random: access input_pool_data directly rather than through pointer
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>
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 3af243b..aebc43c 100644
--- 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:
* =================
@@ -444,9 +444,9 @@
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 = {
@@ -470,7 +470,7 @@
#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);
@@ -497,17 +497,12 @@
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);
@@ -515,7 +510,7 @@
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 };
@@ -545,15 +540,15 @@
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.
@@ -585,10 +580,10 @@
}
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;
};
/*
@@ -716,7 +711,7 @@
return -EINVAL;
/* Cap the value to avoid overflows */
- nbits = min(nbits, POOL_BITS);
+ nbits = min(nbits, POOL_BITS);
credit_entropy_bits(nbits);
return 0;
@@ -728,7 +723,7 @@
*
*********************************************************************/
-#define CRNG_RESEED_INTERVAL (300*HZ)
+#define CRNG_RESEED_INTERVAL (300 * HZ)
static DECLARE_WAIT_QUEUE_HEAD(crng_init_wait);
@@ -751,9 +746,9 @@
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) &&
@@ -769,9 +764,9 @@
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) &&
@@ -841,7 +836,7 @@
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);
@@ -897,7 +892,7 @@
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++;
@@ -978,12 +973,12 @@
*/
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;
@@ -994,7 +989,7 @@
if (len > max)
max = len;
- for (i = 0; i < max ; i++) {
+ for (i = 0; i < max; i++) {
tmp = lfsr;
lfsr >>= 1;
if (tmp & 1)
@@ -1009,11 +1004,11 @@
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) {
@@ -1027,11 +1022,11 @@
}
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);
@@ -1039,8 +1034,7 @@
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;
@@ -1069,9 +1063,9 @@
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) {
@@ -1079,9 +1073,9 @@
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);
}
@@ -1126,7 +1120,6 @@
return ret;
}
-
/*********************************************************************
*
* Entropy input management
@@ -1221,11 +1214,11 @@
* 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;
@@ -1245,19 +1238,19 @@
#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)
@@ -1265,7 +1258,7 @@
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)
@@ -1280,12 +1273,12 @@
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);
@@ -1295,8 +1288,8 @@
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);
@@ -1310,8 +1303,7 @@
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))
@@ -1375,7 +1367,7 @@
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;
@@ -1420,7 +1412,7 @@
/* 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 */
/*
@@ -1478,10 +1470,9 @@
}
#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;
@@ -1489,8 +1480,7 @@
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);
@@ -1542,7 +1532,6 @@
}
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
@@ -1581,7 +1570,7 @@
__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();
@@ -1791,9 +1780,8 @@
}
#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;
@@ -1803,8 +1791,8 @@
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;
@@ -1818,8 +1806,8 @@
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;
@@ -1829,8 +1817,7 @@
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;
@@ -1844,8 +1831,7 @@
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];
@@ -1947,35 +1933,35 @@
}
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)
@@ -2123,7 +2109,7 @@
#endif
{ }
};
-#endif /* CONFIG_SYSCTL */
+#endif /* CONFIG_SYSCTL */
struct batched_entropy {
union {
@@ -2143,7 +2129,7 @@
* 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)
@@ -2168,7 +2154,7 @@
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)
{
@@ -2200,7 +2186,7 @@
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);
@@ -2229,8 +2215,7 @@
* 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;