16);
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- hash[4] = ((__force u16)sport << 16) + (__force u16)dport;
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- memcpy(&hash[5], keyptr->secret, sizeof(__u32) * 7);
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-
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- seq = twothirdsMD4Transform((const __u32 *)daddr, hash) & HASH_MASK;
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- seq += keyptr->count;
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-
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- seq += ktime_to_ns(ktime_get_real());
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-
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- return seq;
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-}
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-EXPORT_SYMBOL(secure_tcpv6_sequence_number);
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-#endif
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-
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-/* The code below is shamelessly stolen from secure_tcp_sequence_number().
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- * All blames to Andrey V. Savochkin <saw@msu.ru>.
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- */
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-__u32 secure_ip_id(__be32 daddr)
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-{
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- struct keydata *keyptr;
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- __u32 hash[4];
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-
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- keyptr = get_keyptr();
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-
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- /*
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- * Pick a unique starting offset for each IP destination.
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- * The dest ip address is placed in the starting vector,
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- * which is then hashed with random data.
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- */
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- hash[0] = (__force __u32)daddr;
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- hash[1] = keyptr->secret[9];
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- hash[2] = keyptr->secret[10];
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- hash[3] = keyptr->secret[11];
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-
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- return half_md4_transform(hash, keyptr->secret);
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-}
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-
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-__u32 secure_ipv6_id(const __be32 daddr[4])
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-{
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- const struct keydata *keyptr;
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- __u32 hash[4];
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-
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- keyptr = get_keyptr();
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-
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- hash[0] = (__force __u32)daddr[0];
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- hash[1] = (__force __u32)daddr[1];
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- hash[2] = (__force __u32)daddr[2];
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- hash[3] = (__force __u32)daddr[3];
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-
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- return half_md4_transform(hash, keyptr->secret);
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-}
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-
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-#ifdef CONFIG_INET
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-
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-__u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr,
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- __be16 sport, __be16 dport)
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-{
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- __u32 seq;
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- __u32 hash[4];
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- struct keydata *keyptr = get_keyptr();
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-
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- /*
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- * Pick a unique starting offset for each TCP connection endpoints
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- * (saddr, daddr, sport, dport).
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- * Note that the words are placed into the starting vector, which is
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- * then mixed with a partial MD4 over random data.
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- */
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- hash[0] = (__force u32)saddr;
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- hash[1] = (__force u32)daddr;
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- hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
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- hash[3] = keyptr->secret[11];
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-
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- seq = half_md4_transform(hash, keyptr->secret) & HASH_MASK;
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- seq += keyptr->count;
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- /*
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- * As close as possible to RFC 793, which
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- * suggests using a 250 kHz clock.
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- * Further reading shows this assumes 2 Mb/s networks.
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- * For 10 Mb/s Ethernet, a 1 MHz clock is appropriate.
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- * For 10 Gb/s Ethernet, a 1 GHz clock should be ok, but
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- * we also need to limit the resolution so that the u32 seq
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- * overlaps less than one time per MSL (2 minutes).
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- * Choosing a clock of 64 ns period is OK. (period of 274 s)
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- */
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- seq += ktime_to_ns(ktime_get_real()) >> 6;
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-
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- return seq;
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-}
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-
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-/* Generate secure starting point for ephemeral IPV4 transport port search */
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-u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
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-{
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- struct keydata *keyptr = get_keyptr();
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- u32 hash[4];
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-
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- /*
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- * Pick a unique starting offset for each ephemeral port search
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- * (saddr, daddr, dport) and 48bits of random data.
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- */
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- hash[0] = (__force u32)saddr;
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- hash[1] = (__force u32)daddr;
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- hash[2] = (__force u32)dport ^ keyptr->secret[10];
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- hash[3] = keyptr->secret[11];
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-
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- return half_md4_transform(hash, keyptr->secret);
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-}
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-EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral);
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-
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-#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
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-u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
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- __be16 dport)
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-{
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- struct keydata *keyptr = get_keyptr();
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- u32 hash[12];
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-
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- memcpy(hash, saddr, 16);
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- hash[4] = (__force u32)dport;
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- memcpy(&hash[5], keyptr->secret, sizeof(__u32) * 7);
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-
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- return twothirdsMD4Transform((const __u32 *)daddr, hash);
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-}
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-#endif
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-
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-#if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
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-/* Similar to secure_tcp_sequence_number but generate a 48 bit value
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- * bit's 32-47 increase every key exchange
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- * 0-31 hash(source, dest)
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- */
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-u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
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- __be16 sport, __be16 dport)
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-{
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- u64 seq;
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- __u32 hash[4];
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- struct keydata *keyptr = get_keyptr();
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-
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- hash[0] = (__force u32)saddr;
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- hash[1] = (__force u32)daddr;
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- hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
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- hash[3] = keyptr->secret[11];
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-
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- seq = half_md4_transform(hash, keyptr->secret);
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- seq |= ((u64)keyptr->count) << (32 - HASH_BITS);
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-
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- seq += ktime_to_ns(ktime_get_real());
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- seq &= (1ull << 48) - 1;
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-
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- return seq;
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-}
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-EXPORT_SYMBOL(secure_dccp_sequence_number);
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-#endif
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-
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-#endif /* CONFIG_INET */
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-
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+late_initcall(random_int_secret_init);
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/*
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* Get a random word for internal kernel use only. Similar to urandom but
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@@ -1646,17 +1315,15 @@ EXPORT_SYMBOL(secure_dccp_sequence_number);
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* value is not cryptographically secure but for several uses the cost of
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* depleting entropy is too high
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*/
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-DEFINE_PER_CPU(__u32 [4], get_random_int_hash);
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+DEFINE_PER_CPU(__u32 [MD5_DIGEST_WORDS], get_random_int_hash);
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unsigned int get_random_int(void)
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{
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- struct keydata *keyptr;
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__u32 *hash = get_cpu_var(get_random_int_hash);
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- int ret;
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+ unsigned int ret;
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- keyptr = get_keyptr();
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hash[0] += current->pid + jiffies + get_cycles();
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-
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- ret = half_md4_transform(hash, keyptr->secret);
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+ md5_transform(hash, random_int_secret);
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+ ret = hash[0];
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put_cpu_var(get_random_int_hash);
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return ret;
|