1 /* 2 * AMD Cryptographic Coprocessor (CCP) RSA crypto API support 3 * 4 * Copyright (C) 2017 Advanced Micro Devices, Inc. 5 * 6 * Author: Gary R Hook <gary.hook@amd.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 */ 12 13 #include <linux/module.h> 14 #include <linux/sched.h> 15 #include <linux/scatterlist.h> 16 #include <linux/crypto.h> 17 #include <crypto/algapi.h> 18 #include <crypto/internal/rsa.h> 19 #include <crypto/internal/akcipher.h> 20 #include <crypto/akcipher.h> 21 #include <crypto/scatterwalk.h> 22 23 #include "ccp-crypto.h" 24 25 static inline struct akcipher_request *akcipher_request_cast( 26 struct crypto_async_request *req) 27 { 28 return container_of(req, struct akcipher_request, base); 29 } 30 31 static inline int ccp_copy_and_save_keypart(u8 **kpbuf, unsigned int *kplen, 32 const u8 *buf, size_t sz) 33 { 34 int nskip; 35 36 for (nskip = 0; nskip < sz; nskip++) 37 if (buf[nskip]) 38 break; 39 *kplen = sz - nskip; 40 *kpbuf = kmemdup(buf + nskip, *kplen, GFP_KERNEL); 41 if (!*kpbuf) 42 return -ENOMEM; 43 44 return 0; 45 } 46 47 static int ccp_rsa_complete(struct crypto_async_request *async_req, int ret) 48 { 49 struct akcipher_request *req = akcipher_request_cast(async_req); 50 struct ccp_rsa_req_ctx *rctx = akcipher_request_ctx(req); 51 52 if (ret) 53 return ret; 54 55 req->dst_len = rctx->cmd.u.rsa.key_size >> 3; 56 57 return 0; 58 } 59 60 static unsigned int ccp_rsa_maxsize(struct crypto_akcipher *tfm) 61 { 62 struct ccp_ctx *ctx = akcipher_tfm_ctx(tfm); 63 64 return ctx->u.rsa.n_len; 65 } 66 67 static int ccp_rsa_crypt(struct akcipher_request *req, bool encrypt) 68 { 69 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req); 70 struct ccp_ctx *ctx = akcipher_tfm_ctx(tfm); 71 struct ccp_rsa_req_ctx *rctx = akcipher_request_ctx(req); 72 int ret = 0; 73 74 memset(&rctx->cmd, 0, sizeof(rctx->cmd)); 75 INIT_LIST_HEAD(&rctx->cmd.entry); 76 rctx->cmd.engine = CCP_ENGINE_RSA; 77 78 rctx->cmd.u.rsa.key_size = ctx->u.rsa.key_len; /* in bits */ 79 if (encrypt) { 80 rctx->cmd.u.rsa.exp = &ctx->u.rsa.e_sg; 81 rctx->cmd.u.rsa.exp_len = ctx->u.rsa.e_len; 82 } else { 83 rctx->cmd.u.rsa.exp = &ctx->u.rsa.d_sg; 84 rctx->cmd.u.rsa.exp_len = ctx->u.rsa.d_len; 85 } 86 rctx->cmd.u.rsa.mod = &ctx->u.rsa.n_sg; 87 rctx->cmd.u.rsa.mod_len = ctx->u.rsa.n_len; 88 rctx->cmd.u.rsa.src = req->src; 89 rctx->cmd.u.rsa.src_len = req->src_len; 90 rctx->cmd.u.rsa.dst = req->dst; 91 92 ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd); 93 94 return ret; 95 } 96 97 static int ccp_rsa_encrypt(struct akcipher_request *req) 98 { 99 return ccp_rsa_crypt(req, true); 100 } 101 102 static int ccp_rsa_decrypt(struct akcipher_request *req) 103 { 104 return ccp_rsa_crypt(req, false); 105 } 106 107 static int ccp_check_key_length(unsigned int len) 108 { 109 /* In bits */ 110 if (len < 8 || len > 4096) 111 return -EINVAL; 112 return 0; 113 } 114 115 static void ccp_rsa_free_key_bufs(struct ccp_ctx *ctx) 116 { 117 /* Clean up old key data */ 118 kzfree(ctx->u.rsa.e_buf); 119 ctx->u.rsa.e_buf = NULL; 120 ctx->u.rsa.e_len = 0; 121 kzfree(ctx->u.rsa.n_buf); 122 ctx->u.rsa.n_buf = NULL; 123 ctx->u.rsa.n_len = 0; 124 kzfree(ctx->u.rsa.d_buf); 125 ctx->u.rsa.d_buf = NULL; 126 ctx->u.rsa.d_len = 0; 127 } 128 129 static int ccp_rsa_setkey(struct crypto_akcipher *tfm, const void *key, 130 unsigned int keylen, bool private) 131 { 132 struct ccp_ctx *ctx = akcipher_tfm_ctx(tfm); 133 struct rsa_key raw_key; 134 int ret; 135 136 ccp_rsa_free_key_bufs(ctx); 137 memset(&raw_key, 0, sizeof(raw_key)); 138 139 /* Code borrowed from crypto/rsa.c */ 140 if (private) 141 ret = rsa_parse_priv_key(&raw_key, key, keylen); 142 else 143 ret = rsa_parse_pub_key(&raw_key, key, keylen); 144 if (ret) 145 goto n_key; 146 147 ret = ccp_copy_and_save_keypart(&ctx->u.rsa.n_buf, &ctx->u.rsa.n_len, 148 raw_key.n, raw_key.n_sz); 149 if (ret) 150 goto key_err; 151 sg_init_one(&ctx->u.rsa.n_sg, ctx->u.rsa.n_buf, ctx->u.rsa.n_len); 152 153 ctx->u.rsa.key_len = ctx->u.rsa.n_len << 3; /* convert to bits */ 154 if (ccp_check_key_length(ctx->u.rsa.key_len)) { 155 ret = -EINVAL; 156 goto key_err; 157 } 158 159 ret = ccp_copy_and_save_keypart(&ctx->u.rsa.e_buf, &ctx->u.rsa.e_len, 160 raw_key.e, raw_key.e_sz); 161 if (ret) 162 goto key_err; 163 sg_init_one(&ctx->u.rsa.e_sg, ctx->u.rsa.e_buf, ctx->u.rsa.e_len); 164 165 if (private) { 166 ret = ccp_copy_and_save_keypart(&ctx->u.rsa.d_buf, 167 &ctx->u.rsa.d_len, 168 raw_key.d, raw_key.d_sz); 169 if (ret) 170 goto key_err; 171 sg_init_one(&ctx->u.rsa.d_sg, 172 ctx->u.rsa.d_buf, ctx->u.rsa.d_len); 173 } 174 175 return 0; 176 177 key_err: 178 ccp_rsa_free_key_bufs(ctx); 179 180 n_key: 181 return ret; 182 } 183 184 static int ccp_rsa_setprivkey(struct crypto_akcipher *tfm, const void *key, 185 unsigned int keylen) 186 { 187 return ccp_rsa_setkey(tfm, key, keylen, true); 188 } 189 190 static int ccp_rsa_setpubkey(struct crypto_akcipher *tfm, const void *key, 191 unsigned int keylen) 192 { 193 return ccp_rsa_setkey(tfm, key, keylen, false); 194 } 195 196 static int ccp_rsa_init_tfm(struct crypto_akcipher *tfm) 197 { 198 struct ccp_ctx *ctx = akcipher_tfm_ctx(tfm); 199 200 akcipher_set_reqsize(tfm, sizeof(struct ccp_rsa_req_ctx)); 201 ctx->complete = ccp_rsa_complete; 202 203 return 0; 204 } 205 206 static void ccp_rsa_exit_tfm(struct crypto_akcipher *tfm) 207 { 208 struct ccp_ctx *ctx = crypto_tfm_ctx(&tfm->base); 209 210 ccp_rsa_free_key_bufs(ctx); 211 } 212 213 static struct akcipher_alg ccp_rsa_defaults = { 214 .encrypt = ccp_rsa_encrypt, 215 .decrypt = ccp_rsa_decrypt, 216 .set_pub_key = ccp_rsa_setpubkey, 217 .set_priv_key = ccp_rsa_setprivkey, 218 .max_size = ccp_rsa_maxsize, 219 .init = ccp_rsa_init_tfm, 220 .exit = ccp_rsa_exit_tfm, 221 .base = { 222 .cra_name = "rsa", 223 .cra_driver_name = "rsa-ccp", 224 .cra_priority = CCP_CRA_PRIORITY, 225 .cra_module = THIS_MODULE, 226 .cra_ctxsize = 2 * sizeof(struct ccp_ctx), 227 }, 228 }; 229 230 struct ccp_rsa_def { 231 unsigned int version; 232 const char *name; 233 const char *driver_name; 234 unsigned int reqsize; 235 struct akcipher_alg *alg_defaults; 236 }; 237 238 static struct ccp_rsa_def rsa_algs[] = { 239 { 240 .version = CCP_VERSION(3, 0), 241 .name = "rsa", 242 .driver_name = "rsa-ccp", 243 .reqsize = sizeof(struct ccp_rsa_req_ctx), 244 .alg_defaults = &ccp_rsa_defaults, 245 } 246 }; 247 248 static int ccp_register_rsa_alg(struct list_head *head, 249 const struct ccp_rsa_def *def) 250 { 251 struct ccp_crypto_akcipher_alg *ccp_alg; 252 struct akcipher_alg *alg; 253 int ret; 254 255 ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL); 256 if (!ccp_alg) 257 return -ENOMEM; 258 259 INIT_LIST_HEAD(&ccp_alg->entry); 260 261 alg = &ccp_alg->alg; 262 *alg = *def->alg_defaults; 263 snprintf(alg->base.cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name); 264 snprintf(alg->base.cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s", 265 def->driver_name); 266 ret = crypto_register_akcipher(alg); 267 if (ret) { 268 pr_err("%s akcipher algorithm registration error (%d)\n", 269 alg->base.cra_name, ret); 270 kfree(ccp_alg); 271 return ret; 272 } 273 274 list_add(&ccp_alg->entry, head); 275 276 return 0; 277 } 278 279 int ccp_register_rsa_algs(struct list_head *head) 280 { 281 int i, ret; 282 unsigned int ccpversion = ccp_version(); 283 284 /* Register the RSA algorithm in standard mode 285 * This works for CCP v3 and later 286 */ 287 for (i = 0; i < ARRAY_SIZE(rsa_algs); i++) { 288 if (rsa_algs[i].version > ccpversion) 289 continue; 290 ret = ccp_register_rsa_alg(head, &rsa_algs[i]); 291 if (ret) 292 return ret; 293 } 294 295 return 0; 296 } 297