1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #pragma ident "%Z%%M% %I% %E% SMI" 27 28 #include <stdio.h> 29 #include <unistd.h> 30 #include <errno.h> 31 #include <string.h> 32 #include <fcntl.h> 33 #include <locale.h> 34 #include <cryptoutil.h> 35 36 #ifdef _REENTRANT 37 38 #include <pthread.h> 39 40 static pthread_mutex_t random_mutex = PTHREAD_MUTEX_INITIALIZER; 41 static pthread_mutex_t urandom_mutex = PTHREAD_MUTEX_INITIALIZER; 42 43 #define RAND_LOCK(x) (void) pthread_mutex_lock(x) 44 #define RAND_UNLOCK(x) (void) pthread_mutex_unlock(x) 45 46 #else 47 48 #define RAND_LOCK(x) 49 #define RAND_UNLOCK(x) 50 51 #endif 52 53 #define RANDOM_DEVICE "/dev/random" /* random device name */ 54 #define URANDOM_DEVICE "/dev/urandom" /* urandom device name */ 55 56 static int random_fd = -1; 57 static int urandom_fd = -1; 58 59 /* 60 * Equivalent of open(2) insulated from EINTR. 61 * Also sets close-on-exec. 62 */ 63 static int 64 OPEN(const char *path, int oflag) 65 { 66 int fd; 67 68 do { 69 if ((fd = open(path, oflag)) >= 0) { 70 (void) fcntl(fd, F_SETFD, FD_CLOEXEC); 71 break; 72 } 73 /* errno definitely set by failed open() */ 74 } while (errno == EINTR); 75 return (fd); 76 } 77 78 /* 79 * Equivalent of read(2) insulated from EINTR. 80 */ 81 static ssize_t 82 READ(int fd, void *dbuf, size_t dlen) 83 { 84 char *marker = dbuf; 85 size_t left = dlen; 86 ssize_t nread = 0, err; 87 88 for (err = 0; left > 0 && nread != -1; marker += nread, left -= nread) { 89 if ((nread = read(fd, marker, left)) < 0) { 90 if (errno == EINTR) { /* keep trying */ 91 nread = 0; 92 continue; 93 } 94 err = nread; /* hard error */ 95 break; 96 } 97 } 98 return (err != 0 ? err : dlen - left); 99 } 100 101 /* 102 * Opens the random number generator devices if not already open. 103 * Always returns the opened fd of the device, or error. 104 */ 105 int 106 pkcs11_open_random(void) 107 { 108 RAND_LOCK(&random_mutex); 109 if (random_fd < 0) 110 random_fd = OPEN(RANDOM_DEVICE, O_RDONLY); 111 RAND_UNLOCK(&random_mutex); 112 return (random_fd); 113 } 114 115 int 116 pkcs11_open_urandom(void) 117 { 118 RAND_LOCK(&urandom_mutex); 119 if (urandom_fd < 0) 120 urandom_fd = OPEN(URANDOM_DEVICE, O_RDONLY); 121 RAND_UNLOCK(&urandom_mutex); 122 return (urandom_fd); 123 } 124 125 /* 126 * Close the random number generator devices if already open. 127 */ 128 void 129 pkcs11_close_random(void) 130 { 131 if (random_fd < 0) 132 return; 133 RAND_LOCK(&random_mutex); 134 (void) close(random_fd); 135 random_fd = -1; 136 RAND_UNLOCK(&random_mutex); 137 } 138 139 void 140 pkcs11_close_urandom(void) 141 { 142 if (urandom_fd < 0) 143 return; 144 RAND_LOCK(&urandom_mutex); 145 (void) close(urandom_fd); 146 urandom_fd = -1; 147 RAND_UNLOCK(&urandom_mutex); 148 } 149 150 /* 151 * Put the requested amount of random data into a preallocated buffer. 152 * Good for passphrase salts, initialization vectors. 153 */ 154 int 155 pkcs11_random_data(void *dbuf, size_t dlen) 156 { 157 if (dbuf == NULL || dlen == 0) 158 return (0); 159 160 /* Read random data directly from /dev/urandom */ 161 if (pkcs11_open_urandom() < 0) 162 return (-1); 163 164 if (READ(urandom_fd, dbuf, dlen) == dlen) 165 return (0); 166 return (-1); 167 } 168 169 /* 170 * Same as pkcs11_random_data but ensures non zero data. 171 */ 172 int 173 pkcs11_nzero_random_data(void *dbuf, size_t dlen) 174 { 175 char extrarand[32]; 176 size_t bytesleft = 0; 177 size_t i = 0; 178 179 /* Start with some random data */ 180 if (pkcs11_random_data(dbuf, dlen) < 0) 181 return (-1); 182 183 /* Walk through data replacing any 0 bytes with more random data */ 184 while (i < dlen) { 185 if (((char *)dbuf)[i] != 0) { 186 i++; 187 continue; 188 } 189 190 if (bytesleft == 0) { 191 bytesleft = sizeof (extrarand); 192 if (pkcs11_random_data(extrarand, bytesleft) < 0) 193 return (-1); 194 } 195 bytesleft--; 196 197 ((char *)dbuf)[i] = extrarand[bytesleft]; 198 } 199 return (0); 200 } 201