From 095a982bb49879e6dea1e846d744652b2bd30e18 Mon Sep 17 00:00:00 2001 From: "Dr. Stephen Henson" Date: Sat, 25 Feb 2017 00:25:04 +0000 Subject: [PATCH] For TLS 1.3 reject SHA1 TLS signatures Reviewed-by: Rich Salz (Merged from https://github.com/openssl/openssl/pull/2739) --- ssl/t1_lib.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c index a7b467973e..099dcdb72a 100644 --- a/ssl/t1_lib.c +++ b/ssl/t1_lib.c @@ -902,10 +902,11 @@ int tls12_check_peer_sigalg(SSL *s, uint16_t sig, EVP_PKEY *pkey) } lu = tls1_lookup_sigalg(sig); /* - * Check sigalgs is known and key type is consistent with signature: - * RSA keys can be used for RSA-PSS + * Check sigalgs is known. Disallow SHA1 with TLS 1.3. Check key type is + * consistent with signature: RSA keys can be used for RSA-PSS */ - if (lu == NULL || (pkeyid != lu->sig + if (lu == NULL || (SSL_IS_TLS13(s) && lu->hash == NID_sha1) + || (pkeyid != lu->sig && (lu->sig != EVP_PKEY_RSA_PSS || pkeyid != EVP_PKEY_RSA))) { SSLerr(SSL_F_TLS12_CHECK_PEER_SIGALG, SSL_R_WRONG_SIGNATURE_TYPE); return 0; @@ -2248,8 +2249,9 @@ int tls_choose_sigalg(SSL *s, int *al) for (i = 0; i < s->cert->shared_sigalgslen; i++) { lu = s->cert->shared_sigalgs[i]; - /* Skip DSA and RSA if not PSS */ - if (lu->sig == EVP_PKEY_DSA || lu->sig == EVP_PKEY_RSA) + /* Skip SHA1, DSA and RSA if not PSS */ + if (lu->hash == NID_sha1 || lu->sig == EVP_PKEY_DSA + || lu->sig == EVP_PKEY_RSA) continue; if (ssl_md(lu->hash_idx) == NULL) continue; -- 2.25.1