/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved. */ #include <sys/types.h> #include <sys/sysmacros.h> #include <sys/modctl.h> #include <sys/conf.h> #include <sys/devops.h> #include <sys/cmn_err.h> #include <sys/kmem.h> #include <sys/stat.h> #include <sys/open.h> #include <sys/file.h> #include <sys/cpuvar.h> #include <sys/disp.h> #include <sys/hsvc.h> #include <sys/machsystm.h> #include <sys/ksynch.h> #include <sys/hypervisor_api.h> #include <sys/n2rng.h> #include <sys/sha1.h> #include <sys/ddi.h> /* near end to get min and max macros right */ #include <sys/sunddi.h> #include <rng/fips_random.h> /* n must be a power of 2 */ #define ROUNDUP(k, n) (((k) + (n) - 1) & ~((n) - 1)) /* * Policy. ENTROPY_STARVATION is the maximum number of calls each * FIPS instance will accept without successfully getting more * entropy. It needs to be large enough to allow RNG operations to * not stall because of health checks, etc. But we don't want it too * large. FIPS 186-2 change 1 (5 October 2001) states that no more * that 2,000,000 DSA signatures (done using this algorithm) should be * done without reseeding. We make sure we add 64 bits of entropy at * most every 10000 operations, hence we will have stirred in 160 bits * of entropy at most once every 30000 operations. Normally, we stir * in 64 bits of entropy for every number generated. */ #define ENTROPY_STARVATION 10000ULL int fips_random(n2rng_t *n2rng, uint8_t *out, size_t nbytes) { int i; fipsrandomstruct_t *frsp; int rv; union { uint32_t as32[SHA1WORDS]; uint64_t as64[ROUNDUP(SHA1WORDS, 2) >> 1]; } entropy = {0}; uint32_t tempout[SHA1WORDS]; for (i = 0; i < nbytes; i += SHA1BYTES) { frsp = &n2rng->n_frs.fipsarray[ atomic_inc_32_nv(&n2rng->n_frs.fips_round_robin_j) % N2RNG_FIPS_INSTANCES]; /* * Since in the new scheme of things, the RNG latency * will be high on reads after the first, we get just * one word of entropy per call. */ if ((rv = n2rng_getentropy(n2rng, (void *)&entropy.as64[1], sizeof (uint64_t))) != 0) { /* * If all rngs have failed, dispatch task to unregister * from kcf and put the driver in an error state. If * recoverable errors persist, a configuration retry * will be initiated. */ if (rv == EPERM) { n2rng_failure(n2rng); return (EIO); } /* Failure with possible recovery */ entropy.as64[1] = 0; } /* * The idea here is that a Niagara2 chip is highly * parallel, with many strands. If we have just one * instance of the FIPS data, then only one FIPS * computation can happen at a time, serializeing all * the RNG stuff. So we make N2RNG_FIPS_INSTANCES, * and use them round-robin, with the counter being * n2rng->n_frs.fips_round_robin_j. We increment the * counter with an atomic op, avoiding having to have * a global muxtex. The atomic ops are also * significantly faster than mutexes. The mutex is * put inside the loop, otherwise one thread reading * many blocks could stall all other strands. */ frsp = &n2rng->n_frs.fipsarray[ atomic_inc_32_nv(&n2rng->n_frs.fips_round_robin_j) % N2RNG_FIPS_INSTANCES]; mutex_enter(&frsp->mtx); if (entropy.as64[1] == 0) { /* * If we did not get any entropy, entropyword * is zero. We get a false positive with * probablitity 2^-64. It's not worth a few * extra stores and tests eliminate the false * positive. */ if (++frsp->entropyhunger > ENTROPY_STARVATION) { mutex_exit(&frsp->mtx); n2rng_unconfigured(n2rng); return (EIO); } } else { frsp->entropyhunger = 0; } /* nbytes - i is bytes to go */ fips_random_inner(frsp->XKEY, tempout, entropy.as32); bcopy(tempout, &out[i], min(nbytes - i, SHA1BYTES)); mutex_exit(&frsp->mtx); } /* Zeroize sensitive information */ entropy.as64[1] = 0; bzero(tempout, SHA1BYTES); return (0); } /* * Initializes one FIPS RNG instance. Must be called once for each * instance. */ int n2rng_fips_random_init(n2rng_t *n2rng, fipsrandomstruct_t *frsp) { /* * All FIPS-approved algorithms will operate as cryptograpic * quality PRNGs even if there is no entropy source. (In * fact, this the only one that accepts entropy on the fly.) * One motivation for this is that they system keeps on * delivering cryptographic quality random numbers, even if * the entropy source fails. */ int rv; static uint32_t FIPS_RNG_NO_USER_INPUT[] = {0, 0, 0, 0, 0}; rv = n2rng_getentropy(n2rng, (void *)frsp->XKEY, ROUNDUP(SHA1BYTES, 8)); if (rv) { return (rv); } frsp->entropyhunger = 0; mutex_init(&frsp->mtx, NULL, MUTEX_DRIVER, NULL); /* compute the first (compare only) random value */ fips_random_inner(frsp->XKEY, frsp->x_jminus1, FIPS_RNG_NO_USER_INPUT); return (0); } void n2rng_fips_random_fini(fipsrandomstruct_t *frsp) { mutex_destroy(&frsp->mtx); /* * Zeroise fips data. Not really necessary, since the * algorithm has backtracking resistance, but do it anyway. */ bzero(frsp, sizeof (fipsrandomstruct_t)); }
