x509_vfy.c

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/* crypto/x509/x509_vfy.c */
/* Copyright (C) 1995-1998 Eric Young ([email protected])
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young ([email protected]).
 * 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 ([email protected]).
 * 
 * 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 ([email protected])"
 *    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 ([email protected])"
 * 
 * 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;
    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 */
        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);
    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 */
        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... */

    /* 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_crl_score = 0;
    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->current_crl=NULL;
    ctx->current_crl_score=0;
    ctx->current_reasons=0;
    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)