Commit ed17c7c1 authored by Richard Levitte's avatar Richard Levitte
Browse files

Fix proxy certificate pathlength verification 



While travelling up the certificate chain, the internal
proxy_path_length must be updated with the pCPathLengthConstraint
value, or verification will not work properly.  This corresponds to
RFC 3820, 4.1.4 (a).

Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
Reviewed-by: default avatarStephen Henson <steve@openssl.org>
parent c8223538

crypto/x509/x509_vfy.c

+18 −4
Original line number Diff line number Diff line
@@ -533,11 +533,25 @@ static int check_chain_extensions(X509_STORE_CTX *ctx) 
         * the next certificate must be a CA certificate.

         */

        if (x->ex_flags & EXFLAG_PROXY) {

            if (x->ex_pcpathlen != -1 && i > x->ex_pcpathlen) {

            /*

             * RFC3820, 4.1.3 (b)(1) stipulates that if pCPathLengthConstraint

             * is less than max_path_length, the former should be copied to

             * the latter, and 4.1.4 (a) stipulates that max_path_length

             * should be verified to be larger than zero and decrement it.

             *

             * Because we're checking the certs in the reverse order, we start

             * with verifying that proxy_path_length isn't larger than pcPLC,

             * and copy the latter to the former if it is, and finally,

             * increment proxy_path_length.

             */

            if (x->ex_pcpathlen != -1) {

                if (proxy_path_length > x->ex_pcpathlen) {

                    if (!verify_cb_cert(ctx, x, i,

                                        X509_V_ERR_PROXY_PATH_LENGTH_EXCEEDED))

                        return 0;

                }

                proxy_path_length = x->ex_pcpathlen;

            }

            proxy_path_length++;

            must_be_ca = 0;

        } else