crypto/x509/x_crl.c

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.] */

#include <openssl/asn1.h>
#include <openssl/asn1t.h>
#include <openssl/digest.h>
#include <openssl/err.h>
#include <openssl/mem.h>
#include <openssl/obj.h>
#include <openssl/stack.h>
#include <openssl/thread.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>

#include <assert.h>

#include "../asn1/internal.h"
#include "../internal.h"
#include "internal.h"

static int X509_REVOKED_cmp(const X509_REVOKED *const *a,
                            const X509_REVOKED *const *b);
static int setup_idp(X509_CRL *crl, ISSUING_DIST_POINT *idp);

ASN1_SEQUENCE(X509_REVOKED) = {
    ASN1_SIMPLE(X509_REVOKED, serialNumber, ASN1_INTEGER),
    ASN1_SIMPLE(X509_REVOKED, revocationDate, ASN1_TIME),
    ASN1_SEQUENCE_OF_OPT(X509_REVOKED, extensions, X509_EXTENSION),
} ASN1_SEQUENCE_END(X509_REVOKED)

static int crl_lookup(X509_CRL *crl, X509_REVOKED **ret, ASN1_INTEGER *serial,
                      X509_NAME *issuer);

// The X509_CRL_INFO structure needs a bit of customisation. Since we cache
// the original encoding the signature wont be affected by reordering of the
// revoked field.
static int crl_inf_cb(int operation, ASN1_VALUE **pval, const ASN1_ITEM *it,
                      void *exarg) {
  X509_CRL_INFO *a = (X509_CRL_INFO *)*pval;

  if (!a || !a->revoked) {
    return 1;
  }
  switch (operation) {
      // Just set cmp function here. We don't sort because that would
      // affect the output of X509_CRL_print().
    case ASN1_OP_D2I_POST:
      (void)sk_X509_REVOKED_set_cmp_func(a->revoked, X509_REVOKED_cmp);
      break;
  }
  return 1;
}


ASN1_SEQUENCE_enc(X509_CRL_INFO, enc, crl_inf_cb) = {
    ASN1_OPT(X509_CRL_INFO, version, ASN1_INTEGER),
    ASN1_SIMPLE(X509_CRL_INFO, sig_alg, X509_ALGOR),
    ASN1_SIMPLE(X509_CRL_INFO, issuer, X509_NAME),
    ASN1_SIMPLE(X509_CRL_INFO, lastUpdate, ASN1_TIME),
    ASN1_OPT(X509_CRL_INFO, nextUpdate, ASN1_TIME),
    ASN1_SEQUENCE_OF_OPT(X509_CRL_INFO, revoked, X509_REVOKED),
    ASN1_EXP_SEQUENCE_OF_OPT(X509_CRL_INFO, extensions, X509_EXTENSION, 0),
} ASN1_SEQUENCE_END_enc(X509_CRL_INFO, X509_CRL_INFO)

// Set CRL entry issuer according to CRL certificate issuer extension. Check
// for unhandled critical CRL entry extensions.

static int crl_set_issuers(X509_CRL *crl) {
  size_t i, k;
  int j;
  GENERAL_NAMES *gens, *gtmp;
  STACK_OF(X509_REVOKED) *revoked;

  revoked = X509_CRL_get_REVOKED(crl);

  gens = NULL;
  for (i = 0; i < sk_X509_REVOKED_num(revoked); i++) {
    X509_REVOKED *rev = sk_X509_REVOKED_value(revoked, i);
    STACK_OF(X509_EXTENSION) *exts;
    ASN1_ENUMERATED *reason;
    X509_EXTENSION *ext;
    gtmp = X509_REVOKED_get_ext_d2i(rev, NID_certificate_issuer, &j, NULL);
    if (!gtmp && (j != -1)) {
      crl->flags |= EXFLAG_INVALID;
      return 1;
    }

    if (gtmp) {
      gens = gtmp;
      if (!crl->issuers) {
        crl->issuers = sk_GENERAL_NAMES_new_null();
        if (!crl->issuers) {
          return 0;
        }
      }
      if (!sk_GENERAL_NAMES_push(crl->issuers, gtmp)) {
        return 0;
      }
    }
    rev->issuer = gens;

    reason = X509_REVOKED_get_ext_d2i(rev, NID_crl_reason, &j, NULL);
    if (!reason && (j != -1)) {
      crl->flags |= EXFLAG_INVALID;
      return 1;
    }

    if (reason) {
      rev->reason = ASN1_ENUMERATED_get(reason);
      ASN1_ENUMERATED_free(reason);
    } else {
      rev->reason = CRL_REASON_NONE;
    }

    // Check for critical CRL entry extensions

    exts = rev->extensions;

    for (k = 0; k < sk_X509_EXTENSION_num(exts); k++) {
      ext = sk_X509_EXTENSION_value(exts, k);
      if (X509_EXTENSION_get_critical(ext)) {
        if (OBJ_obj2nid(X509_EXTENSION_get_object(ext)) ==
            NID_certificate_issuer) {
          continue;
        }
        crl->flags |= EXFLAG_CRITICAL;
        break;
      }
    }
  }

  return 1;
}

// The X509_CRL structure needs a bit of customisation. Cache some extensions
// and hash of the whole CRL.
static int crl_cb(int operation, ASN1_VALUE **pval, const ASN1_ITEM *it,
                  void *exarg) {
  X509_CRL *crl = (X509_CRL *)*pval;
  STACK_OF(X509_EXTENSION) *exts;
  X509_EXTENSION *ext;
  size_t idx;
  int i;

  switch (operation) {
    case ASN1_OP_NEW_POST:
      crl->idp = NULL;
      crl->akid = NULL;
      crl->flags = 0;
      crl->idp_flags = 0;
      crl->idp_reasons = CRLDP_ALL_REASONS;
      crl->issuers = NULL;
      crl->crl_number = NULL;
      crl->base_crl_number = NULL;
      break;

    case ASN1_OP_D2I_POST: {
      // The version must be one of v1(0) or v2(1).
      long version = X509_CRL_VERSION_1;
      if (crl->crl->version != NULL) {
        version = ASN1_INTEGER_get(crl->crl->version);
        // TODO(https://crbug.com/boringssl/364): |X509_CRL_VERSION_1|
        // should also be rejected. This means an explicitly-encoded X.509v1
        // version. v1 is DEFAULT, so DER requires it be omitted.
        if (version < X509_CRL_VERSION_1 || version > X509_CRL_VERSION_2) {
          OPENSSL_PUT_ERROR(X509, X509_R_INVALID_VERSION);
          return 0;
        }
      }

      // Per RFC 5280, section 5.1.2.1, extensions require v2.
      if (version != X509_CRL_VERSION_2 && crl->crl->extensions != NULL) {
        OPENSSL_PUT_ERROR(X509, X509_R_INVALID_FIELD_FOR_VERSION);
        return 0;
      }

      if (!X509_CRL_digest(crl, EVP_sha256(), crl->crl_hash, NULL)) {
        return 0;
      }

      crl->idp =
          X509_CRL_get_ext_d2i(crl, NID_issuing_distribution_point, &i, NULL);
      if (crl->idp != NULL) {
        if (!setup_idp(crl, crl->idp)) {
          return 0;
        }
      } else if (i != -1) {
        return 0;
      }

      crl->akid =
          X509_CRL_get_ext_d2i(crl, NID_authority_key_identifier, &i, NULL);
      if (crl->akid == NULL && i != -1) {
        return 0;
      }

      crl->crl_number = X509_CRL_get_ext_d2i(crl, NID_crl_number, &i, NULL);
      if (crl->crl_number == NULL && i != -1) {
        return 0;
      }

      crl->base_crl_number = X509_CRL_get_ext_d2i(crl, NID_delta_crl, &i, NULL);
      if (crl->base_crl_number == NULL && i != -1) {
        return 0;
      }
      // Delta CRLs must have CRL number
      if (crl->base_crl_number && !crl->crl_number) {
        OPENSSL_PUT_ERROR(X509, X509_R_DELTA_CRL_WITHOUT_CRL_NUMBER);
        return 0;
      }

      // See if we have any unhandled critical CRL extensions and indicate
      // this in a flag. We only currently handle IDP so anything else
      // critical sets the flag. This code accesses the X509_CRL structure
      // directly: applications shouldn't do this.

      exts = crl->crl->extensions;

      for (idx = 0; idx < sk_X509_EXTENSION_num(exts); idx++) {
        int nid;
        ext = sk_X509_EXTENSION_value(exts, idx);
        nid = OBJ_obj2nid(X509_EXTENSION_get_object(ext));
        if (nid == NID_freshest_crl) {
          crl->flags |= EXFLAG_FRESHEST;
        }
        if (X509_EXTENSION_get_critical(ext)) {
          // We handle IDP and deltas
          if ((nid == NID_issuing_distribution_point) ||
              (nid == NID_authority_key_identifier) || (nid == NID_delta_crl)) {
            continue;
          }
          crl->flags |= EXFLAG_CRITICAL;
          break;
        }
      }

      if (!crl_set_issuers(crl)) {
        return 0;
      }

      break;
    }

    case ASN1_OP_FREE_POST:
      AUTHORITY_KEYID_free(crl->akid);
      ISSUING_DIST_POINT_free(crl->idp);
      ASN1_INTEGER_free(crl->crl_number);
      ASN1_INTEGER_free(crl->base_crl_number);
      sk_GENERAL_NAMES_pop_free(crl->issuers, GENERAL_NAMES_free);
      break;
  }
  return 1;
}

// Convert IDP into a more convenient form

static int setup_idp(X509_CRL *crl, ISSUING_DIST_POINT *idp) {
  int idp_only = 0;
  // Set various flags according to IDP
  crl->idp_flags |= IDP_PRESENT;
  if (idp->onlyuser > 0) {
    idp_only++;
    crl->idp_flags |= IDP_ONLYUSER;
  }
  if (idp->onlyCA > 0) {
    idp_only++;
    crl->idp_flags |= IDP_ONLYCA;
  }
  if (idp->onlyattr > 0) {
    idp_only++;
    crl->idp_flags |= IDP_ONLYATTR;
  }

  if (idp_only > 1) {
    crl->idp_flags |= IDP_INVALID;
  }

  if (idp->indirectCRL > 0) {
    crl->idp_flags |= IDP_INDIRECT;
  }

  if (idp->onlysomereasons) {
    crl->idp_flags |= IDP_REASONS;
    if (idp->onlysomereasons->length > 0) {
      crl->idp_reasons = idp->onlysomereasons->data[0];
    }
    if (idp->onlysomereasons->length > 1) {
      crl->idp_reasons |= (idp->onlysomereasons->data[1] << 8);
    }
    crl->idp_reasons &= CRLDP_ALL_REASONS;
  }

  return DIST_POINT_set_dpname(idp->distpoint, X509_CRL_get_issuer(crl));
}

ASN1_SEQUENCE_ref(X509_CRL, crl_cb) = {
    ASN1_SIMPLE(X509_CRL, crl, X509_CRL_INFO),
    ASN1_SIMPLE(X509_CRL, sig_alg, X509_ALGOR),
    ASN1_SIMPLE(X509_CRL, signature, ASN1_BIT_STRING),
} ASN1_SEQUENCE_END_ref(X509_CRL, X509_CRL)

// Although |X509_REVOKED| contains an |X509_NAME|, it can be const. It is not
// affected by https://crbug.com/boringssl/407 because the  |X509_NAME| does
// not participate in serialization.
IMPLEMENT_ASN1_FUNCTIONS_const(X509_REVOKED)
IMPLEMENT_ASN1_DUP_FUNCTION_const(X509_REVOKED)

IMPLEMENT_ASN1_FUNCTIONS(X509_CRL_INFO)
IMPLEMENT_ASN1_FUNCTIONS(X509_CRL)
IMPLEMENT_ASN1_DUP_FUNCTION(X509_CRL)

static int X509_REVOKED_cmp(const X509_REVOKED *const *a,
                            const X509_REVOKED *const *b) {
  return ASN1_STRING_cmp((*a)->serialNumber, (*b)->serialNumber);
}

int X509_CRL_add0_revoked(X509_CRL *crl, X509_REVOKED *rev) {
  X509_CRL_INFO *inf;
  inf = crl->crl;
  if (!inf->revoked) {
    inf->revoked = sk_X509_REVOKED_new(X509_REVOKED_cmp);
  }
  if (!inf->revoked || !sk_X509_REVOKED_push(inf->revoked, rev)) {
    return 0;
  }
  asn1_encoding_clear(&inf->enc);
  return 1;
}

int X509_CRL_verify(X509_CRL *crl, EVP_PKEY *pkey) {
  if (X509_ALGOR_cmp(crl->sig_alg, crl->crl->sig_alg) != 0) {
    OPENSSL_PUT_ERROR(X509, X509_R_SIGNATURE_ALGORITHM_MISMATCH);
    return 0;
  }

  return ASN1_item_verify(ASN1_ITEM_rptr(X509_CRL_INFO), crl->sig_alg,
                          crl->signature, crl->crl, pkey);
}

int X509_CRL_get0_by_serial(X509_CRL *crl, X509_REVOKED **ret,
                            ASN1_INTEGER *serial) {
  return crl_lookup(crl, ret, serial, NULL);
}

int X509_CRL_get0_by_cert(X509_CRL *crl, X509_REVOKED **ret, X509 *x) {
  return crl_lookup(crl, ret, X509_get_serialNumber(x),
                    X509_get_issuer_name(x));
}

static int crl_revoked_issuer_match(X509_CRL *crl, X509_NAME *nm,
                                    X509_REVOKED *rev) {
  size_t i;

  if (!rev->issuer) {
    if (!nm) {
      return 1;
    }
    if (!X509_NAME_cmp(nm, X509_CRL_get_issuer(crl))) {
      return 1;
    }
    return 0;
  }

  if (!nm) {
    nm = X509_CRL_get_issuer(crl);
  }

  for (i = 0; i < sk_GENERAL_NAME_num(rev->issuer); i++) {
    GENERAL_NAME *gen = sk_GENERAL_NAME_value(rev->issuer, i);
    if (gen->type != GEN_DIRNAME) {
      continue;
    }
    if (!X509_NAME_cmp(nm, gen->d.directoryName)) {
      return 1;
    }
  }
  return 0;
}

static CRYPTO_MUTEX g_crl_sort_lock = CRYPTO_MUTEX_INIT;

static int crl_lookup(X509_CRL *crl, X509_REVOKED **ret, ASN1_INTEGER *serial,
                      X509_NAME *issuer) {
  // Use an assert, rather than a runtime error, because returning nothing for a
  // CRL is arguably failing open, rather than closed.
  assert(serial->type == V_ASN1_INTEGER || serial->type == V_ASN1_NEG_INTEGER);
  X509_REVOKED rtmp, *rev;
  size_t idx;
  rtmp.serialNumber = serial;
  // Sort revoked into serial number order if not already sorted. Do this
  // under a lock to avoid race condition.

  CRYPTO_MUTEX_lock_read(&g_crl_sort_lock);
  const int is_sorted = sk_X509_REVOKED_is_sorted(crl->crl->revoked);
  CRYPTO_MUTEX_unlock_read(&g_crl_sort_lock);

  if (!is_sorted) {
    CRYPTO_MUTEX_lock_write(&g_crl_sort_lock);
    if (!sk_X509_REVOKED_is_sorted(crl->crl->revoked)) {
      sk_X509_REVOKED_sort(crl->crl->revoked);
    }
    CRYPTO_MUTEX_unlock_write(&g_crl_sort_lock);
  }

  if (!sk_X509_REVOKED_find(crl->crl->revoked, &idx, &rtmp)) {
    return 0;
  }
  // Need to look for matching name
  for (; idx < sk_X509_REVOKED_num(crl->crl->revoked); idx++) {
    rev = sk_X509_REVOKED_value(crl->crl->revoked, idx);
    if (ASN1_INTEGER_cmp(rev->serialNumber, serial)) {
      return 0;
    }
    if (crl_revoked_issuer_match(crl, issuer, rev)) {
      if (ret) {
        *ret = rev;
      }
      if (rev->reason == CRL_REASON_REMOVE_FROM_CRL) {
        return 2;
      }
      return 1;
    }
  }
  return 0;
}