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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 | // SPDX-License-Identifier: GPL-2.0+ /* * Copyright (c) 2021 IBM Corporation */ #include <linux/module.h> #include <crypto/internal/akcipher.h> #include <crypto/internal/ecc.h> #include <crypto/akcipher.h> #include <crypto/ecdh.h> #include <linux/asn1_decoder.h> #include <linux/scatterlist.h> #include "ecdsasignature.asn1.h" struct ecc_ctx { unsigned int curve_id; const struct ecc_curve *curve; bool pub_key_set; u64 x[ECC_MAX_DIGITS]; /* pub key x and y coordinates */ u64 y[ECC_MAX_DIGITS]; struct ecc_point pub_key; }; struct ecdsa_signature_ctx { const struct ecc_curve *curve; u64 r[ECC_MAX_DIGITS]; u64 s[ECC_MAX_DIGITS]; }; /* * Get the r and s components of a signature from the X509 certificate. */ static int ecdsa_get_signature_rs(u64 *dest, size_t hdrlen, unsigned char tag, const void *value, size_t vlen, unsigned int ndigits) { size_t keylen = ndigits * sizeof(u64); ssize_t diff = vlen - keylen; const char *d = value; u8 rs[ECC_MAX_BYTES]; if (!value || !vlen) return -EINVAL; /* diff = 0: 'value' has exacly the right size * diff > 0: 'value' has too many bytes; one leading zero is allowed that * makes the value a positive integer; error on more * diff < 0: 'value' is missing leading zeros, which we add */ if (diff > 0) { /* skip over leading zeros that make 'value' a positive int */ if (*d == 0) { vlen -= 1; diff--; d++; } if (diff) return -EINVAL; } if (-diff >= keylen) return -EINVAL; if (diff) { /* leading zeros not given in 'value' */ memset(rs, 0, -diff); } memcpy(&rs[-diff], d, vlen); ecc_swap_digits((u64 *)rs, dest, ndigits); return 0; } int ecdsa_get_signature_r(void *context, size_t hdrlen, unsigned char tag, const void *value, size_t vlen) { struct ecdsa_signature_ctx *sig = context; return ecdsa_get_signature_rs(sig->r, hdrlen, tag, value, vlen, sig->curve->g.ndigits); } int ecdsa_get_signature_s(void *context, size_t hdrlen, unsigned char tag, const void *value, size_t vlen) { struct ecdsa_signature_ctx *sig = context; return ecdsa_get_signature_rs(sig->s, hdrlen, tag, value, vlen, sig->curve->g.ndigits); } static int _ecdsa_verify(struct ecc_ctx *ctx, const u64 *hash, const u64 *r, const u64 *s) { const struct ecc_curve *curve = ctx->curve; unsigned int ndigits = curve->g.ndigits; u64 s1[ECC_MAX_DIGITS]; u64 u1[ECC_MAX_DIGITS]; u64 u2[ECC_MAX_DIGITS]; u64 x1[ECC_MAX_DIGITS]; u64 y1[ECC_MAX_DIGITS]; struct ecc_point res = ECC_POINT_INIT(x1, y1, ndigits); /* 0 < r < n and 0 < s < n */ if (vli_is_zero(r, ndigits) || vli_cmp(r, curve->n, ndigits) >= 0 || vli_is_zero(s, ndigits) || vli_cmp(s, curve->n, ndigits) >= 0) return -EBADMSG; /* hash is given */ pr_devel("hash : %016llx %016llx ... %016llx\n", hash[ndigits - 1], hash[ndigits - 2], hash[0]); /* s1 = (s^-1) mod n */ vli_mod_inv(s1, s, curve->n, ndigits); /* u1 = (hash * s1) mod n */ vli_mod_mult_slow(u1, hash, s1, curve->n, ndigits); /* u2 = (r * s1) mod n */ vli_mod_mult_slow(u2, r, s1, curve->n, ndigits); /* res = u1*G + u2 * pub_key */ ecc_point_mult_shamir(&res, u1, &curve->g, u2, &ctx->pub_key, curve); /* res.x = res.x mod n (if res.x > order) */ if (unlikely(vli_cmp(res.x, curve->n, ndigits) == 1)) /* faster alternative for NIST p384, p256 & p192 */ vli_sub(res.x, res.x, curve->n, ndigits); if (!vli_cmp(res.x, r, ndigits)) return 0; return -EKEYREJECTED; } /* * Verify an ECDSA signature. */ static int ecdsa_verify(struct akcipher_request *req) { struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req); struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm); size_t keylen = ctx->curve->g.ndigits * sizeof(u64); struct ecdsa_signature_ctx sig_ctx = { .curve = ctx->curve, }; u8 rawhash[ECC_MAX_BYTES]; u64 hash[ECC_MAX_DIGITS]; unsigned char *buffer; ssize_t diff; int ret; if (unlikely(!ctx->pub_key_set)) return -EINVAL; buffer = kmalloc(req->src_len + req->dst_len, GFP_KERNEL); if (!buffer) return -ENOMEM; sg_pcopy_to_buffer(req->src, sg_nents_for_len(req->src, req->src_len + req->dst_len), buffer, req->src_len + req->dst_len, 0); ret = asn1_ber_decoder(&ecdsasignature_decoder, &sig_ctx, buffer, req->src_len); if (ret < 0) goto error; /* if the hash is shorter then we will add leading zeros to fit to ndigits */ diff = keylen - req->dst_len; if (diff >= 0) { if (diff) memset(rawhash, 0, diff); memcpy(&rawhash[diff], buffer + req->src_len, req->dst_len); } else if (diff < 0) { /* given hash is longer, we take the left-most bytes */ memcpy(&rawhash, buffer + req->src_len, keylen); } ecc_swap_digits((u64 *)rawhash, hash, ctx->curve->g.ndigits); ret = _ecdsa_verify(ctx, hash, sig_ctx.r, sig_ctx.s); error: kfree(buffer); return ret; } static int ecdsa_ecc_ctx_init(struct ecc_ctx *ctx, unsigned int curve_id) { ctx->curve_id = curve_id; ctx->curve = ecc_get_curve(curve_id); if (!ctx->curve) return -EINVAL; return 0; } static void ecdsa_ecc_ctx_deinit(struct ecc_ctx *ctx) { ctx->pub_key_set = false; } static int ecdsa_ecc_ctx_reset(struct ecc_ctx *ctx) { unsigned int curve_id = ctx->curve_id; int ret; ecdsa_ecc_ctx_deinit(ctx); ret = ecdsa_ecc_ctx_init(ctx, curve_id); if (ret == 0) ctx->pub_key = ECC_POINT_INIT(ctx->x, ctx->y, ctx->curve->g.ndigits); return ret; } /* * Set the public key given the raw uncompressed key data from an X509 * certificate. The key data contain the concatenated X and Y coordinates of * the public key. */ static int ecdsa_set_pub_key(struct crypto_akcipher *tfm, const void *key, unsigned int keylen) { struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm); const unsigned char *d = key; const u64 *digits = (const u64 *)&d[1]; unsigned int ndigits; int ret; ret = ecdsa_ecc_ctx_reset(ctx); if (ret < 0) return ret; if (keylen < 1 || (((keylen - 1) >> 1) % sizeof(u64)) != 0) return -EINVAL; /* we only accept uncompressed format indicated by '4' */ if (d[0] != 4) return -EINVAL; keylen--; ndigits = (keylen >> 1) / sizeof(u64); if (ndigits != ctx->curve->g.ndigits) return -EINVAL; ecc_swap_digits(digits, ctx->pub_key.x, ndigits); ecc_swap_digits(&digits[ndigits], ctx->pub_key.y, ndigits); ret = ecc_is_pubkey_valid_full(ctx->curve, &ctx->pub_key); ctx->pub_key_set = ret == 0; return ret; } static void ecdsa_exit_tfm(struct crypto_akcipher *tfm) { struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm); ecdsa_ecc_ctx_deinit(ctx); } static unsigned int ecdsa_max_size(struct crypto_akcipher *tfm) { struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm); return ctx->pub_key.ndigits << ECC_DIGITS_TO_BYTES_SHIFT; } static int ecdsa_nist_p384_init_tfm(struct crypto_akcipher *tfm) { struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm); return ecdsa_ecc_ctx_init(ctx, ECC_CURVE_NIST_P384); } static struct akcipher_alg ecdsa_nist_p384 = { .verify = ecdsa_verify, .set_pub_key = ecdsa_set_pub_key, .max_size = ecdsa_max_size, .init = ecdsa_nist_p384_init_tfm, .exit = ecdsa_exit_tfm, .base = { .cra_name = "ecdsa-nist-p384", .cra_driver_name = "ecdsa-nist-p384-generic", .cra_priority = 100, .cra_module = THIS_MODULE, .cra_ctxsize = sizeof(struct ecc_ctx), }, }; static int ecdsa_nist_p256_init_tfm(struct crypto_akcipher *tfm) { struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm); return ecdsa_ecc_ctx_init(ctx, ECC_CURVE_NIST_P256); } static struct akcipher_alg ecdsa_nist_p256 = { .verify = ecdsa_verify, .set_pub_key = ecdsa_set_pub_key, .max_size = ecdsa_max_size, .init = ecdsa_nist_p256_init_tfm, .exit = ecdsa_exit_tfm, .base = { .cra_name = "ecdsa-nist-p256", .cra_driver_name = "ecdsa-nist-p256-generic", .cra_priority = 100, .cra_module = THIS_MODULE, .cra_ctxsize = sizeof(struct ecc_ctx), }, }; static int ecdsa_nist_p192_init_tfm(struct crypto_akcipher *tfm) { struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm); return ecdsa_ecc_ctx_init(ctx, ECC_CURVE_NIST_P192); } static struct akcipher_alg ecdsa_nist_p192 = { .verify = ecdsa_verify, .set_pub_key = ecdsa_set_pub_key, .max_size = ecdsa_max_size, .init = ecdsa_nist_p192_init_tfm, .exit = ecdsa_exit_tfm, .base = { .cra_name = "ecdsa-nist-p192", .cra_driver_name = "ecdsa-nist-p192-generic", .cra_priority = 100, .cra_module = THIS_MODULE, .cra_ctxsize = sizeof(struct ecc_ctx), }, }; static bool ecdsa_nist_p192_registered; static int __init ecdsa_init(void) { int ret; /* NIST p192 may not be available in FIPS mode */ ret = crypto_register_akcipher(&ecdsa_nist_p192); ecdsa_nist_p192_registered = ret == 0; ret = crypto_register_akcipher(&ecdsa_nist_p256); if (ret) goto nist_p256_error; ret = crypto_register_akcipher(&ecdsa_nist_p384); if (ret) goto nist_p384_error; return 0; nist_p384_error: crypto_unregister_akcipher(&ecdsa_nist_p256); nist_p256_error: if (ecdsa_nist_p192_registered) crypto_unregister_akcipher(&ecdsa_nist_p192); return ret; } static void __exit ecdsa_exit(void) { if (ecdsa_nist_p192_registered) crypto_unregister_akcipher(&ecdsa_nist_p192); crypto_unregister_akcipher(&ecdsa_nist_p256); crypto_unregister_akcipher(&ecdsa_nist_p384); } subsys_initcall(ecdsa_init); module_exit(ecdsa_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Stefan Berger <stefanb@linux.ibm.com>"); MODULE_DESCRIPTION("ECDSA generic algorithm"); MODULE_ALIAS_CRYPTO("ecdsa-generic"); |