random: replace non-blocking pool with a Chacha20-based CRNG
The CRNG is faster, and we don't pretend to track entropy usage in the CRNG any more. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o
parent
b1132deac0
commit
e192be9d9a
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@ -15,72 +15,11 @@
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#include <linux/module.h>
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#include <crypto/chacha20.h>
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static inline u32 rotl32(u32 v, u8 n)
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{
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return (v << n) | (v >> (sizeof(v) * 8 - n));
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}
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static inline u32 le32_to_cpuvp(const void *p)
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{
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return le32_to_cpup(p);
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}
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static void chacha20_block(u32 *state, void *stream)
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{
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u32 x[16], *out = stream;
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int i;
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for (i = 0; i < ARRAY_SIZE(x); i++)
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x[i] = state[i];
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for (i = 0; i < 20; i += 2) {
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x[0] += x[4]; x[12] = rotl32(x[12] ^ x[0], 16);
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x[1] += x[5]; x[13] = rotl32(x[13] ^ x[1], 16);
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x[2] += x[6]; x[14] = rotl32(x[14] ^ x[2], 16);
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x[3] += x[7]; x[15] = rotl32(x[15] ^ x[3], 16);
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x[8] += x[12]; x[4] = rotl32(x[4] ^ x[8], 12);
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x[9] += x[13]; x[5] = rotl32(x[5] ^ x[9], 12);
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x[10] += x[14]; x[6] = rotl32(x[6] ^ x[10], 12);
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x[11] += x[15]; x[7] = rotl32(x[7] ^ x[11], 12);
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x[0] += x[4]; x[12] = rotl32(x[12] ^ x[0], 8);
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x[1] += x[5]; x[13] = rotl32(x[13] ^ x[1], 8);
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x[2] += x[6]; x[14] = rotl32(x[14] ^ x[2], 8);
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x[3] += x[7]; x[15] = rotl32(x[15] ^ x[3], 8);
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x[8] += x[12]; x[4] = rotl32(x[4] ^ x[8], 7);
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x[9] += x[13]; x[5] = rotl32(x[5] ^ x[9], 7);
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x[10] += x[14]; x[6] = rotl32(x[6] ^ x[10], 7);
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x[11] += x[15]; x[7] = rotl32(x[7] ^ x[11], 7);
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x[0] += x[5]; x[15] = rotl32(x[15] ^ x[0], 16);
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x[1] += x[6]; x[12] = rotl32(x[12] ^ x[1], 16);
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x[2] += x[7]; x[13] = rotl32(x[13] ^ x[2], 16);
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x[3] += x[4]; x[14] = rotl32(x[14] ^ x[3], 16);
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x[10] += x[15]; x[5] = rotl32(x[5] ^ x[10], 12);
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x[11] += x[12]; x[6] = rotl32(x[6] ^ x[11], 12);
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x[8] += x[13]; x[7] = rotl32(x[7] ^ x[8], 12);
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x[9] += x[14]; x[4] = rotl32(x[4] ^ x[9], 12);
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x[0] += x[5]; x[15] = rotl32(x[15] ^ x[0], 8);
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x[1] += x[6]; x[12] = rotl32(x[12] ^ x[1], 8);
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x[2] += x[7]; x[13] = rotl32(x[13] ^ x[2], 8);
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x[3] += x[4]; x[14] = rotl32(x[14] ^ x[3], 8);
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x[10] += x[15]; x[5] = rotl32(x[5] ^ x[10], 7);
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x[11] += x[12]; x[6] = rotl32(x[6] ^ x[11], 7);
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x[8] += x[13]; x[7] = rotl32(x[7] ^ x[8], 7);
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x[9] += x[14]; x[4] = rotl32(x[4] ^ x[9], 7);
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}
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for (i = 0; i < ARRAY_SIZE(x); i++)
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out[i] = cpu_to_le32(x[i] + state[i]);
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state[12]++;
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}
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static void chacha20_docrypt(u32 *state, u8 *dst, const u8 *src,
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unsigned int bytes)
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{
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@ -261,6 +261,7 @@
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#include <linux/syscalls.h>
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#include <linux/completion.h>
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#include <linux/uuid.h>
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#include <crypto/chacha20.h>
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#include <asm/processor.h>
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#include <asm/uaccess.h>
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@ -413,6 +414,31 @@ static struct fasync_struct *fasync;
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static DEFINE_SPINLOCK(random_ready_list_lock);
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static LIST_HEAD(random_ready_list);
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struct crng_state {
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__u32 state[16];
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unsigned long init_time;
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spinlock_t lock;
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};
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struct crng_state primary_crng = {
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.lock = __SPIN_LOCK_UNLOCKED(primary_crng.lock),
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};
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/*
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* crng_init = 0 --> Uninitialized
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* 1 --> Initialized
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* 2 --> Initialized from input_pool
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*
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* crng_init is protected by primary_crng->lock, and only increases
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* its value (from 0->1->2).
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*/
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static int crng_init = 0;
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#define crng_ready() (likely(crng_init > 0))
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static int crng_init_cnt = 0;
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#define CRNG_INIT_CNT_THRESH (2*CHACHA20_KEY_SIZE)
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static void extract_crng(__u8 out[CHACHA20_BLOCK_SIZE]);
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static void process_random_ready_list(void);
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/**********************************************************************
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*
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* OS independent entropy store. Here are the functions which handle
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@ -442,10 +468,15 @@ struct entropy_store {
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__u8 last_data[EXTRACT_SIZE];
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};
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static ssize_t extract_entropy(struct entropy_store *r, void *buf,
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size_t nbytes, int min, int rsvd);
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static ssize_t _extract_entropy(struct entropy_store *r, void *buf,
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size_t nbytes, int fips);
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static void crng_reseed(struct crng_state *crng, struct entropy_store *r);
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static void push_to_pool(struct work_struct *work);
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static __u32 input_pool_data[INPUT_POOL_WORDS];
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static __u32 blocking_pool_data[OUTPUT_POOL_WORDS];
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static __u32 nonblocking_pool_data[OUTPUT_POOL_WORDS];
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static struct entropy_store input_pool = {
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.poolinfo = &poolinfo_table[0],
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@ -466,16 +497,6 @@ static struct entropy_store blocking_pool = {
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push_to_pool),
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};
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static struct entropy_store nonblocking_pool = {
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.poolinfo = &poolinfo_table[1],
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.name = "nonblocking",
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.pull = &input_pool,
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.lock = __SPIN_LOCK_UNLOCKED(nonblocking_pool.lock),
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.pool = nonblocking_pool_data,
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.push_work = __WORK_INITIALIZER(nonblocking_pool.push_work,
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push_to_pool),
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};
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static __u32 const twist_table[8] = {
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0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158,
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0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 };
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@ -678,12 +699,6 @@ retry:
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if (!r->initialized && r->entropy_total > 128) {
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r->initialized = 1;
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r->entropy_total = 0;
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if (r == &nonblocking_pool) {
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prandom_reseed_late();
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process_random_ready_list();
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wake_up_all(&urandom_init_wait);
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pr_notice("random: %s pool is initialized\n", r->name);
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}
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}
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trace_credit_entropy_bits(r->name, nbits,
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@ -693,30 +708,27 @@ retry:
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if (r == &input_pool) {
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int entropy_bits = entropy_count >> ENTROPY_SHIFT;
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if (crng_init < 2 && entropy_bits >= 128) {
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crng_reseed(&primary_crng, r);
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entropy_bits = r->entropy_count >> ENTROPY_SHIFT;
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}
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/* should we wake readers? */
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if (entropy_bits >= random_read_wakeup_bits) {
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wake_up_interruptible(&random_read_wait);
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kill_fasync(&fasync, SIGIO, POLL_IN);
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}
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/* If the input pool is getting full, send some
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* entropy to the two output pools, flipping back and
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* forth between them, until the output pools are 75%
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* full.
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* entropy to the blocking pool until it is 75% full.
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*/
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if (entropy_bits > random_write_wakeup_bits &&
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r->initialized &&
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r->entropy_total >= 2*random_read_wakeup_bits) {
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static struct entropy_store *last = &blocking_pool;
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struct entropy_store *other = &blocking_pool;
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if (last == &blocking_pool)
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other = &nonblocking_pool;
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if (other->entropy_count <=
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3 * other->poolinfo->poolfracbits / 4)
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last = other;
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if (last->entropy_count <=
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3 * last->poolinfo->poolfracbits / 4) {
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schedule_work(&last->push_work);
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3 * other->poolinfo->poolfracbits / 4) {
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schedule_work(&other->push_work);
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r->entropy_total = 0;
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}
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}
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@ -734,6 +746,152 @@ static void credit_entropy_bits_safe(struct entropy_store *r, int nbits)
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credit_entropy_bits(r, nbits);
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}
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/*********************************************************************
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*
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* CRNG using CHACHA20
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*
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*********************************************************************/
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#define CRNG_RESEED_INTERVAL (300*HZ)
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static DECLARE_WAIT_QUEUE_HEAD(crng_init_wait);
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static void crng_initialize(struct crng_state *crng)
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{
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int i;
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unsigned long rv;
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memcpy(&crng->state[0], "expand 32-byte k", 16);
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if (crng == &primary_crng)
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_extract_entropy(&input_pool, &crng->state[4],
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sizeof(__u32) * 12, 0);
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else
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get_random_bytes(&crng->state[4], sizeof(__u32) * 12);
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for (i = 4; i < 16; i++) {
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if (!arch_get_random_seed_long(&rv) &&
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!arch_get_random_long(&rv))
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rv = random_get_entropy();
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crng->state[i] ^= rv;
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}
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crng->init_time = jiffies - CRNG_RESEED_INTERVAL - 1;
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}
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static int crng_fast_load(const char *cp, size_t len)
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{
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unsigned long flags;
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char *p;
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if (!spin_trylock_irqsave(&primary_crng.lock, flags))
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return 0;
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if (crng_ready()) {
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spin_unlock_irqrestore(&primary_crng.lock, flags);
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return 0;
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}
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p = (unsigned char *) &primary_crng.state[4];
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while (len > 0 && crng_init_cnt < CRNG_INIT_CNT_THRESH) {
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p[crng_init_cnt % CHACHA20_KEY_SIZE] ^= *cp;
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cp++; crng_init_cnt++; len--;
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}
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if (crng_init_cnt >= CRNG_INIT_CNT_THRESH) {
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crng_init = 1;
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wake_up_interruptible(&crng_init_wait);
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pr_notice("random: fast init done\n");
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}
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spin_unlock_irqrestore(&primary_crng.lock, flags);
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return 1;
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}
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static void crng_reseed(struct crng_state *crng, struct entropy_store *r)
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{
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unsigned long flags;
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int i, num;
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union {
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__u8 block[CHACHA20_BLOCK_SIZE];
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__u32 key[8];
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} buf;
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if (r) {
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num = extract_entropy(r, &buf, 32, 16, 0);
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if (num == 0)
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return;
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} else
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extract_crng(buf.block);
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spin_lock_irqsave(&primary_crng.lock, flags);
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for (i = 0; i < 8; i++) {
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unsigned long rv;
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if (!arch_get_random_seed_long(&rv) &&
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!arch_get_random_long(&rv))
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rv = random_get_entropy();
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crng->state[i+4] ^= buf.key[i] ^ rv;
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}
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memzero_explicit(&buf, sizeof(buf));
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crng->init_time = jiffies;
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if (crng == &primary_crng && crng_init < 2) {
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crng_init = 2;
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process_random_ready_list();
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wake_up_interruptible(&crng_init_wait);
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pr_notice("random: crng init done\n");
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}
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spin_unlock_irqrestore(&primary_crng.lock, flags);
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}
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static inline void crng_wait_ready(void)
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{
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wait_event_interruptible(crng_init_wait, crng_ready());
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}
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static void extract_crng(__u8 out[CHACHA20_BLOCK_SIZE])
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{
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unsigned long v, flags;
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struct crng_state *crng = &primary_crng;
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if (crng_init > 1 &&
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time_after(jiffies, crng->init_time + CRNG_RESEED_INTERVAL))
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crng_reseed(crng, &input_pool);
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spin_lock_irqsave(&crng->lock, flags);
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if (arch_get_random_long(&v))
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crng->state[14] ^= v;
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chacha20_block(&crng->state[0], out);
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if (crng->state[12] == 0)
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crng->state[13]++;
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spin_unlock_irqrestore(&crng->lock, flags);
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}
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static ssize_t extract_crng_user(void __user *buf, size_t nbytes)
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{
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ssize_t ret = 0, i;
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__u8 tmp[CHACHA20_BLOCK_SIZE];
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int large_request = (nbytes > 256);
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while (nbytes) {
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if (large_request && need_resched()) {
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if (signal_pending(current)) {
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if (ret == 0)
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ret = -ERESTARTSYS;
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break;
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}
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schedule();
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}
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extract_crng(tmp);
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i = min_t(int, nbytes, CHACHA20_BLOCK_SIZE);
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if (copy_to_user(buf, tmp, i)) {
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ret = -EFAULT;
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break;
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}
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nbytes -= i;
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buf += i;
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ret += i;
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}
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/* Wipe data just written to memory */
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memzero_explicit(tmp, sizeof(tmp));
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return ret;
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}
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/*********************************************************************
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*
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* Entropy input management
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@ -750,12 +908,12 @@ struct timer_rand_state {
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#define INIT_TIMER_RAND_STATE { INITIAL_JIFFIES, };
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/*
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* Add device- or boot-specific data to the input and nonblocking
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* pools to help initialize them to unique values.
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* Add device- or boot-specific data to the input pool to help
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* initialize it.
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*
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* None of this adds any entropy, it is meant to avoid the
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* problem of the nonblocking pool having similar initial state
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* across largely identical devices.
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* None of this adds any entropy; it is meant to avoid the problem of
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* the entropy pool having similar initial state across largely
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* identical devices.
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*/
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void add_device_randomness(const void *buf, unsigned int size)
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{
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@ -767,11 +925,6 @@ void add_device_randomness(const void *buf, unsigned int size)
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_mix_pool_bytes(&input_pool, buf, size);
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_mix_pool_bytes(&input_pool, &time, sizeof(time));
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spin_unlock_irqrestore(&input_pool.lock, flags);
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spin_lock_irqsave(&nonblocking_pool.lock, flags);
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_mix_pool_bytes(&nonblocking_pool, buf, size);
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_mix_pool_bytes(&nonblocking_pool, &time, sizeof(time));
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spin_unlock_irqrestore(&nonblocking_pool.lock, flags);
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}
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EXPORT_SYMBOL(add_device_randomness);
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@ -802,7 +955,7 @@ static void add_timer_randomness(struct timer_rand_state *state, unsigned num)
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sample.jiffies = jiffies;
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sample.cycles = random_get_entropy();
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sample.num = num;
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r = nonblocking_pool.initialized ? &input_pool : &nonblocking_pool;
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r = &input_pool;
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mix_pool_bytes(r, &sample, sizeof(sample));
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/*
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@ -918,11 +1071,21 @@ void add_interrupt_randomness(int irq, int irq_flags)
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fast_mix(fast_pool);
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add_interrupt_bench(cycles);
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if (!crng_ready()) {
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if ((fast_pool->count >= 64) &&
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crng_fast_load((char *) fast_pool->pool,
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sizeof(fast_pool->pool))) {
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fast_pool->count = 0;
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fast_pool->last = now;
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}
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return;
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}
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if ((fast_pool->count < 64) &&
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!time_after(now, fast_pool->last + HZ))
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return;
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r = nonblocking_pool.initialized ? &input_pool : &nonblocking_pool;
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r = &input_pool;
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if (!spin_trylock(&r->lock))
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return;
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@ -966,9 +1129,6 @@ EXPORT_SYMBOL_GPL(add_disk_randomness);
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*
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*********************************************************************/
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static ssize_t extract_entropy(struct entropy_store *r, void *buf,
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size_t nbytes, int min, int rsvd);
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/*
|
||||
* This utility inline function is responsible for transferring entropy
|
||||
* from the primary pool to the secondary extraction pool. We make
|
||||
|
|
@ -1143,6 +1303,36 @@ static void extract_buf(struct entropy_store *r, __u8 *out)
|
|||
memzero_explicit(&hash, sizeof(hash));
|
||||
}
|
||||
|
||||
static ssize_t _extract_entropy(struct entropy_store *r, void *buf,
|
||||
size_t nbytes, int fips)
|
||||
{
|
||||
ssize_t ret = 0, i;
|
||||
__u8 tmp[EXTRACT_SIZE];
|
||||
unsigned long flags;
|
||||
|
||||
while (nbytes) {
|
||||
extract_buf(r, tmp);
|
||||
|
||||
if (fips) {
|
||||
spin_lock_irqsave(&r->lock, flags);
|
||||
if (!memcmp(tmp, r->last_data, EXTRACT_SIZE))
|
||||
panic("Hardware RNG duplicated output!\n");
|
||||
memcpy(r->last_data, tmp, EXTRACT_SIZE);
|
||||
spin_unlock_irqrestore(&r->lock, flags);
|
||||
}
|
||||
i = min_t(int, nbytes, EXTRACT_SIZE);
|
||||
memcpy(buf, tmp, i);
|
||||
nbytes -= i;
|
||||
buf += i;
|
||||
ret += i;
|
||||
}
|
||||
|
||||
/* Wipe data just returned from memory */
|
||||
memzero_explicit(tmp, sizeof(tmp));
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
/*
|
||||
* This function extracts randomness from the "entropy pool", and
|
||||
* returns it in a buffer.
|
||||
|
|
@ -1155,7 +1345,6 @@ static void extract_buf(struct entropy_store *r, __u8 *out)
|
|||
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];
|
||||
unsigned long flags;
|
||||
|
||||
|
|
@ -1179,27 +1368,7 @@ static ssize_t extract_entropy(struct entropy_store *r, void *buf,
|
|||
xfer_secondary_pool(r, nbytes);
|
||||
nbytes = account(r, nbytes, min, reserved);
|
||||
|
||||
while (nbytes) {
|
||||
extract_buf(r, tmp);
|
||||
|
||||
if (fips_enabled) {
|
||||
spin_lock_irqsave(&r->lock, flags);
|
||||
if (!memcmp(tmp, r->last_data, EXTRACT_SIZE))
|
||||
panic("Hardware RNG duplicated output!\n");
|
||||
memcpy(r->last_data, tmp, EXTRACT_SIZE);
|
||||
spin_unlock_irqrestore(&r->lock, flags);
|
||||
}
|
||||
i = min_t(int, nbytes, EXTRACT_SIZE);
|
||||
memcpy(buf, tmp, i);
|
||||
nbytes -= i;
|
||||
buf += i;
|
||||
ret += i;
|
||||
}
|
||||
|
||||
/* Wipe data just returned from memory */
|
||||
memzero_explicit(tmp, sizeof(tmp));
|
||||
|
||||
return ret;
|
||||
return _extract_entropy(r, buf, nbytes, fips_enabled);
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
@ -1254,15 +1423,26 @@ static ssize_t extract_entropy_user(struct entropy_store *r, void __user *buf,
|
|||
*/
|
||||
void get_random_bytes(void *buf, int nbytes)
|
||||
{
|
||||
__u8 tmp[CHACHA20_BLOCK_SIZE];
|
||||
|
||||
#if DEBUG_RANDOM_BOOT > 0
|
||||
if (unlikely(nonblocking_pool.initialized == 0))
|
||||
if (!crng_ready())
|
||||
printk(KERN_NOTICE "random: %pF get_random_bytes called "
|
||||
"with %d bits of entropy available\n",
|
||||
(void *) _RET_IP_,
|
||||
nonblocking_pool.entropy_total);
|
||||
"with crng_init = %d\n", (void *) _RET_IP_, crng_init);
|
||||
#endif
|
||||
trace_get_random_bytes(nbytes, _RET_IP_);
|
||||
extract_entropy(&nonblocking_pool, buf, nbytes, 0, 0);
|
||||
|
||||
while (nbytes >= CHACHA20_BLOCK_SIZE) {
|
||||
extract_crng(buf);
|
||||
buf += CHACHA20_BLOCK_SIZE;
|
||||
nbytes -= CHACHA20_BLOCK_SIZE;
|
||||
}
|
||||
|
||||
if (nbytes > 0) {
|
||||
extract_crng(tmp);
|
||||
memcpy(buf, tmp, nbytes);
|
||||
memzero_explicit(tmp, nbytes);
|
||||
}
|
||||
}
|
||||
EXPORT_SYMBOL(get_random_bytes);
|
||||
|
||||
|
|
@ -1280,7 +1460,7 @@ int add_random_ready_callback(struct random_ready_callback *rdy)
|
|||
unsigned long flags;
|
||||
int err = -EALREADY;
|
||||
|
||||
if (likely(nonblocking_pool.initialized))
|
||||
if (crng_ready())
|
||||
return err;
|
||||
|
||||
owner = rdy->owner;
|
||||
|
|
@ -1288,7 +1468,7 @@ int add_random_ready_callback(struct random_ready_callback *rdy)
|
|||
return -ENOENT;
|
||||
|
||||
spin_lock_irqsave(&random_ready_list_lock, flags);
|
||||
if (nonblocking_pool.initialized)
|
||||
if (crng_ready())
|
||||
goto out;
|
||||
|
||||
owner = NULL;
|
||||
|
|
@ -1352,7 +1532,7 @@ void get_random_bytes_arch(void *buf, int nbytes)
|
|||
}
|
||||
|
||||
if (nbytes)
|
||||
extract_entropy(&nonblocking_pool, p, nbytes, 0, 0);
|
||||
get_random_bytes(p, nbytes);
|
||||
}
|
||||
EXPORT_SYMBOL(get_random_bytes_arch);
|
||||
|
||||
|
|
@ -1397,7 +1577,7 @@ static int rand_initialize(void)
|
|||
{
|
||||
init_std_data(&input_pool);
|
||||
init_std_data(&blocking_pool);
|
||||
init_std_data(&nonblocking_pool);
|
||||
crng_initialize(&primary_crng);
|
||||
return 0;
|
||||
}
|
||||
early_initcall(rand_initialize);
|
||||
|
|
@ -1459,22 +1639,22 @@ random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
|
|||
static ssize_t
|
||||
urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
|
||||
{
|
||||
unsigned long flags;
|
||||
static int maxwarn = 10;
|
||||
int ret;
|
||||
|
||||
if (unlikely(nonblocking_pool.initialized == 0) &&
|
||||
maxwarn > 0) {
|
||||
if (!crng_ready() && maxwarn > 0) {
|
||||
maxwarn--;
|
||||
printk(KERN_NOTICE "random: %s: uninitialized urandom read "
|
||||
"(%zd bytes read, %d bits of entropy available)\n",
|
||||
current->comm, nbytes, nonblocking_pool.entropy_total);
|
||||
"(%zd bytes read)\n",
|
||||
current->comm, nbytes);
|
||||
spin_lock_irqsave(&primary_crng.lock, flags);
|
||||
crng_init_cnt = 0;
|
||||
spin_unlock_irqrestore(&primary_crng.lock, flags);
|
||||
}
|
||||
|
||||
nbytes = min_t(size_t, nbytes, INT_MAX >> (ENTROPY_SHIFT + 3));
|
||||
ret = extract_entropy_user(&nonblocking_pool, buf, nbytes);
|
||||
|
||||
trace_urandom_read(8 * nbytes, ENTROPY_BITS(&nonblocking_pool),
|
||||
ENTROPY_BITS(&input_pool));
|
||||
ret = extract_crng_user(buf, nbytes);
|
||||
trace_urandom_read(8 * nbytes, 0, ENTROPY_BITS(&input_pool));
|
||||
return ret;
|
||||
}
|
||||
|
||||
|
|
@ -1520,10 +1700,7 @@ static ssize_t random_write(struct file *file, const char __user *buffer,
|
|||
{
|
||||
size_t ret;
|
||||
|
||||
ret = write_pool(&blocking_pool, buffer, count);
|
||||
if (ret)
|
||||
return ret;
|
||||
ret = write_pool(&nonblocking_pool, buffer, count);
|
||||
ret = write_pool(&input_pool, buffer, count);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
|
|
@ -1574,7 +1751,6 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
|
|||
if (!capable(CAP_SYS_ADMIN))
|
||||
return -EPERM;
|
||||
input_pool.entropy_count = 0;
|
||||
nonblocking_pool.entropy_count = 0;
|
||||
blocking_pool.entropy_count = 0;
|
||||
return 0;
|
||||
default:
|
||||
|
|
@ -1616,11 +1792,10 @@ SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count,
|
|||
if (flags & GRND_RANDOM)
|
||||
return _random_read(flags & GRND_NONBLOCK, buf, count);
|
||||
|
||||
if (unlikely(nonblocking_pool.initialized == 0)) {
|
||||
if (!crng_ready()) {
|
||||
if (flags & GRND_NONBLOCK)
|
||||
return -EAGAIN;
|
||||
wait_event_interruptible(urandom_init_wait,
|
||||
nonblocking_pool.initialized);
|
||||
crng_wait_ready();
|
||||
if (signal_pending(current))
|
||||
return -ERESTARTSYS;
|
||||
}
|
||||
|
|
@ -1856,18 +2031,17 @@ void add_hwgenerator_randomness(const char *buffer, size_t count,
|
|||
{
|
||||
struct entropy_store *poolp = &input_pool;
|
||||
|
||||
if (unlikely(nonblocking_pool.initialized == 0))
|
||||
poolp = &nonblocking_pool;
|
||||
else {
|
||||
/* Suspend writing if we're above the trickle
|
||||
* threshold. We'll be woken up again once below
|
||||
* random_write_wakeup_thresh, or when the calling
|
||||
* thread is about to terminate.
|
||||
*/
|
||||
wait_event_interruptible(random_write_wait,
|
||||
kthread_should_stop() ||
|
||||
ENTROPY_BITS(&input_pool) <= random_write_wakeup_bits);
|
||||
if (!crng_ready()) {
|
||||
crng_fast_load(buffer, count);
|
||||
return;
|
||||
}
|
||||
|
||||
/* Suspend writing if we're above the trickle threshold.
|
||||
* We'll be woken up again once below random_write_wakeup_thresh,
|
||||
* or when the calling thread is about to terminate.
|
||||
*/
|
||||
wait_event_interruptible(random_write_wait, kthread_should_stop() ||
|
||||
ENTROPY_BITS(&input_pool) <= random_write_wakeup_bits);
|
||||
mix_pool_bytes(poolp, buffer, count);
|
||||
credit_entropy_bits(poolp, entropy);
|
||||
}
|
||||
|
|
|
|||
|
|
@ -16,6 +16,7 @@ struct chacha20_ctx {
|
|||
u32 key[8];
|
||||
};
|
||||
|
||||
void chacha20_block(u32 *state, void *stream);
|
||||
void crypto_chacha20_init(u32 *state, struct chacha20_ctx *ctx, u8 *iv);
|
||||
int crypto_chacha20_setkey(struct crypto_tfm *tfm, const u8 *key,
|
||||
unsigned int keysize);
|
||||
|
|
|
|||
|
|
@ -22,7 +22,7 @@ KCOV_INSTRUMENT_hweight.o := n
|
|||
lib-y := ctype.o string.o vsprintf.o cmdline.o \
|
||||
rbtree.o radix-tree.o dump_stack.o timerqueue.o\
|
||||
idr.o int_sqrt.o extable.o \
|
||||
sha1.o md5.o irq_regs.o argv_split.o \
|
||||
sha1.o chacha20.o md5.o irq_regs.o argv_split.o \
|
||||
flex_proportions.o ratelimit.o show_mem.o \
|
||||
is_single_threaded.o plist.o decompress.o kobject_uevent.o \
|
||||
earlycpio.o seq_buf.o nmi_backtrace.o nodemask.o
|
||||
|
|
|
|||
|
|
@ -0,0 +1,79 @@
|
|||
/*
|
||||
* ChaCha20 256-bit cipher algorithm, RFC7539
|
||||
*
|
||||
* Copyright (C) 2015 Martin Willi
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
||||
* the Free Software Foundation; either version 2 of the License, or
|
||||
* (at your option) any later version.
|
||||
*/
|
||||
|
||||
#include <linux/kernel.h>
|
||||
#include <linux/export.h>
|
||||
#include <linux/bitops.h>
|
||||
#include <linux/cryptohash.h>
|
||||
#include <asm/unaligned.h>
|
||||
#include <crypto/chacha20.h>
|
||||
|
||||
static inline u32 rotl32(u32 v, u8 n)
|
||||
{
|
||||
return (v << n) | (v >> (sizeof(v) * 8 - n));
|
||||
}
|
||||
|
||||
extern void chacha20_block(u32 *state, void *stream)
|
||||
{
|
||||
u32 x[16], *out = stream;
|
||||
int i;
|
||||
|
||||
for (i = 0; i < ARRAY_SIZE(x); i++)
|
||||
x[i] = state[i];
|
||||
|
||||
for (i = 0; i < 20; i += 2) {
|
||||
x[0] += x[4]; x[12] = rotl32(x[12] ^ x[0], 16);
|
||||
x[1] += x[5]; x[13] = rotl32(x[13] ^ x[1], 16);
|
||||
x[2] += x[6]; x[14] = rotl32(x[14] ^ x[2], 16);
|
||||
x[3] += x[7]; x[15] = rotl32(x[15] ^ x[3], 16);
|
||||
|
||||
x[8] += x[12]; x[4] = rotl32(x[4] ^ x[8], 12);
|
||||
x[9] += x[13]; x[5] = rotl32(x[5] ^ x[9], 12);
|
||||
x[10] += x[14]; x[6] = rotl32(x[6] ^ x[10], 12);
|
||||
x[11] += x[15]; x[7] = rotl32(x[7] ^ x[11], 12);
|
||||
|
||||
x[0] += x[4]; x[12] = rotl32(x[12] ^ x[0], 8);
|
||||
x[1] += x[5]; x[13] = rotl32(x[13] ^ x[1], 8);
|
||||
x[2] += x[6]; x[14] = rotl32(x[14] ^ x[2], 8);
|
||||
x[3] += x[7]; x[15] = rotl32(x[15] ^ x[3], 8);
|
||||
|
||||
x[8] += x[12]; x[4] = rotl32(x[4] ^ x[8], 7);
|
||||
x[9] += x[13]; x[5] = rotl32(x[5] ^ x[9], 7);
|
||||
x[10] += x[14]; x[6] = rotl32(x[6] ^ x[10], 7);
|
||||
x[11] += x[15]; x[7] = rotl32(x[7] ^ x[11], 7);
|
||||
|
||||
x[0] += x[5]; x[15] = rotl32(x[15] ^ x[0], 16);
|
||||
x[1] += x[6]; x[12] = rotl32(x[12] ^ x[1], 16);
|
||||
x[2] += x[7]; x[13] = rotl32(x[13] ^ x[2], 16);
|
||||
x[3] += x[4]; x[14] = rotl32(x[14] ^ x[3], 16);
|
||||
|
||||
x[10] += x[15]; x[5] = rotl32(x[5] ^ x[10], 12);
|
||||
x[11] += x[12]; x[6] = rotl32(x[6] ^ x[11], 12);
|
||||
x[8] += x[13]; x[7] = rotl32(x[7] ^ x[8], 12);
|
||||
x[9] += x[14]; x[4] = rotl32(x[4] ^ x[9], 12);
|
||||
|
||||
x[0] += x[5]; x[15] = rotl32(x[15] ^ x[0], 8);
|
||||
x[1] += x[6]; x[12] = rotl32(x[12] ^ x[1], 8);
|
||||
x[2] += x[7]; x[13] = rotl32(x[13] ^ x[2], 8);
|
||||
x[3] += x[4]; x[14] = rotl32(x[14] ^ x[3], 8);
|
||||
|
||||
x[10] += x[15]; x[5] = rotl32(x[5] ^ x[10], 7);
|
||||
x[11] += x[12]; x[6] = rotl32(x[6] ^ x[11], 7);
|
||||
x[8] += x[13]; x[7] = rotl32(x[7] ^ x[8], 7);
|
||||
x[9] += x[14]; x[4] = rotl32(x[4] ^ x[9], 7);
|
||||
}
|
||||
|
||||
for (i = 0; i < ARRAY_SIZE(x); i++)
|
||||
out[i] = cpu_to_le32(x[i] + state[i]);
|
||||
|
||||
state[12]++;
|
||||
}
|
||||
EXPORT_SYMBOL(chacha20_block);
|
||||
Loading…
Reference in New Issue