From patchwork Mon Jun 13 15:48:37 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Theodore Ts'o X-Patchwork-Id: 9173491 X-Patchwork-Delegate: herbert@gondor.apana.org.au Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 76DB06075D for ; Mon, 13 Jun 2016 15:51:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 66F5A20223 for ; Mon, 13 Jun 2016 15:51:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5B5E32723E; Mon, 13 Jun 2016 15:51:04 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 02B7B20223 for ; Mon, 13 Jun 2016 15:51:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1424678AbcFMPtx (ORCPT ); Mon, 13 Jun 2016 11:49:53 -0400 Received: from imap.thunk.org ([74.207.234.97]:45076 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1424723AbcFMPt3 (ORCPT ); Mon, 13 Jun 2016 11:49:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=thunk.org; s=ef5046eb; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From; bh=aO+AokzPAp+9xfm8Pc59+zWlr1GuWpsQxte9302UMf8=; b=klRWm6H8/GdWnxo8Hk7lVs4ZmOxtJ/tx/2jHSPeD4B4yDiqi12n6ButPlvezlbHcYMQKF2Q0eGvjay1y4nZi0PYgOczOedh4M/oMNHVKQQrqHV/+htRGvYjt77YBzCFzRzZK47ijOXZ0zwgyr4pkMcziRmfd+Y8XivJo35naFxM=; Received: from root (helo=closure.thunk.org) by imap.thunk.org with local-esmtp (Exim 4.84_2) (envelope-from ) id 1bCU73-0005b4-Kr; Mon, 13 Jun 2016 15:49:17 +0000 Received: by closure.thunk.org (Postfix, from userid 15806) id 1CC7582F5CB; Mon, 13 Jun 2016 11:49:16 -0400 (EDT) From: Theodore Ts'o To: Linux Kernel Developers List Cc: linux-crypto@vger.kernel.org, smueller@chronox.de, herbert@gondor.apana.org.au, andi@firstfloor.org, sandyinchina@gmail.com, jsd@av8n.com, hpa@zytor.com, Theodore Ts'o Subject: [PATCH 5/7] random: replace non-blocking pool with a Chacha20-based CRNG Date: Mon, 13 Jun 2016 11:48:37 -0400 Message-Id: <1465832919-11316-6-git-send-email-tytso@mit.edu> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1465832919-11316-1-git-send-email-tytso@mit.edu> References: <1465832919-11316-1-git-send-email-tytso@mit.edu> X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The CRNG is faster, and we don't pretend to track entropy usage in the CRNG any more. Signed-off-by: Theodore Ts'o --- crypto/chacha20_generic.c | 61 -------- drivers/char/random.c | 374 +++++++++++++++++++++++++++++++++------------- include/crypto/chacha20.h | 1 + lib/Makefile | 2 +- lib/chacha20.c | 79 ++++++++++ 5 files changed, 353 insertions(+), 164 deletions(-) create mode 100644 lib/chacha20.c diff --git a/crypto/chacha20_generic.c b/crypto/chacha20_generic.c index da9c899..1cab831 100644 --- a/crypto/chacha20_generic.c +++ b/crypto/chacha20_generic.c @@ -15,72 +15,11 @@ #include #include -static inline u32 rotl32(u32 v, u8 n) -{ - return (v << n) | (v >> (sizeof(v) * 8 - n)); -} - static inline u32 le32_to_cpuvp(const void *p) { return le32_to_cpup(p); } -static 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]++; -} - static void chacha20_docrypt(u32 *state, u8 *dst, const u8 *src, unsigned int bytes) { diff --git a/drivers/char/random.c b/drivers/char/random.c index 83f5cd0..841f9a8 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -261,6 +261,7 @@ #include #include #include +#include #include #include @@ -413,6 +414,29 @@ static struct fasync_struct *fasync; static DEFINE_SPINLOCK(random_ready_list_lock); static LIST_HEAD(random_ready_list); +struct crng_state { + __u32 state[16]; + unsigned long init_time; + spinlock_t lock; +}; + +struct crng_state primary_crng = { + .lock = __SPIN_LOCK_UNLOCKED(primary_crng.lock), +}; + +/* + * crng_init = 0 --> Uninitialized + * 1 --> Initialized + * 2 --> Initialized from input_pool + * + * crng_init is protected by primary_crng->lock, and only increases + * its value (from 0->1->2). + */ +static int crng_init = 0; +#define crng_ready() (likely(crng_init > 0)) +static void extract_crng(__u8 out[CHACHA20_BLOCK_SIZE]); +static void process_random_ready_list(void); + /********************************************************************** * * OS independent entropy store. Here are the functions which handle @@ -442,10 +466,15 @@ struct entropy_store { __u8 last_data[EXTRACT_SIZE]; }; +static ssize_t extract_entropy(struct entropy_store *r, void *buf, + size_t nbytes, int min, int rsvd); +static ssize_t _extract_entropy(struct entropy_store *r, void *buf, + size_t nbytes, int fips); + +static void crng_reseed(struct crng_state *crng, struct entropy_store *r); static void push_to_pool(struct work_struct *work); static __u32 input_pool_data[INPUT_POOL_WORDS]; static __u32 blocking_pool_data[OUTPUT_POOL_WORDS]; -static __u32 nonblocking_pool_data[OUTPUT_POOL_WORDS]; static struct entropy_store input_pool = { .poolinfo = &poolinfo_table[0], @@ -466,16 +495,6 @@ static struct entropy_store blocking_pool = { push_to_pool), }; -static struct entropy_store nonblocking_pool = { - .poolinfo = &poolinfo_table[1], - .name = "nonblocking", - .pull = &input_pool, - .lock = __SPIN_LOCK_UNLOCKED(nonblocking_pool.lock), - .pool = nonblocking_pool_data, - .push_work = __WORK_INITIALIZER(nonblocking_pool.push_work, - push_to_pool), -}; - static __u32 const twist_table[8] = { 0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158, 0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 }; @@ -678,12 +697,6 @@ retry: if (!r->initialized && r->entropy_total > 128) { r->initialized = 1; r->entropy_total = 0; - if (r == &nonblocking_pool) { - prandom_reseed_late(); - process_random_ready_list(); - wake_up_all(&urandom_init_wait); - pr_notice("random: %s pool is initialized\n", r->name); - } } trace_credit_entropy_bits(r->name, nbits, @@ -693,30 +706,27 @@ retry: if (r == &input_pool) { int entropy_bits = entropy_count >> ENTROPY_SHIFT; + if (crng_init < 2 && entropy_bits >= 128) { + crng_reseed(&primary_crng, r); + entropy_bits = r->entropy_count >> ENTROPY_SHIFT; + } + /* should we wake readers? */ if (entropy_bits >= random_read_wakeup_bits) { wake_up_interruptible(&random_read_wait); kill_fasync(&fasync, SIGIO, POLL_IN); } /* If the input pool is getting full, send some - * entropy to the two output pools, flipping back and - * forth between them, until the output pools are 75% - * full. + * entropy to the blocking pool until it is 75% full. */ if (entropy_bits > random_write_wakeup_bits && r->initialized && r->entropy_total >= 2*random_read_wakeup_bits) { - static struct entropy_store *last = &blocking_pool; struct entropy_store *other = &blocking_pool; - if (last == &blocking_pool) - other = &nonblocking_pool; if (other->entropy_count <= - 3 * other->poolinfo->poolfracbits / 4) - last = other; - if (last->entropy_count <= - 3 * last->poolinfo->poolfracbits / 4) { - schedule_work(&last->push_work); + 3 * other->poolinfo->poolfracbits / 4) { + schedule_work(&other->push_work); r->entropy_total = 0; } } @@ -736,6 +746,154 @@ static void credit_entropy_bits_safe(struct entropy_store *r, int nbits) /********************************************************************* * + * CRNG using CHACHA20 + * + *********************************************************************/ + +#define CRNG_RESEED_INTERVAL (300*HZ) + +static DECLARE_WAIT_QUEUE_HEAD(crng_init_wait); + +static void crng_initialize(struct crng_state *crng) +{ + int i; + unsigned long rv; + + memcpy(&crng->state[0], "expand 32-byte k", 16); + if (crng == &primary_crng) + _extract_entropy(&input_pool, &crng->state[4], + sizeof(__u32) * 12, 0); + else + get_random_bytes(&crng->state[4], sizeof(__u32) * 12); + for (i = 4; i < 16; i++) { + if (!arch_get_random_seed_long(&rv) && + !arch_get_random_long(&rv)) + rv = random_get_entropy(); + crng->state[i] ^= rv; + } + crng->init_time = jiffies - CRNG_RESEED_INTERVAL - 1; +} + +static int crng_fast_load(const char *cp, size_t len) +{ + unsigned long flags; + static size_t c = 0; + char *p; + + if (!spin_trylock_irqsave(&primary_crng.lock, flags)) + return 0; + if (crng_ready()) { + spin_unlock_irqrestore(&primary_crng.lock, flags); + return 0; + } + p = (unsigned char *) &primary_crng.state[4]; + p += c; + while (len > 0 && c < CHACHA20_KEY_SIZE) { + *p ^= *cp; + p++; cp++; c++; len--; + } + if (c >= CHACHA20_KEY_SIZE) { + crng_init = 1; + wake_up_interruptible(&crng_init_wait); + pr_notice("random: fast init done\n"); + } + spin_unlock_irqrestore(&primary_crng.lock, flags); + return 1; +} + +static void crng_reseed(struct crng_state *crng, struct entropy_store *r) +{ + unsigned long flags; + int i, num; + union { + __u8 block[CHACHA20_BLOCK_SIZE]; + __u32 key[8]; + } buf; + + if (r) { + num = extract_entropy(r, &buf, 32, 16, 0); + if (num == 0) + return; + } else + extract_crng(buf.block); + spin_lock_irqsave(&primary_crng.lock, flags); + for (i = 0; i < 8; i++) { + unsigned long rv; + if (!arch_get_random_seed_long(&rv) && + !arch_get_random_long(&rv)) + rv = random_get_entropy(); + crng->state[i+4] ^= buf.key[i] ^ rv; + } + memzero_explicit(&buf, sizeof(buf)); + crng->init_time = jiffies; + if (crng == &primary_crng && crng_init < 2) { + crng_init = 2; + process_random_ready_list(); + wake_up_interruptible(&crng_init_wait); + pr_notice("random: crng init done\n"); + } + spin_unlock_irqrestore(&primary_crng.lock, flags); +} + +static inline void crng_wait_ready(void) +{ + wait_event_interruptible(crng_init_wait, crng_ready()); +} + +static void extract_crng(__u8 out[CHACHA20_BLOCK_SIZE]) +{ + unsigned long v, flags; + struct crng_state *crng = &primary_crng; + + if (crng_init > 1 && + time_after(jiffies, crng->init_time + CRNG_RESEED_INTERVAL)) + crng_reseed(crng, &input_pool); + spin_lock_irqsave(&crng->lock, flags); + if (arch_get_random_long(&v)) + crng->state[14] ^= v; + chacha20_block(&crng->state[0], out); + if (crng->state[12] == 0) + crng->state[13]++; + spin_unlock_irqrestore(&crng->lock, flags); +} + +static ssize_t extract_crng_user(void __user *buf, size_t nbytes) +{ + ssize_t ret = 0, i; + __u8 tmp[CHACHA20_BLOCK_SIZE]; + int large_request = (nbytes > 256); + + while (nbytes) { + if (large_request && need_resched()) { + if (signal_pending(current)) { + if (ret == 0) + ret = -ERESTARTSYS; + break; + } + schedule(); + } + + extract_crng(tmp); + i = min_t(int, nbytes, CHACHA20_BLOCK_SIZE); + if (copy_to_user(buf, tmp, i)) { + ret = -EFAULT; + break; + } + + nbytes -= i; + buf += i; + ret += i; + } + + /* Wipe data just written to memory */ + memzero_explicit(tmp, sizeof(tmp)); + + return ret; +} + + +/********************************************************************* + * * Entropy input management * *********************************************************************/ @@ -750,12 +908,12 @@ struct timer_rand_state { #define INIT_TIMER_RAND_STATE { INITIAL_JIFFIES, }; /* - * Add device- or boot-specific data to the input and nonblocking - * pools to help initialize them to unique values. + * Add device- or boot-specific data to the input pool to help + * initialize it. * - * None of this adds any entropy, it is meant to avoid the - * problem of the nonblocking pool having similar initial state - * across largely identical devices. + * None of this adds any entropy; it is meant to avoid the problem of + * the entropy pool having similar initial state across largely + * identical devices. */ void add_device_randomness(const void *buf, unsigned int size) { @@ -767,11 +925,6 @@ void add_device_randomness(const void *buf, unsigned int size) _mix_pool_bytes(&input_pool, buf, size); _mix_pool_bytes(&input_pool, &time, sizeof(time)); spin_unlock_irqrestore(&input_pool.lock, flags); - - spin_lock_irqsave(&nonblocking_pool.lock, flags); - _mix_pool_bytes(&nonblocking_pool, buf, size); - _mix_pool_bytes(&nonblocking_pool, &time, sizeof(time)); - spin_unlock_irqrestore(&nonblocking_pool.lock, flags); } EXPORT_SYMBOL(add_device_randomness); @@ -802,7 +955,7 @@ static void add_timer_randomness(struct timer_rand_state *state, unsigned num) sample.jiffies = jiffies; sample.cycles = random_get_entropy(); sample.num = num; - r = nonblocking_pool.initialized ? &input_pool : &nonblocking_pool; + r = &input_pool; mix_pool_bytes(r, &sample, sizeof(sample)); /* @@ -918,11 +1071,21 @@ void add_interrupt_randomness(int irq, int irq_flags) fast_mix(fast_pool); add_interrupt_bench(cycles); + if (!crng_ready()) { + if ((fast_pool->count >= 64) && + crng_fast_load((char *) fast_pool->pool, + sizeof(fast_pool->pool))) { + fast_pool->count = 0; + fast_pool->last = now; + } + return; + } + if ((fast_pool->count < 64) && !time_after(now, fast_pool->last + HZ)) return; - r = nonblocking_pool.initialized ? &input_pool : &nonblocking_pool; + r = &input_pool; if (!spin_trylock(&r->lock)) return; @@ -966,9 +1129,6 @@ EXPORT_SYMBOL_GPL(add_disk_randomness); * *********************************************************************/ -static ssize_t extract_entropy(struct entropy_store *r, void *buf, - size_t nbytes, int min, int rsvd); - /* * 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); @@ -1462,19 +1642,15 @@ urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) 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 " - "(%d bytes read, %d bits of entropy available)\n", - current->comm, nbytes, nonblocking_pool.entropy_total); + "(%d bytes read)\n", + current->comm, nbytes); } - 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 +1696,7 @@ 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 +1747,6 @@ 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 +1788,10 @@ 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 +2027,17 @@ 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); } diff --git a/include/crypto/chacha20.h b/include/crypto/chacha20.h index 274bbae..20d20f68 100644 --- a/include/crypto/chacha20.h +++ b/include/crypto/chacha20.h @@ -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); diff --git a/lib/Makefile b/lib/Makefile index 499fb35..34e205f 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -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 diff --git a/lib/chacha20.c b/lib/chacha20.c new file mode 100644 index 0000000..250ceed --- /dev/null +++ b/lib/chacha20.c @@ -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 +#include +#include +#include +#include +#include + +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);