From: "Jason A. Donenfeld" Jason@zx2c4.com
commit 6c0eace6e1499712583b6ee62d95161e8b3449f5 upstream.
This gets rid of another abstraction we no longer need. It would be nice if we could instead make pool an array rather than a pointer, but the latent entropy plugin won't be able to do its magic in that case. So instead we put all accesses to the input pool's actual data through the input_pool_data array directly.
Reviewed-by: Dominik Brodowski linux@dominikbrodowski.net Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/char/random.c | 222 +++++++++++++++++++++++--------------------------- 1 file changed, 103 insertions(+), 119 deletions(-)
--- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -124,7 +124,7 @@ * * The primary kernel interface is * - * void get_random_bytes(void *buf, int nbytes); + * void get_random_bytes(void *buf, int nbytes); * * This interface will return the requested number of random bytes, * and place it in the requested buffer. This is equivalent to a @@ -132,10 +132,10 @@ * * For less critical applications, there are the functions: * - * u32 get_random_u32() - * u64 get_random_u64() - * unsigned int get_random_int() - * unsigned long get_random_long() + * u32 get_random_u32() + * u64 get_random_u64() + * unsigned int get_random_int() + * unsigned long get_random_long() * * These are produced by a cryptographic RNG seeded from get_random_bytes, * and so do not deplete the entropy pool as much. These are recommended @@ -197,10 +197,10 @@ * from the devices are: * * void add_device_randomness(const void *buf, unsigned int size); - * void add_input_randomness(unsigned int type, unsigned int code, + * void add_input_randomness(unsigned int type, unsigned int code, * unsigned int value); * void add_interrupt_randomness(int irq); - * void add_disk_randomness(struct gendisk *disk); + * void add_disk_randomness(struct gendisk *disk); * void add_hwgenerator_randomness(const char *buffer, size_t count, * size_t entropy); * void add_bootloader_randomness(const void *buf, unsigned int size); @@ -296,8 +296,8 @@ * /dev/random and /dev/urandom created already, they can be created * by using the commands: * - * mknod /dev/random c 1 8 - * mknod /dev/urandom c 1 9 + * mknod /dev/random c 1 8 + * mknod /dev/urandom c 1 9 * * Acknowledgements: * ================= @@ -443,9 +443,9 @@ static DEFINE_SPINLOCK(random_ready_list static LIST_HEAD(random_ready_list);
struct crng_state { - u32 state[16]; - unsigned long init_time; - spinlock_t lock; + u32 state[16]; + unsigned long init_time; + spinlock_t lock; };
static struct crng_state primary_crng = { @@ -469,7 +469,7 @@ static bool crng_need_final_init = false #define crng_ready() (likely(crng_init > 1)) static int crng_init_cnt = 0; static unsigned long crng_global_init_time = 0; -#define CRNG_INIT_CNT_THRESH (2*CHACHA20_KEY_SIZE) +#define CRNG_INIT_CNT_THRESH (2 * CHACHA20_KEY_SIZE) static void _extract_crng(struct crng_state *crng, u8 out[CHACHA20_BLOCK_SIZE]); static void _crng_backtrack_protect(struct crng_state *crng, u8 tmp[CHACHA20_BLOCK_SIZE], int used); @@ -496,17 +496,12 @@ MODULE_PARM_DESC(ratelimit_disable, "Dis static u32 input_pool_data[POOL_WORDS] __latent_entropy;
static struct { - /* read-only data: */ - u32 *pool; - - /* read-write data: */ spinlock_t lock; u16 add_ptr; u16 input_rotate; int entropy_count; } input_pool = { .lock = __SPIN_LOCK_UNLOCKED(input_pool.lock), - .pool = input_pool_data };
static ssize_t extract_entropy(void *buf, size_t nbytes, int min); @@ -514,7 +509,7 @@ static ssize_t _extract_entropy(void *bu
static void crng_reseed(struct crng_state *crng, bool use_input_pool);
-static u32 const twist_table[8] = { +static const u32 twist_table[8] = { 0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158, 0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 };
@@ -544,15 +539,15 @@ static void _mix_pool_bytes(const void * i = (i - 1) & POOL_WORDMASK;
/* XOR in the various taps */ - w ^= input_pool.pool[i]; - w ^= input_pool.pool[(i + POOL_TAP1) & POOL_WORDMASK]; - w ^= input_pool.pool[(i + POOL_TAP2) & POOL_WORDMASK]; - w ^= input_pool.pool[(i + POOL_TAP3) & POOL_WORDMASK]; - w ^= input_pool.pool[(i + POOL_TAP4) & POOL_WORDMASK]; - w ^= input_pool.pool[(i + POOL_TAP5) & POOL_WORDMASK]; + w ^= input_pool_data[i]; + w ^= input_pool_data[(i + POOL_TAP1) & POOL_WORDMASK]; + w ^= input_pool_data[(i + POOL_TAP2) & POOL_WORDMASK]; + w ^= input_pool_data[(i + POOL_TAP3) & POOL_WORDMASK]; + w ^= input_pool_data[(i + POOL_TAP4) & POOL_WORDMASK]; + w ^= input_pool_data[(i + POOL_TAP5) & POOL_WORDMASK];
/* Mix the result back in with a twist */ - input_pool.pool[i] = (w >> 3) ^ twist_table[w & 7]; + input_pool_data[i] = (w >> 3) ^ twist_table[w & 7];
/* * Normally, we add 7 bits of rotation to the pool. @@ -584,10 +579,10 @@ static void mix_pool_bytes(const void *i }
struct fast_pool { - u32 pool[4]; - unsigned long last; - u16 reg_idx; - u8 count; + u32 pool[4]; + unsigned long last; + u16 reg_idx; + u8 count; };
/* @@ -715,7 +710,7 @@ static int credit_entropy_bits_safe(int return -EINVAL;
/* Cap the value to avoid overflows */ - nbits = min(nbits, POOL_BITS); + nbits = min(nbits, POOL_BITS);
credit_entropy_bits(nbits); return 0; @@ -727,7 +722,7 @@ static int credit_entropy_bits_safe(int * *********************************************************************/
-#define CRNG_RESEED_INTERVAL (300*HZ) +#define CRNG_RESEED_INTERVAL (300 * HZ)
static DECLARE_WAIT_QUEUE_HEAD(crng_init_wait);
@@ -750,9 +745,9 @@ early_param("random.trust_cpu", parse_tr
static bool crng_init_try_arch(struct crng_state *crng) { - int i; - bool arch_init = true; - unsigned long rv; + int i; + bool arch_init = true; + unsigned long rv;
for (i = 4; i < 16; i++) { if (!arch_get_random_seed_long(&rv) && @@ -768,9 +763,9 @@ static bool crng_init_try_arch(struct cr
static bool __init crng_init_try_arch_early(struct crng_state *crng) { - int i; - bool arch_init = true; - unsigned long rv; + int i; + bool arch_init = true; + unsigned long rv;
for (i = 4; i < 16; i++) { if (!arch_get_random_seed_long_early(&rv) && @@ -840,7 +835,7 @@ static void do_numa_crng_init(struct wor struct crng_state *crng; struct crng_state **pool;
- pool = kcalloc(nr_node_ids, sizeof(*pool), GFP_KERNEL|__GFP_NOFAIL); + pool = kcalloc(nr_node_ids, sizeof(*pool), GFP_KERNEL | __GFP_NOFAIL); for_each_online_node(i) { crng = kmalloc_node(sizeof(struct crng_state), GFP_KERNEL | __GFP_NOFAIL, i); @@ -896,7 +891,7 @@ static size_t crng_fast_load(const u8 *c spin_unlock_irqrestore(&primary_crng.lock, flags); return 0; } - p = (u8 *) &primary_crng.state[4]; + p = (u8 *)&primary_crng.state[4]; while (len > 0 && crng_init_cnt < CRNG_INIT_CNT_THRESH) { p[crng_init_cnt % CHACHA20_KEY_SIZE] ^= *cp; cp++; crng_init_cnt++; len--; ret++; @@ -926,12 +921,12 @@ static size_t crng_fast_load(const u8 *c */ static int crng_slow_load(const u8 *cp, size_t len) { - unsigned long flags; - static u8 lfsr = 1; - u8 tmp; - unsigned int i, max = CHACHA20_KEY_SIZE; - const u8 * src_buf = cp; - u8 * dest_buf = (u8 *) &primary_crng.state[4]; + unsigned long flags; + static u8 lfsr = 1; + u8 tmp; + unsigned int i, max = CHACHA20_KEY_SIZE; + const u8 *src_buf = cp; + u8 *dest_buf = (u8 *)&primary_crng.state[4];
if (!spin_trylock_irqsave(&primary_crng.lock, flags)) return 0; @@ -942,7 +937,7 @@ static int crng_slow_load(const u8 *cp, if (len > max) max = len;
- for (i = 0; i < max ; i++) { + for (i = 0; i < max; i++) { tmp = lfsr; lfsr >>= 1; if (tmp & 1) @@ -957,11 +952,11 @@ static int crng_slow_load(const u8 *cp,
static void crng_reseed(struct crng_state *crng, bool use_input_pool) { - unsigned long flags; - int i, num; + unsigned long flags; + int i, num; union { - u8 block[CHACHA20_BLOCK_SIZE]; - u32 key[8]; + u8 block[CHACHA20_BLOCK_SIZE]; + u32 key[8]; } buf;
if (use_input_pool) { @@ -975,11 +970,11 @@ static void crng_reseed(struct crng_stat } spin_lock_irqsave(&crng->lock, flags); for (i = 0; i < 8; i++) { - unsigned long rv; + 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; + crng->state[i + 4] ^= buf.key[i] ^ rv; } memzero_explicit(&buf, sizeof(buf)); WRITE_ONCE(crng->init_time, jiffies); @@ -987,8 +982,7 @@ static void crng_reseed(struct crng_stat crng_finalize_init(crng); }
-static void _extract_crng(struct crng_state *crng, - u8 out[CHACHA20_BLOCK_SIZE]) +static void _extract_crng(struct crng_state *crng, u8 out[CHACHA20_BLOCK_SIZE]) { unsigned long flags, init_time;
@@ -1017,9 +1011,9 @@ static void extract_crng(u8 out[CHACHA20 static void _crng_backtrack_protect(struct crng_state *crng, u8 tmp[CHACHA20_BLOCK_SIZE], int used) { - unsigned long flags; - u32 *s, *d; - int i; + unsigned long flags; + u32 *s, *d; + int i;
used = round_up(used, sizeof(u32)); if (used + CHACHA20_KEY_SIZE > CHACHA20_BLOCK_SIZE) { @@ -1027,9 +1021,9 @@ static void _crng_backtrack_protect(stru used = 0; } spin_lock_irqsave(&crng->lock, flags); - s = (u32 *) &tmp[used]; + s = (u32 *)&tmp[used]; d = &crng->state[4]; - for (i=0; i < 8; i++) + for (i = 0; i < 8; i++) *d++ ^= *s++; spin_unlock_irqrestore(&crng->lock, flags); } @@ -1074,7 +1068,6 @@ static ssize_t extract_crng_user(void __ return ret; }
- /********************************************************************* * * Entropy input management @@ -1169,11 +1162,11 @@ static void add_timer_randomness(struct * Round down by 1 bit on general principles, * and limit entropy estimate to 12 bits. */ - credit_entropy_bits(min_t(int, fls(delta>>1), 11)); + credit_entropy_bits(min_t(int, fls(delta >> 1), 11)); }
void add_input_randomness(unsigned int type, unsigned int code, - unsigned int value) + unsigned int value) { static unsigned char last_value;
@@ -1193,19 +1186,19 @@ static DEFINE_PER_CPU(struct fast_pool, #ifdef ADD_INTERRUPT_BENCH static unsigned long avg_cycles, avg_deviation;
-#define AVG_SHIFT 8 /* Exponential average factor k=1/256 */ -#define FIXED_1_2 (1 << (AVG_SHIFT-1)) +#define AVG_SHIFT 8 /* Exponential average factor k=1/256 */ +#define FIXED_1_2 (1 << (AVG_SHIFT - 1))
static void add_interrupt_bench(cycles_t start) { - long delta = random_get_entropy() - start; + long delta = random_get_entropy() - start;
- /* Use a weighted moving average */ - delta = delta - ((avg_cycles + FIXED_1_2) >> AVG_SHIFT); - avg_cycles += delta; - /* And average deviation */ - delta = abs(delta) - ((avg_deviation + FIXED_1_2) >> AVG_SHIFT); - avg_deviation += delta; + /* Use a weighted moving average */ + delta = delta - ((avg_cycles + FIXED_1_2) >> AVG_SHIFT); + avg_cycles += delta; + /* And average deviation */ + delta = abs(delta) - ((avg_deviation + FIXED_1_2) >> AVG_SHIFT); + avg_deviation += delta; } #else #define add_interrupt_bench(x) @@ -1213,7 +1206,7 @@ static void add_interrupt_bench(cycles_t
static u32 get_reg(struct fast_pool *f, struct pt_regs *regs) { - u32 *ptr = (u32 *) regs; + u32 *ptr = (u32 *)regs; unsigned int idx;
if (regs == NULL) @@ -1228,12 +1221,12 @@ static u32 get_reg(struct fast_pool *f,
void add_interrupt_randomness(int irq) { - struct fast_pool *fast_pool = this_cpu_ptr(&irq_randomness); - struct pt_regs *regs = get_irq_regs(); - unsigned long now = jiffies; - cycles_t cycles = random_get_entropy(); - u32 c_high, j_high; - u64 ip; + struct fast_pool *fast_pool = this_cpu_ptr(&irq_randomness); + struct pt_regs *regs = get_irq_regs(); + unsigned long now = jiffies; + cycles_t cycles = random_get_entropy(); + u32 c_high, j_high; + u64 ip;
if (cycles == 0) cycles = get_reg(fast_pool, regs); @@ -1243,8 +1236,8 @@ void add_interrupt_randomness(int irq) fast_pool->pool[1] ^= now ^ c_high; ip = regs ? instruction_pointer(regs) : _RET_IP_; fast_pool->pool[2] ^= ip; - fast_pool->pool[3] ^= (sizeof(ip) > 4) ? ip >> 32 : - get_reg(fast_pool, regs); + fast_pool->pool[3] ^= + (sizeof(ip) > 4) ? ip >> 32 : get_reg(fast_pool, regs);
fast_mix(fast_pool); add_interrupt_bench(cycles); @@ -1258,8 +1251,7 @@ void add_interrupt_randomness(int irq) return; }
- if ((fast_pool->count < 64) && - !time_after(now, fast_pool->last + HZ)) + if ((fast_pool->count < 64) && !time_after(now, fast_pool->last + HZ)) return;
if (!spin_trylock(&input_pool.lock)) @@ -1323,7 +1315,7 @@ retry: entropy_count = 0; } nfrac = ibytes << (POOL_ENTROPY_SHIFT + 3); - if ((size_t) entropy_count > nfrac) + if ((size_t)entropy_count > nfrac) entropy_count -= nfrac; else entropy_count = 0; @@ -1368,7 +1360,7 @@ static void extract_buf(u8 *out)
/* Generate a hash across the pool */ spin_lock_irqsave(&input_pool.lock, flags); - blake2s_update(&state, (const u8 *)input_pool.pool, POOL_BYTES); + blake2s_update(&state, (const u8 *)input_pool_data, POOL_BYTES); blake2s_final(&state, hash); /* final zeros out state */
/* @@ -1426,10 +1418,9 @@ static ssize_t extract_entropy(void *buf }
#define warn_unseeded_randomness(previous) \ - _warn_unseeded_randomness(__func__, (void *) _RET_IP_, (previous)) + _warn_unseeded_randomness(__func__, (void *)_RET_IP_, (previous))
-static void _warn_unseeded_randomness(const char *func_name, void *caller, - void **previous) +static void _warn_unseeded_randomness(const char *func_name, void *caller, void **previous) { #ifdef CONFIG_WARN_ALL_UNSEEDED_RANDOM const bool print_once = false; @@ -1437,8 +1428,7 @@ static void _warn_unseeded_randomness(co static bool print_once __read_mostly; #endif
- if (print_once || - crng_ready() || + if (print_once || crng_ready() || (previous && (caller == READ_ONCE(*previous)))) return; WRITE_ONCE(*previous, caller); @@ -1446,9 +1436,8 @@ static void _warn_unseeded_randomness(co print_once = true; #endif if (__ratelimit(&unseeded_warning)) - printk_deferred(KERN_NOTICE "random: %s called from %pS " - "with crng_init=%d\n", func_name, caller, - crng_init); + printk_deferred(KERN_NOTICE "random: %s called from %pS with crng_init=%d\n", + func_name, caller, crng_init); }
/* @@ -1491,7 +1480,6 @@ void get_random_bytes(void *buf, int nby } EXPORT_SYMBOL(get_random_bytes);
- /* * Each time the timer fires, we expect that we got an unpredictable * jump in the cycle counter. Even if the timer is running on another @@ -1530,7 +1518,7 @@ static void try_to_generate_entropy(void __setup_timer_on_stack(&stack.timer, entropy_timer, 0, 0); while (!crng_ready()) { if (!timer_pending(&stack.timer)) - mod_timer(&stack.timer, jiffies+1); + mod_timer(&stack.timer, jiffies + 1); mix_pool_bytes(&stack.now, sizeof(stack.now)); schedule(); stack.now = random_get_entropy(); @@ -1740,9 +1728,8 @@ void rand_initialize_disk(struct gendisk } #endif
-static ssize_t -urandom_read_nowarn(struct file *file, char __user *buf, size_t nbytes, - loff_t *ppos) +static ssize_t urandom_read_nowarn(struct file *file, char __user *buf, + size_t nbytes, loff_t *ppos) { int ret;
@@ -1752,8 +1739,8 @@ urandom_read_nowarn(struct file *file, c return ret; }
-static ssize_t -urandom_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) { static int maxwarn = 10;
@@ -1767,8 +1754,8 @@ urandom_read(struct file *file, char __u return urandom_read_nowarn(file, buf, nbytes, ppos); }
-static ssize_t -random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) +static ssize_t random_read(struct file *file, char __user *buf, size_t nbytes, + loff_t *ppos) { int ret;
@@ -1778,8 +1765,7 @@ random_read(struct file *file, char __us return urandom_read_nowarn(file, buf, nbytes, ppos); }
-static unsigned int -random_poll(struct file *file, poll_table * wait) +static unsigned int random_poll(struct file *file, poll_table *wait) { unsigned int mask;
@@ -1793,8 +1779,7 @@ random_poll(struct file *file, poll_tabl return mask; }
-static int -write_pool(const char __user *buffer, size_t count) +static int write_pool(const char __user *buffer, size_t count) { size_t bytes; u32 t, buf[16]; @@ -1896,35 +1881,35 @@ static int random_fasync(int fd, struct }
const struct file_operations random_fops = { - .read = random_read, + .read = random_read, .write = random_write, - .poll = random_poll, + .poll = random_poll, .unlocked_ioctl = random_ioctl, .fasync = random_fasync, .llseek = noop_llseek, };
const struct file_operations urandom_fops = { - .read = urandom_read, + .read = urandom_read, .write = random_write, .unlocked_ioctl = random_ioctl, .fasync = random_fasync, .llseek = noop_llseek, };
-SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count, - unsigned int, flags) +SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count, unsigned int, + flags) { int ret;
- if (flags & ~(GRND_NONBLOCK|GRND_RANDOM|GRND_INSECURE)) + if (flags & ~(GRND_NONBLOCK | GRND_RANDOM | GRND_INSECURE)) return -EINVAL;
/* * Requesting insecure and blocking randomness at the same time makes * no sense. */ - if ((flags & (GRND_INSECURE|GRND_RANDOM)) == (GRND_INSECURE|GRND_RANDOM)) + if ((flags & (GRND_INSECURE | GRND_RANDOM)) == (GRND_INSECURE | GRND_RANDOM)) return -EINVAL;
if (count > INT_MAX) @@ -2072,7 +2057,7 @@ struct ctl_table random_table[] = { #endif { } }; -#endif /* CONFIG_SYSCTL */ +#endif /* CONFIG_SYSCTL */
struct batched_entropy { union { @@ -2092,7 +2077,7 @@ struct batched_entropy { * point prior. */ static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u64) = { - .batch_lock = __SPIN_LOCK_UNLOCKED(batched_entropy_u64.lock), + .batch_lock = __SPIN_LOCK_UNLOCKED(batched_entropy_u64.lock), };
u64 get_random_u64(void) @@ -2117,7 +2102,7 @@ u64 get_random_u64(void) EXPORT_SYMBOL(get_random_u64);
static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u32) = { - .batch_lock = __SPIN_LOCK_UNLOCKED(batched_entropy_u32.lock), + .batch_lock = __SPIN_LOCK_UNLOCKED(batched_entropy_u32.lock), }; u32 get_random_u32(void) { @@ -2149,7 +2134,7 @@ static void invalidate_batched_entropy(v int cpu; unsigned long flags;
- for_each_possible_cpu (cpu) { + for_each_possible_cpu(cpu) { struct batched_entropy *batched_entropy;
batched_entropy = per_cpu_ptr(&batched_entropy_u32, cpu); @@ -2178,8 +2163,7 @@ static void invalidate_batched_entropy(v * Return: A page aligned address within [start, start + range). On error, * @start is returned. */ -unsigned long -randomize_page(unsigned long start, unsigned long range) +unsigned long randomize_page(unsigned long start, unsigned long range) { if (!PAGE_ALIGNED(start)) { range -= PAGE_ALIGN(start) - start;