From 9757a5ad8a3bb3869fc0e159b10ff6061c9d0eda Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Thu, 22 Aug 2019 18:42:05 +0100 Subject: [PATCH] Fix bogus check for EVP_PKEY mandatory digest in check_cert_usable() In commit 6aca8d1a5 ("Honour mandatory digest on private key in has_usable_cert()") I added two checks for the capabilities of the EVP_PKEY being used. One of them was wrong, as it should only be checking the signature of the X.509 cert (by its issuer) against the sigalgs given in a TLS v1.3 signature_algorithms_cert extension. Remove it. Reviewed-by: Matt Caswell Reviewed-by: Ben Kaduk Reviewed-by: Tomas Mraz (Merged from https://github.com/openssl/openssl/pull/9705) --- ssl/t1_lib.c | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c index e5e77023cc..52d58ddd4f 100644 --- a/ssl/t1_lib.c +++ b/ssl/t1_lib.c @@ -2563,27 +2563,23 @@ static int check_cert_usable(SSL *s, const SIGALG_LOOKUP *sig, X509 *x, { const SIGALG_LOOKUP *lu; int mdnid, pknid, default_mdnid; - int mandatory_md = 0; size_t i; /* If the EVP_PKEY reports a mandatory digest, allow nothing else. */ ERR_set_mark(); - switch (EVP_PKEY_get_default_digest_nid(pkey, &default_mdnid)) { - case 2: - mandatory_md = 1; - break; - case 1: - default: /* If it didn't report a mandatory NID, for whatever reasons, - * just clear the error and allow all hashes to be used. */ - break; - } + if (EVP_PKEY_get_default_digest_nid(pkey, &default_mdnid) == 2 && + sig->hash != default_mdnid) + return 0; + + /* 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(x, &mdnid, &pknid, NULL, NULL) - || (mandatory_md && mdnid != default_mdnid)) + || !X509_get_signature_info(x, &mdnid, &pknid, NULL, NULL)) continue; /* * TODO this does not differentiate between the @@ -2596,7 +2592,7 @@ static int check_cert_usable(SSL *s, const SIGALG_LOOKUP *sig, X509 *x, } return 0; } - return !mandatory_md || sig->hash == default_mdnid; + return 1; } /* -- 2.25.1