crypto/x509/x_pubkey.c

   1 /*
   2  * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 /*
  11  * DSA low level APIs are deprecated for public use, but still ok for
  12  * internal use.
  13  */
  14 #include "internal/deprecated.h"
  15
  16 #include <stdio.h>
  17 #include "internal/cryptlib.h"
  18 #include <openssl/asn1t.h>
  19 #include <openssl/x509.h>
  20 #include "crypto/asn1.h"
  21 #include "crypto/evp.h"
  22 #include "crypto/x509.h"
  23 #include <openssl/rsa.h>
  24 #include <openssl/dsa.h>
  25 #include <openssl/encoder.h>
  26
  27 struct X509_pubkey_st {
  28     X509_ALGOR *algor;
  29     ASN1_BIT_STRING *public_key;
  30     EVP_PKEY *pkey;
  31
  32     /* extra data for the callback, used by d2i_PUBKEY_ex */
  33     OPENSSL_CTX *libctx;
  34     const char *propq;
  35 };
  36
  37 static int x509_pubkey_decode(EVP_PKEY **pk, const X509_PUBKEY *key);
  38
  39 /* Minor tweak to operation: free up EVP_PKEY */
  40 static int pubkey_cb(int operation, ASN1_VALUE **pval, const ASN1_ITEM *it,
  41                      void *exarg)
  42 {
  43     if (operation == ASN1_OP_FREE_POST) {
  44         X509_PUBKEY *pubkey = (X509_PUBKEY *)*pval;
  45         EVP_PKEY_free(pubkey->pkey);
  46     } else if (operation == ASN1_OP_D2I_POST) {
  47         /* Attempt to decode public key and cache in pubkey structure. */
  48         X509_PUBKEY *pubkey = (X509_PUBKEY *)*pval;
  49         EVP_PKEY_free(pubkey->pkey);
  50         pubkey->pkey = NULL;
  51         /*
  52          * Opportunistically decode the key but remove any non fatal errors
  53          * from the queue. Subsequent explicit attempts to decode/use the key
  54          * will return an appropriate error.
  55          */
  56         ERR_set_mark();
  57         if (x509_pubkey_decode(&pubkey->pkey, pubkey) == -1)
  58             return 0;
  59         ERR_pop_to_mark();
  60     }
  61     return 1;
  62 }
  63
  64 ASN1_SEQUENCE_cb(X509_PUBKEY, pubkey_cb) = {
  65         ASN1_SIMPLE(X509_PUBKEY, algor, X509_ALGOR),
  66         ASN1_SIMPLE(X509_PUBKEY, public_key, ASN1_BIT_STRING)
  67 } ASN1_SEQUENCE_END_cb(X509_PUBKEY, X509_PUBKEY)
  68
  69 IMPLEMENT_ASN1_FUNCTIONS(X509_PUBKEY)
  70 IMPLEMENT_ASN1_DUP_FUNCTION(X509_PUBKEY)
  71
  72 /* TODO should better be called X509_PUBKEY_set1 */
  73 int X509_PUBKEY_set(X509_PUBKEY **x, EVP_PKEY *pkey)
  74 {
  75     X509_PUBKEY *pk = NULL;
  76
  77     if (x == NULL)
  78         return 0;
  79
  80     if (pkey == NULL)
  81         goto unsupported;
  82
  83     if (pkey->ameth != NULL) {
  84         if ((pk = X509_PUBKEY_new()) == NULL) {
  85             X509err(X509_F_X509_PUBKEY_SET, ERR_R_MALLOC_FAILURE);
  86             goto error;
  87         }
  88         if (pkey->ameth->pub_encode != NULL) {
  89             if (!pkey->ameth->pub_encode(pk, pkey)) {
  90                 X509err(X509_F_X509_PUBKEY_SET,
  91                         X509_R_PUBLIC_KEY_ENCODE_ERROR);
  92                 goto error;
  93             }
  94         } else {
  95             X509err(X509_F_X509_PUBKEY_SET, X509_R_METHOD_NOT_SUPPORTED);
  96             goto error;
  97         }
  98     } else if (pkey->keymgmt != NULL) {
  99         BIO *bmem = BIO_new(BIO_s_mem());
 100         const char *encprop = OSSL_ENCODER_PUBKEY_TO_DER_PQ;
 101         OSSL_ENCODER_CTX *ectx =
 102             OSSL_ENCODER_CTX_new_by_EVP_PKEY(pkey, encprop);
 103
 104         if (OSSL_ENCODER_to_bio(ectx, bmem)) {
 105             const unsigned char *der = NULL;
 106             long derlen = BIO_get_mem_data(bmem, (char **)&der);
 107
 108             pk = d2i_X509_PUBKEY(NULL, &der, derlen);
 109         }
 110
 111         OSSL_ENCODER_CTX_free(ectx);
 112         BIO_free(bmem);
 113     }
 114
 115     if (pk == NULL)
 116         goto unsupported;
 117
 118     X509_PUBKEY_free(*x);
 119     if (!EVP_PKEY_up_ref(pkey)) {
 120         X509err(X509_F_X509_PUBKEY_SET, ERR_R_INTERNAL_ERROR);
 121         goto error;
 122     }
 123     *x = pk;
 124
 125     /*
 126      * pk->pkey is NULL when using the legacy routine, but is non-NULL when
 127      * going through the encoder, and for all intents and purposes, it's
 128      * a perfect copy of |pkey|, just not the same instance.  In that case,
 129      * we could simply return early, right here.
 130      * However, in the interest of being cautious leaning on paranoia, some
 131      * application might very well depend on the passed |pkey| being used
 132      * and none other, so we spend a few more cycles throwing away the newly
 133      * created |pk->pkey| and replace it with |pkey|.
 134      * TODO(3.0) Investigate if it's safe to change to simply return here
 135      * if |pk->pkey != NULL|.
 136      */
 137     if (pk->pkey != NULL)
 138         EVP_PKEY_free(pk->pkey);
 139
 140     pk->pkey = pkey;
 141     return 1;
 142
 143  unsupported:
 144     X509err(X509_F_X509_PUBKEY_SET, X509_R_UNSUPPORTED_ALGORITHM);
 145
 146  error:
 147     X509_PUBKEY_free(pk);
 148     return 0;
 149 }
 150
 151 /*
 152  * Attempt to decode a public key.
 153  * Returns 1 on success, 0 for a decode failure and -1 for a fatal
 154  * error e.g. malloc failure.
 155  */
 156
 157
 158 static int x509_pubkey_decode(EVP_PKEY **ppkey, const X509_PUBKEY *key)
 159 {
 160     EVP_PKEY *pkey = EVP_PKEY_new();
 161
 162     if (pkey == NULL) {
 163         X509err(X509_F_X509_PUBKEY_DECODE, ERR_R_MALLOC_FAILURE);
 164         return -1;
 165     }
 166
 167     if (!EVP_PKEY_set_type(pkey, OBJ_obj2nid(key->algor->algorithm))) {
 168         X509err(X509_F_X509_PUBKEY_DECODE, X509_R_UNSUPPORTED_ALGORITHM);
 169         goto error;
 170     }
 171
 172     if (pkey->ameth->pub_decode) {
 173         /*
 174          * Treat any failure of pub_decode as a decode error. In
 175          * future we could have different return codes for decode
 176          * errors and fatal errors such as malloc failure.
 177          */
 178         if (!pkey->ameth->pub_decode(pkey, key)) {
 179             X509err(X509_F_X509_PUBKEY_DECODE, X509_R_PUBLIC_KEY_DECODE_ERROR);
 180             goto error;
 181         }
 182     } else {
 183         X509err(X509_F_X509_PUBKEY_DECODE, X509_R_METHOD_NOT_SUPPORTED);
 184         goto error;
 185     }
 186
 187     *ppkey = pkey;
 188     return 1;
 189
 190  error:
 191     EVP_PKEY_free(pkey);
 192     return 0;
 193 }
 194
 195 EVP_PKEY *X509_PUBKEY_get0(const X509_PUBKEY *key)
 196 {
 197     EVP_PKEY *ret = NULL;
 198
 199     if (key == NULL || key->public_key == NULL)
 200         return NULL;
 201
 202     if (key->pkey != NULL)
 203         return key->pkey;
 204
 205     /*
 206      * When the key ASN.1 is initially parsed an attempt is made to
 207      * decode the public key and cache the EVP_PKEY structure. If this
 208      * operation fails the cached value will be NULL. Parsing continues
 209      * to allow parsing of unknown key types or unsupported forms.
 210      * We repeat the decode operation so the appropriate errors are left
 211      * in the queue.
 212      */
 213     x509_pubkey_decode(&ret, key);
 214     /* If decode doesn't fail something bad happened */
 215     if (ret != NULL) {
 216         X509err(X509_F_X509_PUBKEY_GET0, ERR_R_INTERNAL_ERROR);
 217         EVP_PKEY_free(ret);
 218     }
 219
 220     return NULL;
 221 }
 222
 223 EVP_PKEY *X509_PUBKEY_get(const X509_PUBKEY *key)
 224 {
 225     EVP_PKEY *ret = X509_PUBKEY_get0(key);
 226
 227     if (ret != NULL && !EVP_PKEY_up_ref(ret)) {
 228         X509err(X509_F_X509_PUBKEY_GET, ERR_R_INTERNAL_ERROR);
 229         ret = NULL;
 230     }
 231     return ret;
 232 }
 233
 234 /*
 235  * Now three pseudo ASN1 routines that take an EVP_PKEY structure and encode
 236  * or decode as X509_PUBKEY
 237  */
 238
 239 EVP_PKEY *d2i_PUBKEY_ex(EVP_PKEY **a, const unsigned char **pp, long length,
 240                         OPENSSL_CTX *libctx, const char *propq)
 241 {
 242     X509_PUBKEY *xpk, *xpk2 = NULL, **pxpk = NULL;
 243     EVP_PKEY *pktmp = NULL;
 244     const unsigned char *q;
 245
 246     q = *pp;
 247
 248     /*
 249      * If libctx or propq are non-NULL, we take advantage of the reuse
 250      * feature.  It's not generally recommended, but is safe enough for
 251      * newly created structures.
 252      */
 253     if (libctx != NULL || propq != NULL) {
 254         xpk2 = OPENSSL_zalloc(sizeof(*xpk2));
 255         if (xpk2 == NULL) {
 256             ERR_raise(ERR_LIB_X509, ERR_R_MALLOC_FAILURE);
 257             return NULL;
 258         }
 259         xpk2->libctx = libctx;
 260         xpk2->propq = propq;
 261         pxpk = &xpk2;
 262     }
 263     xpk = d2i_X509_PUBKEY(pxpk, &q, length);
 264     if (xpk == NULL)
 265         goto end;
 266     pktmp = X509_PUBKEY_get(xpk);
 267     X509_PUBKEY_free(xpk);
 268     xpk2 = NULL;                 /* We know that xpk == xpk2 */
 269     if (pktmp == NULL)
 270         goto end;
 271     *pp = q;
 272     if (a != NULL) {
 273         EVP_PKEY_free(*a);
 274         *a = pktmp;
 275     }
 276  end:
 277     X509_PUBKEY_free(xpk2);
 278     return pktmp;
 279 }
 280
 281 EVP_PKEY *d2i_PUBKEY(EVP_PKEY **a, const unsigned char **pp, long length)
 282 {
 283     return d2i_PUBKEY_ex(a, pp, length, NULL, NULL);
 284 }
 285
 286 int i2d_PUBKEY(const EVP_PKEY *a, unsigned char **pp)
 287 {
 288     int ret = -1;
 289
 290     if (a == NULL)
 291         return 0;
 292     if (a->ameth != NULL) {
 293         X509_PUBKEY *xpk = NULL;
 294
 295         if ((xpk = X509_PUBKEY_new()) == NULL)
 296             return -1;
 297
 298         /* pub_encode() only encode parameters, not the key itself */
 299         if (a->ameth->pub_encode != NULL && a->ameth->pub_encode(xpk, a)) {
 300             xpk->pkey = (EVP_PKEY *)a;
 301             ret = i2d_X509_PUBKEY(xpk, pp);
 302             xpk->pkey = NULL;
 303         }
 304         X509_PUBKEY_free(xpk);
 305     } else if (a->keymgmt != NULL) {
 306         const char *encprop = OSSL_ENCODER_PUBKEY_TO_DER_PQ;
 307         OSSL_ENCODER_CTX *ctx =
 308             OSSL_ENCODER_CTX_new_by_EVP_PKEY(a, encprop);
 309         BIO *out = BIO_new(BIO_s_mem());
 310         BUF_MEM *buf = NULL;
 311
 312         if (ctx != NULL
 313             && out != NULL
 314             && OSSL_ENCODER_CTX_get_encoder(ctx) != NULL
 315             && OSSL_ENCODER_to_bio(ctx, out)
 316             && BIO_get_mem_ptr(out, &buf) > 0) {
 317             ret = buf->length;
 318
 319             if (pp != NULL) {
 320                 if (*pp == NULL) {
 321                     *pp = (unsigned char *)buf->data;
 322                     buf->length = 0;
 323                     buf->data = NULL;
 324                 } else {
 325                     memcpy(*pp, buf->data, ret);
 326                     *pp += ret;
 327                 }
 328             }
 329         }
 330         BIO_free(out);
 331         OSSL_ENCODER_CTX_free(ctx);
 332     }
 333
 334     return ret;
 335 }
 336
 337 /*
 338  * The following are equivalents but which return RSA and DSA keys
 339  */
 340 #ifndef OPENSSL_NO_RSA
 341 RSA *d2i_RSA_PUBKEY(RSA **a, const unsigned char **pp, long length)
 342 {
 343     EVP_PKEY *pkey;
 344     RSA *key;
 345     const unsigned char *q;
 346
 347     q = *pp;
 348     pkey = d2i_PUBKEY(NULL, &q, length);
 349     if (pkey == NULL)
 350         return NULL;
 351     key = EVP_PKEY_get1_RSA(pkey);
 352     EVP_PKEY_free(pkey);
 353     if (key == NULL)
 354         return NULL;
 355     *pp = q;
 356     if (a != NULL) {
 357         RSA_free(*a);
 358         *a = key;
 359     }
 360     return key;
 361 }
 362
 363 int i2d_RSA_PUBKEY(const RSA *a, unsigned char **pp)
 364 {
 365     EVP_PKEY *pktmp;
 366     int ret;
 367     if (!a)
 368         return 0;
 369     pktmp = EVP_PKEY_new();
 370     if (pktmp == NULL) {
 371         ASN1err(ASN1_F_I2D_RSA_PUBKEY, ERR_R_MALLOC_FAILURE);
 372         return -1;
 373     }
 374     (void)EVP_PKEY_assign_RSA(pktmp, (RSA *)a);
 375     ret = i2d_PUBKEY(pktmp, pp);
 376     pktmp->pkey.ptr = NULL;
 377     EVP_PKEY_free(pktmp);
 378     return ret;
 379 }
 380 #endif
 381
 382 #ifndef OPENSSL_NO_DSA
 383 DSA *d2i_DSA_PUBKEY(DSA **a, const unsigned char **pp, long length)
 384 {
 385     EVP_PKEY *pkey;
 386     DSA *key;
 387     const unsigned char *q;
 388
 389     q = *pp;
 390     pkey = d2i_PUBKEY(NULL, &q, length);
 391     if (pkey == NULL)
 392         return NULL;
 393     key = EVP_PKEY_get1_DSA(pkey);
 394     EVP_PKEY_free(pkey);
 395     if (key == NULL)
 396         return NULL;
 397     *pp = q;
 398     if (a != NULL) {
 399         DSA_free(*a);
 400         *a = key;
 401     }
 402     return key;
 403 }
 404
 405 int i2d_DSA_PUBKEY(const DSA *a, unsigned char **pp)
 406 {
 407     EVP_PKEY *pktmp;
 408     int ret;
 409     if (!a)
 410         return 0;
 411     pktmp = EVP_PKEY_new();
 412     if (pktmp == NULL) {
 413         ASN1err(ASN1_F_I2D_DSA_PUBKEY, ERR_R_MALLOC_FAILURE);
 414         return -1;
 415     }
 416     (void)EVP_PKEY_assign_DSA(pktmp, (DSA *)a);
 417     ret = i2d_PUBKEY(pktmp, pp);
 418     pktmp->pkey.ptr = NULL;
 419     EVP_PKEY_free(pktmp);
 420     return ret;
 421 }
 422 #endif
 423
 424 #ifndef OPENSSL_NO_EC
 425 EC_KEY *d2i_EC_PUBKEY(EC_KEY **a, const unsigned char **pp, long length)
 426 {
 427     EVP_PKEY *pkey;
 428     EC_KEY *key;
 429     const unsigned char *q;
 430
 431     q = *pp;
 432     pkey = d2i_PUBKEY(NULL, &q, length);
 433     if (pkey == NULL)
 434         return NULL;
 435     key = EVP_PKEY_get1_EC_KEY(pkey);
 436     EVP_PKEY_free(pkey);
 437     if (key == NULL)
 438         return NULL;
 439     *pp = q;
 440     if (a != NULL) {
 441         EC_KEY_free(*a);
 442         *a = key;
 443     }
 444     return key;
 445 }
 446
 447 int i2d_EC_PUBKEY(const EC_KEY *a, unsigned char **pp)
 448 {
 449     EVP_PKEY *pktmp;
 450     int ret;
 451
 452     if (a == NULL)
 453         return 0;
 454     if ((pktmp = EVP_PKEY_new()) == NULL) {
 455         ASN1err(ASN1_F_I2D_EC_PUBKEY, ERR_R_MALLOC_FAILURE);
 456         return -1;
 457     }
 458     (void)EVP_PKEY_assign_EC_KEY(pktmp, (EC_KEY *)a);
 459     ret = i2d_PUBKEY(pktmp, pp);
 460     pktmp->pkey.ptr = NULL;
 461     EVP_PKEY_free(pktmp);
 462     return ret;
 463 }
 464 #endif
 465
 466 int X509_PUBKEY_set0_param(X509_PUBKEY *pub, ASN1_OBJECT *aobj,
 467                            int ptype, void *pval,
 468                            unsigned char *penc, int penclen)
 469 {
 470     if (!X509_ALGOR_set0(pub->algor, aobj, ptype, pval))
 471         return 0;
 472     if (penc) {
 473         OPENSSL_free(pub->public_key->data);
 474         pub->public_key->data = penc;
 475         pub->public_key->length = penclen;
 476         /* Set number of unused bits to zero */
 477         pub->public_key->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
 478         pub->public_key->flags |= ASN1_STRING_FLAG_BITS_LEFT;
 479     }
 480     return 1;
 481 }
 482
 483 int X509_PUBKEY_get0_param(ASN1_OBJECT **ppkalg,
 484                            const unsigned char **pk, int *ppklen,
 485                            X509_ALGOR **pa, const X509_PUBKEY *pub)
 486 {
 487     if (ppkalg)
 488         *ppkalg = pub->algor->algorithm;
 489     if (pk) {
 490         *pk = pub->public_key->data;
 491         *ppklen = pub->public_key->length;
 492     }
 493     if (pa)
 494         *pa = pub->algor;
 495     return 1;
 496 }
 497
 498 ASN1_BIT_STRING *X509_get0_pubkey_bitstr(const X509 *x)
 499 {
 500     if (x == NULL)
 501         return NULL;
 502     return x->cert_info.key->public_key;
 503 }
 504
 505 /* Returns 1 for equal, 0, for non-equal, < 0 on error */
 506 int X509_PUBKEY_eq(const X509_PUBKEY *a, const X509_PUBKEY *b)
 507 {
 508     X509_ALGOR *algA, *algB;
 509     EVP_PKEY *pA, *pB;
 510
 511     if (a == b)
 512         return 1;
 513     if (a == NULL || b == NULL)
 514         return 0;
 515     if (!X509_PUBKEY_get0_param(NULL, NULL, NULL, &algA, a) || algA == NULL
 516         || !X509_PUBKEY_get0_param(NULL, NULL, NULL, &algB, b) || algB == NULL)
 517         return -2;
 518     if (X509_ALGOR_cmp(algA, algB) != 0)
 519         return 0;
 520     if ((pA = X509_PUBKEY_get0(a)) == NULL
 521         || (pB = X509_PUBKEY_get0(b)) == NULL)
 522         return -2;
 523     return EVP_PKEY_eq(pA, pB);
 524 }
 525
 526 int X509_PUBKEY_get0_libctx(OPENSSL_CTX **plibctx, const char **ppropq,
 527                             const X509_PUBKEY *key)
 528 {
 529     if (plibctx)
 530         *plibctx = key->libctx;
 531     if (ppropq)
 532         *ppropq = key->propq;
 533     return 1;
 534 }