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x509_vfy.c

/* crypto/x509/x509_vfy.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 <stdio.h>
#include <time.h>
#include <errno.h>

#include "cryptlib.h"
#include <openssl/crypto.h>
#include <openssl/lhash.h>
#include <openssl/buffer.h>
#include <openssl/evp.h>
#include <openssl/asn1.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include <openssl/objects.h>

/* CRL score values */

/* No unhandled critical extensions */

#define CRL_SCORE_NOCRITICAL  0x100

/* certificate is within CRL scope */

#define CRL_SCORE_SCOPE       0x080

/* CRL times valid */

#define CRL_SCORE_TIME        0x040

/* Issuer name matches certificate */

#define CRL_SCORE_ISSUER_NAME 0x020

/* If this score or above CRL is probably valid */

#define CRL_SCORE_VALID (CRL_SCORE_NOCRITICAL|CRL_SCORE_TIME|CRL_SCORE_SCOPE)

/* CRL issuer is certificate issuer */

#define CRL_SCORE_ISSUER_CERT 0x018

/* CRL issuer is on certificate path */

#define CRL_SCORE_SAME_PATH   0x008

/* CRL issuer matches CRL AKID */

#define CRL_SCORE_AKID        0x004

/* Have a delta CRL with valid times */

#define CRL_SCORE_TIME_DELTA  0x002

static int null_callback(int ok,X509_STORE_CTX *e);
static int check_issued(X509_STORE_CTX *ctx, X509 *x, X509 *issuer);
static X509 *find_issuer(X509_STORE_CTX *ctx, STACK_OF(X509) *sk, X509 *x);
static int check_chain_extensions(X509_STORE_CTX *ctx);
static int check_name_constraints(X509_STORE_CTX *ctx);
static int check_trust(X509_STORE_CTX *ctx);
static int check_revocation(X509_STORE_CTX *ctx);
static int check_cert(X509_STORE_CTX *ctx);
static int check_policy(X509_STORE_CTX *ctx);

static int get_crl_score(X509_STORE_CTX *ctx, X509 **pissuer,
                  unsigned int *preasons,
                  X509_CRL *crl, X509 *x);
static int get_crl_delta(X509_STORE_CTX *ctx,
                        X509_CRL **pcrl, X509_CRL **pdcrl, X509 *x);
static void get_delta_sk(X509_STORE_CTX *ctx, X509_CRL **dcrl, int *pcrl_score,
                  X509_CRL *base, STACK_OF(X509_CRL) *crls);
static void crl_akid_check(X509_STORE_CTX *ctx, X509_CRL *crl,
                        X509 **pissuer, int *pcrl_score);
static int crl_crldp_check(X509 *x, X509_CRL *crl, int crl_score,
                        unsigned int *preasons);
static int check_crl_path(X509_STORE_CTX *ctx, X509 *x);
static int check_crl_chain(X509_STORE_CTX *ctx,
                  STACK_OF(X509) *cert_path,
                  STACK_OF(X509) *crl_path);

static int internal_verify(X509_STORE_CTX *ctx);
const char X509_version[]="X.509" OPENSSL_VERSION_PTEXT;


static int null_callback(int ok, X509_STORE_CTX *e)
      {
      return ok;
      }

#if 0
static int x509_subject_cmp(X509 **a, X509 **b)
      {
      return X509_subject_name_cmp(*a,*b);
      }
#endif

int X509_verify_cert(X509_STORE_CTX *ctx)
      {
      X509 *x,*xtmp,*chain_ss=NULL;
      X509_NAME *xn;
      int bad_chain = 0;
      X509_VERIFY_PARAM *param = ctx->param;
      int depth,i,ok=0;
      int num;
      int (*cb)(int xok,X509_STORE_CTX *xctx);
      STACK_OF(X509) *sktmp=NULL;
      if (ctx->cert == NULL)
            {
            X509err(X509_F_X509_VERIFY_CERT,X509_R_NO_CERT_SET_FOR_US_TO_VERIFY);
            return -1;
            }

      cb=ctx->verify_cb;

      /* first we make sure the chain we are going to build is
       * present and that the first entry is in place */
      if (ctx->chain == NULL)
            {
            if (  ((ctx->chain=sk_X509_new_null()) == NULL) ||
                  (!sk_X509_push(ctx->chain,ctx->cert)))
                  {
                  X509err(X509_F_X509_VERIFY_CERT,ERR_R_MALLOC_FAILURE);
                  goto end;
                  }
            CRYPTO_add(&ctx->cert->references,1,CRYPTO_LOCK_X509);
            ctx->last_untrusted=1;
            }

      /* We use a temporary STACK so we can chop and hack at it */
      if (ctx->untrusted != NULL
          && (sktmp=sk_X509_dup(ctx->untrusted)) == NULL)
            {
            X509err(X509_F_X509_VERIFY_CERT,ERR_R_MALLOC_FAILURE);
            goto end;
            }

      num=sk_X509_num(ctx->chain);
      x=sk_X509_value(ctx->chain,num-1);
      depth=param->depth;


      for (;;)
            {
            /* If we have enough, we break */
            if (depth < num) break; /* FIXME: If this happens, we should take
                                     * note of it and, if appropriate, use the
                                     * X509_V_ERR_CERT_CHAIN_TOO_LONG error
                                     * code later.
                                     */

            /* If we are self signed, we break */
            xn=X509_get_issuer_name(x);
            if (ctx->check_issued(ctx, x,x)) break;

            /* If we were passed a cert chain, use it first */
            if (ctx->untrusted != NULL)
                  {
                  xtmp=find_issuer(ctx, sktmp,x);
                  if (xtmp != NULL)
                        {
                        if (!sk_X509_push(ctx->chain,xtmp))
                              {
                              X509err(X509_F_X509_VERIFY_CERT,ERR_R_MALLOC_FAILURE);
                              goto end;
                              }
                        CRYPTO_add(&xtmp->references,1,CRYPTO_LOCK_X509);
                        (void)sk_X509_delete_ptr(sktmp,xtmp);
                        ctx->last_untrusted++;
                        x=xtmp;
                        num++;
                        /* reparse the full chain for
                         * the next one */
                        continue;
                        }
                  }
            break;
            }

      /* at this point, chain should contain a list of untrusted
       * certificates.  We now need to add at least one trusted one,
       * if possible, otherwise we complain. */

      /* Examine last certificate in chain and see if it
       * is self signed.
       */

      i=sk_X509_num(ctx->chain);
      x=sk_X509_value(ctx->chain,i-1);
      xn = X509_get_subject_name(x);
      if (ctx->check_issued(ctx, x, x))
            {
            /* we have a self signed certificate */
            if (sk_X509_num(ctx->chain) == 1)
                  {
                  /* We have a single self signed certificate: see if
                   * we can find it in the store. We must have an exact
                   * match to avoid possible impersonation.
                   */
                  ok = ctx->get_issuer(&xtmp, ctx, x);
                  if ((ok <= 0) || X509_cmp(x, xtmp)) 
                        {
                        ctx->error=X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT;
                        ctx->current_cert=x;
                        ctx->error_depth=i-1;
                        if (ok == 1) X509_free(xtmp);
                        bad_chain = 1;
                        ok=cb(0,ctx);
                        if (!ok) goto end;
                        }
                  else 
                        {
                        /* We have a match: replace certificate with store version
                         * so we get any trust settings.
                         */
                        X509_free(x);
                        x = xtmp;
                        (void)sk_X509_set(ctx->chain, i - 1, x);
                        ctx->last_untrusted=0;
                        }
                  }
            else
                  {
                  /* extract and save self signed certificate for later use */
                  chain_ss=sk_X509_pop(ctx->chain);
                  ctx->last_untrusted--;
                  num--;
                  x=sk_X509_value(ctx->chain,num-1);
                  }
            }

      /* We now lookup certs from the certificate store */
      for (;;)
            {
            /* If we have enough, we break */
            if (depth < num) break;

            /* If we are self signed, we break */
            xn=X509_get_issuer_name(x);
            if (ctx->check_issued(ctx,x,x)) break;

            ok = ctx->get_issuer(&xtmp, ctx, x);

            if (ok < 0) return ok;
            if (ok == 0) break;

            x = xtmp;
            if (!sk_X509_push(ctx->chain,x))
                  {
                  X509_free(xtmp);
                  X509err(X509_F_X509_VERIFY_CERT,ERR_R_MALLOC_FAILURE);
                  return 0;
                  }
            num++;
            }

      /* we now have our chain, lets check it... */
      xn=X509_get_issuer_name(x);

      /* Is last certificate looked up self signed? */
      if (!ctx->check_issued(ctx,x,x))
            {
            if ((chain_ss == NULL) || !ctx->check_issued(ctx, x, chain_ss))
                  {
                  if (ctx->last_untrusted >= num)
                        ctx->error=X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY;
                  else
                        ctx->error=X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT;
                  ctx->current_cert=x;
                  }
            else
                  {

                  sk_X509_push(ctx->chain,chain_ss);
                  num++;
                  ctx->last_untrusted=num;
                  ctx->current_cert=chain_ss;
                  ctx->error=X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN;
                  chain_ss=NULL;
                  }

            ctx->error_depth=num-1;
            bad_chain = 1;
            ok=cb(0,ctx);
            if (!ok) goto end;
            }

      /* We have the chain complete: now we need to check its purpose */
      ok = check_chain_extensions(ctx);

      if (!ok) goto end;

      /* Check name constraints */

      ok = check_name_constraints(ctx);
      
      if (!ok) goto end;

      /* The chain extensions are OK: check trust */

      if (param->trust > 0) ok = check_trust(ctx);

      if (!ok) goto end;

      /* We may as well copy down any DSA parameters that are required */
      X509_get_pubkey_parameters(NULL,ctx->chain);

      /* Check revocation status: we do this after copying parameters
       * because they may be needed for CRL signature verification.
       */

      ok = ctx->check_revocation(ctx);
      if(!ok) goto end;

      /* At this point, we have a chain and need to verify it */
      if (ctx->verify != NULL)
            ok=ctx->verify(ctx);
      else
            ok=internal_verify(ctx);
      if(!ok) goto end;

#ifndef OPENSSL_NO_RFC3779
      /* RFC 3779 path validation, now that CRL check has been done */
      ok = v3_asid_validate_path(ctx);
      if (!ok) goto end;
      ok = v3_addr_validate_path(ctx);
      if (!ok) goto end;
#endif

      /* If we get this far evaluate policies */
      if (!bad_chain && (ctx->param->flags & X509_V_FLAG_POLICY_CHECK))
            ok = ctx->check_policy(ctx);
      if(!ok) goto end;
      if (0)
            {
end:
            X509_get_pubkey_parameters(NULL,ctx->chain);
            }
      if (sktmp != NULL) sk_X509_free(sktmp);
      if (chain_ss != NULL) X509_free(chain_ss);
      return ok;
      }


/* Given a STACK_OF(X509) find the issuer of cert (if any)
 */

static X509 *find_issuer(X509_STORE_CTX *ctx, STACK_OF(X509) *sk, X509 *x)
{
      int i;
      X509 *issuer;
      for (i = 0; i < sk_X509_num(sk); i++)
            {
            issuer = sk_X509_value(sk, i);
            if (ctx->check_issued(ctx, x, issuer))
                  return issuer;
            }
      return NULL;
}

/* Given a possible certificate and issuer check them */

static int check_issued(X509_STORE_CTX *ctx, X509 *x, X509 *issuer)
{
      int ret;
      ret = X509_check_issued(issuer, x);
      if (ret == X509_V_OK)
            return 1;
      /* If we haven't asked for issuer errors don't set ctx */
      if (!(ctx->param->flags & X509_V_FLAG_CB_ISSUER_CHECK))
            return 0;

      ctx->error = ret;
      ctx->current_cert = x;
      ctx->current_issuer = issuer;
      return ctx->verify_cb(0, ctx);
      return 0;
}

/* Alternative lookup method: look from a STACK stored in other_ctx */

static int get_issuer_sk(X509 **issuer, X509_STORE_CTX *ctx, X509 *x)
{
      *issuer = find_issuer(ctx, ctx->other_ctx, x);
      if (*issuer)
            {
            CRYPTO_add(&(*issuer)->references,1,CRYPTO_LOCK_X509);
            return 1;
            }
      else
            return 0;
}
      

/* Check a certificate chains extensions for consistency
 * with the supplied purpose
 */

static int check_chain_extensions(X509_STORE_CTX *ctx)
{
#ifdef OPENSSL_NO_CHAIN_VERIFY
      return 1;
#else
      int i, ok=0, must_be_ca, plen = 0;
      X509 *x;
      int (*cb)(int xok,X509_STORE_CTX *xctx);
      int proxy_path_length = 0;
      int purpose;
      int allow_proxy_certs;
      cb=ctx->verify_cb;

      /* must_be_ca can have 1 of 3 values:
         -1: we accept both CA and non-CA certificates, to allow direct
             use of self-signed certificates (which are marked as CA).
         0:  we only accept non-CA certificates.  This is currently not
             used, but the possibility is present for future extensions.
         1:  we only accept CA certificates.  This is currently used for
             all certificates in the chain except the leaf certificate.
      */
      must_be_ca = -1;

      /* CRL path validation */
      if (ctx->parent)
            {
            allow_proxy_certs = 0;
            purpose = X509_PURPOSE_CRL_SIGN;
            }
      else
            {
            allow_proxy_certs =
                  !!(ctx->param->flags & X509_V_FLAG_ALLOW_PROXY_CERTS);
            /* A hack to keep people who don't want to modify their
               software happy */
            if (getenv("OPENSSL_ALLOW_PROXY_CERTS"))
                  allow_proxy_certs = 1;
            purpose = ctx->param->purpose;
            }

      /* Check all untrusted certificates */
      for (i = 0; i < ctx->last_untrusted; i++)
            {
            int ret;
            x = sk_X509_value(ctx->chain, i);
            if (!(ctx->param->flags & X509_V_FLAG_IGNORE_CRITICAL)
                  && (x->ex_flags & EXFLAG_CRITICAL))
                  {
                  ctx->error = X509_V_ERR_UNHANDLED_CRITICAL_EXTENSION;
                  ctx->error_depth = i;
                  ctx->current_cert = x;
                  ok=cb(0,ctx);
                  if (!ok) goto end;
                  }
            if (!allow_proxy_certs && (x->ex_flags & EXFLAG_PROXY))
                  {
                  ctx->error = X509_V_ERR_PROXY_CERTIFICATES_NOT_ALLOWED;
                  ctx->error_depth = i;
                  ctx->current_cert = x;
                  ok=cb(0,ctx);
                  if (!ok) goto end;
                  }
            ret = X509_check_ca(x);
            switch(must_be_ca)
                  {
            case -1:
                  if ((ctx->param->flags & X509_V_FLAG_X509_STRICT)
                        && (ret != 1) && (ret != 0))
                        {
                        ret = 0;
                        ctx->error = X509_V_ERR_INVALID_CA;
                        }
                  else
                        ret = 1;
                  break;
            case 0:
                  if (ret != 0)
                        {
                        ret = 0;
                        ctx->error = X509_V_ERR_INVALID_NON_CA;
                        }
                  else
                        ret = 1;
                  break;
            default:
                  if ((ret == 0)
                        || ((ctx->param->flags & X509_V_FLAG_X509_STRICT)
                              && (ret != 1)))
                        {
                        ret = 0;
                        ctx->error = X509_V_ERR_INVALID_CA;
                        }
                  else
                        ret = 1;
                  break;
                  }
            if (ret == 0)
                  {
                  ctx->error_depth = i;
                  ctx->current_cert = x;
                  ok=cb(0,ctx);
                  if (!ok) goto end;
                  }
            if (ctx->param->purpose > 0)
                  {
                  ret = X509_check_purpose(x, purpose, must_be_ca > 0);
                  if ((ret == 0)
                        || ((ctx->param->flags & X509_V_FLAG_X509_STRICT)
                              && (ret != 1)))
                        {
                        ctx->error = X509_V_ERR_INVALID_PURPOSE;
                        ctx->error_depth = i;
                        ctx->current_cert = x;
                        ok=cb(0,ctx);
                        if (!ok) goto end;
                        }
                  }
            /* Check pathlen if not self issued */
            if ((i > 1) && !(x->ex_flags & EXFLAG_SI)
                     && (x->ex_pathlen != -1)
                     && (plen > (x->ex_pathlen + proxy_path_length + 1)))
                  {
                  ctx->error = X509_V_ERR_PATH_LENGTH_EXCEEDED;
                  ctx->error_depth = i;
                  ctx->current_cert = x;
                  ok=cb(0,ctx);
                  if (!ok) goto end;
                  }
            /* Increment path length if not self issued */
            if (!(x->ex_flags & EXFLAG_SI))
                  plen++;
            /* If this certificate is a proxy certificate, the next
               certificate must be another proxy certificate or a EE
               certificate.  If not, the next certificate must be a
               CA certificate.  */
            if (x->ex_flags & EXFLAG_PROXY)
                  {
                  if (x->ex_pcpathlen != -1 && i > x->ex_pcpathlen)
                        {
                        ctx->error =
                              X509_V_ERR_PROXY_PATH_LENGTH_EXCEEDED;
                        ctx->error_depth = i;
                        ctx->current_cert = x;
                        ok=cb(0,ctx);
                        if (!ok) goto end;
                        }
                  proxy_path_length++;
                  must_be_ca = 0;
                  }
            else
                  must_be_ca = 1;
            }
      ok = 1;
 end:
      return ok;
#endif
}

static int check_name_constraints(X509_STORE_CTX *ctx)
      {
      X509 *x;
      int i, j, rv;
      /* Check name constraints for all certificates */
      for (i = sk_X509_num(ctx->chain) - 1; i >= 0; i--)
            {
            x = sk_X509_value(ctx->chain, i);
            /* Ignore self issued certs unless last in chain */
            if (i && (x->ex_flags & EXFLAG_SI))
                  continue;
            /* Check against constraints for all certificates higher in
             * chain including trust anchor. Trust anchor not strictly
             * speaking needed but if it includes constraints it is to be
             * assumed it expects them to be obeyed.
             */
            for (j = sk_X509_num(ctx->chain) - 1; j > i; j--)
                  {
                  NAME_CONSTRAINTS *nc = sk_X509_value(ctx->chain, j)->nc;
                  if (nc)
                        {
                        rv = NAME_CONSTRAINTS_check(x, nc);
                        if (rv != X509_V_OK)
                              {
                              ctx->error = rv;
                              ctx->error_depth = i;
                              ctx->current_cert = x;
                              if (!ctx->verify_cb(0,ctx))
                                    return 0;
                              }
                        }
                  }
            }
      return 1;
      }

static int check_trust(X509_STORE_CTX *ctx)
{
#ifdef OPENSSL_NO_CHAIN_VERIFY
      return 1;
#else
      int i, ok;
      X509 *x;
      int (*cb)(int xok,X509_STORE_CTX *xctx);
      cb=ctx->verify_cb;
/* For now just check the last certificate in the chain */
      i = sk_X509_num(ctx->chain) - 1;
      x = sk_X509_value(ctx->chain, i);
      ok = X509_check_trust(x, ctx->param->trust, 0);
      if (ok == X509_TRUST_TRUSTED)
            return 1;
      ctx->error_depth = i;
      ctx->current_cert = x;
      if (ok == X509_TRUST_REJECTED)
            ctx->error = X509_V_ERR_CERT_REJECTED;
      else
            ctx->error = X509_V_ERR_CERT_UNTRUSTED;
      ok = cb(0, ctx);
      return ok;
#endif
}

static int check_revocation(X509_STORE_CTX *ctx)
      {
      int i, last, ok;
      if (!(ctx->param->flags & X509_V_FLAG_CRL_CHECK))
            return 1;
      if (ctx->param->flags & X509_V_FLAG_CRL_CHECK_ALL)
            last = sk_X509_num(ctx->chain) - 1;
      else
            {
            /* If checking CRL paths this isn't the EE certificate */
            if (ctx->parent)
                  return 1;
            last = 0;
            }
      for(i = 0; i <= last; i++)
            {
            ctx->error_depth = i;
            ok = check_cert(ctx);
            if (!ok) return ok;
            }
      return 1;
      }

static int check_cert(X509_STORE_CTX *ctx)
      {
      X509_CRL *crl = NULL, *dcrl = NULL;
      X509 *x;
      int ok, cnum;
      cnum = ctx->error_depth;
      x = sk_X509_value(ctx->chain, cnum);
      ctx->current_cert = x;
      ctx->current_issuer = NULL;
      ctx->current_reasons = 0;
      while (ctx->current_reasons != CRLDP_ALL_REASONS)
            {
            /* Try to retrieve relevant CRL */
            if (ctx->get_crl)
                  ok = ctx->get_crl(ctx, &crl, x);
            else
                  ok = get_crl_delta(ctx, &crl, &dcrl, x);
            /* If error looking up CRL, nothing we can do except
             * notify callback
             */
            if(!ok)
                  {
                  ctx->error = X509_V_ERR_UNABLE_TO_GET_CRL;
                  ok = ctx->verify_cb(0, ctx);
                  goto err;
                  }
            ctx->current_crl = crl;
            ok = ctx->check_crl(ctx, crl);
            if (!ok)
                  goto err;

            if (dcrl)
                  {
                  ok = ctx->check_crl(ctx, dcrl);
                  if (!ok)
                        goto err;
                  ok = ctx->cert_crl(ctx, dcrl, x);
                  if (!ok)
                        goto err;
                  }
            else
                  ok = 1;

            /* Don't look in full CRL if delta reason is removefromCRL */
            if (ok != 2)
                  {
                  ok = ctx->cert_crl(ctx, crl, x);
                  if (!ok)
                        goto err;
                  }

            X509_CRL_free(crl);
            X509_CRL_free(dcrl);
            crl = NULL;
            dcrl = NULL;
            }
      err:
      X509_CRL_free(crl);
      X509_CRL_free(dcrl);

      ctx->current_crl = NULL;
      return ok;

      }

/* Check CRL times against values in X509_STORE_CTX */

static int check_crl_time(X509_STORE_CTX *ctx, X509_CRL *crl, int notify)
      {
      time_t *ptime;
      int i;
      if (notify)
            ctx->current_crl = crl;
      if (ctx->param->flags & X509_V_FLAG_USE_CHECK_TIME)
            ptime = &ctx->param->check_time;
      else
            ptime = NULL;

      i=X509_cmp_time(X509_CRL_get_lastUpdate(crl), ptime);
      if (i == 0)
            {
            if (!notify)
                  return 0;
            ctx->error=X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD;
            if (!ctx->verify_cb(0, ctx))
                  return 0;
            }

      if (i > 0)
            {
            if (!notify)
                  return 0;
            ctx->error=X509_V_ERR_CRL_NOT_YET_VALID;
            if (!ctx->verify_cb(0, ctx))
                  return 0;
            }

      if(X509_CRL_get_nextUpdate(crl))
            {
            i=X509_cmp_time(X509_CRL_get_nextUpdate(crl), ptime);

            if (i == 0)
                  {
                  if (!notify)
                        return 0;
                  ctx->error=X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD;
                  if (!ctx->verify_cb(0, ctx))
                        return 0;
                  }
            /* Ignore expiry of base CRL is delta is valid */
            if ((i < 0) && !(ctx->current_crl_score & CRL_SCORE_TIME_DELTA))
                  {
                  if (!notify)
                        return 0;
                  ctx->error=X509_V_ERR_CRL_HAS_EXPIRED;
                  if (!ctx->verify_cb(0, ctx))
                        return 0;
                  }
            }

      if (notify)
            ctx->current_crl = NULL;

      return 1;
      }

static int get_crl_sk(X509_STORE_CTX *ctx, X509_CRL **pcrl, X509_CRL **pdcrl,
                  X509 **pissuer, int *pscore, unsigned int *preasons,
                  STACK_OF(X509_CRL) *crls)
      {
      int i, crl_score, best_score = *pscore;
      unsigned int reasons, best_reasons = 0;
      X509 *x = ctx->current_cert;
      X509_CRL *crl, *best_crl = NULL;
      X509 *crl_issuer = NULL, *best_crl_issuer = NULL;

      for (i = 0; i < sk_X509_CRL_num(crls); i++)
            {
            crl = sk_X509_CRL_value(crls, i);
            reasons = *preasons;
            crl_score = get_crl_score(ctx, &crl_issuer, &reasons, crl, x);

            if (crl_score > best_score)
                  {
                  best_crl = crl;
                  best_crl_issuer = crl_issuer;
                  best_score = crl_score;
                  best_reasons = reasons;
                  }
            }

      if (best_crl)
            {
            if (*pcrl)
                  X509_CRL_free(*pcrl);
            *pcrl = best_crl;
            *pissuer = best_crl_issuer;
            *pscore = best_score;
            *preasons = best_reasons;
            CRYPTO_add(&best_crl->references, 1, CRYPTO_LOCK_X509_CRL);
            if (*pdcrl)
                  {
                  X509_CRL_free(*pdcrl);
                  *pdcrl = NULL;
                  }
            get_delta_sk(ctx, pdcrl, pscore, best_crl, crls);
            }

      if (best_score >= CRL_SCORE_VALID)
            return 1;

      return 0;
      }

/* Compare two CRL extensions for delta checking purposes. They should be
 * both present or both absent. If both present all fields must be identical.
 */

static int crl_extension_match(X509_CRL *a, X509_CRL *b, int nid)
      {
      ASN1_OCTET_STRING *exta, *extb;
      int i;
      i = X509_CRL_get_ext_by_NID(a, nid, 0);
      if (i >= 0)
            {
            /* Can't have multiple occurrences */
            if (X509_CRL_get_ext_by_NID(a, nid, i) != -1)
                  return 0;
            exta = X509_EXTENSION_get_data(X509_CRL_get_ext(a, i));
            }
      else
            exta = NULL;

      i = X509_CRL_get_ext_by_NID(b, nid, 0);

      if (i >= 0)
            {

            if (X509_CRL_get_ext_by_NID(b, nid, i) != -1)
                  return 0;
            extb = X509_EXTENSION_get_data(X509_CRL_get_ext(b, i));
            }
      else
            extb = NULL;

      if (!exta && !extb)
            return 1;

      if (!exta || !extb)
            return 0;


      if (ASN1_OCTET_STRING_cmp(exta, extb))
            return 0;

      return 1;
      }

/* See if a base and delta are compatible */

static int check_delta_base(X509_CRL *delta, X509_CRL *base)
      {
      /* Delta CRL must be a delta */
      if (!delta->base_crl_number)
                  return 0;
      /* Base must have a CRL number */
      if (!base->crl_number)
                  return 0;
      /* Issuer names must match */
      if (X509_NAME_cmp(X509_CRL_get_issuer(base),
                        X509_CRL_get_issuer(delta)))
            return 0;
      /* AKID and IDP must match */
      if (!crl_extension_match(delta, base, NID_authority_key_identifier))
                  return 0;
      if (!crl_extension_match(delta, base, NID_issuing_distribution_point))
                  return 0;
      /* Delta CRL base number must not exceed Full CRL number. */
      if (ASN1_INTEGER_cmp(delta->base_crl_number, base->crl_number) > 0)
                  return 0;
      /* Delta CRL number must exceed full CRL number */
      if (ASN1_INTEGER_cmp(delta->crl_number, base->crl_number) > 0)
                  return 1;
      return 0;
      }

/* For a given base CRL find a delta... maybe extend to delta scoring
 * or retrieve a chain of deltas...
 */

static void get_delta_sk(X509_STORE_CTX *ctx, X509_CRL **dcrl, int *pscore,
                  X509_CRL *base, STACK_OF(X509_CRL) *crls)
      {
      X509_CRL *delta;
      int i;
      if (!(ctx->param->flags & X509_V_FLAG_USE_DELTAS))
            return;
      if (!((ctx->current_cert->ex_flags | base->flags) & EXFLAG_FRESHEST))
            return;
      for (i = 0; i < sk_X509_CRL_num(crls); i++)
            {
            delta = sk_X509_CRL_value(crls, i);
            if (check_delta_base(delta, base))
                  {
                  if (check_crl_time(ctx, delta, 0))
                        *pscore |= CRL_SCORE_TIME_DELTA;
                  CRYPTO_add(&delta->references, 1, CRYPTO_LOCK_X509_CRL);
                  *dcrl = delta;
                  return;
                  }
            }
      *dcrl = NULL;
      }

/* For a given CRL return how suitable it is for the supplied certificate 'x'.
 * The return value is a mask of several criteria.
 * If the issuer is not the certificate issuer this is returned in *pissuer.
 * The reasons mask is also used to determine if the CRL is suitable: if
 * no new reasons the CRL is rejected, otherwise reasons is updated.
 */

static int get_crl_score(X509_STORE_CTX *ctx, X509 **pissuer,
                  unsigned int *preasons,
                  X509_CRL *crl, X509 *x)
      {

      int crl_score = 0;
      unsigned int tmp_reasons = *preasons, crl_reasons;

      /* First see if we can reject CRL straight away */

      /* Invalid IDP cannot be processed */
      if (crl->idp_flags & IDP_INVALID)
            return 0;
      /* Reason codes or indirect CRLs need extended CRL support */
      if (!(ctx->param->flags & X509_V_FLAG_EXTENDED_CRL_SUPPORT))
            {
            if (crl->idp_flags & (IDP_INDIRECT | IDP_REASONS))
                  return 0;
            }
      else if (crl->idp_flags & IDP_REASONS)
            {
            /* If no new reasons reject */
            if (!(crl->idp_reasons & ~tmp_reasons))
                  return 0;
            }
      /* Don't process deltas at this stage */
      else if (crl->base_crl_number)
            return 0;
      /* If issuer name doesn't match certificate need indirect CRL */
      if (X509_NAME_cmp(X509_get_issuer_name(x), X509_CRL_get_issuer(crl)))
            {
            if (!(crl->idp_flags & IDP_INDIRECT))
                  return 0;
            }
      else
            crl_score |= CRL_SCORE_ISSUER_NAME;

      if (!(crl->flags & EXFLAG_CRITICAL))
            crl_score |= CRL_SCORE_NOCRITICAL;

      /* Check expiry */
      if (check_crl_time(ctx, crl, 0))
            crl_score |= CRL_SCORE_TIME;

      /* Check authority key ID and locate certificate issuer */
      crl_akid_check(ctx, crl, pissuer, &crl_score);

      /* If we can't locate certificate issuer at this point forget it */

      if (!(crl_score & CRL_SCORE_AKID))
            return 0;

      /* Check cert for matching CRL distribution points */

      if (crl_crldp_check(x, crl, crl_score, &crl_reasons))
            {
            /* If no new reasons reject */
            if (!(crl_reasons & ~tmp_reasons))
                  return 0;
            tmp_reasons |= crl_reasons;
            crl_score |= CRL_SCORE_SCOPE;
            }

      *preasons = tmp_reasons;

      return crl_score;

      }

static void crl_akid_check(X509_STORE_CTX *ctx, X509_CRL *crl,
                        X509 **pissuer, int *pcrl_score)
      {
      X509 *crl_issuer = NULL;
      X509_NAME *cnm = X509_CRL_get_issuer(crl);
      int cidx = ctx->error_depth;
      int i;

      if (cidx != sk_X509_num(ctx->chain) - 1)
            cidx++;

      crl_issuer = sk_X509_value(ctx->chain, cidx);

      if (X509_check_akid(crl_issuer, crl->akid) == X509_V_OK)
            {
            if (*pcrl_score & CRL_SCORE_ISSUER_NAME)
                  {
                  *pcrl_score |= CRL_SCORE_AKID|CRL_SCORE_ISSUER_CERT;
                  *pissuer = crl_issuer;
                  return;
                  }
            }

      for (cidx++; cidx < sk_X509_num(ctx->chain); cidx++)
            {
            crl_issuer = sk_X509_value(ctx->chain, cidx);
            if (X509_NAME_cmp(X509_get_subject_name(crl_issuer), cnm))
                  continue;
            if (X509_check_akid(crl_issuer, crl->akid) == X509_V_OK)
                  {
                  *pcrl_score |= CRL_SCORE_AKID|CRL_SCORE_SAME_PATH;
                  *pissuer = crl_issuer;
                  return;
                  }
            }

      /* Anything else needs extended CRL support */

      if (!(ctx->param->flags & X509_V_FLAG_EXTENDED_CRL_SUPPORT))
            return;

      /* Otherwise the CRL issuer is not on the path. Look for it in the
       * set of untrusted certificates.
       */
      for (i = 0; i < sk_X509_num(ctx->untrusted); i++)
            {
            crl_issuer = sk_X509_value(ctx->untrusted, i);
            if (X509_NAME_cmp(X509_get_subject_name(crl_issuer), cnm))
                  continue;
            if (X509_check_akid(crl_issuer, crl->akid) == X509_V_OK)
                  {
                  *pissuer = crl_issuer;
                  *pcrl_score |= CRL_SCORE_AKID;
                  return;
                  }
            }
      }

/* Check the path of a CRL issuer certificate. This creates a new
 * X509_STORE_CTX and populates it with most of the parameters from the
 * parent. This could be optimised somewhat since a lot of path checking
 * will be duplicated by the parent, but this will rarely be used in 
 * practice.
 */

static int check_crl_path(X509_STORE_CTX *ctx, X509 *x)
      {
      X509_STORE_CTX crl_ctx;
      int ret;
      /* Don't allow recursive CRL path validation */
      if (ctx->parent)
            return 0;
      if (!X509_STORE_CTX_init(&crl_ctx, ctx->ctx, x, ctx->untrusted))
            return -1;

      crl_ctx.crls = ctx->crls;
      /* Copy verify params across */
      X509_STORE_CTX_set0_param(&crl_ctx, ctx->param);

      crl_ctx.parent = ctx;
      crl_ctx.verify_cb = ctx->verify_cb;

      /* Verify CRL issuer */
      ret = X509_verify_cert(&crl_ctx);

      if (ret <= 0)
            goto err;

      /* Check chain is acceptable */

      ret = check_crl_chain(ctx, ctx->chain, crl_ctx.chain);
      err:
      X509_STORE_CTX_cleanup(&crl_ctx);
      return ret;
      }

/* RFC3280 says nothing about the relationship between CRL path
 * and certificate path, which could lead to situations where a
 * certificate could be revoked or validated by a CA not authorised
 * to do so. RFC5280 is more strict and states that the two paths must
 * end in the same trust anchor, though some discussions remain...
 * until this is resolved we use the RFC5280 version
 */

static int check_crl_chain(X509_STORE_CTX *ctx,
                  STACK_OF(X509) *cert_path,
                  STACK_OF(X509) *crl_path)
      {
      X509 *cert_ta, *crl_ta;
      cert_ta = sk_X509_value(cert_path, sk_X509_num(cert_path) - 1);
      crl_ta = sk_X509_value(crl_path, sk_X509_num(crl_path) - 1);
      if (!X509_cmp(cert_ta, crl_ta))
            return 1;
      return 0;
      }

/* Check for match between two dist point names: three separate cases.
 * 1. Both are relative names and compare X509_NAME types.
 * 2. One full, one relative. Compare X509_NAME to GENERAL_NAMES.
 * 3. Both are full names and compare two GENERAL_NAMES.
 * 4. One is NULL: automatic match.
 */


static int idp_check_dp(DIST_POINT_NAME *a, DIST_POINT_NAME *b)
      {
      X509_NAME *nm = NULL;
      GENERAL_NAMES *gens = NULL;
      GENERAL_NAME *gena, *genb;
      int i, j;
      if (!a || !b)
            return 1;
      if (a->type == 1)
            {
            if (!a->dpname)
                  return 0;
            /* Case 1: two X509_NAME */
            if (b->type == 1)
                  {
                  if (!b->dpname)
                        return 0;
                  if (!X509_NAME_cmp(a->dpname, b->dpname))
                        return 1;
                  else
                        return 0;
                  }
            /* Case 2: set name and GENERAL_NAMES appropriately */
            nm = a->dpname;
            gens = b->name.fullname;
            }
      else if (b->type == 1)
            {
            if (!b->dpname)
                  return 0;
            /* Case 2: set name and GENERAL_NAMES appropriately */
            gens = a->name.fullname;
            nm = b->dpname;
            }

      /* Handle case 2 with one GENERAL_NAMES and one X509_NAME */
      if (nm)
            {
            for (i = 0; i < sk_GENERAL_NAME_num(gens); i++)
                  {
                  gena = sk_GENERAL_NAME_value(gens, i);    
                  if (gena->type != GEN_DIRNAME)
                        continue;
                  if (!X509_NAME_cmp(nm, gena->d.directoryName))
                        return 1;
                  }
            return 0;
            }

      /* Else case 3: two GENERAL_NAMES */

      for (i = 0; i < sk_GENERAL_NAME_num(a->name.fullname); i++)
            {
            gena = sk_GENERAL_NAME_value(a->name.fullname, i);
            for (j = 0; j < sk_GENERAL_NAME_num(b->name.fullname); j++)
                  {
                  genb = sk_GENERAL_NAME_value(b->name.fullname, j);
                  if (!GENERAL_NAME_cmp(gena, genb))
                        return 1;
                  }
            }

      return 0;

      }

static int crldp_check_crlissuer(DIST_POINT *dp, X509_CRL *crl, int crl_score)
      {
      int i;
      X509_NAME *nm = X509_CRL_get_issuer(crl);
      /* If no CRLissuer return is successful iff don't need a match */
      if (!dp->CRLissuer)
            return !!(crl_score & CRL_SCORE_ISSUER_NAME);
      for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++)
            {
            GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i);
            if (gen->type != GEN_DIRNAME)
                  continue;
            if (!X509_NAME_cmp(gen->d.directoryName, nm))
                  return 1;
            }
      return 0;
      }

/* Check CRLDP and IDP */

static int crl_crldp_check(X509 *x, X509_CRL *crl, int crl_score,
                        unsigned int *preasons)
      {
      int i;
      if (crl->idp_flags & IDP_ONLYATTR)
            return 0;
      if (x->ex_flags & EXFLAG_CA)
            {
            if (crl->idp_flags & IDP_ONLYUSER)
                  return 0;
            }
      else
            {
            if (crl->idp_flags & IDP_ONLYCA)
                  return 0;
            }
      *preasons = crl->idp_reasons;
      for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++)
            {
            DIST_POINT *dp = sk_DIST_POINT_value(x->crldp, i);
            if (crldp_check_crlissuer(dp, crl, crl_score))
                  {
                  if (!crl->idp ||
                       idp_check_dp(dp->distpoint, crl->idp->distpoint))
                        {
                        *preasons &= dp->dp_reasons;
                        return 1;
                        }
                  }
            }
      if ((!crl->idp || !crl->idp->distpoint) && (crl_score & CRL_SCORE_ISSUER_NAME))
            return 1;
      return 0;
      }

/* Retrieve CRL corresponding to current certificate.
 * If deltas enabled try to find a delta CRL too
 */
      
static int get_crl_delta(X509_STORE_CTX *ctx,
                        X509_CRL **pcrl, X509_CRL **pdcrl, X509 *x)
      {
      int ok;
      X509 *issuer = NULL;
      int crl_score = 0;
      unsigned int reasons;
      X509_CRL *crl = NULL, *dcrl = NULL;
      STACK_OF(X509_CRL) *skcrl;
      X509_NAME *nm = X509_get_issuer_name(x);
      reasons = ctx->current_reasons;
      ok = get_crl_sk(ctx, &crl, &dcrl, 
                        &issuer, &crl_score, &reasons, ctx->crls);

      if (ok)
            goto done;

      /* Lookup CRLs from store */

      skcrl = ctx->lookup_crls(ctx, nm);

      /* If no CRLs found and a near match from get_crl_sk use that */
      if (!skcrl && crl)
            goto done;

      get_crl_sk(ctx, &crl, &dcrl, &issuer, &crl_score, &reasons, skcrl);

      sk_X509_CRL_pop_free(skcrl, X509_CRL_free);

      done:

      /* If we got any kind of CRL use it and return success */
      if (crl)
            {
            ctx->current_issuer = issuer;
            ctx->current_crl_score = crl_score;
            ctx->current_reasons = reasons;
            *pcrl = crl;
            *pdcrl = dcrl;
            return 1;
            }

      return 0;
      }

/* Check CRL validity */
static int check_crl(X509_STORE_CTX *ctx, X509_CRL *crl)
      {
      X509 *issuer = NULL;
      EVP_PKEY *ikey = NULL;
      int ok = 0, chnum, cnum;
      cnum = ctx->error_depth;
      chnum = sk_X509_num(ctx->chain) - 1;
      /* if we have an alternative CRL issuer cert use that */
      if (ctx->current_issuer)
            issuer = ctx->current_issuer;

      /* Else find CRL issuer: if not last certificate then issuer
       * is next certificate in chain.
       */
      else if (cnum < chnum)
            issuer = sk_X509_value(ctx->chain, cnum + 1);
      else
            {
            issuer = sk_X509_value(ctx->chain, chnum);
            /* If not self signed, can't check signature */
            if(!ctx->check_issued(ctx, issuer, issuer))
                  {
                  ctx->error = X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER;
                  ok = ctx->verify_cb(0, ctx);
                  if(!ok) goto err;
                  }
            }

      if(issuer)
            {
            /* Skip most tests for deltas because they have already
             * been done
             */
            if (!crl->base_crl_number)
                  {
                  /* Check for cRLSign bit if keyUsage present */
                  if ((issuer->ex_flags & EXFLAG_KUSAGE) &&
                        !(issuer->ex_kusage & KU_CRL_SIGN))
                        {
                        ctx->error = X509_V_ERR_KEYUSAGE_NO_CRL_SIGN;
                        ok = ctx->verify_cb(0, ctx);
                        if(!ok) goto err;
                        }

                  if (!(ctx->current_crl_score & CRL_SCORE_SCOPE))
                        {
                        ctx->error = X509_V_ERR_DIFFERENT_CRL_SCOPE;
                        ok = ctx->verify_cb(0, ctx);
                        if(!ok) goto err;
                        }

                  if (!(ctx->current_crl_score & CRL_SCORE_SAME_PATH))
                        {
                        if (check_crl_path(ctx, ctx->current_issuer) <= 0)
                              {
                              ctx->error = X509_V_ERR_CRL_PATH_VALIDATION_ERROR;
                              ok = ctx->verify_cb(0, ctx);
                              if(!ok) goto err;
                              }
                        }

                  if (crl->idp_flags & IDP_INVALID)
                        {
                        ctx->error = X509_V_ERR_INVALID_EXTENSION;
                        ok = ctx->verify_cb(0, ctx);
                        if(!ok) goto err;
                        }


                  }

            if (!(ctx->current_crl_score & CRL_SCORE_TIME))
                  {
                  ok = check_crl_time(ctx, crl, 1);
                  if (!ok)
                        goto err;
                  }

            /* Attempt to get issuer certificate public key */
            ikey = X509_get_pubkey(issuer);

            if(!ikey)
                  {
                  ctx->error=X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY;
                  ok = ctx->verify_cb(0, ctx);
                  if (!ok) goto err;
                  }
            else
                  {
                  /* Verify CRL signature */
                  if(X509_CRL_verify(crl, ikey) <= 0)
                        {
                        ctx->error=X509_V_ERR_CRL_SIGNATURE_FAILURE;
                        ok = ctx->verify_cb(0, ctx);
                        if (!ok) goto err;
                        }
                  }
            }

      ok = 1;

      err:
      EVP_PKEY_free(ikey);
      return ok;
      }

/* Check certificate against CRL */
static int cert_crl(X509_STORE_CTX *ctx, X509_CRL *crl, X509 *x)
      {
      int ok;
      X509_REVOKED *rev;
      /* The rules changed for this... previously if a CRL contained
       * unhandled critical extensions it could still be used to indicate
       * a certificate was revoked. This has since been changed since 
       * critical extension can change the meaning of CRL entries.
       */
      if (crl->flags & EXFLAG_CRITICAL)
            {
            if (ctx->param->flags & X509_V_FLAG_IGNORE_CRITICAL)
                  return 1;
            ctx->error = X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION;
            ok = ctx->verify_cb(0, ctx);
            if(!ok)
                  return 0;
            }
      /* Look for serial number of certificate in CRL
       * If found make sure reason is not removeFromCRL.
       */
      if (X509_CRL_get0_by_cert(crl, &rev, x))
            {
            if (rev->reason == CRL_REASON_REMOVE_FROM_CRL)
                  return 2;
            ctx->error = X509_V_ERR_CERT_REVOKED;
            ok = ctx->verify_cb(0, ctx);
            if (!ok)
                  return 0;
            }

      return 1;
      }

static int check_policy(X509_STORE_CTX *ctx)
      {
      int ret;
      if (ctx->parent)
            return 1;
      ret = X509_policy_check(&ctx->tree, &ctx->explicit_policy, ctx->chain,
                        ctx->param->policies, ctx->param->flags);
      if (ret == 0)
            {
            X509err(X509_F_CHECK_POLICY,ERR_R_MALLOC_FAILURE);
            return 0;
            }
      /* Invalid or inconsistent extensions */
      if (ret == -1)
            {
            /* Locate certificates with bad extensions and notify
             * callback.
             */
            X509 *x;
            int i;
            for (i = 1; i < sk_X509_num(ctx->chain); i++)
                  {
                  x = sk_X509_value(ctx->chain, i);
                  if (!(x->ex_flags & EXFLAG_INVALID_POLICY))
                        continue;
                  ctx->current_cert = x;
                  ctx->error = X509_V_ERR_INVALID_POLICY_EXTENSION;
                  if(!ctx->verify_cb(0, ctx))
                        return 0;
                  }
            return 1;
            }
      if (ret == -2)
            {
            ctx->current_cert = NULL;
            ctx->error = X509_V_ERR_NO_EXPLICIT_POLICY;
            return ctx->verify_cb(0, ctx);
            }

      if (ctx->param->flags & X509_V_FLAG_NOTIFY_POLICY)
            {
            ctx->current_cert = NULL;
            ctx->error = X509_V_OK;
            if (!ctx->verify_cb(2, ctx))
                  return 0;
            }

      return 1;
      }

static int check_cert_time(X509_STORE_CTX *ctx, X509 *x)
      {
      time_t *ptime;
      int i;

      if (ctx->param->flags & X509_V_FLAG_USE_CHECK_TIME)
            ptime = &ctx->param->check_time;
      else
            ptime = NULL;

      i=X509_cmp_time(X509_get_notBefore(x), ptime);
      if (i == 0)
            {
            ctx->error=X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD;
            ctx->current_cert=x;
            if (!ctx->verify_cb(0, ctx))
                  return 0;
            }

      if (i > 0)
            {
            ctx->error=X509_V_ERR_CERT_NOT_YET_VALID;
            ctx->current_cert=x;
            if (!ctx->verify_cb(0, ctx))
                  return 0;
            }

      i=X509_cmp_time(X509_get_notAfter(x), ptime);
      if (i == 0)
            {
            ctx->error=X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD;
            ctx->current_cert=x;
            if (!ctx->verify_cb(0, ctx))
                  return 0;
            }

      if (i < 0)
            {
            ctx->error=X509_V_ERR_CERT_HAS_EXPIRED;
            ctx->current_cert=x;
            if (!ctx->verify_cb(0, ctx))
                  return 0;
            }

      return 1;
      }

static int internal_verify(X509_STORE_CTX *ctx)
      {
      int ok=0,n;
      X509 *xs,*xi;
      EVP_PKEY *pkey=NULL;
      int (*cb)(int xok,X509_STORE_CTX *xctx);

      cb=ctx->verify_cb;

      n=sk_X509_num(ctx->chain);
      ctx->error_depth=n-1;
      n--;
      xi=sk_X509_value(ctx->chain,n);

      if (ctx->check_issued(ctx, xi, xi))
            xs=xi;
      else
            {
            if (n <= 0)
                  {
                  ctx->error=X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE;
                  ctx->current_cert=xi;
                  ok=cb(0,ctx);
                  goto end;
                  }
            else
                  {
                  n--;
                  ctx->error_depth=n;
                  xs=sk_X509_value(ctx->chain,n);
                  }
            }

/*    ctx->error=0;  not needed */
      while (n >= 0)
            {
            ctx->error_depth=n;

            /* Skip signature check for self signed certificates unless
             * explicitly asked for. It doesn't add any security and
             * just wastes time.
             */
            if (!xs->valid && (xs != xi || (ctx->param->flags & X509_V_FLAG_CHECK_SS_SIGNATURE)))
                  {
                  if ((pkey=X509_get_pubkey(xi)) == NULL)
                        {
                        ctx->error=X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY;
                        ctx->current_cert=xi;
                        ok=(*cb)(0,ctx);
                        if (!ok) goto end;
                        }
                  else if (X509_verify(xs,pkey) <= 0)
                        {
                        ctx->error=X509_V_ERR_CERT_SIGNATURE_FAILURE;
                        ctx->current_cert=xs;
                        ok=(*cb)(0,ctx);
                        if (!ok)
                              {
                              EVP_PKEY_free(pkey);
                              goto end;
                              }
                        }
                  EVP_PKEY_free(pkey);
                  pkey=NULL;
                  }

            xs->valid = 1;

            ok = check_cert_time(ctx, xs);
            if (!ok)
                  goto end;

            /* The last error (if any) is still in the error value */
            ctx->current_issuer=xi;
            ctx->current_cert=xs;
            ok=(*cb)(1,ctx);
            if (!ok) goto end;

            n--;
            if (n >= 0)
                  {
                  xi=xs;
                  xs=sk_X509_value(ctx->chain,n);
                  }
            }
      ok=1;
end:
      return ok;
      }

int X509_cmp_current_time(const ASN1_TIME *ctm)
{
      return X509_cmp_time(ctm, NULL);
}

int X509_cmp_time(const ASN1_TIME *ctm, time_t *cmp_time)
      {
      char *str;
      ASN1_TIME atm;
      long offset;
      char buff1[24],buff2[24],*p;
      int i,j;

      p=buff1;
      i=ctm->length;
      str=(char *)ctm->data;
      if (ctm->type == V_ASN1_UTCTIME)
            {
            if ((i < 11) || (i > 17)) return 0;
            memcpy(p,str,10);
            p+=10;
            str+=10;
            }
      else
            {
            if (i < 13) return 0;
            memcpy(p,str,12);
            p+=12;
            str+=12;
            }

      if ((*str == 'Z') || (*str == '-') || (*str == '+'))
            { *(p++)='0'; *(p++)='0'; }
      else
            { 
            *(p++)= *(str++);
            *(p++)= *(str++);
            /* Skip any fractional seconds... */
            if (*str == '.')
                  {
                  str++;
                  while ((*str >= '0') && (*str <= '9')) str++;
                  }
            
            }
      *(p++)='Z';
      *(p++)='\0';

      if (*str == 'Z')
            offset=0;
      else
            {
            if ((*str != '+') && (*str != '-'))
                  return 0;
            offset=((str[1]-'0')*10+(str[2]-'0'))*60;
            offset+=(str[3]-'0')*10+(str[4]-'0');
            if (*str == '-')
                  offset= -offset;
            }
      atm.type=ctm->type;
      atm.flags = 0;
      atm.length=sizeof(buff2);
      atm.data=(unsigned char *)buff2;

      if (X509_time_adj(&atm,-offset*60, cmp_time) == NULL)
            return 0;

      if (ctm->type == V_ASN1_UTCTIME)
            {
            i=(buff1[0]-'0')*10+(buff1[1]-'0');
            if (i < 50) i+=100; /* cf. RFC 2459 */
            j=(buff2[0]-'0')*10+(buff2[1]-'0');
            if (j < 50) j+=100;

            if (i < j) return -1;
            if (i > j) return 1;
            }
      i=strcmp(buff1,buff2);
      if (i == 0) /* wait a second then return younger :-) */
            return -1;
      else
            return i;
      }

ASN1_TIME *X509_gmtime_adj(ASN1_TIME *s, long adj)
{
      return X509_time_adj(s, adj, NULL);
}

ASN1_TIME *X509_time_adj(ASN1_TIME *s, long offset_sec, time_t *in_tm)
      {
      return X509_time_adj_ex(s, 0, offset_sec, in_tm);
      }

ASN1_TIME *X509_time_adj_ex(ASN1_TIME *s,
                        int offset_day, long offset_sec, time_t *in_tm)
      {
      time_t t;

      if (in_tm) t = *in_tm;
      else time(&t);

      if (s && !(s->flags & ASN1_STRING_FLAG_MSTRING))
            {
            if (s->type == V_ASN1_UTCTIME)
                  return ASN1_UTCTIME_adj(s,t, offset_day, offset_sec);
            if (s->type == V_ASN1_GENERALIZEDTIME)
                  return ASN1_GENERALIZEDTIME_adj(s, t, offset_day,
                                                offset_sec);
            }
      return ASN1_TIME_adj(s, t, offset_day, offset_sec);
      }

int X509_get_pubkey_parameters(EVP_PKEY *pkey, STACK_OF(X509) *chain)
      {
      EVP_PKEY *ktmp=NULL,*ktmp2;
      int i,j;

      if ((pkey != NULL) && !EVP_PKEY_missing_parameters(pkey)) return 1;

      for (i=0; i<sk_X509_num(chain); i++)
            {
            ktmp=X509_get_pubkey(sk_X509_value(chain,i));
            if (ktmp == NULL)
                  {
                  X509err(X509_F_X509_GET_PUBKEY_PARAMETERS,X509_R_UNABLE_TO_GET_CERTS_PUBLIC_KEY);
                  return 0;
                  }
            if (!EVP_PKEY_missing_parameters(ktmp))
                  break;
            else
                  {
                  EVP_PKEY_free(ktmp);
                  ktmp=NULL;
                  }
            }
      if (ktmp == NULL)
            {
            X509err(X509_F_X509_GET_PUBKEY_PARAMETERS,X509_R_UNABLE_TO_FIND_PARAMETERS_IN_CHAIN);
            return 0;
            }

      /* first, populate the other certs */
      for (j=i-1; j >= 0; j--)
            {
            ktmp2=X509_get_pubkey(sk_X509_value(chain,j));
            EVP_PKEY_copy_parameters(ktmp2,ktmp);
            EVP_PKEY_free(ktmp2);
            }
      
      if (pkey != NULL) EVP_PKEY_copy_parameters(pkey,ktmp);
      EVP_PKEY_free(ktmp);
      return 1;
      }

int X509_STORE_CTX_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,
           CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func)
      {
      /* This function is (usually) called only once, by
       * SSL_get_ex_data_X509_STORE_CTX_idx (ssl/ssl_cert.c). */
      return CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_X509_STORE_CTX, argl, argp,
                  new_func, dup_func, free_func);
      }

int X509_STORE_CTX_set_ex_data(X509_STORE_CTX *ctx, int idx, void *data)
      {
      return CRYPTO_set_ex_data(&ctx->ex_data,idx,data);
      }

void *X509_STORE_CTX_get_ex_data(X509_STORE_CTX *ctx, int idx)
      {
      return CRYPTO_get_ex_data(&ctx->ex_data,idx);
      }

int X509_STORE_CTX_get_error(X509_STORE_CTX *ctx)
      {
      return ctx->error;
      }

void X509_STORE_CTX_set_error(X509_STORE_CTX *ctx, int err)
      {
      ctx->error=err;
      }

int X509_STORE_CTX_get_error_depth(X509_STORE_CTX *ctx)
      {
      return ctx->error_depth;
      }

X509 *X509_STORE_CTX_get_current_cert(X509_STORE_CTX *ctx)
      {
      return ctx->current_cert;
      }

STACK_OF(X509) *X509_STORE_CTX_get_chain(X509_STORE_CTX *ctx)
      {
      return ctx->chain;
      }

STACK_OF(X509) *X509_STORE_CTX_get1_chain(X509_STORE_CTX *ctx)
      {
      int i;
      X509 *x;
      STACK_OF(X509) *chain;
      if (!ctx->chain || !(chain = sk_X509_dup(ctx->chain))) return NULL;
      for (i = 0; i < sk_X509_num(chain); i++)
            {
            x = sk_X509_value(chain, i);
            CRYPTO_add(&x->references, 1, CRYPTO_LOCK_X509);
            }
      return chain;
      }

X509 *X509_STORE_CTX_get0_current_issuer(X509_STORE_CTX *ctx)
      {
      return ctx->current_issuer;
      }

X509_CRL *X509_STORE_CTX_get0_current_crl(X509_STORE_CTX *ctx)
      {
      return ctx->current_crl;
      }

X509_STORE_CTX *X509_STORE_CTX_get0_parent_ctx(X509_STORE_CTX *ctx)
      {
      return ctx->parent;
      }

void X509_STORE_CTX_set_cert(X509_STORE_CTX *ctx, X509 *x)
      {
      ctx->cert=x;
      }

void X509_STORE_CTX_set_chain(X509_STORE_CTX *ctx, STACK_OF(X509) *sk)
      {
      ctx->untrusted=sk;
      }

void X509_STORE_CTX_set0_crls(X509_STORE_CTX *ctx, STACK_OF(X509_CRL) *sk)
      {
      ctx->crls=sk;
      }

int X509_STORE_CTX_set_purpose(X509_STORE_CTX *ctx, int purpose)
      {
      return X509_STORE_CTX_purpose_inherit(ctx, 0, purpose, 0);
      }

int X509_STORE_CTX_set_trust(X509_STORE_CTX *ctx, int trust)
      {
      return X509_STORE_CTX_purpose_inherit(ctx, 0, 0, trust);
      }

/* This function is used to set the X509_STORE_CTX purpose and trust
 * values. This is intended to be used when another structure has its
 * own trust and purpose values which (if set) will be inherited by
 * the ctx. If they aren't set then we will usually have a default
 * purpose in mind which should then be used to set the trust value.
 * An example of this is SSL use: an SSL structure will have its own
 * purpose and trust settings which the application can set: if they
 * aren't set then we use the default of SSL client/server.
 */

int X509_STORE_CTX_purpose_inherit(X509_STORE_CTX *ctx, int def_purpose,
                        int purpose, int trust)
{
      int idx;
      /* If purpose not set use default */
      if (!purpose) purpose = def_purpose;
      /* If we have a purpose then check it is valid */
      if (purpose)
            {
            X509_PURPOSE *ptmp;
            idx = X509_PURPOSE_get_by_id(purpose);
            if (idx == -1)
                  {
                  X509err(X509_F_X509_STORE_CTX_PURPOSE_INHERIT,
                                    X509_R_UNKNOWN_PURPOSE_ID);
                  return 0;
                  }
            ptmp = X509_PURPOSE_get0(idx);
            if (ptmp->trust == X509_TRUST_DEFAULT)
                  {
                  idx = X509_PURPOSE_get_by_id(def_purpose);
                  if (idx == -1)
                        {
                        X509err(X509_F_X509_STORE_CTX_PURPOSE_INHERIT,
                                    X509_R_UNKNOWN_PURPOSE_ID);
                        return 0;
                        }
                  ptmp = X509_PURPOSE_get0(idx);
                  }
            /* If trust not set then get from purpose default */
            if (!trust) trust = ptmp->trust;
            }
      if (trust)
            {
            idx = X509_TRUST_get_by_id(trust);
            if (idx == -1)
                  {
                  X509err(X509_F_X509_STORE_CTX_PURPOSE_INHERIT,
                                    X509_R_UNKNOWN_TRUST_ID);
                  return 0;
                  }
            }

      if (purpose && !ctx->param->purpose) ctx->param->purpose = purpose;
      if (trust && !ctx->param->trust) ctx->param->trust = trust;
      return 1;
}

X509_STORE_CTX *X509_STORE_CTX_new(void)
{
      X509_STORE_CTX *ctx;
      ctx = (X509_STORE_CTX *)OPENSSL_malloc(sizeof(X509_STORE_CTX));
      if (!ctx)
            {
            X509err(X509_F_X509_STORE_CTX_NEW,ERR_R_MALLOC_FAILURE);
            return NULL;
            }
      memset(ctx, 0, sizeof(X509_STORE_CTX));
      return ctx;
}

void X509_STORE_CTX_free(X509_STORE_CTX *ctx)
{
      X509_STORE_CTX_cleanup(ctx);
      OPENSSL_free(ctx);
}

int X509_STORE_CTX_init(X509_STORE_CTX *ctx, X509_STORE *store, X509 *x509,
           STACK_OF(X509) *chain)
      {
      int ret = 1;
      ctx->ctx=store;
      ctx->current_method=0;
      ctx->cert=x509;
      ctx->untrusted=chain;
      ctx->crls = NULL;
      ctx->last_untrusted=0;
      ctx->other_ctx=NULL;
      ctx->valid=0;
      ctx->chain=NULL;
      ctx->error=0;
      ctx->explicit_policy=0;
      ctx->error_depth=0;
      ctx->current_cert=NULL;
      ctx->current_issuer=NULL;
      ctx->tree = NULL;
      ctx->parent = NULL;

      ctx->param = X509_VERIFY_PARAM_new();

      if (!ctx->param)
            {
            X509err(X509_F_X509_STORE_CTX_INIT,ERR_R_MALLOC_FAILURE);
            return 0;
            }

      /* Inherit callbacks and flags from X509_STORE if not set
       * use defaults.
       */


      if (store)
            ret = X509_VERIFY_PARAM_inherit(ctx->param, store->param);
      else
            ctx->param->inh_flags |= X509_VP_FLAG_DEFAULT|X509_VP_FLAG_ONCE;

      if (store)
            {
            ctx->verify_cb = store->verify_cb;
            ctx->cleanup = store->cleanup;
            }
      else
            ctx->cleanup = 0;

      if (ret)
            ret = X509_VERIFY_PARAM_inherit(ctx->param,
                              X509_VERIFY_PARAM_lookup("default"));

      if (ret == 0)
            {
            X509err(X509_F_X509_STORE_CTX_INIT,ERR_R_MALLOC_FAILURE);
            return 0;
            }

      if (store && store->check_issued)
            ctx->check_issued = store->check_issued;
      else
            ctx->check_issued = check_issued;

      if (store && store->get_issuer)
            ctx->get_issuer = store->get_issuer;
      else
            ctx->get_issuer = X509_STORE_CTX_get1_issuer;

      if (store && store->verify_cb)
            ctx->verify_cb = store->verify_cb;
      else
            ctx->verify_cb = null_callback;

      if (store && store->verify)
            ctx->verify = store->verify;
      else
            ctx->verify = internal_verify;

      if (store && store->check_revocation)
            ctx->check_revocation = store->check_revocation;
      else
            ctx->check_revocation = check_revocation;

      if (store && store->get_crl)
            ctx->get_crl = store->get_crl;
      else
            ctx->get_crl = NULL;

      if (store && store->check_crl)
            ctx->check_crl = store->check_crl;
      else
            ctx->check_crl = check_crl;

      if (store && store->cert_crl)
            ctx->cert_crl = store->cert_crl;
      else
            ctx->cert_crl = cert_crl;

      if (store && store->lookup_certs)
            ctx->lookup_certs = store->lookup_certs;
      else
            ctx->lookup_certs = X509_STORE_get1_certs;

      if (store && store->lookup_crls)
            ctx->lookup_crls = store->lookup_crls;
      else
            ctx->lookup_crls = X509_STORE_get1_crls;

      ctx->check_policy = check_policy;


      /* This memset() can't make any sense anyway, so it's removed. As
       * X509_STORE_CTX_cleanup does a proper "free" on the ex_data, we put a
       * corresponding "new" here and remove this bogus initialisation. */
      /* memset(&(ctx->ex_data),0,sizeof(CRYPTO_EX_DATA)); */
      if(!CRYPTO_new_ex_data(CRYPTO_EX_INDEX_X509_STORE_CTX, ctx,
                        &(ctx->ex_data)))
            {
            OPENSSL_free(ctx);
            X509err(X509_F_X509_STORE_CTX_INIT,ERR_R_MALLOC_FAILURE);
            return 0;
            }
      return 1;
      }

/* Set alternative lookup method: just a STACK of trusted certificates.
 * This avoids X509_STORE nastiness where it isn't needed.
 */

void X509_STORE_CTX_trusted_stack(X509_STORE_CTX *ctx, STACK_OF(X509) *sk)
{
      ctx->other_ctx = sk;
      ctx->get_issuer = get_issuer_sk;
}

void X509_STORE_CTX_cleanup(X509_STORE_CTX *ctx)
      {
      if (ctx->cleanup) ctx->cleanup(ctx);
      if (ctx->param != NULL)
            {
            if (ctx->parent == NULL)
                  X509_VERIFY_PARAM_free(ctx->param);
            ctx->param=NULL;
            }
      if (ctx->tree != NULL)
            {
            X509_policy_tree_free(ctx->tree);
            ctx->tree=NULL;
            }
      if (ctx->chain != NULL)
            {
            sk_X509_pop_free(ctx->chain,X509_free);
            ctx->chain=NULL;
            }
      CRYPTO_free_ex_data(CRYPTO_EX_INDEX_X509_STORE_CTX, ctx, &(ctx->ex_data));
      memset(&ctx->ex_data,0,sizeof(CRYPTO_EX_DATA));
      }

void X509_STORE_CTX_set_depth(X509_STORE_CTX *ctx, int depth)
      {
      X509_VERIFY_PARAM_set_depth(ctx->param, depth);
      }

void X509_STORE_CTX_set_flags(X509_STORE_CTX *ctx, unsigned long flags)
      {
      X509_VERIFY_PARAM_set_flags(ctx->param, flags);
      }

void X509_STORE_CTX_set_time(X509_STORE_CTX *ctx, unsigned long flags, time_t t)
      {
      X509_VERIFY_PARAM_set_time(ctx->param, t);
      }

void X509_STORE_CTX_set_verify_cb(X509_STORE_CTX *ctx,
                          int (*verify_cb)(int, X509_STORE_CTX *))
      {
      ctx->verify_cb=verify_cb;
      }

X509_POLICY_TREE *X509_STORE_CTX_get0_policy_tree(X509_STORE_CTX *ctx)
      {
      return ctx->tree;
      }

int X509_STORE_CTX_get_explicit_policy(X509_STORE_CTX *ctx)
      {
      return ctx->explicit_policy;
      }

int X509_STORE_CTX_set_default(X509_STORE_CTX *ctx, const char *name)
      {
      const X509_VERIFY_PARAM *param;
      param = X509_VERIFY_PARAM_lookup(name);
      if (!param)
            return 0;
      return X509_VERIFY_PARAM_inherit(ctx->param, param);
      }

X509_VERIFY_PARAM *X509_STORE_CTX_get0_param(X509_STORE_CTX *ctx)
      {
      return ctx->param;
      }

void X509_STORE_CTX_set0_param(X509_STORE_CTX *ctx, X509_VERIFY_PARAM *param)
      {
      if (ctx->param)
            X509_VERIFY_PARAM_free(ctx->param);
      ctx->param = param;
      }

IMPLEMENT_STACK_OF(X509)
IMPLEMENT_ASN1_SET_OF(X509)

IMPLEMENT_STACK_OF(X509_NAME)

IMPLEMENT_STACK_OF(X509_ATTRIBUTE)
IMPLEMENT_ASN1_SET_OF(X509_ATTRIBUTE)

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