randomdev_soft.c revision 128320
1128059Smarkm/*- 2128059Smarkm * Copyright (c) 2000-2004 Mark R V Murray 3128059Smarkm * All rights reserved. 4128059Smarkm * 5128059Smarkm * Redistribution and use in source and binary forms, with or without 6128059Smarkm * modification, are permitted provided that the following conditions 7128059Smarkm * are met: 8128059Smarkm * 1. Redistributions of source code must retain the above copyright 9128059Smarkm * notice, this list of conditions and the following disclaimer 10128059Smarkm * in this position and unchanged. 11128059Smarkm * 2. Redistributions in binary form must reproduce the above copyright 12128059Smarkm * notice, this list of conditions and the following disclaimer in the 13128059Smarkm * documentation and/or other materials provided with the distribution. 14128059Smarkm * 15128059Smarkm * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16128059Smarkm * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17128059Smarkm * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18128059Smarkm * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19128059Smarkm * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20128059Smarkm * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21128059Smarkm * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22128059Smarkm * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23128059Smarkm * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24128059Smarkm * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25128059Smarkm * 26128059Smarkm */ 27128059Smarkm 28128059Smarkm#include <sys/cdefs.h> 29128059Smarkm__FBSDID("$FreeBSD: head/sys/dev/random/randomdev_soft.c 128320 2004-04-16 17:07:11Z markm $"); 30128059Smarkm 31128059Smarkm#include <sys/param.h> 32128059Smarkm#include <sys/systm.h> 33128059Smarkm#include <sys/bus.h> 34128059Smarkm#include <sys/conf.h> 35128059Smarkm#include <sys/fcntl.h> 36128059Smarkm#include <sys/kernel.h> 37128059Smarkm#include <sys/kthread.h> 38128059Smarkm#include <sys/lock.h> 39128059Smarkm#include <sys/malloc.h> 40128059Smarkm#include <sys/mutex.h> 41128059Smarkm#include <sys/poll.h> 42128059Smarkm#include <sys/proc.h> 43128059Smarkm#include <sys/random.h> 44128059Smarkm#include <sys/selinfo.h> 45128059Smarkm#include <sys/sysctl.h> 46128059Smarkm#include <sys/uio.h> 47128059Smarkm#include <sys/unistd.h> 48128059Smarkm#include <sys/vnode.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 *); 59128059Smarkmstatic void 60128059Smarkmrandom_harvest_internal(u_int64_t, const void *, u_int, 61128059Smarkm u_int, u_int, enum esource); 62128059Smarkm 63128059Smarkmstruct random_systat random_yarrow = { 64128059Smarkm .ident = "Software, Yarrow", 65128059Smarkm .init = random_yarrow_init, 66128059Smarkm .deinit = random_yarrow_deinit, 67128059Smarkm .read = random_yarrow_read, 68128059Smarkm .write = random_yarrow_write, 69128059Smarkm .reseed = random_yarrow_reseed, 70128059Smarkm .seeded = 0, 71128059Smarkm}; 72128059Smarkm 73128059SmarkmMALLOC_DEFINE(M_ENTROPY, "entropy", "Entropy harvesting buffers"); 74128059Smarkm 75128059Smarkm/* Lockable FIFO queue holding entropy buffers */ 76128059Smarkmstruct entropyfifo { 77128059Smarkm struct mtx lock; 78128059Smarkm int count; 79128059Smarkm STAILQ_HEAD(harvestlist, harvest) head; 80128059Smarkm}; 81128059Smarkm 82128059Smarkm/* Empty entropy buffers */ 83128059Smarkmstatic struct entropyfifo emptyfifo; 84128059Smarkm 85128059Smarkm#define EMPTYBUFFERS 1024 86128059Smarkm 87128059Smarkm/* Harvested entropy */ 88128059Smarkmstatic struct entropyfifo harvestfifo[ENTROPYSOURCE]; 89128059Smarkm 90128059Smarkm/* <0 to end the kthread, 0 to let it run */ 91128059Smarkmstatic int random_kthread_control = 0; 92128059Smarkm 93128059Smarkmstatic struct proc *random_kthread_proc; 94128059Smarkm 95128059Smarkm/* List for the dynamic sysctls */ 96128059Smarkmstruct sysctl_ctx_list random_clist; 97128059Smarkm 98128059Smarkm/* ARGSUSED */ 99128059Smarkmstatic int 100128059Smarkmrandom_check_boolean(SYSCTL_HANDLER_ARGS) 101128059Smarkm{ 102128059Smarkm if (oidp->oid_arg1 != NULL && *(u_int *)(oidp->oid_arg1) != 0) 103128059Smarkm *(u_int *)(oidp->oid_arg1) = 1; 104128059Smarkm return sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req); 105128059Smarkm} 106128059Smarkm 107128059Smarkm/* ARGSUSED */ 108128059Smarkmvoid 109128059Smarkmrandom_yarrow_init(void) 110128059Smarkm{ 111128059Smarkm int error, i; 112128059Smarkm struct harvest *np; 113128059Smarkm struct sysctl_oid *o, *random_o, *random_sys_o, *random_sys_harvest_o; 114128059Smarkm enum esource e; 115128059Smarkm 116128059Smarkm o = SYSCTL_ADD_NODE(&random_clist, 117128059Smarkm SYSCTL_STATIC_CHILDREN(_kern), 118128059Smarkm OID_AUTO, "random", CTLFLAG_RW, 0, 119128059Smarkm "Software Random Number Generator"); 120128059Smarkm 121128059Smarkm random_o = o; 122128059Smarkm 123128059Smarkm random_yarrow_init_alg(&random_clist, random_o); 124128059Smarkm 125128059Smarkm o = SYSCTL_ADD_NODE(&random_clist, 126128059Smarkm SYSCTL_CHILDREN(random_o), 127128059Smarkm OID_AUTO, "sys", CTLFLAG_RW, 0, 128128059Smarkm "Entropy Device Parameters"); 129128059Smarkm 130128059Smarkm random_sys_o = o; 131128059Smarkm 132128059Smarkm o = SYSCTL_ADD_PROC(&random_clist, 133128059Smarkm SYSCTL_CHILDREN(random_sys_o), 134128059Smarkm OID_AUTO, "seeded", CTLTYPE_INT | CTLFLAG_RW, 135128059Smarkm &random_systat.seeded, 0, random_check_boolean, "I", 136128059Smarkm "Seeded State"); 137128059Smarkm 138128059Smarkm o = SYSCTL_ADD_NODE(&random_clist, 139128059Smarkm SYSCTL_CHILDREN(random_sys_o), 140128059Smarkm OID_AUTO, "harvest", CTLFLAG_RW, 0, 141128059Smarkm "Entropy Sources"); 142128059Smarkm 143128059Smarkm random_sys_harvest_o = o; 144128059Smarkm 145128059Smarkm o = SYSCTL_ADD_PROC(&random_clist, 146128059Smarkm SYSCTL_CHILDREN(random_sys_harvest_o), 147128059Smarkm OID_AUTO, "ethernet", CTLTYPE_INT | CTLFLAG_RW, 148128320Smarkm &harvest.ethernet, 1, random_check_boolean, "I", 149128059Smarkm "Harvest NIC entropy"); 150128059Smarkm o = SYSCTL_ADD_PROC(&random_clist, 151128059Smarkm SYSCTL_CHILDREN(random_sys_harvest_o), 152128059Smarkm OID_AUTO, "point_to_point", CTLTYPE_INT | CTLFLAG_RW, 153128320Smarkm &harvest.point_to_point, 1, random_check_boolean, "I", 154128059Smarkm "Harvest serial net entropy"); 155128059Smarkm o = SYSCTL_ADD_PROC(&random_clist, 156128059Smarkm SYSCTL_CHILDREN(random_sys_harvest_o), 157128059Smarkm OID_AUTO, "interrupt", CTLTYPE_INT | CTLFLAG_RW, 158128320Smarkm &harvest.interrupt, 1, random_check_boolean, "I", 159128059Smarkm "Harvest IRQ entropy"); 160128059Smarkm o = SYSCTL_ADD_PROC(&random_clist, 161128059Smarkm SYSCTL_CHILDREN(random_sys_harvest_o), 162128059Smarkm OID_AUTO, "swi", CTLTYPE_INT | CTLFLAG_RW, 163128059Smarkm &harvest.swi, 0, random_check_boolean, "I", 164128059Smarkm "Harvest SWI entropy"); 165128059Smarkm 166128059Smarkm /* Initialise the harvest fifos */ 167128059Smarkm STAILQ_INIT(&emptyfifo.head); 168128059Smarkm emptyfifo.count = 0; 169128059Smarkm mtx_init(&emptyfifo.lock, "entropy harvest buffers", NULL, MTX_SPIN); 170128059Smarkm for (i = 0; i < EMPTYBUFFERS; i++) { 171128059Smarkm np = malloc(sizeof(struct harvest), M_ENTROPY, M_WAITOK); 172128059Smarkm STAILQ_INSERT_TAIL(&emptyfifo.head, np, next); 173128059Smarkm } 174128059Smarkm for (e = RANDOM_START; e < ENTROPYSOURCE; e++) { 175128059Smarkm STAILQ_INIT(&harvestfifo[e].head); 176128059Smarkm harvestfifo[e].count = 0; 177128059Smarkm mtx_init(&harvestfifo[e].lock, "entropy harvest", NULL, 178128059Smarkm MTX_SPIN); 179128059Smarkm } 180128059Smarkm 181128059Smarkm /* Start the hash/reseed thread */ 182128059Smarkm error = kthread_create(random_kthread, NULL, 183128059Smarkm &random_kthread_proc, RFHIGHPID, 0, "yarrow"); 184128059Smarkm if (error != 0) 185128059Smarkm panic("Cannot create entropy maintenance thread."); 186128059Smarkm 187128059Smarkm /* Register the randomness harvesting routine */ 188128059Smarkm random_yarrow_init_harvester(random_harvest_internal, 189128059Smarkm random_yarrow_read); 190128059Smarkm} 191128059Smarkm 192128059Smarkm/* ARGSUSED */ 193128059Smarkmvoid 194128059Smarkmrandom_yarrow_deinit(void) 195128059Smarkm{ 196128059Smarkm struct harvest *np; 197128059Smarkm enum esource e; 198128059Smarkm 199128059Smarkm /* Deregister the randomness harvesting routine */ 200128059Smarkm random_yarrow_deinit_harvester(); 201128059Smarkm 202128059Smarkm /* 203128059Smarkm * Command the hash/reseed thread to end and wait for it to finish 204128059Smarkm */ 205128059Smarkm random_kthread_control = -1; 206128059Smarkm tsleep((void *)&random_kthread_control, PUSER, "term", 0); 207128059Smarkm 208128059Smarkm /* Destroy the harvest fifos */ 209128059Smarkm while (!STAILQ_EMPTY(&emptyfifo.head)) { 210128059Smarkm np = STAILQ_FIRST(&emptyfifo.head); 211128059Smarkm STAILQ_REMOVE_HEAD(&emptyfifo.head, next); 212128059Smarkm free(np, M_ENTROPY); 213128059Smarkm } 214128059Smarkm mtx_destroy(&emptyfifo.lock); 215128059Smarkm for (e = RANDOM_START; e < ENTROPYSOURCE; e++) { 216128059Smarkm while (!STAILQ_EMPTY(&harvestfifo[e].head)) { 217128059Smarkm np = STAILQ_FIRST(&harvestfifo[e].head); 218128059Smarkm STAILQ_REMOVE_HEAD(&harvestfifo[e].head, next); 219128059Smarkm free(np, M_ENTROPY); 220128059Smarkm } 221128059Smarkm mtx_destroy(&harvestfifo[e].lock); 222128059Smarkm } 223128059Smarkm 224128059Smarkm random_yarrow_deinit_alg(); 225128059Smarkm 226128059Smarkm sysctl_ctx_free(&random_clist); 227128059Smarkm} 228128059Smarkm 229128059Smarkm/* ARGSUSED */ 230128059Smarkmstatic void 231128059Smarkmrandom_kthread(void *arg __unused) 232128059Smarkm{ 233128059Smarkm struct harvest *event = NULL; 234128059Smarkm int found, active; 235128059Smarkm enum esource source; 236128059Smarkm 237128059Smarkm /* Process until told to stop */ 238128059Smarkm for (; random_kthread_control == 0;) { 239128059Smarkm 240128059Smarkm active = 0; 241128059Smarkm 242128059Smarkm /* Cycle through all the entropy sources */ 243128059Smarkm for (source = RANDOM_START; source < ENTROPYSOURCE; source++) { 244128059Smarkm 245128059Smarkm found = 0; 246128059Smarkm 247128059Smarkm /* Lock up queue draining */ 248128059Smarkm mtx_lock_spin(&harvestfifo[source].lock); 249128059Smarkm 250128059Smarkm if (!STAILQ_EMPTY(&harvestfifo[source].head)) { 251128059Smarkm 252128059Smarkm /* Get a harvested entropy event */ 253128059Smarkm harvestfifo[source].count--; 254128059Smarkm event = STAILQ_FIRST(&harvestfifo[source].head); 255128059Smarkm STAILQ_REMOVE_HEAD(&harvestfifo[source].head, 256128059Smarkm next); 257128059Smarkm 258128059Smarkm active = found = 1; 259128059Smarkm 260128059Smarkm } 261128059Smarkm /* Unlock the queue */ 262128059Smarkm mtx_unlock_spin(&harvestfifo[source].lock); 263128059Smarkm 264128059Smarkm /* Deal with the event and dispose of it */ 265128059Smarkm if (found) { 266128059Smarkm 267128059Smarkm random_process_event(event); 268128059Smarkm 269128059Smarkm /* Lock the empty event buffer fifo */ 270128059Smarkm mtx_lock_spin(&emptyfifo.lock); 271128059Smarkm 272128059Smarkm STAILQ_INSERT_TAIL(&emptyfifo.head, event, 273128059Smarkm next); 274128059Smarkm 275128059Smarkm mtx_unlock_spin(&emptyfifo.lock); 276128059Smarkm 277128059Smarkm } 278128059Smarkm } 279128059Smarkm 280128059Smarkm /* Found nothing, so don't belabour the issue */ 281128059Smarkm if (!active) 282128059Smarkm tsleep(&harvestfifo, PUSER, "-", hz / 10); 283128059Smarkm 284128059Smarkm } 285128059Smarkm 286128059Smarkm random_set_wakeup_exit(&random_kthread_control); 287128059Smarkm /* NOTREACHED */ 288128059Smarkm} 289128059Smarkm 290128059Smarkm/* Entropy harvesting routine. This is supposed to be fast; do 291128059Smarkm * not do anything slow in here! 292128059Smarkm */ 293128059Smarkmstatic void 294128059Smarkmrandom_harvest_internal(u_int64_t somecounter, const void *entropy, 295128059Smarkm u_int count, u_int bits, u_int frac, enum esource origin) 296128059Smarkm{ 297128059Smarkm struct harvest *event; 298128059Smarkm 299128059Smarkm /* Lock the particular fifo */ 300128059Smarkm mtx_lock_spin(&harvestfifo[origin].lock); 301128059Smarkm 302128059Smarkm /* 303128059Smarkm * Don't make the harvest queues too big - help to prevent low-grade 304128059Smarkm * entropy swamping 305128059Smarkm */ 306128059Smarkm if (harvestfifo[origin].count < RANDOM_FIFO_MAX) { 307128059Smarkm 308128059Smarkm /* Lock the empty event buffer fifo */ 309128059Smarkm mtx_lock_spin(&emptyfifo.lock); 310128059Smarkm 311128059Smarkm if (!STAILQ_EMPTY(&emptyfifo.head)) { 312128059Smarkm event = STAILQ_FIRST(&emptyfifo.head); 313128059Smarkm STAILQ_REMOVE_HEAD(&emptyfifo.head, next); 314128059Smarkm } else 315128059Smarkm event = NULL; 316128059Smarkm 317128059Smarkm mtx_unlock_spin(&emptyfifo.lock); 318128059Smarkm 319128059Smarkm /* If we didn't obtain a buffer, tough */ 320128059Smarkm if (event) { 321128059Smarkm 322128059Smarkm /* Add the harvested data to the fifo */ 323128059Smarkm harvestfifo[origin].count++; 324128059Smarkm event->somecounter = somecounter; 325128059Smarkm event->size = count; 326128059Smarkm event->bits = bits; 327128059Smarkm event->frac = frac; 328128059Smarkm event->source = origin; 329128059Smarkm 330128059Smarkm /* XXXX Come back and make this dynamic! */ 331128059Smarkm count = MIN(count, HARVESTSIZE); 332128059Smarkm memcpy(event->entropy, entropy, count); 333128059Smarkm 334128059Smarkm STAILQ_INSERT_TAIL(&harvestfifo[origin].head, 335128059Smarkm event, next); 336128059Smarkm } 337128059Smarkm } 338128059Smarkm mtx_unlock_spin(&harvestfifo[origin].lock); 339128059Smarkm 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} 370