Differential D19944 Diff 56365 head/sys/dev/random/randomdev.c

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head/sys/dev/random/randomdev.c

Show First 20 Lines • Show All 230 Lines • ▼ Show 20 Lines	if (error == 0) {
if (error == ERESTART \|\| error == EINTR)		if (error == ERESTART \|\| error == EINTR)
error = 0;		error = 0;
}		}
free(random_buf, M_ENTROPY);		free(random_buf, M_ENTROPY);
return (error);		return (error);
}		}

/*-		/*-
* Kernel API version of read_random().		* Kernel API version of read_random(). This is similar to read_random_uio(),
* This is similar to random_alg_read(),		* except it doesn't interface with uio(9). It cannot assumed that random_buf
* except it doesn't interface with uio(9).		* is a multiple of RANDOM_BLOCKSIZE bytes.
* It cannot assumed that random_buf is a multiple of		*
* RANDOM_BLOCKSIZE bytes.		* If the tunable 'kern.random.initial_seeding.bypass_before_seeding' is set
		* non-zero, silently fail to emit random data (matching the pre-r346250
		* behavior). If read_random is called prior to seeding and bypassed because
		* of this tunable, the condition is reported in the read-only sysctl
		* 'kern.random.initial_seeding.read_random_bypassed_before_seeding'.
*/		*/
void		void
READ_RANDOM(void *random_buf, u_int len)		READ_RANDOM(void *random_buf, u_int len)
{		{
u_int read_directly_len;		u_int read_directly_len;

KASSERT(random_buf != NULL, ("No suitable random buffer in %s", __func__));		KASSERT(random_buf != NULL, ("No suitable random buffer in %s", __func__));
p_random_alg_context->ra_pre_read();		p_random_alg_context->ra_pre_read();

		if (len == 0)
		return;

/* (Un)Blocking logic */		/* (Un)Blocking logic */
if (!p_random_alg_context->ra_seeded())		if (__predict_false(!p_random_alg_context->ra_seeded())) {
		if (random_bypass_before_seeding) {
		if (!read_random_bypassed_before_seeding) {
		if (!random_bypass_disable_warnings)
		printf("read_random: WARNING: bypassing"
		" request for random data because "
		"the random device is not yet "
		"seeded and the knob "
		"'bypass_before_seeding' was "
		"enabled.\n");
		read_random_bypassed_before_seeding = true;
		}
		/* Avoid potentially leaking stack garbage */
		memset(random_buf, 0, len);
		return;
		}

(void)randomdev_wait_until_seeded(SEEDWAIT_UNINTERRUPTIBLE);		(void)randomdev_wait_until_seeded(SEEDWAIT_UNINTERRUPTIBLE);
		}
read_rate_increment(roundup2(len, sizeof(uint32_t)));		read_rate_increment(roundup2(len, sizeof(uint32_t)));
if (len == 0)
return;
/*		/*
* The underlying generator expects multiples of		* The underlying generator expects multiples of
* RANDOM_BLOCKSIZE.		* RANDOM_BLOCKSIZE.
*/		*/
read_directly_len = rounddown(len, RANDOM_BLOCKSIZE);		read_directly_len = rounddown(len, RANDOM_BLOCKSIZE);
if (read_directly_len > 0)		if (read_directly_len > 0)
p_random_alg_context->ra_read(random_buf, read_directly_len);		p_random_alg_context->ra_read(random_buf, read_directly_len);
if (read_directly_len < len) {		if (read_directly_len < len) {
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