/*
* random.c -- A strong random number generator
*
- * Version 1.89, last modified 19-Sep-99
+ * Copyright Matt Mackall <mpm@selenic.com>, 2003, 2004, 2005
*
* Copyright Theodore Ts'o, 1994, 1995, 1996, 1997, 1998, 1999. All
* rights reserved.
* Any flaws in the design are solely my responsibility, and should
* not be attributed to the Phil, Colin, or any of authors of PGP.
*
- * The code for SHA transform was taken from Peter Gutmann's
- * implementation, which has been placed in the public domain.
- * The code for MD5 transform was taken from Colin Plumb's
- * implementation, which has been placed in the public domain.
- * The MD5 cryptographic checksum was devised by Ronald Rivest, and is
- * documented in RFC 1321, "The MD5 Message Digest Algorithm".
- *
* Further background information on this topic may be obtained from
* RFC 1750, "Randomness Recommendations for Security", by Donald
* Eastlake, Steve Crocker, and Jeff Schiller.
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/fs.h>
-#include <linux/workqueue.h>
#include <linux/genhd.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/percpu.h>
+#include <linux/cryptohash.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
/*
* Configuration information
*/
-#define DEFAULT_POOL_SIZE 512
-#define SECONDARY_POOL_SIZE 128
-#define BATCH_ENTROPY_SIZE 256
-#define USE_SHA
+#define INPUT_POOL_WORDS 128
+#define OUTPUT_POOL_WORDS 32
+#define SEC_XFER_SIZE 512
/*
* The minimum number of bits of entropy before we wake up a read on
* samples to avoid wasting CPU time and reduce lock contention.
*/
-static int trickle_thresh = DEFAULT_POOL_SIZE * 7;
+static int trickle_thresh = INPUT_POOL_WORDS * 28;
static DEFINE_PER_CPU(int, trickle_count) = 0;
int poolwords;
int tap1, tap2, tap3, tap4, tap5;
} poolinfo_table[] = {
+ /* x^128 + x^103 + x^76 + x^51 +x^25 + x + 1 -- 105 */
+ { 128, 103, 76, 51, 25, 1 },
+ /* x^32 + x^26 + x^20 + x^14 + x^7 + x + 1 -- 15 */
+ { 32, 26, 20, 14, 7, 1 },
+#if 0
/* x^2048 + x^1638 + x^1231 + x^819 + x^411 + x + 1 -- 115 */
{ 2048, 1638, 1231, 819, 411, 1 },
/* x^1024 + x^817 + x^615 + x^412 + x^204 + x + 1 -- 290 */
{ 1024, 817, 615, 412, 204, 1 },
-#if 0 /* Alternate polynomial */
+
/* x^1024 + x^819 + x^616 + x^410 + x^207 + x^2 + 1 -- 115 */
{ 1024, 819, 616, 410, 207, 2 },
-#endif
/* x^512 + x^411 + x^308 + x^208 + x^104 + x + 1 -- 225 */
{ 512, 411, 308, 208, 104, 1 },
-#if 0 /* Alternates */
+
/* x^512 + x^409 + x^307 + x^206 + x^102 + x^2 + 1 -- 95 */
{ 512, 409, 307, 206, 102, 2 },
/* x^512 + x^409 + x^309 + x^205 + x^103 + x^2 + 1 -- 95 */
{ 512, 409, 309, 205, 103, 2 },
-#endif
/* x^256 + x^205 + x^155 + x^101 + x^52 + x + 1 -- 125 */
{ 256, 205, 155, 101, 52, 1 },
- /* x^128 + x^103 + x^76 + x^51 +x^25 + x + 1 -- 105 */
- { 128, 103, 76, 51, 25, 1 },
-#if 0 /* Alternate polynomial */
/* x^128 + x^103 + x^78 + x^51 + x^27 + x^2 + 1 -- 70 */
{ 128, 103, 78, 51, 27, 2 },
-#endif
/* x^64 + x^52 + x^39 + x^26 + x^14 + x + 1 -- 15 */
{ 64, 52, 39, 26, 14, 1 },
-
- /* x^32 + x^26 + x^20 + x^14 + x^7 + x + 1 -- 15 */
- { 32, 26, 20, 14, 7, 1 },
-
- { 0, 0, 0, 0, 0, 0 },
+#endif
};
#define POOLBITS poolwords*32
* hash; hash collisions will occur no more often than chance.
*/
-/*
- * Linux 2.2 compatibility
- */
-#ifndef DECLARE_WAITQUEUE
-#define DECLARE_WAITQUEUE(WAIT, PTR) struct wait_queue WAIT = { PTR, NULL }
-#endif
-#ifndef DECLARE_WAIT_QUEUE_HEAD
-#define DECLARE_WAIT_QUEUE_HEAD(WAIT) struct wait_queue *WAIT
-#endif
-
/*
* Static global variables
*/
-static struct entropy_store *random_state; /* The default global store */
-static struct entropy_store *sec_random_state; /* secondary store */
-static struct entropy_store *urandom_state; /* For urandom */
static DECLARE_WAIT_QUEUE_HEAD(random_read_wait);
static DECLARE_WAIT_QUEUE_HEAD(random_write_wait);
-/*
- * Forward procedure declarations
- */
-#ifdef CONFIG_SYSCTL
-static void sysctl_init_random(struct entropy_store *random_state);
-#endif
-
-/*****************************************************************
- *
- * Utility functions, with some ASM defined functions for speed
- * purposes
- *
- *****************************************************************/
-
-/*
- * Unfortunately, while the GCC optimizer for the i386 understands how
- * to optimize a static rotate left of x bits, it doesn't know how to
- * deal with a variable rotate of x bits. So we use a bit of asm magic.
- */
-#if (!defined (__i386__))
-static inline __u32 rotate_left(int i, __u32 word)
-{
- return (word << i) | (word >> (32 - i));
-}
-#else
-static inline __u32 rotate_left(int i, __u32 word)
-{
- __asm__("roll %%cl,%0"
- :"=r" (word)
- :"0" (word),"c" (i));
- return word;
-}
-#endif
-
-/*
- * More asm magic....
- *
- * For entropy estimation, we need to do an integral base 2
- * logarithm.
- *
- * Note the "12bits" suffix - this is used for numbers between
- * 0 and 4095 only. This allows a few shortcuts.
- */
-#if 0 /* Slow but clear version */
-static inline __u32 int_ln_12bits(__u32 word)
-{
- __u32 nbits = 0;
-
- while (word >>= 1)
- nbits++;
- return nbits;
-}
-#else /* Faster (more clever) version, courtesy Colin Plumb */
-static inline __u32 int_ln_12bits(__u32 word)
-{
- /* Smear msbit right to make an n-bit mask */
- word |= word >> 8;
- word |= word >> 4;
- word |= word >> 2;
- word |= word >> 1;
- /* Remove one bit to make this a logarithm */
- word >>= 1;
- /* Count the bits set in the word */
- word -= (word >> 1) & 0x555;
- word = (word & 0x333) + ((word >> 2) & 0x333);
- word += (word >> 4);
- word += (word >> 8);
- return word & 15;
-}
-#endif
-
#if 0
static int debug = 0;
module_param(debug, bool, 0644);
#define DEBUG_ENT(fmt, arg...) do { if (debug) \
printk(KERN_DEBUG "random %04d %04d %04d: " \
fmt,\
- random_state->entropy_count,\
- sec_random_state->entropy_count,\
- urandom_state->entropy_count,\
+ input_pool.entropy_count,\
+ blocking_pool.entropy_count,\
+ nonblocking_pool.entropy_count,\
## arg); } while (0)
#else
#define DEBUG_ENT(fmt, arg...) do {} while (0)
*
**********************************************************************/
+struct entropy_store;
struct entropy_store {
/* mostly-read data: */
- struct poolinfo poolinfo;
+ struct poolinfo *poolinfo;
__u32 *pool;
const char *name;
+ int limit;
+ struct entropy_store *pull;
/* read-write data: */
spinlock_t lock ____cacheline_aligned_in_smp;
int input_rotate;
};
-/*
- * Initialize the entropy store. The input argument is the size of
- * the random pool.
- *
- * Returns an negative error if there is a problem.
- */
-static int create_entropy_store(int size, const char *name,
- struct entropy_store **ret_bucket)
-{
- struct entropy_store *r;
- struct poolinfo *p;
- int poolwords;
-
- poolwords = (size + 3) / 4; /* Convert bytes->words */
- /* The pool size must be a multiple of 16 32-bit words */
- poolwords = ((poolwords + 15) / 16) * 16;
+static __u32 input_pool_data[INPUT_POOL_WORDS];
+static __u32 blocking_pool_data[OUTPUT_POOL_WORDS];
+static __u32 nonblocking_pool_data[OUTPUT_POOL_WORDS];
- for (p = poolinfo_table; p->poolwords; p++) {
- if (poolwords == p->poolwords)
- break;
- }
- if (p->poolwords == 0)
- return -EINVAL;
-
- r = kmalloc(sizeof(struct entropy_store), GFP_KERNEL);
- if (!r)
- return -ENOMEM;
-
- memset (r, 0, sizeof(struct entropy_store));
- r->poolinfo = *p;
+static struct entropy_store input_pool = {
+ .poolinfo = &poolinfo_table[0],
+ .name = "input",
+ .limit = 1,
+ .lock = SPIN_LOCK_UNLOCKED,
+ .pool = input_pool_data
+};
- r->pool = kmalloc(POOLBYTES, GFP_KERNEL);
- if (!r->pool) {
- kfree(r);
- return -ENOMEM;
- }
- memset(r->pool, 0, POOLBYTES);
- spin_lock_init(&r->lock);
- r->name = name;
- *ret_bucket = r;
- return 0;
-}
+static struct entropy_store blocking_pool = {
+ .poolinfo = &poolinfo_table[1],
+ .name = "blocking",
+ .limit = 1,
+ .pull = &input_pool,
+ .lock = SPIN_LOCK_UNLOCKED,
+ .pool = blocking_pool_data
+};
-/* Clear the entropy pool and associated counters. */
-static void clear_entropy_store(struct entropy_store *r)
-{
- r->add_ptr = 0;
- r->entropy_count = 0;
- r->input_rotate = 0;
- memset(r->pool, 0, r->poolinfo.POOLBYTES);
-}
+static struct entropy_store nonblocking_pool = {
+ .poolinfo = &poolinfo_table[1],
+ .name = "nonblocking",
+ .pull = &input_pool,
+ .lock = SPIN_LOCK_UNLOCKED,
+ .pool = nonblocking_pool_data
+};
/*
* This function adds a byte into the entropy "pool". It does not
0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 };
unsigned long i, add_ptr, tap1, tap2, tap3, tap4, tap5;
int new_rotate, input_rotate;
- int wordmask = r->poolinfo.poolwords - 1;
+ int wordmask = r->poolinfo->poolwords - 1;
__u32 w, next_w;
unsigned long flags;
/* Taps are constant, so we can load them without holding r->lock. */
- tap1 = r->poolinfo.tap1;
- tap2 = r->poolinfo.tap2;
- tap3 = r->poolinfo.tap3;
- tap4 = r->poolinfo.tap4;
- tap5 = r->poolinfo.tap5;
+ tap1 = r->poolinfo->tap1;
+ tap2 = r->poolinfo->tap2;
+ tap3 = r->poolinfo->tap3;
+ tap4 = r->poolinfo->tap4;
+ tap5 = r->poolinfo->tap5;
next_w = *in++;
spin_lock_irqsave(&r->lock, flags);
add_ptr = r->add_ptr;
while (nwords--) {
- w = rotate_left(input_rotate, next_w);
+ w = rol32(next_w, input_rotate);
if (nwords > 0)
next_w = *in++;
i = add_ptr = (add_ptr - 1) & wordmask;
DEBUG_ENT("negative entropy/overflow (%d+%d)\n",
r->entropy_count, nbits);
r->entropy_count = 0;
- } else if (r->entropy_count + nbits > r->poolinfo.POOLBITS) {
- r->entropy_count = r->poolinfo.POOLBITS;
+ } else if (r->entropy_count + nbits > r->poolinfo->POOLBITS) {
+ r->entropy_count = r->poolinfo->POOLBITS;
} else {
r->entropy_count += nbits;
if (nbits)
spin_unlock_irqrestore(&r->lock, flags);
}
-/**********************************************************************
- *
- * Entropy batch input management
- *
- * We batch entropy to be added to avoid increasing interrupt latency
- *
- **********************************************************************/
-
-struct sample {
- __u32 data[2];
- int credit;
-};
-
-static struct sample *batch_entropy_pool, *batch_entropy_copy;
-static int batch_head, batch_tail;
-static DEFINE_SPINLOCK(batch_lock);
-
-static int batch_max;
-static void batch_entropy_process(void *private_);
-static DECLARE_WORK(batch_work, batch_entropy_process, NULL);
-
-/* note: the size must be a power of 2 */
-static int __init batch_entropy_init(int size, struct entropy_store *r)
-{
- batch_entropy_pool = kmalloc(size*sizeof(struct sample), GFP_KERNEL);
- if (!batch_entropy_pool)
- return -1;
- batch_entropy_copy = kmalloc(size*sizeof(struct sample), GFP_KERNEL);
- if (!batch_entropy_copy) {
- kfree(batch_entropy_pool);
- return -1;
- }
- batch_head = batch_tail = 0;
- batch_work.data = r;
- batch_max = size;
- return 0;
-}
-
-/*
- * Changes to the entropy data is put into a queue rather than being added to
- * the entropy counts directly. This is presumably to avoid doing heavy
- * hashing calculations during an interrupt in add_timer_randomness().
- * Instead, the entropy is only added to the pool by keventd.
- */
-static void batch_entropy_store(u32 a, u32 b, int num)
-{
- int new;
- unsigned long flags;
-
- if (!batch_max)
- return;
-
- spin_lock_irqsave(&batch_lock, flags);
-
- batch_entropy_pool[batch_head].data[0] = a;
- batch_entropy_pool[batch_head].data[1] = b;
- batch_entropy_pool[batch_head].credit = num;
-
- if (((batch_head - batch_tail) & (batch_max - 1)) >= (batch_max / 2))
- schedule_delayed_work(&batch_work, 1);
-
- new = (batch_head + 1) & (batch_max - 1);
- if (new == batch_tail)
- DEBUG_ENT("batch entropy buffer full\n");
- else
- batch_head = new;
-
- spin_unlock_irqrestore(&batch_lock, flags);
-}
-
-/*
- * Flush out the accumulated entropy operations, adding entropy to the passed
- * store (normally random_state). If that store has enough entropy, alternate
- * between randomizing the data of the primary and secondary stores.
- */
-static void batch_entropy_process(void *private_)
-{
- struct entropy_store *r = (struct entropy_store *) private_, *p;
- int max_entropy = r->poolinfo.POOLBITS;
- unsigned head, tail;
-
- /* Mixing into the pool is expensive, so copy over the batch
- * data and release the batch lock. The pool is at least half
- * full, so don't worry too much about copying only the used
- * part.
- */
- spin_lock_irq(&batch_lock);
-
- memcpy(batch_entropy_copy, batch_entropy_pool,
- batch_max * sizeof(struct sample));
-
- head = batch_head;
- tail = batch_tail;
- batch_tail = batch_head;
-
- spin_unlock_irq(&batch_lock);
-
- p = r;
- while (head != tail) {
- if (r->entropy_count >= max_entropy) {
- r = (r == sec_random_state) ? random_state :
- sec_random_state;
- max_entropy = r->poolinfo.POOLBITS;
- }
- add_entropy_words(r, batch_entropy_copy[tail].data, 2);
- credit_entropy_store(r, batch_entropy_copy[tail].credit);
- tail = (tail + 1) & (batch_max - 1);
- }
- if (p->entropy_count >= random_read_wakeup_thresh)
- wake_up_interruptible(&random_read_wait);
-}
-
/*********************************************************************
*
* Entropy input management
};
static struct timer_rand_state input_timer_state;
-static struct timer_rand_state extract_timer_state;
static struct timer_rand_state *irq_timer_state[NR_IRQS];
/*
*/
static void add_timer_randomness(struct timer_rand_state *state, unsigned num)
{
- cycles_t data;
- long delta, delta2, delta3, time;
- int entropy = 0;
+ struct {
+ cycles_t cycles;
+ long jiffies;
+ unsigned num;
+ } sample;
+ long delta, delta2, delta3;
preempt_disable();
/* if over the trickle threshold, use only 1 in 4096 samples */
- if (random_state->entropy_count > trickle_thresh &&
+ if (input_pool.entropy_count > trickle_thresh &&
(__get_cpu_var(trickle_count)++ & 0xfff))
goto out;
+ sample.jiffies = jiffies;
+ sample.cycles = get_cycles();
+ sample.num = num;
+ add_entropy_words(&input_pool, (u32 *)&sample, sizeof(sample)/4);
+
/*
* Calculate number of bits of randomness we probably added.
* We take into account the first, second and third-order deltas
* in order to make our estimate.
*/
- time = jiffies;
if (!state->dont_count_entropy) {
- delta = time - state->last_time;
- state->last_time = time;
+ delta = sample.jiffies - state->last_time;
+ state->last_time = sample.jiffies;
delta2 = delta - state->last_delta;
state->last_delta = delta;
* Round down by 1 bit on general principles,
* and limit entropy entimate to 12 bits.
*/
- delta >>= 1;
- delta &= (1 << 12) - 1;
-
- entropy = int_ln_12bits(delta);
+ credit_entropy_store(&input_pool,
+ min_t(int, fls(delta>>1), 11));
}
- /*
- * Use get_cycles() if implemented, otherwise fall back to
- * jiffies.
- */
- data = get_cycles();
- if (data)
- num ^= (u32)((data >> 31) >> 1);
- else
- data = time;
+ if(input_pool.entropy_count >= random_read_wakeup_thresh)
+ wake_up_interruptible(&random_read_wait);
- batch_entropy_store(num, data, entropy);
out:
preempt_enable();
}
EXPORT_SYMBOL(add_disk_randomness);
-/******************************************************************
- *
- * Hash function definition
- *
- *******************************************************************/
-
-/*
- * This chunk of code defines a function
- * void HASH_TRANSFORM(__u32 digest[HASH_BUFFER_SIZE + HASH_EXTRA_SIZE],
- * __u32 const data[16])
- *
- * The function hashes the input data to produce a digest in the first
- * HASH_BUFFER_SIZE words of the digest[] array, and uses HASH_EXTRA_SIZE
- * more words for internal purposes. (This buffer is exported so the
- * caller can wipe it once rather than this code doing it each call,
- * and tacking it onto the end of the digest[] array is the quick and
- * dirty way of doing it.)
- *
- * It so happens that MD5 and SHA share most of the initial vector
- * used to initialize the digest[] array before the first call:
- * 1) 0x67452301
- * 2) 0xefcdab89
- * 3) 0x98badcfe
- * 4) 0x10325476
- * 5) 0xc3d2e1f0 (SHA only)
- *
- * For /dev/random purposes, the length of the data being hashed is
- * fixed in length, so appending a bit count in the usual way is not
- * cryptographically necessary.
- */
-
-#ifdef USE_SHA
-
-#define HASH_BUFFER_SIZE 5
-#define HASH_EXTRA_SIZE 80
-#define HASH_TRANSFORM SHATransform
-
-/* Various size/speed tradeoffs are available. Choose 0..3. */
-#define SHA_CODE_SIZE 0
-
-/*
- * SHA transform algorithm, taken from code written by Peter Gutmann,
- * and placed in the public domain.
- */
-
-/* The SHA f()-functions. */
-
-#define f1(x,y,z) (z ^ (x & (y ^ z))) /* Rounds 0-19: x ? y : z */
-#define f2(x,y,z) (x ^ y ^ z) /* Rounds 20-39: XOR */
-#define f3(x,y,z) ((x & y) + (z & (x ^ y))) /* Rounds 40-59: majority */
-#define f4(x,y,z) (x ^ y ^ z) /* Rounds 60-79: XOR */
-
-/* The SHA Mysterious Constants */
-
-#define K1 0x5A827999L /* Rounds 0-19: sqrt(2) * 2^30 */
-#define K2 0x6ED9EBA1L /* Rounds 20-39: sqrt(3) * 2^30 */
-#define K3 0x8F1BBCDCL /* Rounds 40-59: sqrt(5) * 2^30 */
-#define K4 0xCA62C1D6L /* Rounds 60-79: sqrt(10) * 2^30 */
-
-#define ROTL(n,X) (((X) << n ) | ((X) >> (32 - n)))
-
-#define subRound(a, b, c, d, e, f, k, data) \
- (e += ROTL(5, a) + f(b, c, d) + k + data, b = ROTL(30, b))
-
-static void SHATransform(__u32 digest[85], __u32 const data[16])
-{
- __u32 A, B, C, D, E; /* Local vars */
- __u32 TEMP;
- int i;
-#define W (digest + HASH_BUFFER_SIZE) /* Expanded data array */
-
- /*
- * Do the preliminary expansion of 16 to 80 words. Doing it
- * out-of-line line this is faster than doing it in-line on
- * register-starved machines like the x86, and not really any
- * slower on real processors.
- */
- memcpy(W, data, 16*sizeof(__u32));
- for (i = 0; i < 64; i++) {
- TEMP = W[i] ^ W[i+2] ^ W[i+8] ^ W[i+13];
- W[i+16] = ROTL(1, TEMP);
- }
-
- /* Set up first buffer and local data buffer */
- A = digest[ 0 ];
- B = digest[ 1 ];
- C = digest[ 2 ];
- D = digest[ 3 ];
- E = digest[ 4 ];
-
- /* Heavy mangling, in 4 sub-rounds of 20 iterations each. */
-#if SHA_CODE_SIZE == 0
- /*
- * Approximately 50% of the speed of the largest version, but
- * takes up 1/16 the space. Saves about 6k on an i386 kernel.
- */
- for (i = 0; i < 80; i++) {
- if (i < 40) {
- if (i < 20)
- TEMP = f1(B, C, D) + K1;
- else
- TEMP = f2(B, C, D) + K2;
- } else {
- if (i < 60)
- TEMP = f3(B, C, D) + K3;
- else
- TEMP = f4(B, C, D) + K4;
- }
- TEMP += ROTL(5, A) + E + W[i];
- E = D; D = C; C = ROTL(30, B); B = A; A = TEMP;
- }
-#elif SHA_CODE_SIZE == 1
- for (i = 0; i < 20; i++) {
- TEMP = f1(B, C, D) + K1 + ROTL(5, A) + E + W[i];
- E = D; D = C; C = ROTL(30, B); B = A; A = TEMP;
- }
- for (; i < 40; i++) {
- TEMP = f2(B, C, D) + K2 + ROTL(5, A) + E + W[i];
- E = D; D = C; C = ROTL(30, B); B = A; A = TEMP;
- }
- for (; i < 60; i++) {
- TEMP = f3(B, C, D) + K3 + ROTL(5, A) + E + W[i];
- E = D; D = C; C = ROTL(30, B); B = A; A = TEMP;
- }
- for (; i < 80; i++) {
- TEMP = f4(B, C, D) + K4 + ROTL(5, A) + E + W[i];
- E = D; D = C; C = ROTL(30, B); B = A; A = TEMP;
- }
-#elif SHA_CODE_SIZE == 2
- for (i = 0; i < 20; i += 5) {
- subRound(A, B, C, D, E, f1, K1, W[i ]);
- subRound(E, A, B, C, D, f1, K1, W[i+1]);
- subRound(D, E, A, B, C, f1, K1, W[i+2]);
- subRound(C, D, E, A, B, f1, K1, W[i+3]);
- subRound(B, C, D, E, A, f1, K1, W[i+4]);
- }
- for (; i < 40; i += 5) {
- subRound(A, B, C, D, E, f2, K2, W[i ]);
- subRound(E, A, B, C, D, f2, K2, W[i+1]);
- subRound(D, E, A, B, C, f2, K2, W[i+2]);
- subRound(C, D, E, A, B, f2, K2, W[i+3]);
- subRound(B, C, D, E, A, f2, K2, W[i+4]);
- }
- for (; i < 60; i += 5) {
- subRound(A, B, C, D, E, f3, K3, W[i ]);
- subRound(E, A, B, C, D, f3, K3, W[i+1]);
- subRound(D, E, A, B, C, f3, K3, W[i+2]);
- subRound(C, D, E, A, B, f3, K3, W[i+3]);
- subRound(B, C, D, E, A, f3, K3, W[i+4]);
- }
- for (; i < 80; i += 5) {
- subRound(A, B, C, D, E, f4, K4, W[i ]);
- subRound(E, A, B, C, D, f4, K4, W[i+1]);
- subRound(D, E, A, B, C, f4, K4, W[i+2]);
- subRound(C, D, E, A, B, f4, K4, W[i+3]);
- subRound(B, C, D, E, A, f4, K4, W[i+4]);
- }
-#elif SHA_CODE_SIZE == 3 /* Really large version */
- subRound(A, B, C, D, E, f1, K1, W[ 0]);
- subRound(E, A, B, C, D, f1, K1, W[ 1]);
- subRound(D, E, A, B, C, f1, K1, W[ 2]);
- subRound(C, D, E, A, B, f1, K1, W[ 3]);
- subRound(B, C, D, E, A, f1, K1, W[ 4]);
- subRound(A, B, C, D, E, f1, K1, W[ 5]);
- subRound(E, A, B, C, D, f1, K1, W[ 6]);
- subRound(D, E, A, B, C, f1, K1, W[ 7]);
- subRound(C, D, E, A, B, f1, K1, W[ 8]);
- subRound(B, C, D, E, A, f1, K1, W[ 9]);
- subRound(A, B, C, D, E, f1, K1, W[10]);
- subRound(E, A, B, C, D, f1, K1, W[11]);
- subRound(D, E, A, B, C, f1, K1, W[12]);
- subRound(C, D, E, A, B, f1, K1, W[13]);
- subRound(B, C, D, E, A, f1, K1, W[14]);
- subRound(A, B, C, D, E, f1, K1, W[15]);
- subRound(E, A, B, C, D, f1, K1, W[16]);
- subRound(D, E, A, B, C, f1, K1, W[17]);
- subRound(C, D, E, A, B, f1, K1, W[18]);
- subRound(B, C, D, E, A, f1, K1, W[19]);
-
- subRound(A, B, C, D, E, f2, K2, W[20]);
- subRound(E, A, B, C, D, f2, K2, W[21]);
- subRound(D, E, A, B, C, f2, K2, W[22]);
- subRound(C, D, E, A, B, f2, K2, W[23]);
- subRound(B, C, D, E, A, f2, K2, W[24]);
- subRound(A, B, C, D, E, f2, K2, W[25]);
- subRound(E, A, B, C, D, f2, K2, W[26]);
- subRound(D, E, A, B, C, f2, K2, W[27]);
- subRound(C, D, E, A, B, f2, K2, W[28]);
- subRound(B, C, D, E, A, f2, K2, W[29]);
- subRound(A, B, C, D, E, f2, K2, W[30]);
- subRound(E, A, B, C, D, f2, K2, W[31]);
- subRound(D, E, A, B, C, f2, K2, W[32]);
- subRound(C, D, E, A, B, f2, K2, W[33]);
- subRound(B, C, D, E, A, f2, K2, W[34]);
- subRound(A, B, C, D, E, f2, K2, W[35]);
- subRound(E, A, B, C, D, f2, K2, W[36]);
- subRound(D, E, A, B, C, f2, K2, W[37]);
- subRound(C, D, E, A, B, f2, K2, W[38]);
- subRound(B, C, D, E, A, f2, K2, W[39]);
-
- subRound(A, B, C, D, E, f3, K3, W[40]);
- subRound(E, A, B, C, D, f3, K3, W[41]);
- subRound(D, E, A, B, C, f3, K3, W[42]);
- subRound(C, D, E, A, B, f3, K3, W[43]);
- subRound(B, C, D, E, A, f3, K3, W[44]);
- subRound(A, B, C, D, E, f3, K3, W[45]);
- subRound(E, A, B, C, D, f3, K3, W[46]);
- subRound(D, E, A, B, C, f3, K3, W[47]);
- subRound(C, D, E, A, B, f3, K3, W[48]);
- subRound(B, C, D, E, A, f3, K3, W[49]);
- subRound(A, B, C, D, E, f3, K3, W[50]);
- subRound(E, A, B, C, D, f3, K3, W[51]);
- subRound(D, E, A, B, C, f3, K3, W[52]);
- subRound(C, D, E, A, B, f3, K3, W[53]);
- subRound(B, C, D, E, A, f3, K3, W[54]);
- subRound(A, B, C, D, E, f3, K3, W[55]);
- subRound(E, A, B, C, D, f3, K3, W[56]);
- subRound(D, E, A, B, C, f3, K3, W[57]);
- subRound(C, D, E, A, B, f3, K3, W[58]);
- subRound(B, C, D, E, A, f3, K3, W[59]);
-
- subRound(A, B, C, D, E, f4, K4, W[60]);
- subRound(E, A, B, C, D, f4, K4, W[61]);
- subRound(D, E, A, B, C, f4, K4, W[62]);
- subRound(C, D, E, A, B, f4, K4, W[63]);
- subRound(B, C, D, E, A, f4, K4, W[64]);
- subRound(A, B, C, D, E, f4, K4, W[65]);
- subRound(E, A, B, C, D, f4, K4, W[66]);
- subRound(D, E, A, B, C, f4, K4, W[67]);
- subRound(C, D, E, A, B, f4, K4, W[68]);
- subRound(B, C, D, E, A, f4, K4, W[69]);
- subRound(A, B, C, D, E, f4, K4, W[70]);
- subRound(E, A, B, C, D, f4, K4, W[71]);
- subRound(D, E, A, B, C, f4, K4, W[72]);
- subRound(C, D, E, A, B, f4, K4, W[73]);
- subRound(B, C, D, E, A, f4, K4, W[74]);
- subRound(A, B, C, D, E, f4, K4, W[75]);
- subRound(E, A, B, C, D, f4, K4, W[76]);
- subRound(D, E, A, B, C, f4, K4, W[77]);
- subRound(C, D, E, A, B, f4, K4, W[78]);
- subRound(B, C, D, E, A, f4, K4, W[79]);
-#else
-#error Illegal SHA_CODE_SIZE
-#endif
-
- /* Build message digest */
- digest[0] += A;
- digest[1] += B;
- digest[2] += C;
- digest[3] += D;
- digest[4] += E;
-
- /* W is wiped by the caller */
-#undef W
-}
-
-#undef ROTL
-#undef f1
-#undef f2
-#undef f3
-#undef f4
-#undef K1
-#undef K2
-#undef K3
-#undef K4
-#undef subRound
-
-#else /* !USE_SHA - Use MD5 */
-
-#define HASH_BUFFER_SIZE 4
-#define HASH_EXTRA_SIZE 0
-#define HASH_TRANSFORM MD5Transform
-
-/*
- * MD5 transform algorithm, taken from code written by Colin Plumb,
- * and put into the public domain
- */
-
-/* The four core functions - F1 is optimized somewhat */
-
-/* #define F1(x, y, z) (x & y | ~x & z) */
-#define F1(x, y, z) (z ^ (x & (y ^ z)))
-#define F2(x, y, z) F1(z, x, y)
-#define F3(x, y, z) (x ^ y ^ z)
-#define F4(x, y, z) (y ^ (x | ~z))
-
-/* This is the central step in the MD5 algorithm. */
-#define MD5STEP(f, w, x, y, z, data, s) \
- (w += f(x, y, z) + data, w = w << s | w >> (32 - s), w += x )
-
-/*
- * The core of the MD5 algorithm, this alters an existing MD5 hash to
- * reflect the addition of 16 longwords of new data. MD5Update blocks
- * the data and converts bytes into longwords for this routine.
- */
-static void MD5Transform(__u32 buf[HASH_BUFFER_SIZE], __u32 const in[16])
-{
- __u32 a, b, c, d;
-
- a = buf[0];
- b = buf[1];
- c = buf[2];
- d = buf[3];
-
- MD5STEP(F1, a, b, c, d, in[ 0]+0xd76aa478, 7);
- MD5STEP(F1, d, a, b, c, in[ 1]+0xe8c7b756, 12);
- MD5STEP(F1, c, d, a, b, in[ 2]+0x242070db, 17);
- MD5STEP(F1, b, c, d, a, in[ 3]+0xc1bdceee, 22);
- MD5STEP(F1, a, b, c, d, in[ 4]+0xf57c0faf, 7);
- MD5STEP(F1, d, a, b, c, in[ 5]+0x4787c62a, 12);
- MD5STEP(F1, c, d, a, b, in[ 6]+0xa8304613, 17);
- MD5STEP(F1, b, c, d, a, in[ 7]+0xfd469501, 22);
- MD5STEP(F1, a, b, c, d, in[ 8]+0x698098d8, 7);
- MD5STEP(F1, d, a, b, c, in[ 9]+0x8b44f7af, 12);
- MD5STEP(F1, c, d, a, b, in[10]+0xffff5bb1, 17);
- MD5STEP(F1, b, c, d, a, in[11]+0x895cd7be, 22);
- MD5STEP(F1, a, b, c, d, in[12]+0x6b901122, 7);
- MD5STEP(F1, d, a, b, c, in[13]+0xfd987193, 12);
- MD5STEP(F1, c, d, a, b, in[14]+0xa679438e, 17);
- MD5STEP(F1, b, c, d, a, in[15]+0x49b40821, 22);
-
- MD5STEP(F2, a, b, c, d, in[ 1]+0xf61e2562, 5);
- MD5STEP(F2, d, a, b, c, in[ 6]+0xc040b340, 9);
- MD5STEP(F2, c, d, a, b, in[11]+0x265e5a51, 14);
- MD5STEP(F2, b, c, d, a, in[ 0]+0xe9b6c7aa, 20);
- MD5STEP(F2, a, b, c, d, in[ 5]+0xd62f105d, 5);
- MD5STEP(F2, d, a, b, c, in[10]+0x02441453, 9);
- MD5STEP(F2, c, d, a, b, in[15]+0xd8a1e681, 14);
- MD5STEP(F2, b, c, d, a, in[ 4]+0xe7d3fbc8, 20);
- MD5STEP(F2, a, b, c, d, in[ 9]+0x21e1cde6, 5);
- MD5STEP(F2, d, a, b, c, in[14]+0xc33707d6, 9);
- MD5STEP(F2, c, d, a, b, in[ 3]+0xf4d50d87, 14);
- MD5STEP(F2, b, c, d, a, in[ 8]+0x455a14ed, 20);
- MD5STEP(F2, a, b, c, d, in[13]+0xa9e3e905, 5);
- MD5STEP(F2, d, a, b, c, in[ 2]+0xfcefa3f8, 9);
- MD5STEP(F2, c, d, a, b, in[ 7]+0x676f02d9, 14);
- MD5STEP(F2, b, c, d, a, in[12]+0x8d2a4c8a, 20);
-
- MD5STEP(F3, a, b, c, d, in[ 5]+0xfffa3942, 4);
- MD5STEP(F3, d, a, b, c, in[ 8]+0x8771f681, 11);
- MD5STEP(F3, c, d, a, b, in[11]+0x6d9d6122, 16);
- MD5STEP(F3, b, c, d, a, in[14]+0xfde5380c, 23);
- MD5STEP(F3, a, b, c, d, in[ 1]+0xa4beea44, 4);
- MD5STEP(F3, d, a, b, c, in[ 4]+0x4bdecfa9, 11);
- MD5STEP(F3, c, d, a, b, in[ 7]+0xf6bb4b60, 16);
- MD5STEP(F3, b, c, d, a, in[10]+0xbebfbc70, 23);
- MD5STEP(F3, a, b, c, d, in[13]+0x289b7ec6, 4);
- MD5STEP(F3, d, a, b, c, in[ 0]+0xeaa127fa, 11);
- MD5STEP(F3, c, d, a, b, in[ 3]+0xd4ef3085, 16);
- MD5STEP(F3, b, c, d, a, in[ 6]+0x04881d05, 23);
- MD5STEP(F3, a, b, c, d, in[ 9]+0xd9d4d039, 4);
- MD5STEP(F3, d, a, b, c, in[12]+0xe6db99e5, 11);
- MD5STEP(F3, c, d, a, b, in[15]+0x1fa27cf8, 16);
- MD5STEP(F3, b, c, d, a, in[ 2]+0xc4ac5665, 23);
-
- MD5STEP(F4, a, b, c, d, in[ 0]+0xf4292244, 6);
- MD5STEP(F4, d, a, b, c, in[ 7]+0x432aff97, 10);
- MD5STEP(F4, c, d, a, b, in[14]+0xab9423a7, 15);
- MD5STEP(F4, b, c, d, a, in[ 5]+0xfc93a039, 21);
- MD5STEP(F4, a, b, c, d, in[12]+0x655b59c3, 6);
- MD5STEP(F4, d, a, b, c, in[ 3]+0x8f0ccc92, 10);
- MD5STEP(F4, c, d, a, b, in[10]+0xffeff47d, 15);
- MD5STEP(F4, b, c, d, a, in[ 1]+0x85845dd1, 21);
- MD5STEP(F4, a, b, c, d, in[ 8]+0x6fa87e4f, 6);
- MD5STEP(F4, d, a, b, c, in[15]+0xfe2ce6e0, 10);
- MD5STEP(F4, c, d, a, b, in[ 6]+0xa3014314, 15);
- MD5STEP(F4, b, c, d, a, in[13]+0x4e0811a1, 21);
- MD5STEP(F4, a, b, c, d, in[ 4]+0xf7537e82, 6);
- MD5STEP(F4, d, a, b, c, in[11]+0xbd3af235, 10);
- MD5STEP(F4, c, d, a, b, in[ 2]+0x2ad7d2bb, 15);
- MD5STEP(F4, b, c, d, a, in[ 9]+0xeb86d391, 21);
-
- buf[0] += a;
- buf[1] += b;
- buf[2] += c;
- buf[3] += d;
-}
-
-#undef F1
-#undef F2
-#undef F3
-#undef F4
-#undef MD5STEP
-
-#endif /* !USE_SHA */
+#define EXTRACT_SIZE 10
/*********************************************************************
*
*
*********************************************************************/
-#define EXTRACT_ENTROPY_USER 1
-#define EXTRACT_ENTROPY_SECONDARY 2
-#define EXTRACT_ENTROPY_LIMIT 4
-#define TMP_BUF_SIZE (HASH_BUFFER_SIZE + HASH_EXTRA_SIZE)
-#define SEC_XFER_SIZE (TMP_BUF_SIZE*4)
-
static ssize_t extract_entropy(struct entropy_store *r, void * buf,
- size_t nbytes, int flags);
+ size_t nbytes, int min, int rsvd);
/*
* This utility inline function is responsible for transfering entropy
* from the primary pool to the secondary extraction pool. We make
* sure we pull enough for a 'catastrophic reseed'.
*/
-static inline void xfer_secondary_pool(struct entropy_store *r,
- size_t nbytes, __u32 *tmp)
+static void xfer_secondary_pool(struct entropy_store *r, size_t nbytes)
{
- if (r->entropy_count < nbytes * 8 &&
- r->entropy_count < r->poolinfo.POOLBITS) {
+ __u32 tmp[OUTPUT_POOL_WORDS];
+
+ if (r->pull && r->entropy_count < nbytes * 8 &&
+ r->entropy_count < r->poolinfo->POOLBITS) {
int bytes = max_t(int, random_read_wakeup_thresh / 8,
- min_t(int, nbytes, TMP_BUF_SIZE));
+ min_t(int, nbytes, sizeof(tmp)));
+ int rsvd = r->limit ? 0 : random_read_wakeup_thresh/4;
DEBUG_ENT("going to reseed %s with %d bits "
"(%d of %d requested)\n",
r->name, bytes * 8, nbytes * 8, r->entropy_count);
- bytes=extract_entropy(random_state, tmp, bytes,
- EXTRACT_ENTROPY_LIMIT);
+ bytes=extract_entropy(r->pull, tmp, bytes,
+ random_read_wakeup_thresh / 8, rsvd);
add_entropy_words(r, tmp, (bytes + 3) / 4);
credit_entropy_store(r, bytes*8);
}
}
/*
- * This function extracts randomness from the "entropy pool", and
- * returns it in a buffer. This function computes how many remaining
- * bits of entropy are left in the pool, but it does not restrict the
- * number of bytes that are actually obtained. If the EXTRACT_ENTROPY_USER
- * flag is given, then the buf pointer is assumed to be in user space.
+ * These functions extracts randomness from the "entropy pool", and
+ * returns it in a buffer.
*
- * If the EXTRACT_ENTROPY_SECONDARY flag is given, then we are actually
- * extracting entropy from the secondary pool, and can refill from the
- * primary pool if needed.
+ * The min parameter specifies the minimum amount we can pull before
+ * failing to avoid races that defeat catastrophic reseeding while the
+ * reserved parameter indicates how much entropy we must leave in the
+ * pool after each pull to avoid starving other readers.
*
* Note: extract_entropy() assumes that .poolwords is a multiple of 16 words.
*/
-static ssize_t extract_entropy(struct entropy_store *r, void * buf,
- size_t nbytes, int flags)
-{
- ssize_t ret, i;
- __u32 tmp[TMP_BUF_SIZE], data[16];
- __u32 x;
- unsigned long cpuflags;
- /* Redundant, but just in case... */
- if (r->entropy_count > r->poolinfo.POOLBITS)
- r->entropy_count = r->poolinfo.POOLBITS;
+static size_t account(struct entropy_store *r, size_t nbytes, int min,
+ int reserved)
+{
+ unsigned long flags;
- if (flags & EXTRACT_ENTROPY_SECONDARY)
- xfer_secondary_pool(r, nbytes, tmp);
+ BUG_ON(r->entropy_count > r->poolinfo->POOLBITS);
/* Hold lock while accounting */
- spin_lock_irqsave(&r->lock, cpuflags);
+ spin_lock_irqsave(&r->lock, flags);
DEBUG_ENT("trying to extract %d bits from %s\n",
nbytes * 8, r->name);
- if (flags & EXTRACT_ENTROPY_LIMIT && nbytes >= r->entropy_count / 8)
- nbytes = r->entropy_count / 8;
+ /* Can we pull enough? */
+ if (r->entropy_count / 8 < min + reserved) {
+ nbytes = 0;
+ } else {
+ /* If limited, never pull more than available */
+ if (r->limit && nbytes + reserved >= r->entropy_count / 8)
+ nbytes = r->entropy_count/8 - reserved;
- if (r->entropy_count / 8 >= nbytes)
- r->entropy_count -= nbytes*8;
- else
- r->entropy_count = 0;
+ if(r->entropy_count / 8 >= nbytes + reserved)
+ r->entropy_count -= nbytes*8;
+ else
+ r->entropy_count = reserved;
- if (r->entropy_count < random_write_wakeup_thresh)
- wake_up_interruptible(&random_write_wait);
+ if (r->entropy_count < random_write_wakeup_thresh)
+ wake_up_interruptible(&random_write_wait);
+ }
DEBUG_ENT("debiting %d entropy credits from %s%s\n",
- nbytes * 8, r->name,
- flags & EXTRACT_ENTROPY_LIMIT ? "" : " (unlimited)");
+ nbytes * 8, r->name, r->limit ? "" : " (unlimited)");
+
+ spin_unlock_irqrestore(&r->lock, flags);
+
+ return nbytes;
+}
- spin_unlock_irqrestore(&r->lock, cpuflags);
+static void extract_buf(struct entropy_store *r, __u8 *out)
+{
+ int i, x;
+ __u32 data[16], buf[5 + SHA_WORKSPACE_WORDS];
+
+ sha_init(buf);
+ /*
+ * As we hash the pool, we mix intermediate values of
+ * the hash back into the pool. This eliminates
+ * backtracking attacks (where the attacker knows
+ * the state of the pool plus the current outputs, and
+ * attempts to find previous ouputs), unless the hash
+ * function can be inverted.
+ */
+ for (i = 0, x = 0; i < r->poolinfo->poolwords; i += 16, x+=2) {
+ sha_transform(buf, (__u8 *)r->pool+i, buf + 5);
+ add_entropy_words(r, &buf[x % 5], 1);
+ }
+
+ /*
+ * To avoid duplicates, we atomically extract a
+ * portion of the pool while mixing, and hash one
+ * final time.
+ */
+ __add_entropy_words(r, &buf[x % 5], 1, data);
+ sha_transform(buf, (__u8 *)data, buf + 5);
+
+ /*
+ * In case the hash function has some recognizable
+ * output pattern, we fold it in half.
+ */
+
+ buf[0] ^= buf[3];
+ buf[1] ^= buf[4];
+ buf[0] ^= rol32(buf[3], 16);
+ memcpy(out, buf, EXTRACT_SIZE);
+ memset(buf, 0, sizeof(buf));
+}
+
+static ssize_t extract_entropy(struct entropy_store *r, void * buf,
+ size_t nbytes, int min, int reserved)
+{
+ ssize_t ret = 0, i;
+ __u8 tmp[EXTRACT_SIZE];
+
+ xfer_secondary_pool(r, nbytes);
+ nbytes = account(r, nbytes, min, reserved);
- ret = 0;
while (nbytes) {
- /*
- * Check if we need to break out or reschedule....
- */
- if ((flags & EXTRACT_ENTROPY_USER) && need_resched()) {
+ extract_buf(r, tmp);
+ i = min_t(int, nbytes, EXTRACT_SIZE);
+ memcpy(buf, tmp, i);
+ nbytes -= i;
+ buf += i;
+ ret += i;
+ }
+
+ /* Wipe data just returned from memory */
+ memset(tmp, 0, sizeof(tmp));
+
+ return ret;
+}
+
+static ssize_t extract_entropy_user(struct entropy_store *r, void __user *buf,
+ size_t nbytes)
+{
+ ssize_t ret = 0, i;
+ __u8 tmp[EXTRACT_SIZE];
+
+ xfer_secondary_pool(r, nbytes);
+ nbytes = account(r, nbytes, 0, 0);
+
+ while (nbytes) {
+ if (need_resched()) {
if (signal_pending(current)) {
if (ret == 0)
ret = -ERESTARTSYS;
break;
}
-
schedule();
}
- /* Hash the pool to get the output */
- tmp[0] = 0x67452301;
- tmp[1] = 0xefcdab89;
- tmp[2] = 0x98badcfe;
- tmp[3] = 0x10325476;
-#ifdef USE_SHA
- tmp[4] = 0xc3d2e1f0;
-#endif
- /*
- * As we hash the pool, we mix intermediate values of
- * the hash back into the pool. This eliminates
- * backtracking attacks (where the attacker knows
- * the state of the pool plus the current outputs, and
- * attempts to find previous ouputs), unless the hash
- * function can be inverted.
- */
- for (i = 0, x = 0; i < r->poolinfo.poolwords; i += 16, x+=2) {
- HASH_TRANSFORM(tmp, r->pool+i);
- add_entropy_words(r, &tmp[x%HASH_BUFFER_SIZE], 1);
+ extract_buf(r, tmp);
+ i = min_t(int, nbytes, EXTRACT_SIZE);
+ if (copy_to_user(buf, tmp, i)) {
+ ret = -EFAULT;
+ break;
}
- /*
- * To avoid duplicates, we atomically extract a
- * portion of the pool while mixing, and hash one
- * final time.
- */
- __add_entropy_words(r, &tmp[x%HASH_BUFFER_SIZE], 1, data);
- HASH_TRANSFORM(tmp, data);
-
- /*
- * In case the hash function has some recognizable
- * output pattern, we fold it in half.
- */
- for (i = 0; i < HASH_BUFFER_SIZE/2; i++)
- tmp[i] ^= tmp[i + (HASH_BUFFER_SIZE+1)/2];
-#if HASH_BUFFER_SIZE & 1 /* There's a middle word to deal with */
- x = tmp[HASH_BUFFER_SIZE/2];
- x ^= (x >> 16); /* Fold it in half */
- ((__u16 *)tmp)[HASH_BUFFER_SIZE-1] = (__u16)x;
-#endif
-
- /* Copy data to destination buffer */
- i = min(nbytes, HASH_BUFFER_SIZE*sizeof(__u32)/2);
- if (flags & EXTRACT_ENTROPY_USER) {
- i -= copy_to_user(buf, (__u8 const *)tmp, i);
- if (!i) {
- ret = -EFAULT;
- break;
- }
- } else
- memcpy(buf, (__u8 const *)tmp, i);
-
nbytes -= i;
buf += i;
ret += i;
*/
void get_random_bytes(void *buf, int nbytes)
{
- struct entropy_store *r = urandom_state;
- int flags = EXTRACT_ENTROPY_SECONDARY;
-
- if (!r)
- r = sec_random_state;
- if (!r) {
- r = random_state;
- flags = 0;
- }
- if (!r) {
- printk(KERN_NOTICE "get_random_bytes called before "
- "random driver initialization\n");
- return;
- }
- extract_entropy(r, (char *) buf, nbytes, flags);
+ extract_entropy(&nonblocking_pool, buf, nbytes, 0, 0);
}
EXPORT_SYMBOL(get_random_bytes);
-/*********************************************************************
- *
- * Functions to interface with Linux
- *
- *********************************************************************/
-
/*
- * Initialize the random pool with standard stuff.
+ * init_std_data - initialize pool with system data
+ *
+ * @r: pool to initialize
*
- * NOTE: This is an OS-dependent function.
+ * This function clears the pool's entropy count and mixes some system
+ * data into the pool to prepare it for use. The pool is not cleared
+ * as that can only decrease the entropy in the pool.
*/
static void init_std_data(struct entropy_store *r)
{
struct timeval tv;
- __u32 words[2];
- char *p;
- int i;
+ unsigned long flags;
- do_gettimeofday(&tv);
- words[0] = tv.tv_sec;
- words[1] = tv.tv_usec;
- add_entropy_words(r, words, 2);
+ spin_lock_irqsave(&r->lock, flags);
+ r->entropy_count = 0;
+ spin_unlock_irqrestore(&r->lock, flags);
- /*
- * This doesn't lock system.utsname. However, we are generating
- * entropy so a race with a name set here is fine.
- */
- p = (char *) &system_utsname;
- for (i = sizeof(system_utsname) / sizeof(words); i; i--) {
- memcpy(words, p, sizeof(words));
- add_entropy_words(r, words, sizeof(words)/4);
- p += sizeof(words);
- }
+ do_gettimeofday(&tv);
+ add_entropy_words(r, (__u32 *)&tv, sizeof(tv)/4);
+ add_entropy_words(r, (__u32 *)&system_utsname,
+ sizeof(system_utsname)/4);
}
static int __init rand_initialize(void)
{
- int i;
-
- if (create_entropy_store(DEFAULT_POOL_SIZE, "primary", &random_state))
- goto err;
- if (batch_entropy_init(BATCH_ENTROPY_SIZE, random_state))
- goto err;
- if (create_entropy_store(SECONDARY_POOL_SIZE, "secondary",
- &sec_random_state))
- goto err;
- if (create_entropy_store(SECONDARY_POOL_SIZE, "urandom",
- &urandom_state))
- goto err;
- clear_entropy_store(random_state);
- clear_entropy_store(sec_random_state);
- clear_entropy_store(urandom_state);
- init_std_data(random_state);
- init_std_data(sec_random_state);
- init_std_data(urandom_state);
-#ifdef CONFIG_SYSCTL
- sysctl_init_random(random_state);
-#endif
- for (i = 0; i < NR_IRQS; i++)
- irq_timer_state[i] = NULL;
- memset(&input_timer_state, 0, sizeof(struct timer_rand_state));
- memset(&extract_timer_state, 0, sizeof(struct timer_rand_state));
- extract_timer_state.dont_count_entropy = 1;
+ init_std_data(&input_pool);
+ init_std_data(&blocking_pool);
+ init_std_data(&nonblocking_pool);
return 0;
-err:
- return -1;
}
module_init(rand_initialize);
static ssize_t
random_read(struct file * file, char __user * buf, size_t nbytes, loff_t *ppos)
{
- DECLARE_WAITQUEUE(wait, current);
ssize_t n, retval = 0, count = 0;
if (nbytes == 0)
DEBUG_ENT("reading %d bits\n", n*8);
- n = extract_entropy(sec_random_state, buf, n,
- EXTRACT_ENTROPY_USER |
- EXTRACT_ENTROPY_LIMIT |
- EXTRACT_ENTROPY_SECONDARY);
+ n = extract_entropy_user(&blocking_pool, buf, n);
DEBUG_ENT("read got %d bits (%d still needed)\n",
n*8, (nbytes-n)*8);
retval = -EAGAIN;
break;
}
+
+ DEBUG_ENT("sleeping?\n");
+
+ wait_event_interruptible(random_read_wait,
+ input_pool.entropy_count >=
+ random_read_wakeup_thresh);
+
+ DEBUG_ENT("awake\n");
+
if (signal_pending(current)) {
retval = -ERESTARTSYS;
break;
}
- set_current_state(TASK_INTERRUPTIBLE);
- add_wait_queue(&random_read_wait, &wait);
-
- if (sec_random_state->entropy_count / 8 == 0)
- schedule();
-
- set_current_state(TASK_RUNNING);
- remove_wait_queue(&random_read_wait, &wait);
-
continue;
}
urandom_read(struct file * file, char __user * buf,
size_t nbytes, loff_t *ppos)
{
- int flags = EXTRACT_ENTROPY_USER;
- unsigned long cpuflags;
-
- spin_lock_irqsave(&random_state->lock, cpuflags);
- if (random_state->entropy_count > random_state->poolinfo.POOLBITS)
- flags |= EXTRACT_ENTROPY_SECONDARY;
- spin_unlock_irqrestore(&random_state->lock, cpuflags);
-
- return extract_entropy(urandom_state, buf, nbytes, flags);
+ return extract_entropy_user(&nonblocking_pool, buf, nbytes);
}
static unsigned int
poll_wait(file, &random_read_wait, wait);
poll_wait(file, &random_write_wait, wait);
mask = 0;
- if (random_state->entropy_count >= random_read_wakeup_thresh)
+ if (input_pool.entropy_count >= random_read_wakeup_thresh)
mask |= POLLIN | POLLRDNORM;
- if (random_state->entropy_count < random_write_wakeup_thresh)
+ if (input_pool.entropy_count < random_write_wakeup_thresh)
mask |= POLLOUT | POLLWRNORM;
return mask;
}
c -= bytes;
p += bytes;
- add_entropy_words(random_state, buf, (bytes + 3) / 4);
+ add_entropy_words(&input_pool, buf, (bytes + 3) / 4);
}
if (p == buffer) {
return (ssize_t)ret;
switch (cmd) {
case RNDGETENTCNT:
- ent_count = random_state->entropy_count;
+ ent_count = input_pool.entropy_count;
if (put_user(ent_count, p))
return -EFAULT;
return 0;
return -EPERM;
if (get_user(ent_count, p))
return -EFAULT;
- credit_entropy_store(random_state, ent_count);
+ credit_entropy_store(&input_pool, ent_count);
/*
* Wake up waiting processes if we have enough
* entropy.
*/
- if (random_state->entropy_count >= random_read_wakeup_thresh)
+ if (input_pool.entropy_count >= random_read_wakeup_thresh)
wake_up_interruptible(&random_read_wait);
return 0;
case RNDADDENTROPY:
size, &file->f_pos);
if (retval < 0)
return retval;
- credit_entropy_store(random_state, ent_count);
+ credit_entropy_store(&input_pool, ent_count);
/*
* Wake up waiting processes if we have enough
* entropy.
*/
- if (random_state->entropy_count >= random_read_wakeup_thresh)
+ if (input_pool.entropy_count >= random_read_wakeup_thresh)
wake_up_interruptible(&random_read_wait);
return 0;
case RNDZAPENTCNT:
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- random_state->entropy_count = 0;
- return 0;
case RNDCLEARPOOL:
- /* Clear the entropy pool and associated counters. */
+ /* Clear the entropy pool counters. */
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- clear_entropy_store(random_state);
- init_std_data(random_state);
+ init_std_data(&input_pool);
+ init_std_data(&blocking_pool);
+ init_std_data(&nonblocking_pool);
return 0;
default:
return -EINVAL;
#include <linux/sysctl.h>
-static int min_read_thresh, max_read_thresh;
-static int min_write_thresh, max_write_thresh;
+static int min_read_thresh = 8, min_write_thresh;
+static int max_read_thresh = INPUT_POOL_WORDS * 32;
+static int max_write_thresh = INPUT_POOL_WORDS * 32;
static char sysctl_bootid[16];
/*
static int proc_do_uuid(ctl_table *table, int write, struct file *filp,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
- ctl_table fake_table;
+ ctl_table fake_table = {0};
unsigned char buf[64], tmp_uuid[16], *uuid;
uuid = table->data;
return 1;
}
-static int sysctl_poolsize = DEFAULT_POOL_SIZE;
+static int sysctl_poolsize = INPUT_POOL_WORDS * 32;
ctl_table random_table[] = {
{
.ctl_name = RANDOM_POOLSIZE,
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = &proc_dointvec,
+ .data = &input_pool.entropy_count,
},
{
.ctl_name = RANDOM_READ_THRESH,
},
{ .ctl_name = 0 }
};
-
-static void sysctl_init_random(struct entropy_store *random_state)
-{
- min_read_thresh = 8;
- min_write_thresh = 0;
- max_read_thresh = max_write_thresh = random_state->poolinfo.POOLBITS;
- random_table[1].data = &random_state->entropy_count;
-}
#endif /* CONFIG_SYSCTL */
/********************************************************************
*
********************************************************************/
-#ifdef CONFIG_INET
/*
* TCP initial sequence number picking. This uses the random number
* generator to pick an initial secret value. This value is hashed
#define K2 013240474631UL
#define K3 015666365641UL
-/*
- * Basic cut-down MD4 transform. Returns only 32 bits of result.
- */
-static __u32 halfMD4Transform (__u32 const buf[4], __u32 const in[8])
-{
- __u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3];
-
- /* Round 1 */
- ROUND(F, a, b, c, d, in[0] + K1, 3);
- ROUND(F, d, a, b, c, in[1] + K1, 7);
- ROUND(F, c, d, a, b, in[2] + K1, 11);
- ROUND(F, b, c, d, a, in[3] + K1, 19);
- ROUND(F, a, b, c, d, in[4] + K1, 3);
- ROUND(F, d, a, b, c, in[5] + K1, 7);
- ROUND(F, c, d, a, b, in[6] + K1, 11);
- ROUND(F, b, c, d, a, in[7] + K1, 19);
-
- /* Round 2 */
- ROUND(G, a, b, c, d, in[1] + K2, 3);
- ROUND(G, d, a, b, c, in[3] + K2, 5);
- ROUND(G, c, d, a, b, in[5] + K2, 9);
- ROUND(G, b, c, d, a, in[7] + K2, 13);
- ROUND(G, a, b, c, d, in[0] + K2, 3);
- ROUND(G, d, a, b, c, in[2] + K2, 5);
- ROUND(G, c, d, a, b, in[4] + K2, 9);
- ROUND(G, b, c, d, a, in[6] + K2, 13);
-
- /* Round 3 */
- ROUND(H, a, b, c, d, in[3] + K3, 3);
- ROUND(H, d, a, b, c, in[7] + K3, 9);
- ROUND(H, c, d, a, b, in[2] + K3, 11);
- ROUND(H, b, c, d, a, in[6] + K3, 15);
- ROUND(H, a, b, c, d, in[1] + K3, 3);
- ROUND(H, d, a, b, c, in[5] + K3, 9);
- ROUND(H, c, d, a, b, in[0] + K3, 11);
- ROUND(H, b, c, d, a, in[4] + K3, 15);
-
- return buf[1] + b; /* "most hashed" word */
- /* Alternative: return sum of all words? */
-}
-
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
static __u32 twothirdsMD4Transform (__u32 const buf[4], __u32 const in[12])
EXPORT_SYMBOL(secure_tcpv6_sequence_number);
#endif
+/* The code below is shamelessly stolen from secure_tcp_sequence_number().
+ * All blames to Andrey V. Savochkin <saw@msu.ru>.
+ */
+__u32 secure_ip_id(__u32 daddr)
+{
+ struct keydata *keyptr;
+ __u32 hash[4];
+
+ keyptr = get_keyptr();
+
+ /*
+ * Pick a unique starting offset for each IP destination.
+ * The dest ip address is placed in the starting vector,
+ * which is then hashed with random data.
+ */
+ hash[0] = daddr;
+ hash[1] = keyptr->secret[9];
+ hash[2] = keyptr->secret[10];
+ hash[3] = keyptr->secret[11];
+
+ return half_md4_transform(hash, keyptr->secret);
+}
+
+#ifdef CONFIG_INET
+
__u32 secure_tcp_sequence_number(__u32 saddr, __u32 daddr,
__u16 sport, __u16 dport)
{
hash[2]=(sport << 16) + dport;
hash[3]=keyptr->secret[11];
- seq = halfMD4Transform(hash, keyptr->secret) & HASH_MASK;
+ seq = half_md4_transform(hash, keyptr->secret) & HASH_MASK;
seq += keyptr->count;
/*
* As close as possible to RFC 793, which
EXPORT_SYMBOL(secure_tcp_sequence_number);
-/* The code below is shamelessly stolen from secure_tcp_sequence_number().
- * All blames to Andrey V. Savochkin <saw@msu.ru>.
- */
-__u32 secure_ip_id(__u32 daddr)
-{
- struct keydata *keyptr;
- __u32 hash[4];
- keyptr = get_keyptr();
-
- /*
- * Pick a unique starting offset for each IP destination.
- * The dest ip address is placed in the starting vector,
- * which is then hashed with random data.
- */
- hash[0] = daddr;
- hash[1] = keyptr->secret[9];
- hash[2] = keyptr->secret[10];
- hash[3] = keyptr->secret[11];
-
- return halfMD4Transform(hash, keyptr->secret);
-}
/* Generate secure starting point for ephemeral TCP port search */
u32 secure_tcp_port_ephemeral(__u32 saddr, __u32 daddr, __u16 dport)
hash[2] = dport ^ keyptr->secret[10];
hash[3] = keyptr->secret[11];
- return halfMD4Transform(hash, keyptr->secret);
+ return half_md4_transform(hash, keyptr->secret);
}
-#ifdef CONFIG_SYN_COOKIES
-/*
- * Secure SYN cookie computation. This is the algorithm worked out by
- * Dan Bernstein and Eric Schenk.
- *
- * For linux I implement the 1 minute counter by looking at the jiffies clock.
- * The count is passed in as a parameter, so this code doesn't much care.
- */
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+u32 secure_tcpv6_port_ephemeral(const __u32 *saddr, const __u32 *daddr, __u16 dport)
+{
+ struct keydata *keyptr = get_keyptr();
+ u32 hash[12];
-#define COOKIEBITS 24 /* Upper bits store count */
-#define COOKIEMASK (((__u32)1 << COOKIEBITS) - 1)
+ memcpy(hash, saddr, 16);
+ hash[4] = dport;
+ memcpy(&hash[5],keyptr->secret,sizeof(__u32) * 7);
-static int syncookie_init;
-static __u32 syncookie_secret[2][16-3+HASH_BUFFER_SIZE];
+ return twothirdsMD4Transform(daddr, hash);
+}
+EXPORT_SYMBOL(secure_tcpv6_port_ephemeral);
+#endif
-__u32 secure_tcp_syn_cookie(__u32 saddr, __u32 daddr, __u16 sport,
- __u16 dport, __u32 sseq, __u32 count, __u32 data)
-{
- __u32 tmp[16 + HASH_BUFFER_SIZE + HASH_EXTRA_SIZE];
- __u32 seq;
+#endif /* CONFIG_INET */
- /*
- * Pick two random secrets the first time we need a cookie.
- */
- if (syncookie_init == 0) {
- get_random_bytes(syncookie_secret, sizeof(syncookie_secret));
- syncookie_init = 1;
- }
+/*
+ * Get a random word for internal kernel use only. Similar to urandom but
+ * with the goal of minimal entropy pool depletion. As a result, the random
+ * value is not cryptographically secure but for several uses the cost of
+ * depleting entropy is too high
+ */
+unsigned int get_random_int(void)
+{
/*
- * Compute the secure sequence number.
- * The output should be:
- * HASH(sec1,saddr,sport,daddr,dport,sec1) + sseq + (count * 2^24)
- * + (HASH(sec2,saddr,sport,daddr,dport,count,sec2) % 2^24).
- * Where sseq is their sequence number and count increases every
- * minute by 1.
- * As an extra hack, we add a small "data" value that encodes the
- * MSS into the second hash value.
+ * Use IP's RNG. It suits our purpose perfectly: it re-keys itself
+ * every second, from the entropy pool (and thus creates a limited
+ * drain on it), and uses halfMD4Transform within the second. We
+ * also mix it with jiffies and the PID:
*/
-
- memcpy(tmp + 3, syncookie_secret[0], sizeof(syncookie_secret[0]));
- tmp[0]=saddr;
- tmp[1]=daddr;
- tmp[2]=(sport << 16) + dport;
- HASH_TRANSFORM(tmp+16, tmp);
- seq = tmp[17] + sseq + (count << COOKIEBITS);
-
- memcpy(tmp + 3, syncookie_secret[1], sizeof(syncookie_secret[1]));
- tmp[0]=saddr;
- tmp[1]=daddr;
- tmp[2]=(sport << 16) + dport;
- tmp[3] = count; /* minute counter */
- HASH_TRANSFORM(tmp + 16, tmp);
-
- /* Add in the second hash and the data */
- return seq + ((tmp[17] + data) & COOKIEMASK);
+ return secure_ip_id(current->pid + jiffies);
}
/*
- * This retrieves the small "data" value from the syncookie.
- * If the syncookie is bad, the data returned will be out of
- * range. This must be checked by the caller.
+ * randomize_range() returns a start address such that
*
- * The count value used to generate the cookie must be within
- * "maxdiff" if the current (passed-in) "count". The return value
- * is (__u32)-1 if this test fails.
+ * [...... <range> .....]
+ * start end
+ *
+ * a <range> with size "len" starting at the return value is inside in the
+ * area defined by [start, end], but is otherwise randomized.
*/
-__u32 check_tcp_syn_cookie(__u32 cookie, __u32 saddr, __u32 daddr, __u16 sport,
- __u16 dport, __u32 sseq, __u32 count, __u32 maxdiff)
+unsigned long
+randomize_range(unsigned long start, unsigned long end, unsigned long len)
{
- __u32 tmp[16 + HASH_BUFFER_SIZE + HASH_EXTRA_SIZE];
- __u32 diff;
-
- if (syncookie_init == 0)
- return (__u32)-1; /* Well, duh! */
-
- /* Strip away the layers from the cookie */
- memcpy(tmp + 3, syncookie_secret[0], sizeof(syncookie_secret[0]));
- tmp[0]=saddr;
- tmp[1]=daddr;
- tmp[2]=(sport << 16) + dport;
- HASH_TRANSFORM(tmp + 16, tmp);
- cookie -= tmp[17] + sseq;
- /* Cookie is now reduced to (count * 2^24) ^ (hash % 2^24) */
-
- diff = (count - (cookie >> COOKIEBITS)) & ((__u32)-1 >> COOKIEBITS);
- if (diff >= maxdiff)
- return (__u32)-1;
-
- memcpy(tmp+3, syncookie_secret[1], sizeof(syncookie_secret[1]));
- tmp[0] = saddr;
- tmp[1] = daddr;
- tmp[2] = (sport << 16) + dport;
- tmp[3] = count - diff; /* minute counter */
- HASH_TRANSFORM(tmp + 16, tmp);
-
- return (cookie - tmp[17]) & COOKIEMASK; /* Leaving the data behind */
+ unsigned long range = end - len - start;
+
+ if (end <= start + len)
+ return 0;
+ return PAGE_ALIGN(get_random_int() % range + start);
}
-#endif
-#endif /* CONFIG_INET */
git://git.onelab.eu / linux-2.6.git / blobdiff