Index: head/sys/dev/random/random_harvestq.c =================================================================== --- head/sys/dev/random/random_harvestq.c (revision 288702) +++ head/sys/dev/random/random_harvestq.c (revision 288703) @@ -1,477 +1,486 @@ /*- * 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 __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if defined(RANDOM_LOADABLE) #include #include #endif #include #include #include #include static void random_kthread(void); static void random_sources_feed(void); static u_int read_rate; /* List for the dynamic sysctls */ static struct sysctl_ctx_list random_clist; /* * 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; /* * 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; /* Allow the sysadmin to select the broad category of * entropy types to harvest. */ u_int hc_source_mask; /* * Lockless ring buffer holding entropy events * If ring.in == ring.out, * the buffer is empty. * If ring.in != ring.out, * the buffer contains harvested entropy. * If (ring.in + 1) == ring.out (mod RANDOM_RING_MAX), * the buffer is full. * * NOTE: ring.in points to the last added element, * and ring.out points to the last consumed element. * * The ring.in variable needs locking as there are multiple * sources to the ring. Only the sources may change ring.in, * but the consumer may examine it. * * The ring.out variable does not need locking as there is * only one consumer. Only the consumer may change ring.out, * but the sources may examine it. */ struct entropy_ring { struct harvest_event ring[RANDOM_RING_MAX]; volatile u_int in; volatile u_int out; } hc_entropy_ring; struct fast_entropy_accumulator { volatile u_int pos; uint32_t buf[RANDOM_ACCUM_MAX]; } hc_entropy_fast_accumulator; } harvest_context; static struct kproc_desc random_proc_kp = { "rand_harvestq", random_kthread, &harvest_context.hc_kthread_proc, }; /* Pass the given event straight through to Fortuna/Yarrow/Whatever. */ static __inline void random_harvestq_fast_process_event(struct harvest_event *event) { #if defined(RANDOM_LOADABLE) RANDOM_CONFIG_S_LOCK(); if (p_random_alg_context) #endif p_random_alg_context->ra_event_processor(event); #if defined(RANDOM_LOADABLE) RANDOM_CONFIG_S_UNLOCK(); #endif } static void random_kthread(void) { u_int maxloop, ring_out, i; /* * Locking is not needed as this is the only place we modify ring.out, and * we only examine ring.in without changing it. Both of these are volatile, * and this is a unique thread. */ for (random_kthread_control = 1; random_kthread_control;) { /* Deal with events, if any. Restrict the number we do in one go. */ maxloop = RANDOM_RING_MAX; while (harvest_context.hc_entropy_ring.out != harvest_context.hc_entropy_ring.in) { ring_out = (harvest_context.hc_entropy_ring.out + 1)%RANDOM_RING_MAX; random_harvestq_fast_process_event(harvest_context.hc_entropy_ring.ring + ring_out); harvest_context.hc_entropy_ring.out = ring_out; if (!--maxloop) break; } random_sources_feed(); /* XXX: FIX!! Increase the high-performance data rate? Need some measurements first. */ for (i = 0; i < RANDOM_ACCUM_MAX; i++) { if (harvest_context.hc_entropy_fast_accumulator.buf[i]) { random_harvest_direct(harvest_context.hc_entropy_fast_accumulator.buf + i, sizeof(harvest_context.hc_entropy_fast_accumulator.buf[0]), 4, RANDOM_UMA); harvest_context.hc_entropy_fast_accumulator.buf[i] = 0; } } /* XXX: FIX!! This is a *great* place to pass hardware/live entropy to random(9) */ tsleep_sbt(&harvest_context.hc_kthread_proc, 0, "-", SBT_1S/10, 0, C_PREL(1)); } random_kthread_control = -1; wakeup(&harvest_context.hc_kthread_proc); kproc_exit(0); /* NOTREACHED */ } /* This happens well after SI_SUB_RANDOM */ SYSINIT(random_device_h_proc, SI_SUB_CREATE_INIT, SI_ORDER_ANY, kproc_start, &random_proc_kp); /* * 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; 2 for Yarrow and 32 * for Fortuna. */ static void random_sources_feed(void) { uint32_t entropy[HARVESTSIZE]; struct random_sources *rrs; u_int i, n, local_read_rate; /* * Step over all of live entropy sources, and feed their output * to the system-wide RNG. */ #if defined(RANDOM_LOADABLE) RANDOM_CONFIG_S_LOCK(); if (p_random_alg_context) { /* It's an indenting error. Yeah, Yeah. */ #endif local_read_rate = atomic_readandclear_32(&read_rate); LIST_FOREACH(rrs, &source_list, rrs_entries) { for (i = 0; i < p_random_alg_context->ra_poolcount*(local_read_rate + 1); i++) { n = rrs->rrs_source->rs_read(entropy, sizeof(entropy)); - KASSERT((n > 0 && n <= sizeof(entropy)), ("very bad return from rs_read (= %d) in %s", n, __func__)); + KASSERT((n <= sizeof(entropy)), ("%s: rs_read returned too much data (%d > %d) in %s", __func__, n, sizeof(entropy))); + /* It would appear that in some circumstances (e.g. virtualisation), + * the underlying hardware entropy source might not always return + * random numbers. Accept this but make a noise. If too much happens, + * can that source be trusted? + */ + if (n == 0) { + printf("%s: rs_read for hardware device '%s' returned no entropy.\n", __func__, rrs->rrs_source->rs_ident); + continue; + } random_harvest_direct(entropy, n, (n*8)/2, rrs->rrs_source->rs_source); } } explicit_bzero(entropy, sizeof(entropy)); #if defined(RANDOM_LOADABLE) } RANDOM_CONFIG_S_UNLOCK(); #endif } void read_rate_increment(u_int chunk) { atomic_add_32(&read_rate, chunk); } /* ARGSUSED */ RANDOM_CHECK_UINT(harvestmask, 0, RANDOM_HARVEST_EVERYTHING_MASK); /* ARGSUSED */ 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 = RANDOM_ENVIRONMENTAL_END; i >= 0; i--) sbuf_cat(&sbuf, (harvest_context.hc_source_mask & (1 << i)) ? "1" : "0"); error = sbuf_finish(&sbuf); sbuf_delete(&sbuf); } return (error); } static const char *(random_source_descr[]) = { "CACHED", "ATTACH", "KEYBOARD", "MOUSE", "NET_TUN", "NET_ETHER", "NET_NG", "INTERRUPT", "SWI", "FS_ATIME", "UMA", /* ENVIRONMENTAL_END */ "PURE_OCTEON", "PURE_SAFE", "PURE_GLXSB", "PURE_UBSEC", "PURE_HIFN", "PURE_RDRAND", "PURE_NEHEMIAH", "PURE_RNDTEST", /* "ENTROPYSOURCE" */ }; /* ARGSUSED */ static int random_print_harvestmask_symbolic(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 = RANDOM_ENVIRONMENTAL_END; i >= 0; i--) { sbuf_cat(&sbuf, (i == RANDOM_ENVIRONMENTAL_END) ? "" : ","); sbuf_cat(&sbuf, !(harvest_context.hc_source_mask & (1 << i)) ? "[" : ""); sbuf_cat(&sbuf, random_source_descr[i]); sbuf_cat(&sbuf, !(harvest_context.hc_source_mask & (1 << i)) ? "]" : ""); } error = sbuf_finish(&sbuf); sbuf_delete(&sbuf); } return (error); } /* ARGSUSED */ static void random_harvestq_init(void *unused __unused) { struct sysctl_oid *random_sys_o; random_sys_o = SYSCTL_ADD_NODE(&random_clist, SYSCTL_STATIC_CHILDREN(_kern_random), OID_AUTO, "harvest", CTLFLAG_RW, 0, "Entropy Device Parameters"); harvest_context.hc_source_mask = RANDOM_HARVEST_EVERYTHING_MASK; SYSCTL_ADD_PROC(&random_clist, SYSCTL_CHILDREN(random_sys_o), OID_AUTO, "mask", CTLTYPE_UINT | CTLFLAG_RW, &harvest_context.hc_source_mask, 0, random_check_uint_harvestmask, "IU", "Entropy harvesting mask"); SYSCTL_ADD_PROC(&random_clist, SYSCTL_CHILDREN(random_sys_o), OID_AUTO, "mask_bin", CTLTYPE_STRING | CTLFLAG_RD, NULL, 0, random_print_harvestmask, "A", "Entropy harvesting mask (printable)"); SYSCTL_ADD_PROC(&random_clist, SYSCTL_CHILDREN(random_sys_o), OID_AUTO, "mask_symbolic", CTLTYPE_STRING | CTLFLAG_RD, NULL, 0, random_print_harvestmask_symbolic, "A", "Entropy harvesting mask (symbolic)"); RANDOM_HARVEST_INIT_LOCK(); harvest_context.hc_entropy_ring.in = harvest_context.hc_entropy_ring.out = 0; } SYSINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_SECOND, random_harvestq_init, NULL); /* * 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, e.g. Fortuna or Yarrow. */ /* ARGSUSED */ static void random_harvestq_prime(void *unused __unused) { struct harvest_event event; size_t count, size, i; uint8_t *keyfile, *data; /* * Get entropy that may have been preloaded by loader(8) * and use it to pre-charge the entropy harvest queue. */ keyfile = preload_search_by_type(RANDOM_HARVESTQ_BOOT_ENTROPY_FILE); if (keyfile != NULL) { data = preload_fetch_addr(keyfile); size = preload_fetch_size(keyfile); /* Trim the size. If the admin has a file with a funny size, we lose some. Tough. */ size -= (size % sizeof(event.he_entropy)); if (data != NULL && size != 0) { for (i = 0; i < size; i += sizeof(event.he_entropy)) { count = sizeof(event.he_entropy); event.he_somecounter = (uint32_t)get_cyclecount(); event.he_size = count; event.he_bits = count/4; /* Underestimate the size for Yarrow */ event.he_source = RANDOM_CACHED; event.he_destination = harvest_context.hc_destination[0]++; memcpy(event.he_entropy, data + i, sizeof(event.he_entropy)); random_harvestq_fast_process_event(&event); explicit_bzero(&event, sizeof(event)); } explicit_bzero(data, size); if (bootverbose) printf("random: read %zu bytes from preloaded cache\n", size); } else if (bootverbose) printf("random: no preloaded entropy cache\n"); } } SYSINIT(random_device_prime, SI_SUB_RANDOM, SI_ORDER_FOURTH, random_harvestq_prime, NULL); /* ARGSUSED */ 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); sysctl_ctx_free(&random_clist); } SYSUNINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_SECOND, 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 will usually cause lots of failures of the "Lockless read" * check a few lines below. 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, u_int bits, enum random_entropy_source origin) { struct harvest_event *event; u_int ring_in; KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin)); if (!(harvest_context.hc_source_mask & (1 << origin))) return; RANDOM_HARVEST_LOCK(); ring_in = (harvest_context.hc_entropy_ring.in + 1)%RANDOM_RING_MAX; if (ring_in != harvest_context.hc_entropy_ring.out) { /* The ring is not full */ event = harvest_context.hc_entropy_ring.ring + ring_in; event->he_somecounter = (uint32_t)get_cyclecount(); event->he_source = origin; event->he_destination = harvest_context.hc_destination[origin]++; event->he_bits = bits; 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); } harvest_context.hc_entropy_ring.in = ring_in; } 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 bits, enum random_entropy_source origin) { u_int pos; KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin)); /* XXX: FIX!! The above KASSERT is BS. Right now we ignore most structure and just accumulate the supplied data */ if (!(harvest_context.hc_source_mask & (1 << origin))) return; pos = harvest_context.hc_entropy_fast_accumulator.pos; harvest_context.hc_entropy_fast_accumulator.buf[pos] ^= jenkins_hash(entropy, size, (uint32_t)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, u_int bits, enum random_entropy_source origin) { struct harvest_event event; KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin)); if (!(harvest_context.hc_source_mask & (1 << origin))) return; size = MIN(size, sizeof(event.he_entropy)); event.he_somecounter = (uint32_t)get_cyclecount(); event.he_size = size; event.he_bits = bits; event.he_source = origin; event.he_destination = harvest_context.hc_destination[origin]++; memcpy(event.he_entropy, entropy, size); random_harvestq_fast_process_event(&event); explicit_bzero(&event, sizeof(event)); } MODULE_VERSION(random_harvestq, 1);