Add trust setting support to the verify code. It now checks the

trust settings of the root CA.

After a few fixes it seems to work OK.

Still need to add support to SSL and S/MIME code though.

CHANGES

@@ -12,15 +12,21 @@
      DSA key was used because it didn't fix the digest.
      [Steve Henson]
 
-  *) Very preliminary certificate chain verify code. Currently just tests
-     the untrusted certificates for consistency with the verify purpose
-     (which is set when the X509_STORE_CTX structure is set up) and checks
-     the pathlength. There is a NO_CHAIN_VERIFY compilation option to keep
-     the old behaviour: this is because when it is finally working it will
-     reject chains with invalid extensions whereas before it made no checks
-     at all.
-
-     Preliminary untested trust code. 
+  *) Initial certificate chain verify code. Currently tests the untrusted
+     certificates for consistency with the verify purpose (which is set
+     when the X509_STORE_CTX structure is set up) and checks the pathlength.
+
+     There is a NO_CHAIN_VERIFY compilation option to keep the old behaviour:
+     this is because when it is finally working it will reject chains with
+     invalid extensions whereas every previous version of OpenSSL and SSLeay
+     made no checks at all.
+
+     Trust code: checks the root CA for the relevant trust settings. Trust
+     settings have an initial value consistent with the verify purpose: e.g.
+     if the verify purpose is for SSL client use it expects the CA to be
+     trusted for SSL client use. However the default value can be changed to
+     permit custom trust settings: one example of this would be to only trust
+     certificates from a specific "secure" set of CAs.
 
      Also added X509_STORE_CTX_new() and X509_STORE_CTX_free() functions
      which should be used for version portability: especially since the

apps/verify.c

@@ -85,6 +85,7 @@ int MAIN(int argc, char **argv)
 	X509_LOOKUP *lookup=NULL;
 
 	X509_PURPOSE_add_standard();
+	X509_TRUST_add_standard();
 	X509V3_add_standard_extensions();
 	cert_ctx=X509_STORE_new();
 	if (cert_ctx == NULL) goto end;
@@ -199,6 +200,7 @@ end:
 	sk_X509_pop_free(untrusted, X509_free);
 	X509V3_EXT_cleanup();
 	X509_PURPOSE_cleanup();
+	X509_TRUST_cleanup();
 	EXIT(ret);
 	}
 

crypto/asn1/t_x509a.c

@@ -99,13 +99,13 @@ int X509_CERT_AUX_print(BIO *out, X509_CERT_AUX *aux, int indent)
 	int i;
 	if(!aux) return 1;
 	if(aux->trust) {
-		BIO_printf(out, "%*sTrusted for:\n", indent, "");
+		BIO_printf(out, "%*sTrusted Uses:\n", indent, "");
 		ASN1_BIT_STRING_name_print(out, aux->trust, tbits, indent + 2);
-	} else BIO_printf(out, "%*sNo Trust Settings\n", indent + 2, "");
+	} else BIO_printf(out, "%*sNo Trusted Uses.\n", indent, "");
 	if(aux->reject) {
-		BIO_printf(out, "%*sUntrusted for:\n", indent, "");
+		BIO_printf(out, "%*sRejected Uses:\n", indent, "");
 		ASN1_BIT_STRING_name_print(out, aux->reject, tbits, indent + 2);
-	} else BIO_printf(out, "%*sNo Untrusted Settings\n", indent + 2, "");
+	} else BIO_printf(out, "%*sNo Rejected Uses.\n", indent, "");
 	if(aux->othertrust) {
 		first = 1;
 		BIO_printf(out, "%*sOther Trusted Uses:\n%*s",
@@ -121,7 +121,7 @@ int X509_CERT_AUX_print(BIO *out, X509_CERT_AUX *aux, int indent)
 	}
 	if(aux->otherreject) {
 		first = 1;
-		BIO_printf(out, "%*sOther Untrusted Uses:\n%*s",
+		BIO_printf(out, "%*sOther Rejected Uses:\n%*s",
 						indent, "", indent + 2, "");
 		for(i = 0; i < sk_ASN1_OBJECT_num(aux->otherreject); i++) {
 			if(!first) BIO_puts(out, ", ");

crypto/x509/x509.h

@@ -1098,6 +1098,7 @@ int X509_TRUST_get_trust(X509_TRUST *xp);
 #define X509_F_X509_REQ_PRINT				 121
 #define X509_F_X509_REQ_PRINT_FP			 122
 #define X509_F_X509_REQ_TO_X509				 123
+#define X509_F_X509_SET_PURPOSE_AND_TRUST		 134
 #define X509_F_X509_STORE_ADD_CERT			 124
 #define X509_F_X509_STORE_ADD_CRL			 125
 #define X509_F_X509_TO_X509_REQ				 126
@@ -1122,6 +1123,7 @@ int X509_TRUST_get_trust(X509_TRUST *xp);
 #define X509_R_UNABLE_TO_GET_CERTS_PUBLIC_KEY		 108
 #define X509_R_UNKNOWN_KEY_TYPE				 117
 #define X509_R_UNKNOWN_NID				 109
+#define X509_R_UNKNOWN_TRUST_ID				 120
 #define X509_R_UNSUPPORTED_ALGORITHM			 111
 #define X509_R_WRONG_LOOKUP_TYPE			 112
 

crypto/x509/x509_err.c

@@ -91,10 +91,11 @@ static ERR_STRING_DATA X509_str_functs[]=
 {ERR_PACK(0,X509_F_X509_REQ_PRINT,0),	"X509_REQ_print"},
 {ERR_PACK(0,X509_F_X509_REQ_PRINT_FP,0),	"X509_REQ_print_fp"},
 {ERR_PACK(0,X509_F_X509_REQ_TO_X509,0),	"X509_REQ_to_X509"},
+{ERR_PACK(0,X509_F_X509_SET_PURPOSE_AND_TRUST,0),	"X509_set_purpose_and_trust"},
 {ERR_PACK(0,X509_F_X509_STORE_ADD_CERT,0),	"X509_STORE_add_cert"},
 {ERR_PACK(0,X509_F_X509_STORE_ADD_CRL,0),	"X509_STORE_add_crl"},
 {ERR_PACK(0,X509_F_X509_TO_X509_REQ,0),	"X509_to_X509_REQ"},
-{ERR_PACK(0,X509_F_X509_TRUST_ADD,0),	"X509_TRUST_ADD"},
+{ERR_PACK(0,X509_F_X509_TRUST_ADD,0),	"X509_TRUST_add"},
 {ERR_PACK(0,X509_F_X509_VERIFY_CERT,0),	"X509_verify_cert"},
 {0,NULL}
 	};
@@ -118,6 +119,7 @@ static ERR_STRING_DATA X509_str_reasons[]=
 {X509_R_UNABLE_TO_GET_CERTS_PUBLIC_KEY   ,"unable to get certs public key"},
 {X509_R_UNKNOWN_KEY_TYPE                 ,"unknown key type"},
 {X509_R_UNKNOWN_NID                      ,"unknown nid"},
+{X509_R_UNKNOWN_TRUST_ID                 ,"unknown trust id"},
 {X509_R_UNSUPPORTED_ALGORITHM            ,"unsupported algorithm"},
 {X509_R_WRONG_LOOKUP_TYPE                ,"wrong lookup type"},
 {0,NULL}

crypto/x509/x509_txt.c

@@ -126,6 +126,10 @@ const char *X509_verify_cert_error_string(long n)
 		return ("path length constraint exceeded");
 	case X509_V_ERR_INVALID_PURPOSE:
 		return ("unsupported certificate purpose");
+	case X509_V_ERR_CERT_UNTRUSTED:
+		return ("certificate not trusted");
+	case X509_V_ERR_CERT_REJECTED:
+		return ("certificate rejected");
 	case X509_V_ERR_APPLICATION_VERIFICATION:
 		return("application verification failure");
 	default:

crypto/x509/x509_vfy.c

@@ -72,6 +72,7 @@
 
 static int null_callback(int ok,X509_STORE_CTX *e);
 static int check_chain_purpose(X509_STORE_CTX *ctx);
+static int check_trust(X509_STORE_CTX *ctx);
 static int internal_verify(X509_STORE_CTX *ctx);
 const char *X509_version="X.509" OPENSSL_VERSION_PTEXT;
 
@@ -297,6 +298,12 @@ int X509_verify_cert(X509_STORE_CTX *ctx)
 
 	if(!ok) goto end;
 
+	/* The chain extensions are OK: check trust */
+
+	if(ctx->trust_purpose > 0) ok = check_trust(ctx);
+
+	if(!ok) goto end;
+
 	/* We may as well copy down any DSA parameters that are required */
 	X509_get_pubkey_parameters(NULL,ctx->chain);
 
@@ -356,6 +363,30 @@ static int check_chain_purpose(X509_STORE_CTX *ctx)
 #endif
 }
 
+static int check_trust(X509_STORE_CTX *ctx)
+{
+#ifdef NO_CHAIN_VERIFY
+	return 1;
+#else
+	int i, ok;
+	X509 *x;
+	int (*cb)();
+	cb=ctx->ctx->verify_cb;
+	if (cb == NULL) cb=null_callback;
+/* 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->trust_purpose, 0);
+	if(ok == X509_TRUST_TRUSTED) return 1;
+	ctx->error_depth = sk_X509_num(ctx->chain) - 1;
+	ctx->current_cert = x;
+	if(ok == X509_TRUST_REJECTED) ctx->error = X509_V_ERR_CERT_REJECTED;
+	else ctx->error = X509_V_ERR_CERT_UNTRUSTED;
+	ok = cb(0, ctx);
+	return(ok);
+#endif
+}
+
 static int internal_verify(X509_STORE_CTX *ctx)
 	{
 	int i,ok=0,n;
@@ -696,9 +727,10 @@ void X509_STORE_CTX_set_chain(X509_STORE_CTX *ctx, STACK_OF(X509) *sk)
 	ctx->untrusted=sk;
 	}
 
-void X509_STORE_CTX_chain_purpose(X509_STORE_CTX *ctx, int purpose)
+int X509_STORE_CTX_chain_purpose(X509_STORE_CTX *ctx, int purpose)
 	{
-	ctx->chain_purpose = purpose;
+		return X509_set_purpose_and_trust(purpose,
+				&ctx->chain_purpose, &ctx->trust_purpose);
 	}
 
 void X509_STORE_CTX_trust_purpose(X509_STORE_CTX *ctx, int purpose)
@@ -706,6 +738,22 @@ void X509_STORE_CTX_trust_purpose(X509_STORE_CTX *ctx, int purpose)
 	ctx->trust_purpose = purpose;
 	}
 
+int X509_set_purpose_and_trust(int id, int *purp, int *trust)
+{
+	X509_PURPOSE *ptmp;
+	int idx;
+	idx = X509_PURPOSE_get_by_id(id);
+	if(idx == -1) {
+		X509err(X509_F_X509_SET_PURPOSE_AND_TRUST,
+					X509_R_UNKNOWN_TRUST_ID);
+		return 0;
+	}
+	ptmp = X509_PURPOSE_iget(idx);
+	if(purp) *purp = id;
+	if(trust) *trust = ptmp->trust_id;
+	return 1;
+}
+
 IMPLEMENT_STACK_OF(X509)
 IMPLEMENT_ASN1_SET_OF(X509)
 

crypto/x509/x509_vfy.h

@@ -263,6 +263,8 @@ struct x509_store_state_st      /* X509_STORE_CTX */
 #define		X509_V_ERR_INVALID_CA				24
 #define		X509_V_ERR_PATH_LENGTH_EXCEEDED			25
 #define		X509_V_ERR_INVALID_PURPOSE			26
+#define		X509_V_ERR_CERT_UNTRUSTED			27
+#define		X509_V_ERR_CERT_REJECTED			28
 
 /* The application is not happy */
 #define		X509_V_ERR_APPLICATION_VERIFICATION		50
@@ -347,8 +349,9 @@ X509 *	X509_STORE_CTX_get_current_cert(X509_STORE_CTX *ctx);
 STACK_OF(X509) *X509_STORE_CTX_get_chain(X509_STORE_CTX *ctx);
 void	X509_STORE_CTX_set_cert(X509_STORE_CTX *c,X509 *x);
 void	X509_STORE_CTX_set_chain(X509_STORE_CTX *c,STACK_OF(X509) *sk);
-void X509_STORE_CTX_chain_purpose(X509_STORE_CTX *ctx, int purpose);
+int X509_STORE_CTX_chain_purpose(X509_STORE_CTX *ctx, int purpose);
 void X509_STORE_CTX_trust_purpose(X509_STORE_CTX *ctx, int purpose);
+int X509_set_purpose_and_trust(int id, int *purp, int *trust);
 
 #ifdef  __cplusplus
 }

crypto/x509v3/v3_lib.c

@@ -128,10 +128,13 @@ int X509V3_EXT_add_alias(int nid_to, int nid_from)
 	return 1;
 }
 
+static int added_exts = 0;
+
 void X509V3_EXT_cleanup(void)
 {
 	sk_pop_free(ext_list, ext_list_free);
 	ext_list = NULL;
+	added_exts = 0;
 }
 
 static void ext_list_free(X509V3_EXT_METHOD *ext)
@@ -147,6 +150,7 @@ extern X509V3_EXT_METHOD v3_crl_num, v3_crl_reason, v3_cpols, v3_crld;
 
 int X509V3_add_standard_extensions(void)
 {
+	if(added_exts) return 1;
 	X509V3_EXT_add_list(v3_ns_ia5_list);
 	X509V3_EXT_add_list(v3_alt);
 	X509V3_EXT_add(&v3_bcons);
@@ -162,6 +166,7 @@ int X509V3_add_standard_extensions(void)
 	X509V3_EXT_add(&v3_crl_reason);
 	X509V3_EXT_add(&v3_cpols);
 	X509V3_EXT_add(&v3_crld);
+	added_exts = 1;
 	return 1;
 }
 

crypto/x509v3/v3_purp.c

@@ -222,7 +222,7 @@ static void x509v3_cache_extensions(X509 *x)
 	if(x->ex_flags & EXFLAG_SET) return;
 	X509_digest(x, EVP_sha1(), x->sha1_hash, NULL);
 	/* Does subject name match issuer ? */
-	if(X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)))
+	if(!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)))
 			 x->ex_flags |= EXFLAG_SS;
 	/* V1 should mean no extensions ... */
 	if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1;