/*- * Copyright (c) 2017 Oliver Pinter * Copyright (c) 2017 W. Dean Freeman * Copyright (c) 2000-2015 Mark R V Murray * Copyright (c) 2013 Arthur Mesh * Copyright (c) 2004 Robert N. M. Watson * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer * in this position and unchanged. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if defined(RANDOM_ENABLE_ETHER) #define _RANDOM_HARVEST_ETHER_OFF 0 #else #define _RANDOM_HARVEST_ETHER_OFF (1u << RANDOM_NET_ETHER) #endif #if defined(RANDOM_ENABLE_UMA) #define _RANDOM_HARVEST_UMA_OFF 0 #else #define _RANDOM_HARVEST_UMA_OFF (1u << RANDOM_UMA) #endif /* * Note that random_sources_feed() will also use this to try and split up * entropy into a subset of pools per iteration with the goal of feeding * HARVESTSIZE into every pool at least once per second. */ #define RANDOM_KTHREAD_HZ 10 static void random_kthread(void); static void random_sources_feed(void); /* * Random must initialize much earlier than epoch, but we can initialize the * epoch code before SMP starts. Prior to SMP, we can safely bypass * concurrency primitives. */ static __read_mostly bool epoch_inited; static __read_mostly epoch_t rs_epoch; static const char *random_source_descr[ENTROPYSOURCE]; /* * How many events to queue up. We create this many items in * an 'empty' queue, then transfer them to the 'harvest' queue with * supplied junk. When used, they are transferred back to the * 'empty' queue. */ #define RANDOM_RING_MAX 1024 #define RANDOM_ACCUM_MAX 8 /* 1 to let the kernel thread run, 0 to terminate, -1 to mark completion */ volatile int random_kthread_control; /* Allow the sysadmin to select the broad category of * entropy types to harvest. */ __read_frequently u_int hc_source_mask; struct random_sources { CK_LIST_ENTRY(random_sources) rrs_entries; struct random_source *rrs_source; }; static CK_LIST_HEAD(sources_head, random_sources) source_list = CK_LIST_HEAD_INITIALIZER(source_list); SYSCTL_NODE(_kern_random, OID_AUTO, harvest, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, "Entropy Device Parameters"); /* * Put all the harvest queue context stuff in one place. * this make is a bit easier to lock and protect. */ static struct harvest_context { /* The harvest mutex protects all of harvest_context and * the related data. */ struct mtx hc_mtx; /* Round-robin destination cache. */ u_int hc_destination[ENTROPYSOURCE]; /* The context of the kernel thread processing harvested entropy */ struct proc *hc_kthread_proc; /* * A pair of buffers for queued events. New events are added to the * active queue while the kthread processes the other one in parallel. */ struct entropy_buffer { struct harvest_event ring[RANDOM_RING_MAX]; u_int pos; } hc_entropy_buf[2]; u_int hc_active_buf; struct fast_entropy_accumulator { volatile u_int pos; uint32_t buf[RANDOM_ACCUM_MAX]; } hc_entropy_fast_accumulator; } harvest_context; #define RANDOM_HARVEST_INIT_LOCK() mtx_init(&harvest_context.hc_mtx, \ "entropy harvest mutex", NULL, MTX_SPIN) #define RANDOM_HARVEST_LOCK() mtx_lock_spin(&harvest_context.hc_mtx) #define RANDOM_HARVEST_UNLOCK() mtx_unlock_spin(&harvest_context.hc_mtx) static struct kproc_desc random_proc_kp = { "rand_harvestq", random_kthread, &harvest_context.hc_kthread_proc, }; /* Pass the given event straight through to Fortuna/Whatever. */ static __inline void random_harvestq_fast_process_event(struct harvest_event *event) { p_random_alg_context->ra_event_processor(event); explicit_bzero(event, sizeof(*event)); } static void random_kthread(void) { struct harvest_context *hc; hc = &harvest_context; for (random_kthread_control = 1; random_kthread_control;) { struct entropy_buffer *buf; u_int entries; /* Deal with queued events. */ RANDOM_HARVEST_LOCK(); buf = &hc->hc_entropy_buf[hc->hc_active_buf]; entries = buf->pos; buf->pos = 0; hc->hc_active_buf = (hc->hc_active_buf + 1) % nitems(hc->hc_entropy_buf); RANDOM_HARVEST_UNLOCK(); for (u_int i = 0; i < entries; i++) random_harvestq_fast_process_event(&buf->ring[i]); /* Poll sources of noise. */ random_sources_feed(); /* XXX: FIX!! Increase the high-performance data rate? Need some measurements first. */ for (u_int i = 0; i < RANDOM_ACCUM_MAX; i++) { if (hc->hc_entropy_fast_accumulator.buf[i]) { random_harvest_direct(&hc->hc_entropy_fast_accumulator.buf[i], sizeof(hc->hc_entropy_fast_accumulator.buf[0]), RANDOM_UMA); hc->hc_entropy_fast_accumulator.buf[i] = 0; } } /* XXX: FIX!! This is a *great* place to pass hardware/live entropy to random(9) */ tsleep_sbt(&hc->hc_kthread_proc, 0, "-", SBT_1S/RANDOM_KTHREAD_HZ, 0, C_PREL(1)); } random_kthread_control = -1; wakeup(&hc->hc_kthread_proc); kproc_exit(0); /* NOTREACHED */ } SYSINIT(random_device_h_proc, SI_SUB_KICK_SCHEDULER, SI_ORDER_ANY, kproc_start, &random_proc_kp); _Static_assert(SI_SUB_KICK_SCHEDULER > SI_SUB_RANDOM, "random kthread starting before subsystem initialization"); static void rs_epoch_init(void *dummy __unused) { rs_epoch = epoch_alloc("Random Sources", EPOCH_PREEMPT); epoch_inited = true; } SYSINIT(rs_epoch_init, SI_SUB_EPOCH, SI_ORDER_ANY, rs_epoch_init, NULL); /* * Run through all fast sources reading entropy for the given * number of rounds, which should be a multiple of the number * of entropy accumulation pools in use; it is 32 for Fortuna. */ static void random_sources_feed(void) { uint32_t entropy[HARVESTSIZE]; struct epoch_tracker et; struct random_sources *rrs; u_int i, n, npools; bool rse_warm; rse_warm = epoch_inited; /* * Evenly-ish distribute pool population across the second based on how * frequently random_kthread iterates. * * For Fortuna, the math currently works out as such: * * 64 bits * 4 pools = 256 bits per iteration * 256 bits * 10 Hz = 2560 bits per second, 320 B/s * */ npools = howmany(p_random_alg_context->ra_poolcount, RANDOM_KTHREAD_HZ); /*- * If we're not seeded yet, attempt to perform a "full seed", filling * all of the PRNG's pools with entropy; if there is enough entropy * available from "fast" entropy sources this will allow us to finish * seeding and unblock the boot process immediately rather than being * stuck for a few seconds with random_kthread gradually collecting a * small chunk of entropy every 1 / RANDOM_KTHREAD_HZ seconds. * * We collect RANDOM_FORTUNA_DEFPOOLSIZE bytes per pool, i.e. enough * to fill Fortuna's pools in the default configuration. With another * PRNG or smaller pools for Fortuna, we might collect more entropy * than needed to fill the pools, but this is harmless; alternatively, * a different PRNG, larger pools, or fast entropy sources which are * not able to provide as much entropy as we request may result in the * not being fully seeded (and thus remaining blocked) but in that * case we will return here after 1 / RANDOM_KTHREAD_HZ seconds and * try again for a large amount of entropy. */ if (!p_random_alg_context->ra_seeded()) npools = howmany(p_random_alg_context->ra_poolcount * RANDOM_FORTUNA_DEFPOOLSIZE, sizeof(entropy)); /* * Step over all of live entropy sources, and feed their output * to the system-wide RNG. */ if (rse_warm) epoch_enter_preempt(rs_epoch, &et); CK_LIST_FOREACH(rrs, &source_list, rrs_entries) { for (i = 0; i < npools; i++) { n = rrs->rrs_source->rs_read(entropy, sizeof(entropy)); KASSERT((n <= sizeof(entropy)), ("%s: rs_read returned too much data (%u > %zu)", __func__, n, sizeof(entropy))); /* * Sometimes the HW entropy source doesn't have anything * ready for us. This isn't necessarily untrustworthy. * We don't perform any other verification of an entropy * source (i.e., length is allowed to be anywhere from 1 * to sizeof(entropy), quality is unchecked, etc), so * don't balk verbosely at slow random sources either. * There are reports that RDSEED on x86 metal falls * behind the rate at which we query it, for example. * But it's still a better entropy source than RDRAND. */ if (n == 0) continue; random_harvest_direct(entropy, n, rrs->rrs_source->rs_source); } } if (rse_warm) epoch_exit_preempt(rs_epoch, &et); explicit_bzero(entropy, sizeof(entropy)); } /* * State used for conducting NIST SP 800-90B health tests on entropy sources. */ static struct health_test_softc { uint32_t ht_rct_value[HARVESTSIZE + 1]; u_int ht_rct_count; /* number of samples with the same value */ u_int ht_rct_limit; /* constant after init */ uint32_t ht_apt_value[HARVESTSIZE + 1]; u_int ht_apt_count; /* number of samples with the same value */ u_int ht_apt_seq; /* sequence number of the last sample */ u_int ht_apt_cutoff; /* constant after init */ uint64_t ht_total_samples; bool ondemand; /* Set to true to restart the state machine */ enum { INIT = 0, /* initial state */ DISABLED, /* health checking is disabled */ STARTUP, /* doing startup tests, samples are discarded */ STEADY, /* steady-state operation */ FAILED, /* health check failed, discard samples */ } ht_state; } healthtest[ENTROPYSOURCE]; #define RANDOM_SELFTEST_STARTUP_SAMPLES 1024 /* 4.3, requirement 4 */ #define RANDOM_SELFTEST_APT_WINDOW 512 /* 4.4.2 */ static void copy_event(uint32_t dst[static HARVESTSIZE + 1], const struct harvest_event *event) { memset(dst, 0, sizeof(uint32_t) * (HARVESTSIZE + 1)); memcpy(dst, event->he_entropy, event->he_size); dst[HARVESTSIZE] = event->he_somecounter; } static void random_healthtest_rct_init(struct health_test_softc *ht, const struct harvest_event *event) { ht->ht_rct_count = 1; copy_event(ht->ht_rct_value, event); } /* * Apply the repitition count test to a sample. * * Return false if the test failed, i.e., we observed >= C consecutive samples * with the same value, and true otherwise. */ static bool random_healthtest_rct_next(struct health_test_softc *ht, const struct harvest_event *event) { uint32_t val[HARVESTSIZE + 1]; copy_event(val, event); if (memcmp(val, ht->ht_rct_value, sizeof(ht->ht_rct_value)) != 0) { ht->ht_rct_count = 1; memcpy(ht->ht_rct_value, val, sizeof(ht->ht_rct_value)); return (true); } else { ht->ht_rct_count++; return (ht->ht_rct_count < ht->ht_rct_limit); } } static void random_healthtest_apt_init(struct health_test_softc *ht, const struct harvest_event *event) { ht->ht_apt_count = 1; ht->ht_apt_seq = 1; copy_event(ht->ht_apt_value, event); } static bool random_healthtest_apt_next(struct health_test_softc *ht, const struct harvest_event *event) { uint32_t val[HARVESTSIZE + 1]; if (ht->ht_apt_seq == 0) { random_healthtest_apt_init(ht, event); return (true); } copy_event(val, event); if (memcmp(val, ht->ht_apt_value, sizeof(ht->ht_apt_value)) == 0) { ht->ht_apt_count++; if (ht->ht_apt_count >= ht->ht_apt_cutoff) return (false); } ht->ht_apt_seq++; if (ht->ht_apt_seq == RANDOM_SELFTEST_APT_WINDOW) ht->ht_apt_seq = 0; return (true); } /* * Run the health tests for the given event. This is assumed to be called from * a serialized context. */ bool random_harvest_healthtest(const struct harvest_event *event) { struct health_test_softc *ht; ht = &healthtest[event->he_source]; /* * Was on-demand testing requested? Restart the state machine if so, * restarting the startup tests. */ if (atomic_load_bool(&ht->ondemand)) { atomic_store_bool(&ht->ondemand, false); ht->ht_state = INIT; } switch (ht->ht_state) { case __predict_false(INIT): /* Store the first sample and initialize test state. */ random_healthtest_rct_init(ht, event); random_healthtest_apt_init(ht, event); ht->ht_total_samples = 0; ht->ht_state = STARTUP; return (false); case DISABLED: /* No health testing for this source. */ return (true); case STEADY: case STARTUP: ht->ht_total_samples++; if (random_healthtest_rct_next(ht, event) && random_healthtest_apt_next(ht, event)) { if (ht->ht_state == STARTUP && ht->ht_total_samples >= RANDOM_SELFTEST_STARTUP_SAMPLES) { printf( "random: health test passed for source %s\n", random_source_descr[event->he_source]); ht->ht_state = STEADY; } return (ht->ht_state == STEADY); } ht->ht_state = FAILED; printf( "random: health test failed for source %s, discarding samples\n", random_source_descr[event->he_source]); /* FALLTHROUGH */ case FAILED: return (false); } } static bool nist_healthtest_enabled = false; SYSCTL_BOOL(_kern_random, OID_AUTO, nist_healthtest_enabled, CTLFLAG_RDTUN, &nist_healthtest_enabled, 0, "Enable NIST SP 800-90B health tests for noise sources"); static void random_healthtest_init(enum random_entropy_source source) { struct health_test_softc *ht; ht = &healthtest[source]; KASSERT(ht->ht_state == INIT, ("%s: health test state is %d for source %d", __func__, ht->ht_state, source)); /* * If health-testing is enabled, validate all sources except CACHED and * VMGENID: they are deterministic sources used only a small, fixed * number of times, so statistical testing is not applicable. */ if (!nist_healthtest_enabled || source == RANDOM_CACHED || source == RANDOM_PURE_VMGENID) { ht->ht_state = DISABLED; return; } /* * Set cutoff values for the two tests, assuming that each sample has * min-entropy of 1 bit and allowing for an error rate of 1 in 2^{34}. * With a sample rate of RANDOM_KTHREAD_HZ, we expect to see an false * positive once in ~54.5 years. * * The RCT limit comes from the formula in section 4.4.1. * * The APT cutoff is calculated using the formula in section 4.4.2 * footnote 10 with the window size changed from 512 to 511, since the * test as written counts the number of samples equal to the first * sample in the window, and thus tests W-1 samples. */ ht->ht_rct_limit = 35; ht->ht_apt_cutoff = 330; } static int random_healthtest_ondemand(SYSCTL_HANDLER_ARGS) { u_int mask, source; int error; mask = 0; error = sysctl_handle_int(oidp, &mask, 0, req); if (error != 0 || req->newptr == NULL) return (error); while (mask != 0) { source = ffs(mask) - 1; if (source < nitems(healthtest)) atomic_store_bool(&healthtest[source].ondemand, true); mask &= ~(1u << source); } return (0); } SYSCTL_PROC(_kern_random, OID_AUTO, nist_healthtest_ondemand, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0, random_healthtest_ondemand, "I", "Re-run NIST SP 800-90B startup health tests for a noise source"); static int random_check_uint_harvestmask(SYSCTL_HANDLER_ARGS) { static const u_int user_immutable_mask = (((1 << ENTROPYSOURCE) - 1) & (-1UL << RANDOM_PURE_START)) | _RANDOM_HARVEST_ETHER_OFF | _RANDOM_HARVEST_UMA_OFF; int error; u_int value, orig_value; orig_value = value = hc_source_mask; error = sysctl_handle_int(oidp, &value, 0, req); if (error != 0 || req->newptr == NULL) return (error); if (flsl(value) > ENTROPYSOURCE) return (EINVAL); /* * Disallow userspace modification of pure entropy sources. */ hc_source_mask = (value & ~user_immutable_mask) | (orig_value & user_immutable_mask); return (0); } SYSCTL_PROC(_kern_random_harvest, OID_AUTO, mask, CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, NULL, 0, random_check_uint_harvestmask, "IU", "Entropy harvesting mask"); static int random_print_harvestmask(SYSCTL_HANDLER_ARGS) { struct sbuf sbuf; int error, i; error = sysctl_wire_old_buffer(req, 0); if (error == 0) { sbuf_new_for_sysctl(&sbuf, NULL, 128, req); for (i = ENTROPYSOURCE - 1; i >= 0; i--) sbuf_cat(&sbuf, (hc_source_mask & (1 << i)) ? "1" : "0"); error = sbuf_finish(&sbuf); sbuf_delete(&sbuf); } return (error); } SYSCTL_PROC(_kern_random_harvest, OID_AUTO, mask_bin, CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, random_print_harvestmask, "A", "Entropy harvesting mask (printable)"); static const char *random_source_descr[ENTROPYSOURCE] = { [RANDOM_CACHED] = "CACHED", [RANDOM_ATTACH] = "ATTACH", [RANDOM_KEYBOARD] = "KEYBOARD", [RANDOM_MOUSE] = "MOUSE", [RANDOM_NET_TUN] = "NET_TUN", [RANDOM_NET_ETHER] = "NET_ETHER", [RANDOM_NET_NG] = "NET_NG", [RANDOM_INTERRUPT] = "INTERRUPT", [RANDOM_SWI] = "SWI", [RANDOM_FS_ATIME] = "FS_ATIME", [RANDOM_UMA] = "UMA", [RANDOM_CALLOUT] = "CALLOUT", [RANDOM_RANDOMDEV] = "RANDOMDEV", /* ENVIRONMENTAL_END */ [RANDOM_PURE_OCTEON] = "PURE_OCTEON", /* PURE_START */ [RANDOM_PURE_SAFE] = "PURE_SAFE", [RANDOM_PURE_GLXSB] = "PURE_GLXSB", [RANDOM_PURE_HIFN] = "PURE_HIFN", [RANDOM_PURE_RDRAND] = "PURE_RDRAND", [RANDOM_PURE_NEHEMIAH] = "PURE_NEHEMIAH", [RANDOM_PURE_RNDTEST] = "PURE_RNDTEST", [RANDOM_PURE_VIRTIO] = "PURE_VIRTIO", [RANDOM_PURE_BROADCOM] = "PURE_BROADCOM", [RANDOM_PURE_CCP] = "PURE_CCP", [RANDOM_PURE_DARN] = "PURE_DARN", [RANDOM_PURE_TPM] = "PURE_TPM", [RANDOM_PURE_VMGENID] = "PURE_VMGENID", [RANDOM_PURE_QUALCOMM] = "PURE_QUALCOMM", [RANDOM_PURE_ARMV8] = "PURE_ARMV8", [RANDOM_PURE_ARM_TRNG] = "PURE_ARM_TRNG", /* "ENTROPYSOURCE" */ }; static int random_print_harvestmask_symbolic(SYSCTL_HANDLER_ARGS) { struct sbuf sbuf; int error, i; bool first; first = true; error = sysctl_wire_old_buffer(req, 0); if (error == 0) { sbuf_new_for_sysctl(&sbuf, NULL, 128, req); for (i = ENTROPYSOURCE - 1; i >= 0; i--) { if (i >= RANDOM_PURE_START && (hc_source_mask & (1 << i)) == 0) continue; if (!first) sbuf_cat(&sbuf, ","); sbuf_cat(&sbuf, !(hc_source_mask & (1 << i)) ? "[" : ""); sbuf_cat(&sbuf, random_source_descr[i]); sbuf_cat(&sbuf, !(hc_source_mask & (1 << i)) ? "]" : ""); first = false; } error = sbuf_finish(&sbuf); sbuf_delete(&sbuf); } return (error); } SYSCTL_PROC(_kern_random_harvest, OID_AUTO, mask_symbolic, CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, random_print_harvestmask_symbolic, "A", "Entropy harvesting mask (symbolic)"); static void random_harvestq_init(void *unused __unused) { static const u_int almost_everything_mask = (((1 << (RANDOM_ENVIRONMENTAL_END + 1)) - 1) & ~_RANDOM_HARVEST_ETHER_OFF & ~_RANDOM_HARVEST_UMA_OFF); hc_source_mask = almost_everything_mask; RANDOM_HARVEST_INIT_LOCK(); harvest_context.hc_active_buf = 0; for (int i = 0; i < ENTROPYSOURCE; i++) random_healthtest_init(i); } SYSINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_THIRD, random_harvestq_init, NULL); /* * Subroutine to slice up a contiguous chunk of 'entropy' and feed it into the * underlying algorithm. Returns number of bytes actually fed into underlying * algorithm. */ static size_t random_early_prime(char *entropy, size_t len) { struct harvest_event event; size_t i; len = rounddown(len, sizeof(event.he_entropy)); if (len == 0) return (0); for (i = 0; i < len; i += sizeof(event.he_entropy)) { event.he_somecounter = random_get_cyclecount(); event.he_size = sizeof(event.he_entropy); event.he_source = RANDOM_CACHED; event.he_destination = harvest_context.hc_destination[RANDOM_CACHED]++; memcpy(event.he_entropy, entropy + i, sizeof(event.he_entropy)); random_harvestq_fast_process_event(&event); } explicit_bzero(entropy, len); return (len); } /* * Subroutine to search for known loader-loaded files in memory and feed them * into the underlying algorithm early in boot. Returns the number of bytes * loaded (zero if none were loaded). */ static size_t random_prime_loader_file(const char *type) { uint8_t *keyfile, *data; size_t size; keyfile = preload_search_by_type(type); if (keyfile == NULL) return (0); data = preload_fetch_addr(keyfile); size = preload_fetch_size(keyfile); if (data == NULL) return (0); return (random_early_prime(data, size)); } /* * This is used to prime the RNG by grabbing any early random stuff * known to the kernel, and inserting it directly into the hashing * module, currently Fortuna. */ static void random_harvestq_prime(void *unused __unused) { size_t size; /* * Get entropy that may have been preloaded by loader(8) * and use it to pre-charge the entropy harvest queue. */ size = random_prime_loader_file(RANDOM_CACHED_BOOT_ENTROPY_MODULE); if (bootverbose) { if (size > 0) printf("random: read %zu bytes from preloaded cache\n", size); else printf("random: no preloaded entropy cache\n"); } size = random_prime_loader_file(RANDOM_PLATFORM_BOOT_ENTROPY_MODULE); if (bootverbose) { if (size > 0) printf("random: read %zu bytes from platform bootloader\n", size); else printf("random: no platform bootloader entropy\n"); } } SYSINIT(random_device_prime, SI_SUB_RANDOM, SI_ORDER_MIDDLE, random_harvestq_prime, NULL); static void random_harvestq_deinit(void *unused __unused) { /* Command the hash/reseed thread to end and wait for it to finish */ random_kthread_control = 0; while (random_kthread_control >= 0) tsleep(&harvest_context.hc_kthread_proc, 0, "harvqterm", hz/5); } SYSUNINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_THIRD, random_harvestq_deinit, NULL); /*- * Entropy harvesting queue routine. * * This is supposed to be fast; do not do anything slow in here! * It is also illegal (and morally reprehensible) to insert any * high-rate data here. "High-rate" is defined as a data source * that is likely to fill up the buffer in much less than 100ms. * This includes the "always-on" sources like the Intel "rdrand" * or the VIA Nehamiah "xstore" sources. */ /* XXXRW: get_cyclecount() is cheap on most modern hardware, where cycle * counters are built in, but on older hardware it will do a real time clock * read which can be quite expensive. */ void random_harvest_queue_(const void *entropy, u_int size, enum random_entropy_source origin) { struct harvest_context *hc; struct entropy_buffer *buf; struct harvest_event *event; KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid", __func__, origin)); hc = &harvest_context; RANDOM_HARVEST_LOCK(); buf = &hc->hc_entropy_buf[hc->hc_active_buf]; if (buf->pos < RANDOM_RING_MAX) { event = &buf->ring[buf->pos++]; event->he_somecounter = random_get_cyclecount(); event->he_source = origin; event->he_destination = hc->hc_destination[origin]++; if (size <= sizeof(event->he_entropy)) { event->he_size = size; memcpy(event->he_entropy, entropy, size); } else { /* Big event, so squash it */ event->he_size = sizeof(event->he_entropy[0]); event->he_entropy[0] = jenkins_hash(entropy, size, (uint32_t)(uintptr_t)event); } } RANDOM_HARVEST_UNLOCK(); } /*- * Entropy harvesting fast routine. * * This is supposed to be very fast; do not do anything slow in here! * This is the right place for high-rate harvested data. */ void random_harvest_fast_(const void *entropy, u_int size) { u_int pos; pos = harvest_context.hc_entropy_fast_accumulator.pos; harvest_context.hc_entropy_fast_accumulator.buf[pos] ^= jenkins_hash(entropy, size, random_get_cyclecount()); harvest_context.hc_entropy_fast_accumulator.pos = (pos + 1)%RANDOM_ACCUM_MAX; } /*- * Entropy harvesting direct routine. * * This is not supposed to be fast, but will only be used during * (e.g.) booting when initial entropy is being gathered. */ void random_harvest_direct_(const void *entropy, u_int size, enum random_entropy_source origin) { struct harvest_event event; KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin)); size = MIN(size, sizeof(event.he_entropy)); event.he_somecounter = random_get_cyclecount(); event.he_size = size; event.he_source = origin; event.he_destination = harvest_context.hc_destination[origin]++; memcpy(event.he_entropy, entropy, size); random_harvestq_fast_process_event(&event); } void random_harvest_register_source(enum random_entropy_source source) { hc_source_mask |= (1 << source); } void random_harvest_deregister_source(enum random_entropy_source source) { hc_source_mask &= ~(1 << source); } void random_source_register(struct random_source *rsource) { struct random_sources *rrs; KASSERT(rsource != NULL, ("invalid input to %s", __func__)); rrs = malloc(sizeof(*rrs), M_ENTROPY, M_WAITOK); rrs->rrs_source = rsource; random_harvest_register_source(rsource->rs_source); printf("random: registering fast source %s\n", rsource->rs_ident); RANDOM_HARVEST_LOCK(); CK_LIST_INSERT_HEAD(&source_list, rrs, rrs_entries); RANDOM_HARVEST_UNLOCK(); } void random_source_deregister(struct random_source *rsource) { struct random_sources *rrs = NULL; KASSERT(rsource != NULL, ("invalid input to %s", __func__)); random_harvest_deregister_source(rsource->rs_source); RANDOM_HARVEST_LOCK(); CK_LIST_FOREACH(rrs, &source_list, rrs_entries) if (rrs->rrs_source == rsource) { CK_LIST_REMOVE(rrs, rrs_entries); break; } RANDOM_HARVEST_UNLOCK(); if (rrs != NULL && epoch_inited) epoch_wait_preempt(rs_epoch); free(rrs, M_ENTROPY); } static int random_source_handler(SYSCTL_HANDLER_ARGS) { struct epoch_tracker et; struct random_sources *rrs; struct sbuf sbuf; int error, count; error = sysctl_wire_old_buffer(req, 0); if (error != 0) return (error); sbuf_new_for_sysctl(&sbuf, NULL, 64, req); count = 0; epoch_enter_preempt(rs_epoch, &et); CK_LIST_FOREACH(rrs, &source_list, rrs_entries) { sbuf_cat(&sbuf, (count++ ? ",'" : "'")); sbuf_cat(&sbuf, rrs->rrs_source->rs_ident); sbuf_cat(&sbuf, "'"); } epoch_exit_preempt(rs_epoch, &et); error = sbuf_finish(&sbuf); sbuf_delete(&sbuf); return (error); } SYSCTL_PROC(_kern_random, OID_AUTO, random_sources, CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, random_source_handler, "A", "List of active fast entropy sources."); MODULE_VERSION(random_harvestq, 1);