1 /*- 2 * Copyright (c) 2004 Mark R V Murray 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer 10 * in this position and unchanged. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 #include <sys/param.h> 32 #include <sys/time.h> 33 #include <sys/lock.h> 34 #include <sys/mutex.h> 35 #include <sys/selinfo.h> 36 #include <sys/systm.h> 37 38 #include <dev/random/randomdev.h> 39 40 #define RANDOM_BLOCK_SIZE 256 41 #define CIPHER_BLOCK_SIZE 16 42 43 static void random_nehemiah_init(void); 44 static int random_nehemiah_read(void *, int); 45 46 struct random_systat random_nehemiah = { 47 .ident = "Hardware, VIA Nehemiah", 48 .init = random_nehemiah_init, 49 .deinit = (random_deinit_func_t *)random_null_func, 50 .read = random_nehemiah_read, 51 .write = (random_write_func_t *)random_null_func, 52 .reseed = (random_reseed_func_t *)random_null_func, 53 .seeded = 1, 54 }; 55 56 union VIA_ACE_CW { 57 uint64_t raw; 58 struct { 59 u_int round_count : 4; 60 u_int algorithm_type : 3; 61 u_int key_generation_type : 1; 62 u_int intermediate : 1; 63 u_int decrypt : 1; 64 u_int key_size : 2; 65 u_int filler0 : 20; 66 u_int filler1 : 32; 67 u_int filler2 : 32; 68 u_int filler3 : 32; 69 } field; 70 }; 71 72 /* The extra 7 is to allow an 8-byte write on the last byte of the 73 * arrays. The ACE wants the AES data 16-byte/128-bit aligned, and 74 * it _always_ writes n*64 bits. The RNG does not care about alignment, 75 * and it always writes n*32 bits or n*64 bits. 76 */ 77 static uint8_t key[CIPHER_BLOCK_SIZE+7] __aligned(16); 78 static uint8_t iv[CIPHER_BLOCK_SIZE+7] __aligned(16); 79 static uint8_t in[RANDOM_BLOCK_SIZE+7] __aligned(16); 80 static uint8_t out[RANDOM_BLOCK_SIZE+7] __aligned(16); 81 82 static union VIA_ACE_CW acw __aligned(16); 83 84 /* ARGSUSED */ 85 static __inline size_t 86 VIA_RNG_store(void *buf) 87 { 88 #if defined(__GNUC__) || defined(__INTEL_COMPILER) 89 uint32_t retval = 0; 90 uint32_t rate = 0; 91 92 /* The .byte line is really VIA C3 "xstore" instruction */ 93 __asm __volatile( 94 "movl $0,%%edx \n\t" 95 ".byte 0x0f, 0xa7, 0xc0" 96 : "=a" (retval), "+d" (rate), "+D" (buf) 97 : 98 : "memory" 99 ); 100 if (rate == 0) 101 return (retval&0x1f); 102 #endif 103 return (0); 104 } 105 106 /* ARGSUSED */ 107 static __inline void 108 VIA_ACE_cbc(void *in, void *out, size_t count, void *key, union VIA_ACE_CW *cw, void *iv) 109 { 110 #if defined(__GNUC__) || defined(__INTEL_COMPILER) 111 /* The .byte line is really VIA C3 "xcrypt-cbc" instruction */ 112 __asm __volatile( 113 "pushf \n\t" 114 "popf \n\t" 115 "rep \n\t" 116 ".byte 0x0f, 0xa7, 0xc8" 117 : "+a" (iv), "+c" (count), "+D" (out), "+S" (in) 118 : "b" (key), "d" (cw) 119 : "cc", "memory" 120 ); 121 #endif 122 } 123 124 static void 125 random_nehemiah_init(void) 126 { 127 acw.raw = 0ULL; 128 acw.field.round_count = 12; 129 } 130 131 static int 132 random_nehemiah_read(void *buf, int c) 133 { 134 int i; 135 size_t count, ret; 136 uint8_t *p; 137 138 /* Get a random AES key */ 139 count = 0; 140 p = key; 141 do { 142 ret = VIA_RNG_store(p); 143 p += ret; 144 count += ret; 145 } while (count < CIPHER_BLOCK_SIZE); 146 147 /* Get a random AES IV */ 148 count = 0; 149 p = iv; 150 do { 151 ret = VIA_RNG_store(p); 152 p += ret; 153 count += ret; 154 } while (count < CIPHER_BLOCK_SIZE); 155 156 /* Get a block of random bytes */ 157 count = 0; 158 p = in; 159 do { 160 ret = VIA_RNG_store(p); 161 p += ret; 162 count += ret; 163 } while (count < RANDOM_BLOCK_SIZE); 164 165 /* This is a Davies-Meyer hash of the most paranoid variety; the 166 * key, IV and the data are all read directly from the hardware RNG. 167 * All of these are used precisely once. 168 */ 169 VIA_ACE_cbc(in, out, RANDOM_BLOCK_SIZE/CIPHER_BLOCK_SIZE, 170 key, &acw, iv); 171 for (i = 0; i < RANDOM_BLOCK_SIZE; i++) 172 out[i] ^= in[i]; 173 174 c = MIN(RANDOM_BLOCK_SIZE, c); 175 memcpy(buf, out, (size_t)c); 176 177 return (c); 178 } 179