X-Git-Url: https://git.openssl.org/?p=openssl.git;a=blobdiff_plain;f=crypto%2Fx509%2Fx509_vfy.c;h=6f3274c3a20bb95790a88819761ba652482496d6;hp=57113672328165652e4cb6ffb1b2dbdb8c38d95f;hb=fa0f834c204020e9d2ce5508070f7a2eda663442;hpb=3f791ca8188b71cba77e718d2d5c2ed7613d3b6a

diff --git a/crypto/x509/x509_vfy.c b/crypto/x509/x509_vfy.c
index 5711367232..6f3274c3a2 100644
--- a/crypto/x509/x509_vfy.c
+++ b/crypto/x509/x509_vfy.c
@@ -70,16 +70,72 @@
 #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;
+const char X509_version[]="X.509" OPENSSL_VERSION_PTEXT;
 
 
 static int null_callback(int ok, X509_STORE_CTX *e)
@@ -164,7 +220,7 @@ int X509_verify_cert(X509_STORE_CTX *ctx)
 					goto end;
 					}
 				CRYPTO_add(&xtmp->references,1,CRYPTO_LOCK_X509);
-				sk_X509_delete_ptr(sktmp,xtmp);
+				(void)sk_X509_delete_ptr(sktmp,xtmp);
 				ctx->last_untrusted++;
 				x=xtmp;
 				num++;
@@ -214,7 +270,7 @@ int X509_verify_cert(X509_STORE_CTX *ctx)
 				 */
 				X509_free(x);
 				x = xtmp;
-				sk_X509_set(ctx->chain, i - 1, x);
+				(void)sk_X509_set(ctx->chain, i - 1, x);
 				ctx->last_untrusted=0;
 				}
 			}
@@ -289,6 +345,12 @@ int X509_verify_cert(X509_STORE_CTX *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);
@@ -312,6 +374,14 @@ int X509_verify_cert(X509_STORE_CTX *ctx)
 		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);
@@ -386,12 +456,12 @@ static int check_chain_extensions(X509_STORE_CTX *ctx)
 #ifdef OPENSSL_NO_CHAIN_VERIFY
 	return 1;
 #else
-	int i, ok=0, must_be_ca;
+	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 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:
@@ -404,10 +474,22 @@ 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++)
@@ -474,8 +556,7 @@ 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)))
@@ -487,9 +568,10 @@ static int check_chain_extensions(X509_STORE_CTX *ctx)
 				if (!ok) goto end;
 				}
 			}
-		/* Check pathlen */
-		if ((i > 1) && (x->ex_pathlen != -1)
-			   && (i > (x->ex_pathlen + proxy_path_length + 1)))
+		/* 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;
@@ -497,6 +579,9 @@ static int check_chain_extensions(X509_STORE_CTX *ctx)
 			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
@@ -524,6 +609,42 @@ 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_trust(X509_STORE_CTX *ctx)
 {
 #ifdef OPENSSL_NO_CHAIN_VERIFY
@@ -570,30 +691,65 @@ 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;
 	cnum = ctx->error_depth;
 	x = sk_X509_value(ctx->chain, cnum);
 	ctx->current_cert = x;
-	/* 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_issuer = NULL;
+	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;
+		/* 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;
 		}
-	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;
 
 	}
@@ -604,7 +760,8 @@ 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
@@ -613,15 +770,19 @@ 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;
 		}
 
@@ -631,92 +792,545 @@ 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;
 	}
 
-/* Lookup CRLs from the supplied list. Look for matching isser name
- * and validity. If we can't find a valid CRL return the last one
- * with matching name. This gives more meaningful error codes. Otherwise
- * we'd get a CRL not found error if a CRL existed with matching name but
- * was invalid.
- */
-
-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;
+	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);
-		if (X509_NAME_cmp(nm, X509_CRL_get_issuer(crl)))
-			continue;
-		if (check_crl_time(ctx, crl, 0))
+		reasons = *preasons;
+		crl_score = get_crl_score(ctx, &crl_issuer, &reasons, crl, x);
+
+		if (crl_score > best_score)
 			{
-			*pcrl = crl;
-			CRYPTO_add(&crl->references, 1, CRYPTO_LOCK_X509);
-			return 1;
+			best_crl = crl;
+			best_crl_issuer = crl_issuer;
+			best_score = crl_score;
+			best_reasons = reasons;
 			}
-		best_crl = crl;
 		}
+
 	if (best_crl)
 		{
+		if (*pcrl)
+			X509_CRL_free(*pcrl);
 		*pcrl = best_crl;
-		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;
 	}
 
-/* Retrieve CRL corresponding to certificate: currently just a
- * subject lookup: maybe use AKID later...
+/* 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 get_crl(X509_STORE_CTX *ctx, X509_CRL **pcrl, X509 *x)
+
+static int crl_extension_match(X509_CRL *a, X509_CRL *b, int nid)
 	{
-	int ok;
-	X509_CRL *crl = NULL;
-	X509_OBJECT xobj;
-	X509_NAME *nm;
-	nm = X509_get_issuer_name(x);
-	ok = get_crl_sk(ctx, &crl, nm, ctx->crls);
-	if (ok)
+	ASN1_OCTET_STRING *exta, *extb;
+	int i;
+	i = X509_CRL_get_ext_by_NID(a, nid, 0);
+	if (i >= 0)
 		{
-		*pcrl = crl;
+		/* 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;
 
-	ok = X509_STORE_get_by_subject(ctx, X509_LU_CRL, nm, &xobj);
+	}
 
-	if (!ok)
+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 we got a near match from get_crl_sk use that */
-		if (crl)
+		if (*pcrl_score & CRL_SCORE_ISSUER_NAME)
 			{
-			*pcrl = crl;
-			return 1;
+			*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)
+		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;
 		}
 
-	*pcrl = xobj.data.crl;
+	/* 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)
-		X509_CRL_free(crl);
-	return 1;
+		{
+		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 */
@@ -727,10 +1341,14 @@ static int check_crl(X509_STORE_CTX *ctx, X509_CRL *crl)
 	int ok = 0, chnum, cnum;
 	cnum = ctx->error_depth;
 	chnum = sk_X509_num(ctx->chain) - 1;
-	/* Find CRL issuer: if not last certificate then issuer
+	/* 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.
 	 */
-	if(cnum < chnum)
+	else if (cnum < chnum)
 		issuer = sk_X509_value(ctx->chain, cnum + 1);
 	else
 		{
@@ -746,13 +1364,52 @@ 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))
+		/* Skip most tests for deltas because they have already
+		 * been done
+		 */
+		if (!crl->base_crl_number)
 			{
-			ctx->error = X509_V_ERR_KEYUSAGE_NO_CRL_SIGN;
-			ok = ctx->verify_cb(0, ctx);
-			if(!ok) goto err;
+			/* 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))
+					{
+					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 */
@@ -776,10 +1433,6 @@ 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:
@@ -790,62 +1443,43 @@ static int check_crl(X509_STORE_CTX *ctx, X509_CRL *crl)
 /* Check certificate against CRL */
 static int cert_crl(X509_STORE_CTX *ctx, X509_CRL *crl, X509 *x)
 	{
-	int idx, ok;
-	X509_REVOKED rtmp;
-	STACK_OF(X509_EXTENSION) *exts;
-	X509_EXTENSION *ext;
-	/* Look for serial number of certificate in CRL */
-	rtmp.serialNumber = X509_get_serialNumber(x);
-	/* Sort revoked into serial number order if not already sorted.
-	 * Do this under a lock to avoid race condition.
- 	 */
-	if (!sk_X509_REVOKED_is_sorted(crl->crl->revoked))
+	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)
 		{
-		CRYPTO_w_lock(CRYPTO_LOCK_X509_CRL);
-		sk_X509_REVOKED_sort(crl->crl->revoked);
-		CRYPTO_w_unlock(CRYPTO_LOCK_X509_CRL);
+		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;
 		}
-	idx = sk_X509_REVOKED_find(crl->crl->revoked, &rtmp);
-	/* If found assume revoked: want something cleverer than
-	 * this to handle entry extensions in V2 CRLs.
+	/* Look for serial number of certificate in CRL
+	 * If found make sure reason is not removeFromCRL.
 	 */
-	if(idx >= 0)
+	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;
+		if (!ok)
+			return 0;
 		}
 
-	if (ctx->param->flags & X509_V_FLAG_IGNORE_CRITICAL)
-		return 1;
-
-	/* See if we have any critical CRL extensions: since we
-	 * currently don't handle any CRL extensions the CRL must be
-	 * rejected. 
-	 * This code accesses the X509_CRL structure directly: applications
-	 * shouldn't do this.
-	 */
-
-	exts = crl->crl->extensions;
-
-	for (idx = 0; idx < sk_X509_EXTENSION_num(exts); idx++)
-		{
-		ext = sk_X509_EXTENSION_value(exts, idx);
-		if (ext->critical > 0)
-			{
-			ctx->error =
-				X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION;
-			ok = ctx->verify_cb(0, ctx);
-			if(!ok) return 0;
-			break;
-			}
-		}
 	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)
@@ -868,7 +1502,8 @@ 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;
 		}
@@ -1029,12 +1664,12 @@ end:
 	return ok;
 	}
 
-int X509_cmp_current_time(ASN1_TIME *ctm)
+int X509_cmp_current_time(const ASN1_TIME *ctm)
 {
 	return X509_cmp_time(ctm, NULL);
 }
 
-int X509_cmp_time(ASN1_TIME *ctm, time_t *cmp_time)
+int X509_cmp_time(const ASN1_TIME *ctm, time_t *cmp_time)
 	{
 	char *str;
 	ASN1_TIME atm;
@@ -1081,7 +1716,7 @@ int X509_cmp_time(ASN1_TIME *ctm, time_t *cmp_time)
 		offset=0;
 	else
 		{
-		if ((*str != '+') && (str[5] != '-'))
+		if ((*str != '+') && (*str != '-'))
 			return 0;
 		offset=((str[1]-'0')*10+(str[2]-'0'))*60;
 		offset+=(str[3]-'0')*10+(str[4]-'0');
@@ -1353,6 +1988,7 @@ int X509_STORE_CTX_init(X509_STORE_CTX *ctx, X509_STORE *store, X509 *x509,
 	ctx->current_cert=NULL;
 	ctx->current_issuer=NULL;
 	ctx->tree = NULL;
+	ctx->parent = NULL;
 
 	ctx->param = X509_VERIFY_PARAM_new();
 
@@ -1418,7 +2054,7 @@ 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;
@@ -1430,6 +2066,16 @@ int X509_STORE_CTX_init(X509_STORE_CTX *ctx, X509_STORE *store, X509 *x509,
 	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;
 
 
@@ -1460,9 +2106,17 @@ void X509_STORE_CTX_trusted_stack(X509_STORE_CTX *ctx, STACK_OF(X509) *sk)
 void X509_STORE_CTX_cleanup(X509_STORE_CTX *ctx)
 	{
 	if (ctx->cleanup) ctx->cleanup(ctx);
-	X509_VERIFY_PARAM_free(ctx->param);
-	if (ctx->tree)
+	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);