forked from luck/tmp_suning_uos_patched
random: remove the blocking pool
There is no longer any interface to read data from the blocking pool, so remove it. This enables quite a bit of code deletion, much of which will be done in subsequent patches. Signed-off-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/511225a224bf0a291149d3c0b8b45393cd03ab96.1577088521.git.luto@kernel.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Andy Lutomirski
Theodore Ts'o
parent
30c08efec8
commit
90ea1c6436
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@ -470,7 +470,6 @@ static const struct poolinfo {
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/*
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* Static global variables
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*/
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static DECLARE_WAIT_QUEUE_HEAD(random_read_wait);
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static DECLARE_WAIT_QUEUE_HEAD(random_write_wait);
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static struct fasync_struct *fasync;
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@ -530,7 +529,6 @@ struct entropy_store {
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__u32 *pool;
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const char *name;
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struct entropy_store *pull;
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struct work_struct push_work;
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/* read-write data: */
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unsigned long last_pulled;
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@ -549,9 +547,7 @@ 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] __latent_entropy;
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static __u32 blocking_pool_data[OUTPUT_POOL_WORDS] __latent_entropy;
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static struct entropy_store input_pool = {
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.poolinfo = &poolinfo_table[0],
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@ -560,16 +556,6 @@ static struct entropy_store input_pool = {
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.pool = input_pool_data
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};
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static struct entropy_store blocking_pool = {
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.poolinfo = &poolinfo_table[1],
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.name = "blocking",
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.pull = &input_pool,
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.lock = __SPIN_LOCK_UNLOCKED(blocking_pool.lock),
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.pool = blocking_pool_data,
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.push_work = __WORK_INITIALIZER(blocking_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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@ -765,15 +751,11 @@ static void credit_entropy_bits(struct entropy_store *r, int nbits)
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entropy_count = 0;
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} else if (entropy_count > pool_size)
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entropy_count = pool_size;
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if ((r == &blocking_pool) && !r->initialized &&
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(entropy_count >> ENTROPY_SHIFT) > 128)
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has_initialized = 1;
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if (cmpxchg(&r->entropy_count, orig, entropy_count) != orig)
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goto retry;
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if (has_initialized) {
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r->initialized = 1;
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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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@ -782,7 +764,6 @@ static void credit_entropy_bits(struct entropy_store *r, int nbits)
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if (r == &input_pool) {
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int entropy_bits = entropy_count >> ENTROPY_SHIFT;
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struct entropy_store *other = &blocking_pool;
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if (crng_init < 2) {
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if (entropy_bits < 128)
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@ -790,27 +771,6 @@ static void credit_entropy_bits(struct entropy_store *r, int nbits)
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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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/* initialize the blocking pool if necessary */
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if (entropy_bits >= random_read_wakeup_bits &&
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!other->initialized) {
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schedule_work(&other->push_work);
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return;
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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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wq_has_sleeper(&random_read_wait)) {
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wake_up_interruptible(&random_read_wait);
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}
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/* If the input pool is getting full, and the blocking
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* pool has room, send some entropy to the blocking
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* pool.
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*/
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if (!work_pending(&other->push_work) &&
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(ENTROPY_BITS(r) > 6 * r->poolinfo->poolbytes) &&
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(ENTROPY_BITS(other) <= 6 * other->poolinfo->poolbytes))
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schedule_work(&other->push_work);
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}
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}
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@ -1422,22 +1382,6 @@ static void _xfer_secondary_pool(struct entropy_store *r, size_t nbytes)
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credit_entropy_bits(r, bytes*8);
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}
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/*
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* Used as a workqueue function so that when the input pool is getting
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* full, we can "spill over" some entropy to the output pools. That
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* way the output pools can store some of the excess entropy instead
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* of letting it go to waste.
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*/
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static void push_to_pool(struct work_struct *work)
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{
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struct entropy_store *r = container_of(work, struct entropy_store,
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push_work);
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BUG_ON(!r);
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_xfer_secondary_pool(r, random_read_wakeup_bits/8);
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trace_push_to_pool(r->name, r->entropy_count >> ENTROPY_SHIFT,
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r->pull->entropy_count >> ENTROPY_SHIFT);
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}
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/*
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* This function decides how many bytes to actually take from the
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* given pool, and also debits the entropy count accordingly.
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@ -1616,54 +1560,6 @@ static ssize_t extract_entropy(struct entropy_store *r, void *buf,
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return _extract_entropy(r, buf, nbytes, fips_enabled);
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}
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/*
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* This function extracts randomness from the "entropy pool", and
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* returns it in a userspace buffer.
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*/
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static ssize_t extract_entropy_user(struct entropy_store *r, void __user *buf,
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size_t nbytes)
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{
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ssize_t ret = 0, i;
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__u8 tmp[EXTRACT_SIZE];
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int large_request = (nbytes > 256);
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trace_extract_entropy_user(r->name, nbytes, ENTROPY_BITS(r), _RET_IP_);
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if (!r->initialized && r->pull) {
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xfer_secondary_pool(r, ENTROPY_BITS(r->pull)/8);
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if (!r->initialized)
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return 0;
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}
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xfer_secondary_pool(r, nbytes);
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nbytes = account(r, nbytes, 0, 0);
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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_buf(r, tmp);
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i = min_t(int, nbytes, EXTRACT_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 returned from memory */
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memzero_explicit(tmp, sizeof(tmp));
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return ret;
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}
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#define warn_unseeded_randomness(previous) \
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_warn_unseeded_randomness(__func__, (void *) _RET_IP_, (previous))
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@ -1954,7 +1850,6 @@ static void __init init_std_data(struct entropy_store *r)
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int __init rand_initialize(void)
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{
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init_std_data(&input_pool);
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init_std_data(&blocking_pool);
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crng_initialize(&primary_crng);
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crng_global_init_time = jiffies;
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if (ratelimit_disable) {
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@ -2123,7 +2018,6 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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input_pool.entropy_count = 0;
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blocking_pool.entropy_count = 0;
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return 0;
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case RNDRESEEDCRNG:
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if (!capable(CAP_SYS_ADMIN))
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