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Code Issues Releases Wiki Activity

random: remove incomplete last_data logic

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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: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2022-01-12 15:22:30 +01:00
parent d38bb08535
commit a4bfa9b318
1 changed files with 4 additions and 35 deletions
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39
drivers/char/random.c
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@ -337,7 +337,6 @@
#include <linux/spinlock.h>
#include <linux/kthread.h>
#include <linux/percpu.h>
#include <linux/fips.h>
#include <linux/ptrace.h>
#include <linux/workqueue.h>
#include <linux/irq.h>
@ -517,14 +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;
@ -821,7 +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();
@ -1426,22 +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;
@ -1467,28 +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) \