randomdev_soft.c revision 192774
1128059Smarkm/*- 2192774Smarkm * Copyright (c) 2000-2009 Mark R V Murray 3136338Srwatson * Copyright (c) 2004 Robert N. M. Watson 4128059Smarkm * All rights reserved. 5128059Smarkm * 6128059Smarkm * Redistribution and use in source and binary forms, with or without 7128059Smarkm * modification, are permitted provided that the following conditions 8128059Smarkm * are met: 9128059Smarkm * 1. Redistributions of source code must retain the above copyright 10128059Smarkm * notice, this list of conditions and the following disclaimer 11128059Smarkm * in this position and unchanged. 12128059Smarkm * 2. Redistributions in binary form must reproduce the above copyright 13128059Smarkm * notice, this list of conditions and the following disclaimer in the 14128059Smarkm * documentation and/or other materials provided with the distribution. 15128059Smarkm * 16128059Smarkm * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17128059Smarkm * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18128059Smarkm * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19128059Smarkm * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20128059Smarkm * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21128059Smarkm * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22128059Smarkm * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23128059Smarkm * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24128059Smarkm * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25128059Smarkm * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26128059Smarkm * 27128059Smarkm */ 28128059Smarkm 29128059Smarkm#include <sys/cdefs.h> 30128059Smarkm__FBSDID("$FreeBSD: head/sys/dev/random/randomdev_soft.c 192774 2009-05-25 22:50:11Z markm $"); 31128059Smarkm 32128059Smarkm#include <sys/param.h> 33128059Smarkm#include <sys/systm.h> 34128059Smarkm#include <sys/bus.h> 35128059Smarkm#include <sys/conf.h> 36128059Smarkm#include <sys/fcntl.h> 37128059Smarkm#include <sys/kernel.h> 38128059Smarkm#include <sys/kthread.h> 39128059Smarkm#include <sys/lock.h> 40128059Smarkm#include <sys/malloc.h> 41128059Smarkm#include <sys/mutex.h> 42128059Smarkm#include <sys/poll.h> 43128059Smarkm#include <sys/proc.h> 44128059Smarkm#include <sys/random.h> 45128059Smarkm#include <sys/selinfo.h> 46128059Smarkm#include <sys/sysctl.h> 47128059Smarkm#include <sys/uio.h> 48128059Smarkm#include <sys/unistd.h> 49128059Smarkm 50128059Smarkm#include <machine/bus.h> 51128059Smarkm#include <machine/cpu.h> 52128059Smarkm 53128059Smarkm#include <dev/random/randomdev.h> 54128059Smarkm#include <dev/random/randomdev_soft.h> 55128059Smarkm 56128059Smarkm#define RANDOM_FIFO_MAX 256 /* How many events to queue up */ 57128059Smarkm 58128059Smarkmstatic void random_kthread(void *); 59192774Smarkmstatic void 60128059Smarkmrandom_harvest_internal(u_int64_t, const void *, u_int, 61128059Smarkm u_int, u_int, enum esource); 62153575Spsstatic int random_yarrow_poll(int event,struct thread *td); 63153575Spsstatic int random_yarrow_block(int flag); 64185254Scpercivastatic void random_yarrow_flush_reseed(void); 65128059Smarkm 66128059Smarkmstruct random_systat random_yarrow = { 67128059Smarkm .ident = "Software, Yarrow", 68128059Smarkm .init = random_yarrow_init, 69128059Smarkm .deinit = random_yarrow_deinit, 70153575Sps .block = random_yarrow_block, 71128059Smarkm .read = random_yarrow_read, 72128059Smarkm .write = random_yarrow_write, 73153575Sps .poll = random_yarrow_poll, 74185254Scperciva .reseed = random_yarrow_flush_reseed, 75132346Smarkm .seeded = 1, 76128059Smarkm}; 77128059Smarkm 78128059SmarkmMALLOC_DEFINE(M_ENTROPY, "entropy", "Entropy harvesting buffers"); 79128059Smarkm 80136338Srwatson/* 81136338Srwatson * The harvest mutex protects the consistency of the entropy fifos and 82136338Srwatson * empty fifo. 83136338Srwatson */ 84136338Srwatsonstruct mtx harvest_mtx; 85136338Srwatson 86128059Smarkm/* Lockable FIFO queue holding entropy buffers */ 87128059Smarkmstruct entropyfifo { 88128059Smarkm int count; 89128059Smarkm STAILQ_HEAD(harvestlist, harvest) head; 90128059Smarkm}; 91128059Smarkm 92128059Smarkm/* Empty entropy buffers */ 93128059Smarkmstatic struct entropyfifo emptyfifo; 94128059Smarkm 95128059Smarkm#define EMPTYBUFFERS 1024 96128059Smarkm 97128059Smarkm/* Harvested entropy */ 98144291Smarkmstatic struct entropyfifo harvestfifo[ENTROPYSOURCE]; 99128059Smarkm 100185254Scperciva/* <0 to end the kthread, 0 to let it run, 1 to flush the harvest queues */ 101128059Smarkmstatic int random_kthread_control = 0; 102128059Smarkm 103128059Smarkmstatic struct proc *random_kthread_proc; 104128059Smarkm 105128059Smarkm/* List for the dynamic sysctls */ 106128059Smarkmstruct sysctl_ctx_list random_clist; 107128059Smarkm 108128059Smarkm/* ARGSUSED */ 109128059Smarkmstatic int 110128059Smarkmrandom_check_boolean(SYSCTL_HANDLER_ARGS) 111128059Smarkm{ 112128059Smarkm if (oidp->oid_arg1 != NULL && *(u_int *)(oidp->oid_arg1) != 0) 113128059Smarkm *(u_int *)(oidp->oid_arg1) = 1; 114128059Smarkm return sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req); 115128059Smarkm} 116128059Smarkm 117128059Smarkm/* ARGSUSED */ 118128059Smarkmvoid 119128059Smarkmrandom_yarrow_init(void) 120128059Smarkm{ 121128059Smarkm int error, i; 122128059Smarkm struct harvest *np; 123170067Srwatson struct sysctl_oid *random_o, *random_sys_o, *random_sys_harvest_o; 124128059Smarkm enum esource e; 125128059Smarkm 126170067Srwatson random_o = SYSCTL_ADD_NODE(&random_clist, 127128059Smarkm SYSCTL_STATIC_CHILDREN(_kern), 128128059Smarkm OID_AUTO, "random", CTLFLAG_RW, 0, 129128059Smarkm "Software Random Number Generator"); 130128059Smarkm 131128059Smarkm random_yarrow_init_alg(&random_clist, random_o); 132128059Smarkm 133170067Srwatson random_sys_o = SYSCTL_ADD_NODE(&random_clist, 134128059Smarkm SYSCTL_CHILDREN(random_o), 135128059Smarkm OID_AUTO, "sys", CTLFLAG_RW, 0, 136128059Smarkm "Entropy Device Parameters"); 137128059Smarkm 138170067Srwatson SYSCTL_ADD_PROC(&random_clist, 139128059Smarkm SYSCTL_CHILDREN(random_sys_o), 140128059Smarkm OID_AUTO, "seeded", CTLTYPE_INT | CTLFLAG_RW, 141132346Smarkm &random_systat.seeded, 1, random_check_boolean, "I", 142128059Smarkm "Seeded State"); 143128059Smarkm 144170067Srwatson random_sys_harvest_o = SYSCTL_ADD_NODE(&random_clist, 145128059Smarkm SYSCTL_CHILDREN(random_sys_o), 146128059Smarkm OID_AUTO, "harvest", CTLFLAG_RW, 0, 147128059Smarkm "Entropy Sources"); 148128059Smarkm 149170067Srwatson SYSCTL_ADD_PROC(&random_clist, 150128059Smarkm SYSCTL_CHILDREN(random_sys_harvest_o), 151128059Smarkm OID_AUTO, "ethernet", CTLTYPE_INT | CTLFLAG_RW, 152128320Smarkm &harvest.ethernet, 1, random_check_boolean, "I", 153128059Smarkm "Harvest NIC entropy"); 154170067Srwatson SYSCTL_ADD_PROC(&random_clist, 155128059Smarkm SYSCTL_CHILDREN(random_sys_harvest_o), 156128059Smarkm OID_AUTO, "point_to_point", CTLTYPE_INT | CTLFLAG_RW, 157128320Smarkm &harvest.point_to_point, 1, random_check_boolean, "I", 158128059Smarkm "Harvest serial net entropy"); 159170067Srwatson SYSCTL_ADD_PROC(&random_clist, 160128059Smarkm SYSCTL_CHILDREN(random_sys_harvest_o), 161128059Smarkm OID_AUTO, "interrupt", CTLTYPE_INT | CTLFLAG_RW, 162128320Smarkm &harvest.interrupt, 1, random_check_boolean, "I", 163128059Smarkm "Harvest IRQ entropy"); 164170067Srwatson SYSCTL_ADD_PROC(&random_clist, 165128059Smarkm SYSCTL_CHILDREN(random_sys_harvest_o), 166128059Smarkm OID_AUTO, "swi", CTLTYPE_INT | CTLFLAG_RW, 167128059Smarkm &harvest.swi, 0, random_check_boolean, "I", 168128059Smarkm "Harvest SWI entropy"); 169128059Smarkm 170128059Smarkm /* Initialise the harvest fifos */ 171128059Smarkm STAILQ_INIT(&emptyfifo.head); 172128059Smarkm emptyfifo.count = 0; 173128059Smarkm for (i = 0; i < EMPTYBUFFERS; i++) { 174128059Smarkm np = malloc(sizeof(struct harvest), M_ENTROPY, M_WAITOK); 175128059Smarkm STAILQ_INSERT_TAIL(&emptyfifo.head, np, next); 176128059Smarkm } 177128059Smarkm for (e = RANDOM_START; e < ENTROPYSOURCE; e++) { 178128059Smarkm STAILQ_INIT(&harvestfifo[e].head); 179128059Smarkm harvestfifo[e].count = 0; 180128059Smarkm } 181128059Smarkm 182136338Srwatson mtx_init(&harvest_mtx, "entropy harvest mutex", NULL, MTX_SPIN); 183136338Srwatson 184128059Smarkm /* Start the hash/reseed thread */ 185172836Sjulian error = kproc_create(random_kthread, NULL, 186128059Smarkm &random_kthread_proc, RFHIGHPID, 0, "yarrow"); 187128059Smarkm if (error != 0) 188128059Smarkm panic("Cannot create entropy maintenance thread."); 189128059Smarkm 190128059Smarkm /* Register the randomness harvesting routine */ 191128059Smarkm random_yarrow_init_harvester(random_harvest_internal, 192128059Smarkm random_yarrow_read); 193128059Smarkm} 194128059Smarkm 195128059Smarkm/* ARGSUSED */ 196128059Smarkmvoid 197128059Smarkmrandom_yarrow_deinit(void) 198128059Smarkm{ 199128059Smarkm struct harvest *np; 200128059Smarkm enum esource e; 201128059Smarkm 202128059Smarkm /* Deregister the randomness harvesting routine */ 203128059Smarkm random_yarrow_deinit_harvester(); 204128059Smarkm 205128059Smarkm /* 206128059Smarkm * Command the hash/reseed thread to end and wait for it to finish 207128059Smarkm */ 208128059Smarkm random_kthread_control = -1; 209157815Sjhb tsleep((void *)&random_kthread_control, 0, "term", 0); 210128059Smarkm 211128059Smarkm /* Destroy the harvest fifos */ 212128059Smarkm while (!STAILQ_EMPTY(&emptyfifo.head)) { 213128059Smarkm np = STAILQ_FIRST(&emptyfifo.head); 214128059Smarkm STAILQ_REMOVE_HEAD(&emptyfifo.head, next); 215128059Smarkm free(np, M_ENTROPY); 216128059Smarkm } 217128059Smarkm for (e = RANDOM_START; e < ENTROPYSOURCE; e++) { 218128059Smarkm while (!STAILQ_EMPTY(&harvestfifo[e].head)) { 219128059Smarkm np = STAILQ_FIRST(&harvestfifo[e].head); 220128059Smarkm STAILQ_REMOVE_HEAD(&harvestfifo[e].head, next); 221128059Smarkm free(np, M_ENTROPY); 222128059Smarkm } 223128059Smarkm } 224128059Smarkm 225128059Smarkm random_yarrow_deinit_alg(); 226128059Smarkm 227136338Srwatson mtx_destroy(&harvest_mtx); 228136338Srwatson 229128059Smarkm sysctl_ctx_free(&random_clist); 230128059Smarkm} 231128059Smarkm 232128059Smarkm/* ARGSUSED */ 233128059Smarkmstatic void 234128059Smarkmrandom_kthread(void *arg __unused) 235128059Smarkm{ 236136338Srwatson STAILQ_HEAD(, harvest) local_queue; 237128059Smarkm struct harvest *event = NULL; 238192774Smarkm int local_count; 239128059Smarkm enum esource source; 240128059Smarkm 241136338Srwatson STAILQ_INIT(&local_queue); 242137152Srwatson local_count = 0; 243136338Srwatson 244128059Smarkm /* Process until told to stop */ 245185254Scperciva for (; random_kthread_control >= 0;) { 246128059Smarkm 247128059Smarkm /* Cycle through all the entropy sources */ 248136338Srwatson mtx_lock_spin(&harvest_mtx); 249128059Smarkm for (source = RANDOM_START; source < ENTROPYSOURCE; source++) { 250136338Srwatson /* 251136338Srwatson * Drain entropy source records into a thread-local 252136338Srwatson * queue for processing while not holding the mutex. 253136338Srwatson */ 254137152Srwatson STAILQ_CONCAT(&local_queue, &harvestfifo[source].head); 255137152Srwatson local_count += harvestfifo[source].count; 256137152Srwatson harvestfifo[source].count = 0; 257136338Srwatson } 258128059Smarkm 259136338Srwatson /* 260136338Srwatson * Deal with events, if any, dropping the mutex as we process 261136338Srwatson * each event. Then push the events back into the empty 262136338Srwatson * fifo. 263136338Srwatson */ 264136338Srwatson if (!STAILQ_EMPTY(&local_queue)) { 265136338Srwatson mtx_unlock_spin(&harvest_mtx); 266136338Srwatson STAILQ_FOREACH(event, &local_queue, next) 267128059Smarkm random_process_event(event); 268136338Srwatson mtx_lock_spin(&harvest_mtx); 269137152Srwatson STAILQ_CONCAT(&emptyfifo.head, &local_queue); 270137152Srwatson emptyfifo.count += local_count; 271137152Srwatson local_count = 0; 272128059Smarkm } 273136338Srwatson mtx_unlock_spin(&harvest_mtx); 274128059Smarkm 275137152Srwatson KASSERT(local_count == 0, ("random_kthread: local_count %d", 276137152Srwatson local_count)); 277137152Srwatson 278185254Scperciva /* 279185254Scperciva * If a queue flush was commanded, it has now happened, 280185254Scperciva * and we can mark this by resetting the command. 281185254Scperciva */ 282185254Scperciva if (random_kthread_control == 1) 283185254Scperciva random_kthread_control = 0; 284185254Scperciva 285192774Smarkm /* Work done, so don't belabour the issue */ 286192774Smarkm pause("-", hz / 10); 287128059Smarkm 288128059Smarkm } 289128059Smarkm 290128059Smarkm random_set_wakeup_exit(&random_kthread_control); 291128059Smarkm /* NOTREACHED */ 292128059Smarkm} 293128059Smarkm 294128059Smarkm/* Entropy harvesting routine. This is supposed to be fast; do 295128059Smarkm * not do anything slow in here! 296128059Smarkm */ 297128059Smarkmstatic void 298128059Smarkmrandom_harvest_internal(u_int64_t somecounter, const void *entropy, 299128059Smarkm u_int count, u_int bits, u_int frac, enum esource origin) 300128059Smarkm{ 301128059Smarkm struct harvest *event; 302128059Smarkm 303136434Srwatson KASSERT(origin == RANDOM_START || origin == RANDOM_WRITE || 304136434Srwatson origin == RANDOM_KEYBOARD || origin == RANDOM_MOUSE || 305136434Srwatson origin == RANDOM_NET || origin == RANDOM_INTERRUPT || 306144291Smarkm origin == RANDOM_PURE, 307136434Srwatson ("random_harvest_internal: origin %d invalid\n", origin)); 308136434Srwatson 309133465Srwatson /* Lockless read to avoid lock operations if fifo is full. */ 310133465Srwatson if (harvestfifo[origin].count >= RANDOM_FIFO_MAX) 311133465Srwatson return; 312133465Srwatson 313136338Srwatson mtx_lock_spin(&harvest_mtx); 314128059Smarkm 315128059Smarkm /* 316128059Smarkm * Don't make the harvest queues too big - help to prevent low-grade 317128059Smarkm * entropy swamping 318128059Smarkm */ 319128059Smarkm if (harvestfifo[origin].count < RANDOM_FIFO_MAX) { 320136338Srwatson event = STAILQ_FIRST(&emptyfifo.head); 321136338Srwatson if (event != NULL) { 322136338Srwatson /* Add the harvested data to the fifo */ 323128059Smarkm STAILQ_REMOVE_HEAD(&emptyfifo.head, next); 324128059Smarkm harvestfifo[origin].count++; 325128059Smarkm event->somecounter = somecounter; 326128059Smarkm event->size = count; 327128059Smarkm event->bits = bits; 328128059Smarkm event->frac = frac; 329128059Smarkm event->source = origin; 330128059Smarkm 331128059Smarkm /* XXXX Come back and make this dynamic! */ 332128059Smarkm count = MIN(count, HARVESTSIZE); 333128059Smarkm memcpy(event->entropy, entropy, count); 334128059Smarkm 335128059Smarkm STAILQ_INSERT_TAIL(&harvestfifo[origin].head, 336128059Smarkm event, next); 337128059Smarkm } 338128059Smarkm } 339136338Srwatson mtx_unlock_spin(&harvest_mtx); 340128059Smarkm} 341128059Smarkm 342128059Smarkmvoid 343128059Smarkmrandom_yarrow_write(void *buf, int count) 344128059Smarkm{ 345128059Smarkm int i; 346128059Smarkm u_int chunk; 347128059Smarkm 348128059Smarkm /* 349128059Smarkm * Break the input up into HARVESTSIZE chunks. The writer has too 350128059Smarkm * much control here, so "estimate" the the entropy as zero. 351128059Smarkm */ 352128059Smarkm for (i = 0; i < count; i += HARVESTSIZE) { 353128059Smarkm chunk = HARVESTSIZE; 354128059Smarkm if (i + chunk >= count) 355128059Smarkm chunk = (u_int)(count - i); 356128059Smarkm random_harvest_internal(get_cyclecount(), (char *)buf + i, 357128059Smarkm chunk, 0, 0, RANDOM_WRITE); 358128059Smarkm } 359128059Smarkm} 360128059Smarkm 361128059Smarkmvoid 362128059Smarkmrandom_yarrow_unblock(void) 363128059Smarkm{ 364128059Smarkm if (!random_systat.seeded) { 365128059Smarkm random_systat.seeded = 1; 366128059Smarkm selwakeuppri(&random_systat.rsel, PUSER); 367128059Smarkm wakeup(&random_systat); 368128059Smarkm } 369128059Smarkm} 370153575Sps 371153575Spsstatic int 372153575Spsrandom_yarrow_poll(int events, struct thread *td) 373153575Sps{ 374153575Sps int revents = 0; 375153575Sps mtx_lock(&random_reseed_mtx); 376153575Sps 377153575Sps if (random_systat.seeded) 378153575Sps revents = events & (POLLIN | POLLRDNORM); 379153575Sps else 380153575Sps selrecord(td, &random_systat.rsel); 381192774Smarkm 382153575Sps mtx_unlock(&random_reseed_mtx); 383153575Sps return revents; 384153575Sps} 385153575Sps 386153575Spsstatic int 387153575Spsrandom_yarrow_block(int flag) 388153575Sps{ 389153575Sps int error = 0; 390153575Sps 391153575Sps mtx_lock(&random_reseed_mtx); 392153575Sps 393153575Sps /* Blocking logic */ 394153575Sps while (random_systat.seeded && !error) { 395153575Sps if (flag & O_NONBLOCK) 396153575Sps error = EWOULDBLOCK; 397153575Sps else { 398153575Sps printf("Entropy device is blocking.\n"); 399153575Sps error = msleep(&random_systat, 400153575Sps &random_reseed_mtx, 401153575Sps PUSER | PCATCH, "block", 0); 402153575Sps } 403153575Sps } 404153575Sps mtx_unlock(&random_reseed_mtx); 405153575Sps 406153575Sps return error; 407192774Smarkm} 408185254Scperciva 409185254Scperciva/* Helper routine to perform explicit reseeds */ 410185254Scpercivastatic void 411185254Scpercivarandom_yarrow_flush_reseed(void) 412185254Scperciva{ 413185254Scperciva /* Command a entropy queue flush and wait for it to finish */ 414185254Scperciva random_kthread_control = 1; 415185254Scperciva while (random_kthread_control) 416185254Scperciva pause("-", hz / 10); 417185254Scperciva 418185254Scperciva random_yarrow_reseed(); 419185254Scperciva} 420