From: Andy Lutomirski <luto@xxxxxxxxxx> commit 90ea1c6436d26e62496616fb5891e00819ff4849 upstream. 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@xxxxxxxxxx> Link: https://lore.kernel.org/r/511225a224bf0a291149d3c0b8b45393cd03ab96.1577088521.git.luto@xxxxxxxxxx Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/char/random.c | 106 -------------------------------------------------- 1 file changed, 106 deletions(-) --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -470,7 +470,6 @@ static const struct poolinfo { /* * Static global variables */ -static DECLARE_WAIT_QUEUE_HEAD(random_read_wait); static DECLARE_WAIT_QUEUE_HEAD(random_write_wait); static struct fasync_struct *fasync; @@ -532,7 +531,6 @@ struct entropy_store { __u32 *pool; const char *name; struct entropy_store *pull; - struct work_struct push_work; /* read-write data: */ unsigned long last_pulled; @@ -551,9 +549,7 @@ static ssize_t _extract_entropy(struct e 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], @@ -562,16 +558,6 @@ 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 }; @@ -767,15 +753,11 @@ retry: 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); } @@ -784,7 +766,6 @@ 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) @@ -792,27 +773,6 @@ retry: 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); - } - /* 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); } } @@ -1439,22 +1399,6 @@ static void _xfer_secondary_pool(struct } /* - * 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. */ @@ -1632,54 +1576,6 @@ static ssize_t extract_entropy(struct en 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)) @@ -1910,7 +1806,6 @@ static void __init init_std_data(struct int __init rand_initialize(void) { init_std_data(&input_pool); - init_std_data(&blocking_pool); if (crng_need_final_init) crng_finalize_init(&primary_crng); crng_initialize(&primary_crng); @@ -2081,7 +1976,6 @@ static long random_ioctl(struct file *f, 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))
