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 <machine/pcb.h> 39 40 #include <dev/random/randomdev.h> 41 42 #define RANDOM_BLOCK_SIZE 256 43 #define CIPHER_BLOCK_SIZE 16 44 45 static void random_nehemiah_init(void); 46 static void random_nehemiah_deinit(void); 47 static int random_nehemiah_read(void *, int); 48 49 struct random_systat random_nehemiah = { 50 .ident = "Hardware, VIA Nehemiah", 51 .init = random_nehemiah_init, 52 .deinit = random_nehemiah_deinit, 53 .read = random_nehemiah_read, 54 .write = (random_write_func_t *)random_null_func, 55 .reseed = (random_reseed_func_t *)random_null_func, 56 .seeded = 1, 57 }; 58 59 union VIA_ACE_CW { 60 uint64_t raw; 61 struct { 62 u_int round_count : 4; 63 u_int algorithm_type : 3; 64 u_int key_generation_type : 1; 65 u_int intermediate : 1; 66 u_int decrypt : 1; 67 u_int key_size : 2; 68 u_int filler0 : 20; 69 u_int filler1 : 32; 70 u_int filler2 : 32; 71 u_int filler3 : 32; 72 } field; 73 }; 74 75 /* The extra 7 is to allow an 8-byte write on the last byte of the 76 * arrays. The ACE wants the AES data 16-byte/128-bit aligned, and 77 * it _always_ writes n*64 bits. The RNG does not care about alignment, 78 * and it always writes n*32 bits or n*64 bits. 79 */ 80 static uint8_t key[CIPHER_BLOCK_SIZE+7] __aligned(16); 81 static uint8_t iv[CIPHER_BLOCK_SIZE+7] __aligned(16); 82 static uint8_t in[RANDOM_BLOCK_SIZE+7] __aligned(16); 83 static uint8_t out[RANDOM_BLOCK_SIZE+7] __aligned(16); 84 85 static union VIA_ACE_CW acw __aligned(16); 86 87 static struct fpu_kern_ctx fpu_ctx_save; 88 89 static struct mtx random_nehemiah_mtx; 90 91 /* ARGSUSED */ 92 static __inline size_t 93 VIA_RNG_store(void *buf) 94 { 95 #ifdef __GNUCLIKE_ASM 96 uint32_t retval = 0; 97 uint32_t rate = 0; 98 99 /* The .byte line is really VIA C3 "xstore" instruction */ 100 __asm __volatile( 101 "movl $0,%%edx \n\t" 102 ".byte 0x0f, 0xa7, 0xc0" 103 : "=a" (retval), "+d" (rate), "+D" (buf) 104 : 105 : "memory" 106 ); 107 if (rate == 0) 108 return (retval&0x1f); 109 #endif 110 return (0); 111 } 112 113 /* ARGSUSED */ 114 static __inline void 115 VIA_ACE_cbc(void *in, void *out, size_t count, void *key, union VIA_ACE_CW *cw, void *iv) 116 { 117 #ifdef __GNUCLIKE_ASM 118 /* The .byte line is really VIA C3 "xcrypt-cbc" instruction */ 119 __asm __volatile( 120 "pushf \n\t" 121 "popf \n\t" 122 "rep \n\t" 123 ".byte 0x0f, 0xa7, 0xc8" 124 : "+a" (iv), "+c" (count), "+D" (out), "+S" (in) 125 : "b" (key), "d" (cw) 126 : "cc", "memory" 127 ); 128 #endif 129 } 130 131 static void 132 random_nehemiah_init(void) 133 { 134 acw.raw = 0ULL; 135 acw.field.round_count = 12; 136 137 mtx_init(&random_nehemiah_mtx, "random nehemiah", NULL, MTX_DEF); 138 } 139 140 void 141 random_nehemiah_deinit(void) 142 { 143 mtx_destroy(&random_nehemiah_mtx); 144 } 145 146 static int 147 random_nehemiah_read(void *buf, int c) 148 { 149 int i, error; 150 size_t count, ret; 151 uint8_t *p; 152 153 mtx_lock(&random_nehemiah_mtx); 154 error = fpu_kern_enter(curthread, &fpu_ctx_save, FPU_KERN_NORMAL); 155 if (error != 0) { 156 mtx_unlock(&random_nehemiah_mtx); 157 return (0); 158 } 159 160 /* Get a random AES key */ 161 count = 0; 162 p = key; 163 do { 164 ret = VIA_RNG_store(p); 165 p += ret; 166 count += ret; 167 } while (count < CIPHER_BLOCK_SIZE); 168 169 /* Get a random AES IV */ 170 count = 0; 171 p = iv; 172 do { 173 ret = VIA_RNG_store(p); 174 p += ret; 175 count += ret; 176 } while (count < CIPHER_BLOCK_SIZE); 177 178 /* Get a block of random bytes */ 179 count = 0; 180 p = in; 181 do { 182 ret = VIA_RNG_store(p); 183 p += ret; 184 count += ret; 185 } while (count < RANDOM_BLOCK_SIZE); 186 187 /* This is a Davies-Meyer hash of the most paranoid variety; the 188 * key, IV and the data are all read directly from the hardware RNG. 189 * All of these are used precisely once. 190 */ 191 VIA_ACE_cbc(in, out, RANDOM_BLOCK_SIZE/CIPHER_BLOCK_SIZE, 192 key, &acw, iv); 193 for (i = 0; i < RANDOM_BLOCK_SIZE; i++) 194 out[i] ^= in[i]; 195 196 c = MIN(RANDOM_BLOCK_SIZE, c); 197 memcpy(buf, out, (size_t)c); 198 199 fpu_kern_leave(curthread, &fpu_ctx_save); 200 mtx_unlock(&random_nehemiah_mtx); 201 return (c); 202 } 203