Add opaque ID structure.
[openssl.git] / crypto / x509 / x509_vfy.c
index caa39950e0233d11e8ef8ba18b762fad1fbd1c3e..ab9bf8d18420f92b0a33f021b23a560a996352b9 100644 (file)
 #include <openssl/x509.h>
 #include <openssl/x509v3.h>
 #include <openssl/objects.h>
+#include "vpm_int.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_id(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 crl_akid_check(X509_STORE_CTX *ctx, X509_CRL *crl, X509 **pissuer);
-static int idp_check_scope(X509 *x, X509_CRL *crl);
+
+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;
 
@@ -95,11 +151,45 @@ static int x509_subject_cmp(X509 **a, X509 **b)
        return X509_subject_name_cmp(*a,*b);
        }
 #endif
+/* Return 1 is a certificate is self signed */
+static int cert_self_signed(X509 *x)
+       {
+       X509_check_purpose(x, -1, 0);
+       if (x->ex_flags & EXFLAG_SS)
+               return 1;
+       else
+               return 0;
+       }
+
+/* Given a certificate try and find an exact match in the store */
+
+static X509 *lookup_cert_match(X509_STORE_CTX *ctx, X509 *x)
+       {
+       STACK_OF(X509) *certs;
+       X509 *xtmp = NULL;
+       int i;
+       /* Lookup all certs with matching subject name */
+       certs = ctx->lookup_certs(ctx, X509_get_subject_name(x));
+       if (certs == NULL)
+               return NULL;
+       /* Look for exact match */
+       for (i = 0; i < sk_X509_num(certs); i++)
+               {
+               xtmp = sk_X509_value(certs, i);
+               if (!X509_cmp(xtmp, x))
+                       break;
+               }
+       if (i < sk_X509_num(certs))
+               CRYPTO_add(&xtmp->references,1,CRYPTO_LOCK_X509);
+       else
+               xtmp = NULL;
+       sk_X509_pop_free(certs, X509_free);
+       return xtmp;
+       }
 
 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;
@@ -151,8 +241,23 @@ int X509_verify_cert(X509_STORE_CTX *ctx)
                                         */
 
                /* If we are self signed, we break */
-               xn=X509_get_issuer_name(x);
-               if (ctx->check_issued(ctx, x,x)) break;
+               if (cert_self_signed(x))
+                       break;
+               /* If asked see if we can find issuer in trusted store first */
+               if (ctx->param->flags & X509_V_FLAG_TRUSTED_FIRST)
+                       {
+                       ok = ctx->get_issuer(&xtmp, ctx, x);
+                       if (ok < 0)
+                               return ok;
+                       /* If successful for now free up cert so it
+                        * will be picked up again later.
+                        */
+                       if (ok > 0)
+                               {
+                               X509_free(xtmp);
+                               break;
+                               }
+                       }
 
                /* If we were passed a cert chain, use it first */
                if (ctx->untrusted != NULL)
@@ -188,8 +293,7 @@ int X509_verify_cert(X509_STORE_CTX *ctx)
 
        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))
+       if (cert_self_signed(x))
                {
                /* we have a self signed certificate */
                if (sk_X509_num(ctx->chain) == 1)
@@ -237,8 +341,8 @@ int X509_verify_cert(X509_STORE_CTX *ctx)
                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;
+               if (cert_self_signed(x))
+                       break;
 
                ok = ctx->get_issuer(&xtmp, ctx, x);
 
@@ -256,10 +360,14 @@ int X509_verify_cert(X509_STORE_CTX *ctx)
                }
 
        /* 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))
+       i = check_trust(ctx);
+
+       /* If explicitly rejected error */
+       if (i == X509_TRUST_REJECTED)
+               goto end;
+       /* If not explicitly trusted then indicate error */
+       if (i != X509_TRUST_TRUSTED)
                {
                if ((chain_ss == NULL) || !ctx->check_issued(ctx, x, chain_ss))
                        {
@@ -291,9 +399,13 @@ int X509_verify_cert(X509_STORE_CTX *ctx)
 
        if (!ok) goto end;
 
-       /* The chain extensions are OK: check trust */
+       /* Check name constraints */
 
-       if (param->trust > 0) ok = check_trust(ctx);
+       ok = check_name_constraints(ctx);
+       
+       if (!ok) goto end;
+
+       ok = check_id(ctx);
 
        if (!ok) goto end;
 
@@ -307,6 +419,17 @@ int X509_verify_cert(X509_STORE_CTX *ctx)
        ok = ctx->check_revocation(ctx);
        if(!ok) goto end;
 
+       i = X509_chain_check_suiteb(&ctx->error_depth, NULL, ctx->chain,
+                                                       ctx->param->flags);
+       if (i != X509_V_OK)
+               {
+               ctx->error = i;
+               ctx->current_cert = sk_X509_value(ctx->chain, ctx->error_depth);
+               ok = cb(0, 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);
@@ -359,6 +482,24 @@ 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)
+               {
+               int i;
+               X509 *ch;
+               /* Special case: single self signed certificate */
+               if (cert_self_signed(x) && sk_X509_num(ctx->chain) == 1)
+                       return 1;
+               for (i = 0; i < sk_X509_num(ctx->chain); i++)
+                       {
+                       ch = sk_X509_value(ctx->chain, i);
+                       if (ch == issuer || !X509_cmp(ch, issuer))
+                               {
+                               ret = X509_V_ERR_PATH_LOOP;
+                               break;
+                               }
+                       }
+               }
+
        if (ret == X509_V_OK)
                return 1;
        /* If we haven't asked for issuer errors don't set ctx */
@@ -400,8 +541,8 @@ static int check_chain_extensions(X509_STORE_CTX *ctx)
        X509 *x;
        int (*cb)(int xok,X509_STORE_CTX *xctx);
        int proxy_path_length = 0;
-       int allow_proxy_certs =
-               !!(ctx->param->flags & X509_V_FLAG_ALLOW_PROXY_CERTS);
+       int purpose;
+       int allow_proxy_certs;
        cb=ctx->verify_cb;
 
        /* must_be_ca can have 1 of 3 values:
@@ -414,10 +555,22 @@ static int check_chain_extensions(X509_STORE_CTX *ctx)
        */
        must_be_ca = -1;
 
-       /* A hack to keep people who don't want to modify their software
-          happy */
-       if (getenv("OPENSSL_ALLOW_PROXY_CERTS"))
-               allow_proxy_certs = 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++)
@@ -484,8 +637,7 @@ static int check_chain_extensions(X509_STORE_CTX *ctx)
                        }
                if (ctx->param->purpose > 0)
                        {
-                       ret = X509_check_purpose(x, ctx->param->purpose,
-                               must_be_ca > 0);
+                       ret = X509_check_purpose(x, purpose, must_be_ca > 0);
                        if ((ret == 0)
                                || ((ctx->param->flags & X509_V_FLAG_X509_STRICT)
                                        && (ret != 1)))
@@ -538,30 +690,123 @@ static int check_chain_extensions(X509_STORE_CTX *ctx)
 #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_id_error(X509_STORE_CTX *ctx, int errcode)
+       {
+       ctx->error = errcode;
+       ctx->current_cert = ctx->cert;
+       ctx->error_depth = 0;
+       return ctx->verify_cb(0, ctx);
+       }
+
+static int check_id(X509_STORE_CTX *ctx)
+       {
+       X509_VERIFY_PARAM *vpm = ctx->param;
+       X509_VERIFY_PARAM_ID *id = vpm->id;
+       X509 *x = ctx->cert;
+       if (id->host && !X509_check_host(x, id->host, id->hostlen, 0))
+               {
+               if (!check_id_error(ctx, X509_V_ERR_HOSTNAME_MISMATCH))
+                       return 0;
+               }
+       if (id->email && !X509_check_email(x, id->email, id->emaillen, 0))
+               {
+               if (!check_id_error(ctx, X509_V_ERR_EMAIL_MISMATCH))
+                       return 0;
+               }
+       if (id->ip && !X509_check_ip(x, id->ip, id->iplen, 0))
+               {
+               if (!check_id_error(ctx, X509_V_ERR_IP_ADDRESS_MISMATCH))
+                       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;
+       X509 *x = NULL;
        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
+       /* Check all trusted certificates in chain */
+       for (i = ctx->last_untrusted; i < sk_X509_num(ctx->chain); i++)
+               {
+               x = sk_X509_value(ctx->chain, i);
+               ok = X509_check_trust(x, ctx->param->trust, 0);
+               /* If explicitly trusted return trusted */
+               if (ok == X509_TRUST_TRUSTED)
+                       return X509_TRUST_TRUSTED;
+               /* If explicitly rejected notify callback and reject if
+                * not overridden.
+                */
+               if (ok == X509_TRUST_REJECTED)
+                       {
+                       ctx->error_depth = i;
+                       ctx->current_cert = x;
+                       ctx->error = X509_V_ERR_CERT_REJECTED;
+                       ok = cb(0, ctx);
+                       if (!ok)
+                               return X509_TRUST_REJECTED;
+                       }
+               }
+       /* If we accept partial chains and have at least one trusted
+        * certificate return success.
+        */
+       if (ctx->param->flags & X509_V_FLAG_PARTIAL_CHAIN)
+               {
+               X509 *mx;
+               if (ctx->last_untrusted < sk_X509_num(ctx->chain))
+                       return X509_TRUST_TRUSTED;
+               x = sk_X509_value(ctx->chain, 0);
+               mx = lookup_cert_match(ctx, x);
+               if (mx)
+                       {
+                       (void)sk_X509_set(ctx->chain, 0, mx);
+                       X509_free(x);
+                       ctx->last_untrusted = 0;
+                       return X509_TRUST_TRUSTED;
+                       }
+               }
+
+       /* If no trusted certs in chain at all return untrusted and
+        * allow standard (no issuer cert) etc errors to be indicated.
+        */
+       return X509_TRUST_UNTRUSTED;
 }
 
 static int check_revocation(X509_STORE_CTX *ctx)
@@ -572,7 +817,12 @@ static int check_revocation(X509_STORE_CTX *ctx)
        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;
@@ -584,31 +834,77 @@ static int check_revocation(X509_STORE_CTX *ctx)
 
 static int check_cert(X509_STORE_CTX *ctx)
        {
-       X509_CRL *crl = NULL;
+       X509_CRL *crl = NULL, *dcrl = NULL;
        X509 *x;
        int ok, cnum;
+       unsigned int last_reasons;
        cnum = ctx->error_depth;
        x = sk_X509_value(ctx->chain, cnum);
        ctx->current_cert = x;
        ctx->current_issuer = NULL;
-       /* Try to retrieve relevant CRL */
-       ok = ctx->get_crl(ctx, &crl, x);
-       /* If error looking up CRL, nothing we can do except
-        * notify callback
-        */
-       if(!ok)
+       ctx->current_crl_score = 0;
+       ctx->current_reasons = 0;
+       while (ctx->current_reasons != CRLDP_ALL_REASONS)
                {
-               ctx->error = X509_V_ERR_UNABLE_TO_GET_CRL;
-               ok = ctx->verify_cb(0, ctx);
-               goto err;
+               last_reasons = ctx->current_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;
+               /* If reasons not updated we wont get anywhere by
+                * another iteration, so exit loop.
+                */
+               if (last_reasons == ctx->current_reasons)
+                       {
+                       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;
-       ok = ctx->cert_crl(ctx, crl, x);
        err:
-       ctx->current_crl = NULL;
        X509_CRL_free(crl);
+       X509_CRL_free(dcrl);
+
+       ctx->current_crl = NULL;
        return ok;
 
        }
@@ -619,7 +915,8 @@ static int check_crl_time(X509_STORE_CTX *ctx, X509_CRL *crl, int notify)
        {
        time_t *ptime;
        int i;
-       ctx->current_crl = crl;
+       if (notify)
+               ctx->current_crl = crl;
        if (ctx->param->flags & X509_V_FLAG_USE_CHECK_TIME)
                ptime = &ctx->param->check_time;
        else
@@ -628,15 +925,19 @@ static int check_crl_time(X509_STORE_CTX *ctx, X509_CRL *crl, int notify)
        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 (!notify || !ctx->verify_cb(0, ctx))
+               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 (!notify || !ctx->verify_cb(0, ctx))
+               if (!ctx->verify_cb(0, ctx))
                        return 0;
                }
 
@@ -646,147 +947,467 @@ static int check_crl_time(X509_STORE_CTX *ctx, X509_CRL *crl, int notify)
 
                if (i == 0)
                        {
+                       if (!notify)
+                               return 0;
                        ctx->error=X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD;
-                       if (!notify || !ctx->verify_cb(0, ctx))
+                       if (!ctx->verify_cb(0, ctx))
                                return 0;
                        }
-
-               if (i < 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 (!notify || !ctx->verify_cb(0, ctx))
+                       if (!ctx->verify_cb(0, ctx))
                                return 0;
                        }
                }
 
-       ctx->current_crl = NULL;
+       if (notify)
+               ctx->current_crl = NULL;
 
        return 1;
        }
 
-/* Based on a set of possible CRLs decide which one is best suited
- * to handle the current certificate. This is determined by a number
- * of criteria. If any of the "must" criteria is not satisfied then
- * the candidate CRL is rejected. If all "must" and all "should" are
- * satisfied the CRL is accepted. If no CRL satisfies all criteria then
- * a "best CRL" is used to provide some meaningful error information.
- *
- * CRL issuer name must match "nm" if not NULL.
- * If IDP is present:
- *   a. it must be consistent.
- *   b. onlyuser, onlyCA, onlyAA should match certificate being checked.
- *   c. indirectCRL must be FALSE.
- *   d. onlysomereason must be absent.
- *   e. if name present a DP in certificate CRLDP must match.
- * If AKID present it should match certificate AKID.
- * Check time should fall between lastUpdate and nextUpdate.
- */
-
-/* IDP name field matches CRLDP or IDP name not present */
-#define CRL_SCORE_SCOPE                4
-/* AKID present and matches cert, or AKID not present */
-#define CRL_SCORE_AKID         2
-/* times OK */
-#define CRL_SCORE_TIME         1
-
-#define CRL_SCORE_ALL          7
-
-/* IDP flags which cause a CRL to be rejected */
-
-#define IDP_REJECT     (IDP_INVALID|IDP_INDIRECT|IDP_REASONS)
-
-static int get_crl_sk(X509_STORE_CTX *ctx, X509_CRL **pcrl,
-                       X509_NAME *nm, STACK_OF(X509_CRL) *crls)
+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 = -1;
+       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, *best_crl_issuer = NULL;
+       X509 *crl_issuer = NULL, *best_crl_issuer = NULL;
+
        for (i = 0; i < sk_X509_CRL_num(crls); i++)
                {
-               crl_score = 0;
-               crl_issuer = NULL;
                crl = sk_X509_CRL_value(crls, i);
-               if (nm && X509_NAME_cmp(nm, X509_CRL_get_issuer(crl)))
-                       continue;
-               if (check_crl_time(ctx, crl, 0))
-                       crl_score |= CRL_SCORE_TIME;
-
-               if (crl->idp_flags & IDP_PRESENT)
-                       {
-                       if (crl->idp_flags & IDP_REJECT)
-                               continue;
-                       if (idp_check_scope(ctx->current_cert, crl))
-                               crl_score |= CRL_SCORE_SCOPE;
-                       }
-               else
-                       crl_score |= CRL_SCORE_SCOPE;
-
-               if (crl_akid_check(ctx, crl, &crl_issuer))
-                       crl_score |= CRL_SCORE_AKID;
-               /* If CRL matches criteria and issuer is not different use it */
-               if (crl_score == CRL_SCORE_ALL && !crl_issuer)
-                       {
-                       *pcrl = crl;
-                       CRYPTO_add(&crl->references, 1, CRYPTO_LOCK_X509_CRL);
-                       return 1;
-                       }
+               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;
-               ctx->current_issuer = best_crl_issuer;
-               CRYPTO_add(&best_crl->references, 1, CRYPTO_LOCK_X509);
+               *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;
        }
 
-static int crl_akid_check(X509_STORE_CTX *ctx, X509_CRL *crl, X509 **pissuer)
+/* 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)
        {
-       X509 *crl_issuer;
-       int cidx = ctx->error_depth;
-       if (!crl->akid)
+       ASN1_OCTET_STRING *exta, *extb;
+       int i;
+       i = X509_CRL_get_ext_by_NID(a, nid, -1);
+       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, -1);
+
+       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)
-               return 1;
-       /* If crl_issuer is self issued we may get a match further along the
-        * chain.
+               {
+               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.
         */
-       if (crl_issuer->ex_flags & EXFLAG_SI)
+       for (i = 0; i < sk_X509_num(ctx->untrusted); i++)
                {
-               for (cidx++; cidx < sk_X509_num(ctx->chain); cidx++)
+               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)
                        {
-                       crl_issuer = sk_X509_value(ctx->chain, cidx);
-                       if (X509_check_akid(crl_issuer, crl->akid) == X509_V_OK)
-                               {
-                               *pissuer = crl_issuer;
+                       *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;
-                               }
-                       if (!(crl_issuer->ex_flags & EXFLAG_SI))
-                               break;
+                       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 IDP name matches at least one CRLDP name */
+/* Check CRLDP and IDP */
 
-static int idp_check_scope(X509 *x, X509_CRL *crl)
+static int crl_crldp_check(X509 *x, X509_CRL *crl, int crl_score,
+                               unsigned int *preasons)
        {
-       int i, j, k;
-       GENERAL_NAMES *inames, *dnames;
+       int i;
        if (crl->idp_flags & IDP_ONLYATTR)
                return 0;
        if (x->ex_flags & EXFLAG_CA)
@@ -799,79 +1420,68 @@ static int idp_check_scope(X509 *x, X509_CRL *crl)
                if (crl->idp_flags & IDP_ONLYCA)
                        return 0;
                }
-       if (!crl->idp->distpoint)
-               return 1;
-       if (crl->idp->distpoint->type != 0)
-               return 1;
-       if (!x->crldp)
-               return 0;
-       inames = crl->idp->distpoint->name.fullname;
-       for (i = 0; i < sk_GENERAL_NAME_num(inames); i++)
+       *preasons = crl->idp_reasons;
+       for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++)
                {
-               GENERAL_NAME *igen = sk_GENERAL_NAME_value(inames, i);
-               for (j = 0; j < sk_DIST_POINT_num(x->crldp); j++)
+               DIST_POINT *dp = sk_DIST_POINT_value(x->crldp, i);
+               if (crldp_check_crlissuer(dp, crl, crl_score))
                        {
-                       DIST_POINT *dp = sk_DIST_POINT_value(x->crldp, j);
-                       /* We don't handle these at present */
-                       if (dp->reasons || dp->CRLissuer)
-                               continue;
-                       if (!dp->distpoint || (dp->distpoint->type != 0))
-                               continue;
-                       dnames = dp->distpoint->name.fullname;
-                       for (k = 0; k < sk_GENERAL_NAME_num(dnames); k++)
+                       if (!crl->idp ||
+                            idp_check_dp(dp->distpoint, crl->idp->distpoint))
                                {
-                               GENERAL_NAME *cgen =
-                                       sk_GENERAL_NAME_value(dnames, k);
-                               if (!GENERAL_NAME_cmp(igen, cgen))
-                                       return 1;
+                               *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. Currently only
- * one CRL is retrieved. Multiple CRLs may be needed if we handle
- * CRLs partitioned on reason code later.
+/* Retrieve CRL corresponding to current certificate.
+ * If deltas enabled try to find a delta CRL too
  */
        
-static int get_crl(X509_STORE_CTX *ctx, X509_CRL **pcrl, X509 *x)
+static int get_crl_delta(X509_STORE_CTX *ctx,
+                               X509_CRL **pcrl, X509_CRL **pdcrl, X509 *x)
        {
        int ok;
-       X509_CRL *crl = NULL;
+       X509 *issuer = NULL;
+       int crl_score = 0;
+       unsigned int reasons;
+       X509_CRL *crl = NULL, *dcrl = NULL;
        STACK_OF(X509_CRL) *skcrl;
-       X509_NAME *nm;
-       nm = X509_get_issuer_name(x);
-       ok = get_crl_sk(ctx, &crl, nm, ctx->crls);
+       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)
-               {
-               *pcrl = crl;
-               return 1;
-               }
+               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)
-               {
-               if (crl)
-                       {
-                       *pcrl = crl;
-                       return 1;
-                       }
-               return 0;
-               }
+       if (!skcrl && crl)
+               goto done;
 
-       get_crl_sk(ctx, &crl, NULL, skcrl);
+       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;
                }
 
@@ -889,6 +1499,7 @@ static int check_crl(X509_STORE_CTX *ctx, X509_CRL *crl)
        /* 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.
         */
@@ -908,35 +1519,52 @@ static int check_crl(X509_STORE_CTX *ctx, X509_CRL *crl)
 
        if(issuer)
                {
-               /* 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 (crl->idp_flags & IDP_PRESENT)
+               /* Skip most tests for deltas because they have already
+                * been done
+                */
+               if (!crl->base_crl_number)
                        {
-                       if (crl->idp_flags & IDP_INVALID)
+                       /* Check for cRLSign bit if keyUsage present */
+                       if ((issuer->ex_flags & EXFLAG_KUSAGE) &&
+                               !(issuer->ex_kusage & KU_CRL_SIGN))
                                {
-                               ctx->error = X509_V_ERR_INVALID_EXTENSION;
+                               ctx->error = X509_V_ERR_KEYUSAGE_NO_CRL_SIGN;
                                ok = ctx->verify_cb(0, ctx);
                                if(!ok) goto err;
                                }
-                       if (crl->idp_flags & (IDP_REASONS|IDP_INDIRECT))
+
+                       if (!(ctx->current_crl_score & CRL_SCORE_SCOPE))
                                {
-                               ctx->error = X509_V_ERR_UNSUPPORTED_EXTENSION_FEATURE;
+                               ctx->error = X509_V_ERR_DIFFERENT_CRL_SCOPE;
                                ok = ctx->verify_cb(0, ctx);
                                if(!ok) goto err;
                                }
-                       if (!idp_check_scope(ctx->current_cert, crl))
+
+                       if (!(ctx->current_crl_score & CRL_SCORE_SAME_PATH))
                                {
-                               ctx->error = X509_V_ERR_DIFFERENT_CRL_SCOPE;
+                               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 */
@@ -950,6 +1578,15 @@ static int check_crl(X509_STORE_CTX *ctx, X509_CRL *crl)
                        }
                else
                        {
+                       int rv;
+                       rv = X509_CRL_check_suiteb(crl, ikey, ctx->param->flags);
+                       if (rv != X509_V_OK)
+                               {
+                               ctx->error=rv;
+                               ok = ctx->verify_cb(0, ctx);
+                               if (!ok)
+                                       goto err;
+                               }
                        /* Verify CRL signature */
                        if(X509_CRL_verify(crl, ikey) <= 0)
                                {
@@ -960,10 +1597,6 @@ static int check_crl(X509_STORE_CTX *ctx, X509_CRL *crl)
                        }
                }
 
-       ok = check_crl_time(ctx, crl, 1);
-       if (!ok)
-               goto err;
-
        ok = 1;
 
        err:
@@ -975,18 +1608,12 @@ static int check_crl(X509_STORE_CTX *ctx, X509_CRL *crl)
 static int cert_crl(X509_STORE_CTX *ctx, X509_CRL *crl, X509 *x)
        {
        int ok;
-       /* Look for serial number of certificate in CRL
-        * If found assume revoked: want something cleverer than
-        * this to handle entry extensions in V2 CRLs.
+       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 (X509_CRL_get0_by_serial(crl, NULL, X509_get_serialNumber(x)) > 0)
-               {
-               ctx->error = X509_V_ERR_CERT_REVOKED;
-               ok = ctx->verify_cb(0, ctx);
-               if (!ok)
-                       return 0;
-               }
-
        if (crl->flags & EXFLAG_CRITICAL)
                {
                if (ctx->param->flags & X509_V_FLAG_IGNORE_CRITICAL)
@@ -996,6 +1623,18 @@ static int cert_crl(X509_STORE_CTX *ctx, X509_CRL *crl, X509 *x)
                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;
        }
@@ -1003,6 +1642,8 @@ static int cert_crl(X509_STORE_CTX *ctx, X509_CRL *crl, X509 *x)
 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)
@@ -1025,7 +1666,8 @@ static int check_policy(X509_STORE_CTX *ctx)
                                continue;
                        ctx->current_cert = x;
                        ctx->error = X509_V_ERR_INVALID_POLICY_EXTENSION;
-                       ret = ctx->verify_cb(0, ctx);
+                       if(!ctx->verify_cb(0, ctx))
+                               return 0;
                        }
                return 1;
                }
@@ -1112,6 +1754,11 @@ static int internal_verify(X509_STORE_CTX *ctx)
                xs=xi;
        else
                {
+               if (ctx->param->flags & X509_V_FLAG_PARTIAL_CHAIN && n == 0)
+                       {
+                       xs = xi;
+                       goto check_cert;
+                       }
                if (n <= 0)
                        {
                        ctx->error=X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE;
@@ -1131,7 +1778,12 @@ static int internal_verify(X509_STORE_CTX *ctx)
        while (n >= 0)
                {
                ctx->error_depth=n;
-               if (!xs->valid)
+
+               /* 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)
                                {
@@ -1141,13 +1793,6 @@ static int internal_verify(X509_STORE_CTX *ctx)
                                if (!ok) goto end;
                                }
                        else if (X509_verify(xs,pkey) <= 0)
-                               /* XXX  For the final trusted self-signed cert,
-                                * this is a waste of time.  That check should
-                                * optional so that e.g. 'openssl x509' can be
-                                * used to detect invalid self-signatures, but
-                                * we don't verify again and again in SSL
-                                * handshakes and the like once the cert has
-                                * been declared trusted. */
                                {
                                ctx->error=X509_V_ERR_CERT_SIGNATURE_FAILURE;
                                ctx->current_cert=xs;
@@ -1164,6 +1809,7 @@ static int internal_verify(X509_STORE_CTX *ctx)
 
                xs->valid = 1;
 
+               check_cert:
                ok = check_cert_time(ctx, xs);
                if (!ok)
                        goto end;
@@ -1246,10 +1892,11 @@ int X509_cmp_time(const ASN1_TIME *ctm, time_t *cmp_time)
                        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)
+       if (X509_time_adj(&atm, offset*60, cmp_time) == NULL)
                return 0;
 
        if (ctm->type == V_ASN1_UTCTIME)
@@ -1274,19 +1921,28 @@ 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 adj, time_t *in_tm)
+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;
-       int type = -1;
 
        if (in_tm) t = *in_tm;
        else time(&t);
 
-       t+=adj;
-       if (s) type = s->type;
-       if (type == V_ASN1_UTCTIME) return ASN1_UTCTIME_set(s,t);
-       if (type == V_ASN1_GENERALIZEDTIME) return ASN1_GENERALIZEDTIME_set(s, t);
-       return ASN1_TIME_set(s, 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)
@@ -1331,6 +1987,125 @@ int X509_get_pubkey_parameters(EVP_PKEY *pkey, STACK_OF(X509) *chain)
        return 1;
        }
 
+/* Make a delta CRL as the diff between two full CRLs */
+
+X509_CRL *X509_CRL_diff(X509_CRL *base, X509_CRL *newer,
+                       EVP_PKEY *skey, const EVP_MD *md, unsigned int flags)
+       {
+       X509_CRL *crl = NULL;
+       int i;
+       STACK_OF(X509_REVOKED) *revs = NULL;
+       /* CRLs can't be delta already */
+       if (base->base_crl_number || newer->base_crl_number)
+                       {
+                       X509err(X509_F_X509_CRL_DIFF, X509_R_CRL_ALREADY_DELTA);
+                       return NULL;
+                       }
+       /* Base and new CRL must have a CRL number */
+       if (!base->crl_number || !newer->crl_number)
+                       {
+                       X509err(X509_F_X509_CRL_DIFF, X509_R_NO_CRL_NUMBER);
+                       return NULL;
+                       }
+       /* Issuer names must match */
+       if (X509_NAME_cmp(X509_CRL_get_issuer(base),
+                               X509_CRL_get_issuer(newer)))
+                       {
+                       X509err(X509_F_X509_CRL_DIFF, X509_R_ISSUER_MISMATCH);
+                       return NULL;
+                       }
+       /* AKID and IDP must match */
+       if (!crl_extension_match(base, newer, NID_authority_key_identifier))
+                       {
+                       X509err(X509_F_X509_CRL_DIFF, X509_R_AKID_MISMATCH);
+                       return NULL;
+                       }
+       if (!crl_extension_match(base, newer, NID_issuing_distribution_point))
+                       {
+                       X509err(X509_F_X509_CRL_DIFF, X509_R_IDP_MISMATCH);
+                       return NULL;
+                       }
+       /* Newer CRL number must exceed full CRL number */
+       if (ASN1_INTEGER_cmp(newer->crl_number, base->crl_number) <= 0)
+                       {
+                       X509err(X509_F_X509_CRL_DIFF, X509_R_NEWER_CRL_NOT_NEWER);
+                       return NULL;
+                       }
+       /* CRLs must verify */
+       if (skey && (X509_CRL_verify(base, skey) <= 0 ||
+                       X509_CRL_verify(newer, skey) <= 0))
+               {
+               X509err(X509_F_X509_CRL_DIFF, X509_R_CRL_VERIFY_FAILURE);
+               return NULL;
+               }
+       /* Create new CRL */
+       crl = X509_CRL_new();
+       if (!crl || !X509_CRL_set_version(crl, 1))
+               goto memerr;
+       /* Set issuer name */
+       if (!X509_CRL_set_issuer_name(crl, X509_CRL_get_issuer(newer)))
+               goto memerr;
+
+       if (!X509_CRL_set_lastUpdate(crl, X509_CRL_get_lastUpdate(newer)))
+               goto memerr;
+       if (!X509_CRL_set_nextUpdate(crl, X509_CRL_get_nextUpdate(newer)))
+               goto memerr;
+
+       /* Set base CRL number: must be critical */
+
+       if (!X509_CRL_add1_ext_i2d(crl, NID_delta_crl, base->crl_number, 1, 0))
+               goto memerr;
+
+       /* Copy extensions across from newest CRL to delta: this will set
+        * CRL number to correct value too.
+        */
+
+       for (i = 0; i < X509_CRL_get_ext_count(newer); i++)
+               {
+               X509_EXTENSION *ext;
+               ext = X509_CRL_get_ext(newer, i);
+               if (!X509_CRL_add_ext(crl, ext, -1))
+                       goto memerr;
+               }
+
+       /* Go through revoked entries, copying as needed */
+
+       revs = X509_CRL_get_REVOKED(newer);
+
+       for (i = 0; i < sk_X509_REVOKED_num(revs); i++)
+               {
+               X509_REVOKED *rvn, *rvtmp;
+               rvn = sk_X509_REVOKED_value(revs, i);
+               /* Add only if not also in base.
+                * TODO: need something cleverer here for some more complex
+                * CRLs covering multiple CAs.
+                */
+               if (!X509_CRL_get0_by_serial(base, &rvtmp, rvn->serialNumber))
+                       {
+                       rvtmp = X509_REVOKED_dup(rvn);
+                       if (!rvtmp)
+                               goto memerr;
+                       if (!X509_CRL_add0_revoked(crl, rvtmp))
+                               {
+                               X509_REVOKED_free(rvtmp);
+                               goto memerr;
+                               }
+                       }
+               }
+       /* TODO: optionally prune deleted entries */
+
+       if (skey && md && !X509_CRL_sign(crl, skey, md))
+               goto memerr;
+       
+       return crl;
+
+       memerr:
+       X509err(X509_F_X509_CRL_DIFF, ERR_R_MALLOC_FAILURE);
+       if (crl)
+               X509_CRL_free(crl);
+       return NULL;
+       }
+
 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)
        {
@@ -1377,16 +2152,24 @@ STACK_OF(X509) *X509_STORE_CTX_get_chain(X509_STORE_CTX *ctx)
 
 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;
+       if (!ctx->chain)
+               return NULL;
+       return X509_chain_up_ref(ctx->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)
@@ -1509,7 +2292,11 @@ int X509_STORE_CTX_init(X509_STORE_CTX *ctx, X509_STORE *store, X509 *x509,
        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();
 
@@ -1527,7 +2314,7 @@ int X509_STORE_CTX_init(X509_STORE_CTX *ctx, X509_STORE *store, X509 *x509,
        if (store)
                ret = X509_VERIFY_PARAM_inherit(ctx->param, store->param);
        else
-               ctx->param->flags |= X509_VP_FLAG_DEFAULT|X509_VP_FLAG_ONCE;
+               ctx->param->inh_flags |= X509_VP_FLAG_DEFAULT|X509_VP_FLAG_ONCE;
 
        if (store)
                {
@@ -1575,7 +2362,7 @@ int X509_STORE_CTX_init(X509_STORE_CTX *ctx, X509_STORE *store, X509 *x509,
        if (store && store->get_crl)
                ctx->get_crl = store->get_crl;
        else
-               ctx->get_crl = get_crl;
+               ctx->get_crl = NULL;
 
        if (store && store->check_crl)
                ctx->check_crl = store->check_crl;
@@ -1629,7 +2416,8 @@ void X509_STORE_CTX_cleanup(X509_STORE_CTX *ctx)
        if (ctx->cleanup) ctx->cleanup(ctx);
        if (ctx->param != NULL)
                {
-               X509_VERIFY_PARAM_free(ctx->param);
+               if (ctx->parent == NULL)
+                       X509_VERIFY_PARAM_free(ctx->param);
                ctx->param=NULL;
                }
        if (ctx->tree != NULL)