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Commit 12f17e3f authored by Jason A. Donenfeld's avatar Jason A. Donenfeld Committed by Greg Kroah-Hartman
Browse files

random: remove incomplete last_data logic 



commit a4bfa9b31802c14ff5847123c12b98d5e36b3985 upstream.

There were a few things added under the "if (fips_enabled)" banner,
which never really got completed, and the FIPS people anyway are
choosing a different direction. Rather than keep around this halfbaked
code, get rid of it so that we can focus on a single design of the RNG
rather than two designs.

Reviewed-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent adcbbb44

drivers/char/random.c

+4 −36
Original line number Diff line number Diff line
@@ -337,8 +337,6 @@ 
#include <linux/spinlock.h>

#include <linux/kthread.h>

#include <linux/percpu.h>

#include <linux/cryptohash.h>

#include <linux/fips.h>

#include <linux/ptrace.h>

#include <linux/workqueue.h>

#include <linux/irq.h>
@@ -518,14 +516,12 @@ struct entropy_store { 
	u16 add_ptr;

	u16 input_rotate;

	int entropy_count;

	unsigned int last_data_init:1;

	u8 last_data[EXTRACT_SIZE];

};



static ssize_t extract_entropy(struct entropy_store *r, void *buf,

			       size_t nbytes, int min, int rsvd);

static ssize_t _extract_entropy(struct entropy_store *r, void *buf,

				size_t nbytes, int fips);

				size_t nbytes);



static void crng_reseed(struct crng_state *crng, struct entropy_store *r);

static u32 input_pool_data[INPUT_POOL_WORDS] __latent_entropy;
@@ -822,7 +818,7 @@ static void crng_initialize_secondary(struct crng_state *crng) 


static void __init crng_initialize_primary(struct crng_state *crng)

{

	_extract_entropy(&input_pool, &crng->state[4], sizeof(u32) * 12, 0);

	_extract_entropy(&input_pool, &crng->state[4], sizeof(u32) * 12);

	if (crng_init_try_arch_early(crng) && trust_cpu && crng_init < 2) {

		invalidate_batched_entropy();

		numa_crng_init();
@@ -1427,22 +1423,13 @@ static void extract_buf(struct entropy_store *r, u8 *out) 
}



static ssize_t _extract_entropy(struct entropy_store *r, void *buf,

				size_t nbytes, int fips)

				size_t nbytes)

{

	ssize_t ret = 0, i;

	u8 tmp[EXTRACT_SIZE];

	unsigned long flags;



	while (nbytes) {

		extract_buf(r, tmp);



		if (fips) {

			spin_lock_irqsave(&r->lock, flags);

			if (!memcmp(tmp, r->last_data, EXTRACT_SIZE))

				panic("Hardware RNG duplicated output!\n");

			memcpy(r->last_data, tmp, EXTRACT_SIZE);

			spin_unlock_irqrestore(&r->lock, flags);

		}

		i = min_t(int, nbytes, EXTRACT_SIZE);

		memcpy(buf, tmp, i);

		nbytes -= i;
@@ -1468,28 +1455,9 @@ static ssize_t _extract_entropy(struct entropy_store *r, void *buf, 
static ssize_t extract_entropy(struct entropy_store *r, void *buf,

				 size_t nbytes, int min, int reserved)

{

	u8 tmp[EXTRACT_SIZE];

	unsigned long flags;



	/* if last_data isn't primed, we need EXTRACT_SIZE extra bytes */

	if (fips_enabled) {

		spin_lock_irqsave(&r->lock, flags);

		if (!r->last_data_init) {

			r->last_data_init = 1;

			spin_unlock_irqrestore(&r->lock, flags);

			trace_extract_entropy(r->name, EXTRACT_SIZE,

					      ENTROPY_BITS(r), _RET_IP_);

			extract_buf(r, tmp);

			spin_lock_irqsave(&r->lock, flags);

			memcpy(r->last_data, tmp, EXTRACT_SIZE);

		}

		spin_unlock_irqrestore(&r->lock, flags);

	}



	trace_extract_entropy(r->name, nbytes, ENTROPY_BITS(r), _RET_IP_);

	nbytes = account(r, nbytes, min, reserved);



	return _extract_entropy(r, buf, nbytes, fips_enabled);

	return _extract_entropy(r, buf, nbytes);

}



#define warn_unseeded_randomness(previous) \