Add code to download CRLs based on CRLDP extension.

Just a sample, real world applications would have to be cleverer.

1 files changed, 78 insertions, 1 deletions

diff --git a/apps/apps.c b/apps/apps.c
index adf78665b0..7f057fb4b2 100644
--- a/apps/apps.c
+++ b/apps/apps.c
@@ -929,7 +929,7 @@ end:
 	return(x);
 	}
 
-X509_CRL *load_crl(char *infile, int format)
+X509_CRL *load_crl(const char *infile, int format)
 	{
 	X509_CRL *x=NULL;
 	BIO *in=NULL;
@@ -2974,6 +2974,83 @@ void print_cert_checks(BIO *bio, X509 *x,
 		}
 	}
 
+/* Get first http URL from a DIST_POINT structure */
+
+static const char *get_dp_url(DIST_POINT *dp)
+	{
+	GENERAL_NAMES *gens;
+	GENERAL_NAME *gen;
+	int i, gtype;
+	ASN1_STRING *uri;
+	if (!dp->distpoint || dp->distpoint->type != 0)
+		return NULL;
+	gens = dp->distpoint->name.fullname;
+	for (i = 0; i < sk_GENERAL_NAME_num(gens); i++)
+		{
+		gen = sk_GENERAL_NAME_value(gens, i);
+		uri = GENERAL_NAME_get0_value(gen, &gtype);
+		if (gtype == GEN_URI && ASN1_STRING_length(uri) > 6)
+			{
+			char *uptr = (char *)ASN1_STRING_data(uri);
+			if (!strncmp(uptr, "http://", 7))
+				return uptr;
+			}
+		}		
+	return NULL;
+	}
+		
+
+/* Look through a CRLDP structure and attempt to find an http URL to downloads
+ * a CRL from.
+ */
+
+static X509_CRL *load_crl_crldp(STACK_OF(DIST_POINT) *crldp)
+	{
+	int i;
+	const char *urlptr = NULL;
+	for (i = 0; i < sk_DIST_POINT_num(crldp); i++)
+		{
+		DIST_POINT *dp = sk_DIST_POINT_value(crldp, i);
+		urlptr = get_dp_url(dp);
+		if (urlptr)
+			return load_crl(urlptr, FORMAT_HTTP);
+		}
+	return NULL;
+	}
+
+/* Example of downloading CRLs from CRLDP: not usable for real world
+ * as it always downloads, doesn't support non-blocking I/O and doesn't
+ * cache anything.
+ */
+
+static STACK_OF(X509_CRL) *crls_http_cb(X509_STORE_CTX *ctx, X509_NAME *nm)
+	{
+	X509 *x;
+	STACK_OF(X509_CRL) *crls = NULL;
+	X509_CRL *crl;
+	STACK_OF(DIST_POINT) *crldp;
+	x = X509_STORE_CTX_get_current_cert(ctx);
+	crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, NULL, NULL);
+	crl = load_crl_crldp(crldp);
+	sk_DIST_POINT_pop_free(crldp, DIST_POINT_free);
+	if (!crl)
+		return NULL;
+	crls = sk_X509_CRL_new_null();
+	sk_X509_CRL_push(crls, crl);
+	/* Try to download delta CRL */
+	crldp = X509_get_ext_d2i(x, NID_freshest_crl, NULL, NULL);
+	crl = load_crl_crldp(crldp);
+	sk_DIST_POINT_pop_free(crldp, DIST_POINT_free);
+	if (crl)
+		sk_X509_CRL_push(crls, crl);
+	return crls;
+	}
+
+void store_setup_crl_download(X509_STORE *st)
+	{
+	X509_STORE_set_lookup_crls_cb(st, crls_http_cb);
+	}
+
 /*
  * Platform-specific sections
  */