Commit 6aca8d1a authored by David Woodhouse's avatar David Woodhouse Committed by Nicola Tuveri
Browse files

Honour mandatory digest on private key in has_usable_cert() 



If the private key says it can only support one specific digest, then
don't ask it to perform a different one.

Fixes: #7348

Reviewed-by: default avatarNicola Tuveri <nic.tuv@gmail.com>
Reviewed-by: default avatarRichard Levitte <levitte@openssl.org>

(cherry picked from commit 2d263a4a73f852005b16359873475d48755999ad)

Reviewed-by: default avatarMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7609)
parent abaa2311

ssl/t1_lib.c

+18 −3
Original line number Diff line number Diff line
@@ -2537,7 +2537,8 @@ static int tls12_get_cert_sigalg_idx(const SSL *s, const SIGALG_LOOKUP *lu) 
static int has_usable_cert(SSL *s, const SIGALG_LOOKUP *sig, int idx)

{

    const SIGALG_LOOKUP *lu;

    int mdnid, pknid;

    int mdnid, pknid, default_mdnid;

    int mandatory_md = 0;

    size_t i;



    /* TLS 1.2 callers can override lu->sig_idx, but not TLS 1.3 callers. */
@@ -2545,12 +2546,26 @@ static int has_usable_cert(SSL *s, const SIGALG_LOOKUP *sig, int idx) 
        idx = sig->sig_idx;

    if (!ssl_has_cert(s, idx))

        return 0;

    /* If the EVP_PKEY reports a mandatory digest, allow nothing else. */

    ERR_set_mark();

    switch (EVP_PKEY_get_default_digest_nid(s->cert->pkeys[idx].privatekey,

                                            &default_mdnid)) {

    case 2:

        mandatory_md = 1;

        break;

    case 1:

        break;

    default: /* If it didn't report a mandatory NID, for whatever reasons,

              * just clear the error and allow all hashes to be used. */

        ERR_pop_to_mark();

    }

    if (s->s3->tmp.peer_cert_sigalgs != NULL) {

        for (i = 0; i < s->s3->tmp.peer_cert_sigalgslen; i++) {

            lu = tls1_lookup_sigalg(s->s3->tmp.peer_cert_sigalgs[i]);

            if (lu == NULL

                || !X509_get_signature_info(s->cert->pkeys[idx].x509, &mdnid,

                                            &pknid, NULL, NULL))

                                            &pknid, NULL, NULL)

                || (mandatory_md && mdnid != default_mdnid))

                continue;

            /*

             * TODO this does not differentiate between the
@@ -2563,7 +2578,7 @@ static int has_usable_cert(SSL *s, const SIGALG_LOOKUP *sig, int idx) 
        }

        return 0;

    }

    return 1;

    return !mandatory_md || sig->hash == default_mdnid;

}



/*