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path: root/drivers/char/random.c
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Diffstat (limited to 'drivers/char/random.c')
-rw-r--r--drivers/char/random.c316
1 files changed, 53 insertions, 263 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index cda12933a17d..c7f9584de2c8 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -307,6 +307,8 @@
* Eastlake, Steve Crocker, and Jeff Schiller.
*/
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
#include <linux/utsname.h>
#include <linux/module.h>
#include <linux/kernel.h>
@@ -354,7 +356,6 @@
#define INPUT_POOL_WORDS (1 << (INPUT_POOL_SHIFT-5))
#define OUTPUT_POOL_SHIFT 10
#define OUTPUT_POOL_WORDS (1 << (OUTPUT_POOL_SHIFT-5))
-#define SEC_XFER_SIZE 512
#define EXTRACT_SIZE 10
@@ -371,12 +372,6 @@
#define ENTROPY_BITS(r) ((r)->entropy_count >> ENTROPY_SHIFT)
/*
- * The minimum number of bits of entropy before we wake up a read on
- * /dev/random. Should be enough to do a significant reseed.
- */
-static int random_read_wakeup_bits = 64;
-
-/*
* If the entropy count falls under this number of bits, then we
* should wake up processes which are selecting or polling on write
* access to /dev/random.
@@ -436,42 +431,11 @@ static const struct poolinfo {
/* was: x^128 + x^103 + x^76 + x^51 +x^25 + x + 1 */
/* x^128 + x^104 + x^76 + x^51 +x^25 + x + 1 */
{ S(128), 104, 76, 51, 25, 1 },
- /* was: x^32 + x^26 + x^20 + x^14 + x^7 + x + 1 */
- /* x^32 + x^26 + x^19 + x^14 + x^7 + x + 1 */
- { S(32), 26, 19, 14, 7, 1 },
-#if 0
- /* x^2048 + x^1638 + x^1231 + x^819 + x^411 + x + 1 -- 115 */
- { S(2048), 1638, 1231, 819, 411, 1 },
-
- /* x^1024 + x^817 + x^615 + x^412 + x^204 + x + 1 -- 290 */
- { S(1024), 817, 615, 412, 204, 1 },
-
- /* x^1024 + x^819 + x^616 + x^410 + x^207 + x^2 + 1 -- 115 */
- { S(1024), 819, 616, 410, 207, 2 },
-
- /* x^512 + x^411 + x^308 + x^208 + x^104 + x + 1 -- 225 */
- { S(512), 411, 308, 208, 104, 1 },
-
- /* x^512 + x^409 + x^307 + x^206 + x^102 + x^2 + 1 -- 95 */
- { S(512), 409, 307, 206, 102, 2 },
- /* x^512 + x^409 + x^309 + x^205 + x^103 + x^2 + 1 -- 95 */
- { S(512), 409, 309, 205, 103, 2 },
-
- /* x^256 + x^205 + x^155 + x^101 + x^52 + x + 1 -- 125 */
- { S(256), 205, 155, 101, 52, 1 },
-
- /* x^128 + x^103 + x^78 + x^51 + x^27 + x^2 + 1 -- 70 */
- { S(128), 103, 78, 51, 27, 2 },
-
- /* x^64 + x^52 + x^39 + x^26 + x^14 + x + 1 -- 15 */
- { S(64), 52, 39, 26, 14, 1 },
-#endif
};
/*
* Static global variables
*/
-static DECLARE_WAIT_QUEUE_HEAD(random_read_wait);
static DECLARE_WAIT_QUEUE_HEAD(random_write_wait);
static struct fasync_struct *fasync;
@@ -530,11 +494,8 @@ struct entropy_store {
const struct poolinfo *poolinfo;
__u32 *pool;
const char *name;
- struct entropy_store *pull;
- struct work_struct push_work;
/* read-write data: */
- unsigned long last_pulled;
spinlock_t lock;
unsigned short add_ptr;
unsigned short input_rotate;
@@ -550,9 +511,7 @@ 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] __latent_entropy;
-static __u32 blocking_pool_data[OUTPUT_POOL_WORDS] __latent_entropy;
static struct entropy_store input_pool = {
.poolinfo = &poolinfo_table[0],
@@ -561,16 +520,6 @@ static struct entropy_store input_pool = {
.pool = input_pool_data
};
-static struct entropy_store blocking_pool = {
- .poolinfo = &poolinfo_table[1],
- .name = "blocking",
- .pull = &input_pool,
- .lock = __SPIN_LOCK_UNLOCKED(blocking_pool.lock),
- .pool = blocking_pool_data,
- .push_work = __WORK_INITIALIZER(blocking_pool.push_work,
- push_to_pool),
-};
-
static __u32 const twist_table[8] = {
0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158,
0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 };
@@ -759,22 +708,17 @@ retry:
} while (unlikely(entropy_count < pool_size-2 && pnfrac));
}
- if (unlikely(entropy_count < 0)) {
- pr_warn("random: negative entropy/overflow: pool %s count %d\n",
+ if (WARN_ON(entropy_count < 0)) {
+ pr_warn("negative entropy/overflow: pool %s count %d\n",
r->name, entropy_count);
- WARN_ON(1);
entropy_count = 0;
} else if (entropy_count > pool_size)
entropy_count = pool_size;
- if ((r == &blocking_pool) && !r->initialized &&
- (entropy_count >> ENTROPY_SHIFT) > 128)
- has_initialized = 1;
if (cmpxchg(&r->entropy_count, orig, entropy_count) != orig)
goto retry;
if (has_initialized) {
r->initialized = 1;
- wake_up_interruptible(&random_read_wait);
kill_fasync(&fasync, SIGIO, POLL_IN);
}
@@ -783,36 +727,13 @@ retry:
if (r == &input_pool) {
int entropy_bits = entropy_count >> ENTROPY_SHIFT;
- struct entropy_store *other = &blocking_pool;
if (crng_init < 2) {
if (entropy_bits < 128)
return;
crng_reseed(&primary_crng, r);
- entropy_bits = r->entropy_count >> ENTROPY_SHIFT;
- }
-
- /* initialize the blocking pool if necessary */
- if (entropy_bits >= random_read_wakeup_bits &&
- !other->initialized) {
- schedule_work(&other->push_work);
- return;
- }
-
- /* should we wake readers? */
- if (entropy_bits >= random_read_wakeup_bits &&
- wq_has_sleeper(&random_read_wait)) {
- wake_up_interruptible(&random_read_wait);
- kill_fasync(&fasync, SIGIO, POLL_IN);
+ entropy_bits = ENTROPY_BITS(r);
}
- /* If the input pool is getting full, and the blocking
- * pool has room, send some entropy to the blocking
- * pool.
- */
- if (!work_pending(&other->push_work) &&
- (ENTROPY_BITS(r) > 6 * r->poolinfo->poolbytes) &&
- (ENTROPY_BITS(other) <= 6 * other->poolinfo->poolbytes))
- schedule_work(&other->push_work);
}
}
@@ -884,7 +805,7 @@ static void crng_initialize(struct crng_state *crng)
invalidate_batched_entropy();
numa_crng_init();
crng_init = 2;
- pr_notice("random: crng done (trusting CPU's manufacturer)\n");
+ pr_notice("crng done (trusting CPU's manufacturer)\n");
}
crng->init_time = jiffies - CRNG_RESEED_INTERVAL - 1;
}
@@ -946,8 +867,7 @@ static int crng_fast_load(const char *cp, size_t len)
if (crng_init_cnt >= CRNG_INIT_CNT_THRESH) {
invalidate_batched_entropy();
crng_init = 1;
- wake_up_interruptible(&crng_init_wait);
- pr_notice("random: fast init done\n");
+ pr_notice("fast init done\n");
}
return 1;
}
@@ -1032,16 +952,15 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r)
crng_init = 2;
process_random_ready_list();
wake_up_interruptible(&crng_init_wait);
- pr_notice("random: crng init done\n");
+ kill_fasync(&fasync, SIGIO, POLL_IN);
+ pr_notice("crng init done\n");
if (unseeded_warning.missed) {
- pr_notice("random: %d get_random_xx warning(s) missed "
- "due to ratelimiting\n",
+ pr_notice("%d get_random_xx warning(s) missed due to ratelimiting\n",
unseeded_warning.missed);
unseeded_warning.missed = 0;
}
if (urandom_warning.missed) {
- pr_notice("random: %d urandom warning(s) missed "
- "due to ratelimiting\n",
+ pr_notice("%d urandom warning(s) missed due to ratelimiting\n",
urandom_warning.missed);
urandom_warning.missed = 0;
}
@@ -1246,7 +1165,7 @@ static void add_timer_randomness(struct timer_rand_state *state, unsigned num)
/*
* delta is now minimum absolute delta.
* Round down by 1 bit on general principles,
- * and limit entropy entimate to 12 bits.
+ * and limit entropy estimate to 12 bits.
*/
credit_entropy_bits(r, min_t(int, fls(delta>>1), 11));
}
@@ -1390,57 +1309,6 @@ EXPORT_SYMBOL_GPL(add_disk_randomness);
*********************************************************************/
/*
- * This utility inline function is responsible for transferring entropy
- * from the primary pool to the secondary extraction pool. We make
- * sure we pull enough for a 'catastrophic reseed'.
- */
-static void _xfer_secondary_pool(struct entropy_store *r, size_t nbytes);
-static void xfer_secondary_pool(struct entropy_store *r, size_t nbytes)
-{
- if (!r->pull ||
- r->entropy_count >= (nbytes << (ENTROPY_SHIFT + 3)) ||
- r->entropy_count > r->poolinfo->poolfracbits)
- return;
-
- _xfer_secondary_pool(r, nbytes);
-}
-
-static void _xfer_secondary_pool(struct entropy_store *r, size_t nbytes)
-{
- __u32 tmp[OUTPUT_POOL_WORDS];
-
- int bytes = nbytes;
-
- /* pull at least as much as a wakeup */
- bytes = max_t(int, bytes, random_read_wakeup_bits / 8);
- /* but never more than the buffer size */
- bytes = min_t(int, bytes, sizeof(tmp));
-
- trace_xfer_secondary_pool(r->name, bytes * 8, nbytes * 8,
- ENTROPY_BITS(r), ENTROPY_BITS(r->pull));
- bytes = extract_entropy(r->pull, tmp, bytes,
- random_read_wakeup_bits / 8, 0);
- mix_pool_bytes(r, tmp, bytes);
- credit_entropy_bits(r, bytes*8);
-}
-
-/*
- * Used as a workqueue function so that when the input pool is getting
- * full, we can "spill over" some entropy to the output pools. That
- * way the output pools can store some of the excess entropy instead
- * of letting it go to waste.
- */
-static void push_to_pool(struct work_struct *work)
-{
- struct entropy_store *r = container_of(work, struct entropy_store,
- push_work);
- BUG_ON(!r);
- _xfer_secondary_pool(r, random_read_wakeup_bits/8);
- trace_push_to_pool(r->name, r->entropy_count >> ENTROPY_SHIFT,
- r->pull->entropy_count >> ENTROPY_SHIFT);
-}
-
-/*
* This function decides how many bytes to actually take from the
* given pool, and also debits the entropy count accordingly.
*/
@@ -1465,10 +1333,9 @@ retry:
if (ibytes < min)
ibytes = 0;
- if (unlikely(entropy_count < 0)) {
- pr_warn("random: negative entropy count: pool %s count %d\n",
+ if (WARN_ON(entropy_count < 0)) {
+ pr_warn("negative entropy count: pool %s count %d\n",
r->name, entropy_count);
- WARN_ON(1);
entropy_count = 0;
}
nfrac = ibytes << (ENTROPY_SHIFT + 3);
@@ -1481,8 +1348,7 @@ retry:
goto retry;
trace_debit_entropy(r->name, 8 * ibytes);
- if (ibytes &&
- (r->entropy_count >> ENTROPY_SHIFT) < random_write_wakeup_bits) {
+ if (ibytes && ENTROPY_BITS(r) < random_write_wakeup_bits) {
wake_up_interruptible(&random_write_wait);
kill_fasync(&fasync, SIGIO, POLL_OUT);
}
@@ -1603,7 +1469,6 @@ static ssize_t extract_entropy(struct entropy_store *r, void *buf,
spin_unlock_irqrestore(&r->lock, flags);
trace_extract_entropy(r->name, EXTRACT_SIZE,
ENTROPY_BITS(r), _RET_IP_);
- xfer_secondary_pool(r, EXTRACT_SIZE);
extract_buf(r, tmp);
spin_lock_irqsave(&r->lock, flags);
memcpy(r->last_data, tmp, EXTRACT_SIZE);
@@ -1612,60 +1477,11 @@ static ssize_t extract_entropy(struct entropy_store *r, void *buf,
}
trace_extract_entropy(r->name, nbytes, ENTROPY_BITS(r), _RET_IP_);
- xfer_secondary_pool(r, nbytes);
nbytes = account(r, nbytes, min, reserved);
return _extract_entropy(r, buf, nbytes, fips_enabled);
}
-/*
- * This function extracts randomness from the "entropy pool", and
- * returns it in a userspace buffer.
- */
-static ssize_t extract_entropy_user(struct entropy_store *r, void __user *buf,
- size_t nbytes)
-{
- ssize_t ret = 0, i;
- __u8 tmp[EXTRACT_SIZE];
- int large_request = (nbytes > 256);
-
- trace_extract_entropy_user(r->name, nbytes, ENTROPY_BITS(r), _RET_IP_);
- if (!r->initialized && r->pull) {
- xfer_secondary_pool(r, ENTROPY_BITS(r->pull)/8);
- if (!r->initialized)
- return 0;
- }
- xfer_secondary_pool(r, nbytes);
- nbytes = account(r, nbytes, 0, 0);
-
- while (nbytes) {
- if (large_request && need_resched()) {
- if (signal_pending(current)) {
- if (ret == 0)
- ret = -ERESTARTSYS;
- break;
- }
- schedule();
- }
-
- extract_buf(r, tmp);
- i = min_t(int, nbytes, EXTRACT_SIZE);
- if (copy_to_user(buf, tmp, i)) {
- ret = -EFAULT;
- break;
- }
-
- nbytes -= i;
- buf += i;
- ret += i;
- }
-
- /* Wipe data just returned from memory */
- memzero_explicit(tmp, sizeof(tmp));
-
- return ret;
-}
-
#define warn_unseeded_randomness(previous) \
_warn_unseeded_randomness(__func__, (void *) _RET_IP_, (previous))
@@ -1687,8 +1503,9 @@ static void _warn_unseeded_randomness(const char *func_name, void *caller,
print_once = true;
#endif
if (__ratelimit(&unseeded_warning))
- pr_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);
}
/*
@@ -1931,7 +1748,6 @@ static void __init init_std_data(struct entropy_store *r)
ktime_t now = ktime_get_real();
unsigned long rv;
- r->last_pulled = jiffies;
mix_pool_bytes(r, &now, sizeof(now));
for (i = r->poolinfo->poolbytes; i > 0; i -= sizeof(rv)) {
if (!arch_get_random_seed_long(&rv) &&
@@ -1955,7 +1771,6 @@ static void __init init_std_data(struct entropy_store *r)
int __init rand_initialize(void)
{
init_std_data(&input_pool);
- init_std_data(&blocking_pool);
crng_initialize(&primary_crng);
crng_global_init_time = jiffies;
if (ratelimit_disable) {
@@ -1983,40 +1798,15 @@ void rand_initialize_disk(struct gendisk *disk)
#endif
static ssize_t
-_random_read(int nonblock, char __user *buf, size_t nbytes)
+urandom_read_nowarn(struct file *file, char __user *buf, size_t nbytes,
+ loff_t *ppos)
{
- ssize_t n;
-
- if (nbytes == 0)
- return 0;
-
- nbytes = min_t(size_t, nbytes, SEC_XFER_SIZE);
- while (1) {
- n = extract_entropy_user(&blocking_pool, buf, nbytes);
- if (n < 0)
- return n;
- trace_random_read(n*8, (nbytes-n)*8,
- ENTROPY_BITS(&blocking_pool),
- ENTROPY_BITS(&input_pool));
- if (n > 0)
- return n;
-
- /* Pool is (near) empty. Maybe wait and retry. */
- if (nonblock)
- return -EAGAIN;
-
- wait_event_interruptible(random_read_wait,
- blocking_pool.initialized &&
- (ENTROPY_BITS(&input_pool) >= random_read_wakeup_bits));
- if (signal_pending(current))
- return -ERESTARTSYS;
- }
-}
+ int ret;
-static ssize_t
-random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
-{
- return _random_read(file->f_flags & O_NONBLOCK, buf, nbytes);
+ nbytes = min_t(size_t, nbytes, INT_MAX >> (ENTROPY_SHIFT + 3));
+ ret = extract_crng_user(buf, nbytes);
+ trace_urandom_read(8 * nbytes, 0, ENTROPY_BITS(&input_pool));
+ return ret;
}
static ssize_t
@@ -2024,22 +1814,29 @@ urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
{
unsigned long flags;
static int maxwarn = 10;
- int ret;
if (!crng_ready() && maxwarn > 0) {
maxwarn--;
if (__ratelimit(&urandom_warning))
- printk(KERN_NOTICE "random: %s: uninitialized "
- "urandom read (%zd bytes read)\n",
- current->comm, nbytes);
+ pr_notice("%s: uninitialized urandom read (%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_crng_user(buf, nbytes);
- trace_urandom_read(8 * nbytes, 0, ENTROPY_BITS(&input_pool));
- return ret;
+
+ 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)
+{
+ int ret;
+
+ ret = wait_for_random_bytes();
+ if (ret != 0)
+ return ret;
+ return urandom_read_nowarn(file, buf, nbytes, ppos);
}
static __poll_t
@@ -2047,10 +1844,10 @@ random_poll(struct file *file, poll_table * wait)
{
__poll_t mask;
- poll_wait(file, &random_read_wait, wait);
+ poll_wait(file, &crng_init_wait, wait);
poll_wait(file, &random_write_wait, wait);
mask = 0;
- if (ENTROPY_BITS(&input_pool) >= random_read_wakeup_bits)
+ if (crng_ready())
mask |= EPOLLIN | EPOLLRDNORM;
if (ENTROPY_BITS(&input_pool) < random_write_wakeup_bits)
mask |= EPOLLOUT | EPOLLWRNORM;
@@ -2141,7 +1938,6 @@ 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;
- blocking_pool.entropy_count = 0;
return 0;
case RNDRESEEDCRNG:
if (!capable(CAP_SYS_ADMIN))
@@ -2185,23 +1981,27 @@ SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count,
{
int ret;
- if (flags & ~(GRND_NONBLOCK|GRND_RANDOM))
+ 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))
return -EINVAL;
if (count > INT_MAX)
count = INT_MAX;
- if (flags & GRND_RANDOM)
- return _random_read(flags & GRND_NONBLOCK, buf, count);
-
- if (!crng_ready()) {
+ if (!(flags & GRND_INSECURE) && !crng_ready()) {
if (flags & GRND_NONBLOCK)
return -EAGAIN;
ret = wait_for_random_bytes();
if (unlikely(ret))
return ret;
}
- return urandom_read(NULL, buf, count, NULL);
+ return urandom_read_nowarn(NULL, buf, count, NULL);
}
/********************************************************************
@@ -2214,8 +2014,7 @@ SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count,
#include <linux/sysctl.h>
-static int min_read_thresh = 8, min_write_thresh;
-static int max_read_thresh = OUTPUT_POOL_WORDS * 32;
+static int min_write_thresh;
static int max_write_thresh = INPUT_POOL_WORDS * 32;
static int random_min_urandom_seed = 60;
static char sysctl_bootid[16];
@@ -2291,15 +2090,6 @@ struct ctl_table random_table[] = {
.data = &input_pool.entropy_count,
},
{
- .procname = "read_wakeup_threshold",
- .data = &random_read_wakeup_bits,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = proc_dointvec_minmax,
- .extra1 = &min_read_thresh,
- .extra2 = &max_read_thresh,
- },
- {
.procname = "write_wakeup_threshold",
.data = &random_write_wakeup_bits,
.maxlen = sizeof(int),
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-22 22:40:28 +0300