Commit 9d84d4ed authored by Dr. Stephen Henson's avatar Dr. Stephen Henson
Browse files

Initial support for CRL path validation. This supports distinct certificate 

and CRL signing keys.
parent 2e0c7db9

CHANGES

+9 −0
Original line number Diff line number Diff line
@@ -4,6 +4,15 @@ 


 Changes between 0.9.8i and 0.9.9  [xx XXX xxxx]



  *) Add support for distinct certificate and CRL paths. The CRL issuer

     certificate is validated separately in this case. Only enabled if

     an extended CRL support flag is set: this flag will enable additional

     CRL functionality in future.



     This work was sponsored by Google.

     [Steve Henson]

     



  *) Add support for policy mappings extension.



     This work was sponsored by Google.

apps/apps.c

+2 −0
Original line number Diff line number Diff line
@@ -2239,6 +2239,8 @@ int args_verify(char ***pargs, int *pargc, 
		flags |= X509_V_FLAG_INHIBIT_MAP;

	else if (!strcmp(arg, "-x509_strict"))

		flags |= X509_V_FLAG_X509_STRICT;

	else if (!strcmp(arg, "-extended_crl"))

		flags |= X509_V_FLAG_EXTENDED_CRL_SUPPORT;

	else if (!strcmp(arg, "-policy_print"))

		flags |= X509_V_FLAG_NOTIFY_POLICY;

	else

crypto/x509/x509_vfy.c

+97 −19
Original line number Diff line number Diff line
@@ -81,6 +81,10 @@ 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 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;
@@ -407,8 +411,8 @@ 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:
@@ -421,10 +425,22 @@ 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 */

	/* 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++)
@@ -491,8 +507,7 @@ 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)))
@@ -795,9 +810,7 @@ static int crl_akid_check(X509_STORE_CTX *ctx, X509_CRL *crl, X509 **pissuer) 
	{

	X509 *crl_issuer;

	int cidx = ctx->error_depth;

#if 0

	int i;

#endif

	if (!crl->akid)

		return 1;

	if (cidx != sk_X509_num(ctx->chain) - 1)
@@ -824,15 +837,15 @@ static int crl_akid_check(X509_STORE_CTX *ctx, X509_CRL *crl, X509 **pissuer) 
		}





	/* Anything else needs extended CRL support */



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

		return 0;



	/* Otherwise the CRL issuer is not on the path. Look for it in the

	 * set of untrusted certificates.

	 */



#if 0

	/* FIXME: not enabled yet because the CRL issuer certifcate is not

	 * validated.

	 */



	for (i = 0; i < sk_X509_num(ctx->untrusted); i++)

		{

		crl_issuer = sk_X509_value(ctx->untrusted, i);
@@ -840,16 +853,77 @@ static int crl_akid_check(X509_STORE_CTX *ctx, X509_CRL *crl, X509 **pissuer) 
					X509_CRL_get_issuer(crl)))

			continue;

		if (X509_check_akid(crl_issuer, crl->akid) == X509_V_OK)

			{

			if (check_crl_path(ctx, crl_issuer))

				{

				*pissuer = crl_issuer;

				return 1;

				}

			}

#endif

		}



	return 0;

	}



/* 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;

	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);



	/* Maybe send path check result back to parent? */

	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.
@@ -1127,6 +1201,8 @@ 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)
@@ -1635,6 +1711,7 @@ 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();
@@ -1754,6 +1831,7 @@ void X509_STORE_CTX_cleanup(X509_STORE_CTX *ctx) 
	if (ctx->cleanup) ctx->cleanup(ctx);

	if (ctx->param != NULL)

		{

		if (ctx->parent == NULL)

			X509_VERIFY_PARAM_free(ctx->param);

		ctx->param=NULL;

		}

crypto/x509/x509_vfy.h

+4 −0
Original line number Diff line number Diff line
@@ -269,6 +269,8 @@ struct x509_store_ctx_st /* X509_STORE_CTX */ 
	X509 *current_issuer;	/* cert currently being tested as valid issuer */

	X509_CRL *current_crl;	/* current CRL */



	X509_STORE_CTX *parent; /* For CRL path validation: parent context */



	CRYPTO_EX_DATA ex_data;

	} /* X509_STORE_CTX */;
@@ -377,6 +379,8 @@ void X509_STORE_CTX_set_depth(X509_STORE_CTX *ctx, int depth); 
#define X509_V_FLAG_INHIBIT_MAP			0x400

/* Notify callback that policy is OK */

#define X509_V_FLAG_NOTIFY_POLICY		0x800

/* Extended CRL features such as indirect CRLs, alternate CRL signing keys */

#define X509_V_FLAG_EXTENDED_CRL_SUPPORT	0x1000



#define X509_VP_FLAG_DEFAULT			0x1

#define X509_VP_FLAG_OVERWRITE			0x2