Commit ffd2df13 authored by Richard Levitte's avatar Richard Levitte
Browse files

X509_check_issued: check that signature algo matches signing key algo 

This implements 3.5.18 "Consistent Public Key and Signature Algorithms"
from RFC 4158 "Internet X.509 Public Key Infrastructure: Certification
Path Building"

Ref: https://tools.ietf.org/html/rfc4158#section-3.5.18



Fixes #7899

Reviewed-by: default avatarMatthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/7919)
parent 5aa2a7ea

crypto/x509/x509_txt.c

+4 −0
Original line number Diff line number Diff line
@@ -174,6 +174,10 @@ const char *X509_verify_cert_error_string(long n) 
        return "OCSP verification failed";

    case X509_V_ERR_OCSP_CERT_UNKNOWN:

        return "OCSP unknown cert";

    case X509_V_ERR_SIGNATURE_ALGORITHM_MISMATCH:

        return "Subject signature algorithm and issuer public key algorithm mismatch";

    case X509_V_ERR_NO_ISSUER_PUBLIC_KEY:

        return "Issuer certificate doesn't have a public key";



    default:

        /* Printing an error number into a static buffer is not thread-safe */

crypto/x509v3/v3_purp.c

+21 −2
Original line number Diff line number Diff line
@@ -764,8 +764,9 @@ static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca) 
 * subject name.

 * These are:

 * 1. Check issuer_name(subject) == subject_name(issuer)

 * 2. If akid(subject) exists check it matches issuer

 * 3. If key_usage(issuer) exists check it supports certificate signing

 * 2. If akid(subject) exists, check that it matches issuer

 * 3. Check that issuer public key algorithm matches subject signature algorithm

 * 4. If key_usage(issuer) exists, check that it supports certificate signing

 * returns 0 for OK, positive for reason for mismatch, reasons match

 * codes for X509_verify_cert()

 */
@@ -785,6 +786,24 @@ int X509_check_issued(X509 *issuer, X509 *subject) 
            return ret;

    }



    {

        /*

         * Check if the subject signature algorithm matches the issuer's PUBKEY

         * algorithm

         */

        EVP_PKEY *i_pkey = X509_get0_pubkey(issuer);

        X509_ALGOR *s_algor = &subject->cert_info.signature;

        int s_pknid = NID_undef, s_mdnid = NID_undef;



        if (i_pkey == NULL)

            return X509_V_ERR_NO_ISSUER_PUBLIC_KEY;



        if (!OBJ_find_sigid_algs(OBJ_obj2nid(s_algor->algorithm),

                                 &s_mdnid, &s_pknid)

            || EVP_PKEY_type(s_pknid) != EVP_PKEY_base_id(i_pkey))

            return X509_V_ERR_SIGNATURE_ALGORITHM_MISMATCH;

    }



    if (subject->ex_flags & EXFLAG_PROXY) {

        if (ku_reject(issuer, KU_DIGITAL_SIGNATURE))

            return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE;

include/openssl/x509_vfy.h

+4 −0
Original line number Diff line number Diff line
@@ -185,6 +185,10 @@ void X509_STORE_CTX_set_depth(X509_STORE_CTX *ctx, int depth); 
# define         X509_V_ERR_OCSP_VERIFY_FAILED                   74  /* Couldn't verify cert through OCSP */

# define         X509_V_ERR_OCSP_CERT_UNKNOWN                    75  /* Certificate wasn't recognized by the OCSP responder */



# define         X509_V_ERR_SIGNATURE_ALGORITHM_MISMATCH         76

# define         X509_V_ERR_NO_ISSUER_PUBLIC_KEY                 77





/* Certificate verify flags */



# if !OPENSSL_API_1_1_0