linux/drivers/crypto/ccp/ccp-crypto-rsa.c
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   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
  25static 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
  31static 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 = kzalloc(*kplen, GFP_KERNEL);
  41        if (!*kpbuf)
  42                return -ENOMEM;
  43        memcpy(*kpbuf, buf + nskip, *kplen);
  44
  45        return 0;
  46}
  47
  48static int ccp_rsa_complete(struct crypto_async_request *async_req, int ret)
  49{
  50        struct akcipher_request *req = akcipher_request_cast(async_req);
  51        struct ccp_rsa_req_ctx *rctx = akcipher_request_ctx(req);
  52
  53        if (ret)
  54                return ret;
  55
  56        req->dst_len = rctx->cmd.u.rsa.key_size >> 3;
  57
  58        return 0;
  59}
  60
  61static unsigned int ccp_rsa_maxsize(struct crypto_akcipher *tfm)
  62{
  63        if (ccp_version() > CCP_VERSION(3, 0))
  64                return CCP5_RSA_MAXMOD;
  65        else
  66                return CCP_RSA_MAXMOD;
  67}
  68
  69static int ccp_rsa_crypt(struct akcipher_request *req, bool encrypt)
  70{
  71        struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
  72        struct ccp_ctx *ctx = akcipher_tfm_ctx(tfm);
  73        struct ccp_rsa_req_ctx *rctx = akcipher_request_ctx(req);
  74        int ret = 0;
  75
  76        memset(&rctx->cmd, 0, sizeof(rctx->cmd));
  77        INIT_LIST_HEAD(&rctx->cmd.entry);
  78        rctx->cmd.engine = CCP_ENGINE_RSA;
  79
  80        rctx->cmd.u.rsa.key_size = ctx->u.rsa.key_len; /* in bits */
  81        if (encrypt) {
  82                rctx->cmd.u.rsa.exp = &ctx->u.rsa.e_sg;
  83                rctx->cmd.u.rsa.exp_len = ctx->u.rsa.e_len;
  84        } else {
  85                rctx->cmd.u.rsa.exp = &ctx->u.rsa.d_sg;
  86                rctx->cmd.u.rsa.exp_len = ctx->u.rsa.d_len;
  87        }
  88        rctx->cmd.u.rsa.mod = &ctx->u.rsa.n_sg;
  89        rctx->cmd.u.rsa.mod_len = ctx->u.rsa.n_len;
  90        rctx->cmd.u.rsa.src = req->src;
  91        rctx->cmd.u.rsa.src_len = req->src_len;
  92        rctx->cmd.u.rsa.dst = req->dst;
  93
  94        ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
  95
  96        return ret;
  97}
  98
  99static int ccp_rsa_encrypt(struct akcipher_request *req)
 100{
 101        return ccp_rsa_crypt(req, true);
 102}
 103
 104static int ccp_rsa_decrypt(struct akcipher_request *req)
 105{
 106        return ccp_rsa_crypt(req, false);
 107}
 108
 109static int ccp_check_key_length(unsigned int len)
 110{
 111        /* In bits */
 112        if (len < 8 || len > 4096)
 113                return -EINVAL;
 114        return 0;
 115}
 116
 117static void ccp_rsa_free_key_bufs(struct ccp_ctx *ctx)
 118{
 119        /* Clean up old key data */
 120        kzfree(ctx->u.rsa.e_buf);
 121        ctx->u.rsa.e_buf = NULL;
 122        ctx->u.rsa.e_len = 0;
 123        kzfree(ctx->u.rsa.n_buf);
 124        ctx->u.rsa.n_buf = NULL;
 125        ctx->u.rsa.n_len = 0;
 126        kzfree(ctx->u.rsa.d_buf);
 127        ctx->u.rsa.d_buf = NULL;
 128        ctx->u.rsa.d_len = 0;
 129}
 130
 131static int ccp_rsa_setkey(struct crypto_akcipher *tfm, const void *key,
 132                          unsigned int keylen, bool private)
 133{
 134        struct ccp_ctx *ctx = akcipher_tfm_ctx(tfm);
 135        struct rsa_key raw_key;
 136        int ret;
 137
 138        ccp_rsa_free_key_bufs(ctx);
 139        memset(&raw_key, 0, sizeof(raw_key));
 140
 141        /* Code borrowed from crypto/rsa.c */
 142        if (private)
 143                ret = rsa_parse_priv_key(&raw_key, key, keylen);
 144        else
 145                ret = rsa_parse_pub_key(&raw_key, key, keylen);
 146        if (ret)
 147                goto n_key;
 148
 149        ret = ccp_copy_and_save_keypart(&ctx->u.rsa.n_buf, &ctx->u.rsa.n_len,
 150                                        raw_key.n, raw_key.n_sz);
 151        if (ret)
 152                goto key_err;
 153        sg_init_one(&ctx->u.rsa.n_sg, ctx->u.rsa.n_buf, ctx->u.rsa.n_len);
 154
 155        ctx->u.rsa.key_len = ctx->u.rsa.n_len << 3; /* convert to bits */
 156        if (ccp_check_key_length(ctx->u.rsa.key_len)) {
 157                ret = -EINVAL;
 158                goto key_err;
 159        }
 160
 161        ret = ccp_copy_and_save_keypart(&ctx->u.rsa.e_buf, &ctx->u.rsa.e_len,
 162                                        raw_key.e, raw_key.e_sz);
 163        if (ret)
 164                goto key_err;
 165        sg_init_one(&ctx->u.rsa.e_sg, ctx->u.rsa.e_buf, ctx->u.rsa.e_len);
 166
 167        if (private) {
 168                ret = ccp_copy_and_save_keypart(&ctx->u.rsa.d_buf,
 169                                                &ctx->u.rsa.d_len,
 170                                                raw_key.d, raw_key.d_sz);
 171                if (ret)
 172                        goto key_err;
 173                sg_init_one(&ctx->u.rsa.d_sg,
 174                            ctx->u.rsa.d_buf, ctx->u.rsa.d_len);
 175        }
 176
 177        return 0;
 178
 179key_err:
 180        ccp_rsa_free_key_bufs(ctx);
 181
 182n_key:
 183        return ret;
 184}
 185
 186static int ccp_rsa_setprivkey(struct crypto_akcipher *tfm, const void *key,
 187                              unsigned int keylen)
 188{
 189        return ccp_rsa_setkey(tfm, key, keylen, true);
 190}
 191
 192static int ccp_rsa_setpubkey(struct crypto_akcipher *tfm, const void *key,
 193                             unsigned int keylen)
 194{
 195        return ccp_rsa_setkey(tfm, key, keylen, false);
 196}
 197
 198static int ccp_rsa_init_tfm(struct crypto_akcipher *tfm)
 199{
 200        struct ccp_ctx *ctx = akcipher_tfm_ctx(tfm);
 201
 202        akcipher_set_reqsize(tfm, sizeof(struct ccp_rsa_req_ctx));
 203        ctx->complete = ccp_rsa_complete;
 204
 205        return 0;
 206}
 207
 208static void ccp_rsa_exit_tfm(struct crypto_akcipher *tfm)
 209{
 210        struct ccp_ctx *ctx = crypto_tfm_ctx(&tfm->base);
 211
 212        ccp_rsa_free_key_bufs(ctx);
 213}
 214
 215static struct akcipher_alg ccp_rsa_defaults = {
 216        .encrypt = ccp_rsa_encrypt,
 217        .decrypt = ccp_rsa_decrypt,
 218        .sign = ccp_rsa_decrypt,
 219        .verify = ccp_rsa_encrypt,
 220        .set_pub_key = ccp_rsa_setpubkey,
 221        .set_priv_key = ccp_rsa_setprivkey,
 222        .max_size = ccp_rsa_maxsize,
 223        .init = ccp_rsa_init_tfm,
 224        .exit = ccp_rsa_exit_tfm,
 225        .base = {
 226                .cra_name = "rsa",
 227                .cra_driver_name = "rsa-ccp",
 228                .cra_priority = CCP_CRA_PRIORITY,
 229                .cra_module = THIS_MODULE,
 230                .cra_ctxsize = 2 * sizeof(struct ccp_ctx),
 231        },
 232};
 233
 234struct ccp_rsa_def {
 235        unsigned int version;
 236        const char *name;
 237        const char *driver_name;
 238        unsigned int reqsize;
 239        struct akcipher_alg *alg_defaults;
 240};
 241
 242static struct ccp_rsa_def rsa_algs[] = {
 243        {
 244                .version        = CCP_VERSION(3, 0),
 245                .name           = "rsa",
 246                .driver_name    = "rsa-ccp",
 247                .reqsize        = sizeof(struct ccp_rsa_req_ctx),
 248                .alg_defaults   = &ccp_rsa_defaults,
 249        }
 250};
 251
 252int ccp_register_rsa_alg(struct list_head *head, const struct ccp_rsa_def *def)
 253{
 254        struct ccp_crypto_akcipher_alg *ccp_alg;
 255        struct akcipher_alg *alg;
 256        int ret;
 257
 258        ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
 259        if (!ccp_alg)
 260                return -ENOMEM;
 261
 262        INIT_LIST_HEAD(&ccp_alg->entry);
 263
 264        alg = &ccp_alg->alg;
 265        *alg = *def->alg_defaults;
 266        snprintf(alg->base.cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name);
 267        snprintf(alg->base.cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s",
 268                 def->driver_name);
 269        ret = crypto_register_akcipher(alg);
 270        if (ret) {
 271                pr_err("%s akcipher algorithm registration error (%d)\n",
 272                       alg->base.cra_name, ret);
 273                kfree(ccp_alg);
 274                return ret;
 275        }
 276
 277        list_add(&ccp_alg->entry, head);
 278
 279        return 0;
 280}
 281
 282int ccp_register_rsa_algs(struct list_head *head)
 283{
 284        int i, ret;
 285        unsigned int ccpversion = ccp_version();
 286
 287        /* Register the RSA algorithm in standard mode
 288         * This works for CCP v3 and later
 289         */
 290        for (i = 0; i < ARRAY_SIZE(rsa_algs); i++) {
 291                if (rsa_algs[i].version > ccpversion)
 292                        continue;
 293                ret = ccp_register_rsa_alg(head, &rsa_algs[i]);
 294                if (ret)
 295                        return ret;
 296        }
 297
 298        return 0;
 299}
 300