From 3a8c7b1a08b2766a7f8a388eee14442281b4e295 Mon Sep 17 00:00:00 2001 From: Adam Langley Date: Thu, 24 Jan 2013 16:27:14 -0500 Subject: [PATCH 19/36] tls12_digests Fixes a bug with handling TLS 1.2 and digest functions for DSA and ECDSA keys. --- ssl/s3_clnt.c | 26 +++++++++++++-- ssl/ssl3.h | 11 +++++- ssl/ssl_cert.c | 20 ----------- ssl/ssl_lib.c | 35 +++++++++++-------- ssl/ssl_locl.h | 4 +-- ssl/t1_lib.c | 104 ++++++++++++++++++++------------------------------------- 6 files changed, 94 insertions(+), 106 deletions(-) diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c index c9196b3..1f3b376 100644 --- a/ssl/s3_clnt.c +++ b/ssl/s3_clnt.c @@ -1990,12 +1990,13 @@ int ssl3_get_certificate_request(SSL *s) SSLerr(SSL_F_SSL3_GET_CERTIFICATE_REQUEST,SSL_R_DATA_LENGTH_TOO_LONG); goto err; } - if ((llen & 1) || !tls1_process_sigalgs(s, p, llen)) + if (llen & 1) { ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_DECODE_ERROR); SSLerr(SSL_F_SSL3_GET_CERTIFICATE_REQUEST,SSL_R_SIGNATURE_ALGORITHMS_ERROR); goto err; } + tls1_process_sigalgs(s, p, llen); p += llen; } @@ -3017,7 +3018,28 @@ int ssl3_send_client_verify(SSL *s) { long hdatalen = 0; void *hdata; - const EVP_MD *md = s->cert->key->digest; + const EVP_MD *md; + switch (ssl_cert_type(NULL, pkey)) + { + case SSL_PKEY_RSA_ENC: + md = s->s3->digest_rsa; + break; + case SSL_PKEY_DSA_SIGN: + md = s->s3->digest_dsa; + break; + case SSL_PKEY_ECC: + md = s->s3->digest_ecdsa; + break; + default: + md = NULL; + } + if (!md) + /* Unlike with the SignatureAlgorithm extension (sent by clients), + * there are no default algorithms for the CertificateRequest message + * (sent by servers). However, now that we've sent a certificate + * for which we don't really know what hash to use for signing, the + * best we can do is try a default algorithm. */ + md = EVP_sha1(); hdatalen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata); if (hdatalen <= 0 || !tls12_get_sigandhash(p, pkey, md)) diff --git a/ssl/ssl3.h b/ssl/ssl3.h index 29098e4..3229995 100644 --- a/ssl/ssl3.h +++ b/ssl/ssl3.h @@ -550,6 +550,16 @@ typedef struct ssl3_state_st * verified Channel ID from the client: a P256 point, (x,y), where * each are big-endian values. */ unsigned char tlsext_channel_id[64]; + + /* These point to the digest function to use for signatures made with + * each type of public key. A NULL value indicates that the default + * digest should be used, which is SHA1 as of TLS 1.2. + * + * (These should be in the tmp member, but we have to put them here to + * ensure binary compatibility with earlier OpenSSL 1.0.* releases.) */ + const EVP_MD *digest_rsa; + const EVP_MD *digest_dsa; + const EVP_MD *digest_ecdsa; } SSL3_STATE; #endif @@ -700,4 +710,3 @@ typedef struct ssl3_state_st } #endif #endif - diff --git a/ssl/ssl_cert.c b/ssl/ssl_cert.c index 5123a89..bc4150b 100644 --- a/ssl/ssl_cert.c +++ b/ssl/ssl_cert.c @@ -160,21 +160,6 @@ int SSL_get_ex_data_X509_STORE_CTX_idx(void) return ssl_x509_store_ctx_idx; } -static void ssl_cert_set_default_md(CERT *cert) - { - /* Set digest values to defaults */ -#ifndef OPENSSL_NO_DSA - cert->pkeys[SSL_PKEY_DSA_SIGN].digest = EVP_sha1(); -#endif -#ifndef OPENSSL_NO_RSA - cert->pkeys[SSL_PKEY_RSA_SIGN].digest = EVP_sha1(); - cert->pkeys[SSL_PKEY_RSA_ENC].digest = EVP_sha1(); -#endif -#ifndef OPENSSL_NO_ECDSA - cert->pkeys[SSL_PKEY_ECC].digest = EVP_sha1(); -#endif - } - CERT *ssl_cert_new(void) { CERT *ret; @@ -189,7 +174,6 @@ CERT *ssl_cert_new(void) ret->key= &(ret->pkeys[SSL_PKEY_RSA_ENC]); ret->references=1; - ssl_cert_set_default_md(ret); return(ret); } @@ -322,10 +306,6 @@ CERT *ssl_cert_dup(CERT *cert) * chain is held inside SSL_CTX */ ret->references=1; - /* Set digests to defaults. NB: we don't copy existing values as they - * will be set during handshake. - */ - ssl_cert_set_default_md(ret); return(ret); diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c index 5f8b0b0..e360550 100644 --- a/ssl/ssl_lib.c +++ b/ssl/ssl_lib.c @@ -2345,32 +2345,41 @@ EVP_PKEY *ssl_get_sign_pkey(SSL *s,const SSL_CIPHER *cipher, const EVP_MD **pmd) { unsigned long alg_a; CERT *c; - int idx = -1; alg_a = cipher->algorithm_auth; c=s->cert; + /* SHA1 is the default for all signature algorithms up to TLS 1.2, + * except RSA which is handled specially in s3_srvr.c */ + if (pmd) + *pmd = EVP_sha1(); + if ((alg_a & SSL_aDSS) && - (c->pkeys[SSL_PKEY_DSA_SIGN].privatekey != NULL)) - idx = SSL_PKEY_DSA_SIGN; + (c->pkeys[SSL_PKEY_DSA_SIGN].privatekey != NULL)) + { + if (pmd && s->s3 && s->s3->digest_dsa) + *pmd = s->s3->digest_dsa; + return c->pkeys[SSL_PKEY_DSA_SIGN].privatekey; + } else if (alg_a & SSL_aRSA) { + if (pmd && s->s3 && s->s3->digest_rsa) + *pmd = s->s3->digest_rsa; if (c->pkeys[SSL_PKEY_RSA_SIGN].privatekey != NULL) - idx = SSL_PKEY_RSA_SIGN; - else if (c->pkeys[SSL_PKEY_RSA_ENC].privatekey != NULL) - idx = SSL_PKEY_RSA_ENC; + return c->pkeys[SSL_PKEY_RSA_SIGN].privatekey; + if (c->pkeys[SSL_PKEY_RSA_ENC].privatekey != NULL) + return c->pkeys[SSL_PKEY_RSA_ENC].privatekey; } else if ((alg_a & SSL_aECDSA) && (c->pkeys[SSL_PKEY_ECC].privatekey != NULL)) - idx = SSL_PKEY_ECC; - if (idx == -1) { - SSLerr(SSL_F_SSL_GET_SIGN_PKEY,ERR_R_INTERNAL_ERROR); - return(NULL); + if (pmd && s->s3 && s->s3->digest_ecdsa) + *pmd = s->s3->digest_ecdsa; + return c->pkeys[SSL_PKEY_ECC].privatekey; } - if (pmd) - *pmd = c->pkeys[idx].digest; - return c->pkeys[idx].privatekey; + + SSLerr(SSL_F_SSL_GET_SIGN_PKEY,ERR_R_INTERNAL_ERROR); + return(NULL); } void ssl_update_cache(SSL *s,int mode) diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h index 6d38f0f..3e89fcb 100644 --- a/ssl/ssl_locl.h +++ b/ssl/ssl_locl.h @@ -485,8 +485,6 @@ typedef struct cert_pkey_st { X509 *x509; EVP_PKEY *privatekey; - /* Digest to use when signing */ - const EVP_MD *digest; } CERT_PKEY; typedef struct cert_st @@ -1142,7 +1140,7 @@ int ssl_add_clienthello_renegotiate_ext(SSL *s, unsigned char *p, int *len, int ssl_parse_clienthello_renegotiate_ext(SSL *s, unsigned char *d, int len, int *al); long ssl_get_algorithm2(SSL *s); -int tls1_process_sigalgs(SSL *s, const unsigned char *data, int dsize); +void tls1_process_sigalgs(SSL *s, const unsigned char *data, int dsize); int tls12_get_req_sig_algs(SSL *s, unsigned char *p); int ssl_add_clienthello_use_srtp_ext(SSL *s, unsigned char *p, int *len, int maxlen); diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c index 26805e4..6af51a9 100644 --- a/ssl/t1_lib.c +++ b/ssl/t1_lib.c @@ -897,6 +897,13 @@ int ssl_parse_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char *d, in s->servername_done = 0; s->tlsext_status_type = -1; + + /* Reset TLS 1.2 digest functions to defaults because they don't carry + * over to a renegotiation. */ + s->s3->digest_rsa = NULL; + s->s3->digest_dsa = NULL; + s->s3->digest_ecdsa = NULL; + #ifndef OPENSSL_NO_NEXTPROTONEG s->s3->next_proto_neg_seen = 0; #endif @@ -1198,11 +1205,7 @@ int ssl_parse_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char *d, in *al = SSL_AD_DECODE_ERROR; return 0; } - if (!tls1_process_sigalgs(s, data, dsize)) - { - *al = SSL_AD_DECODE_ERROR; - return 0; - } + tls1_process_sigalgs(s, data, dsize); } else if (type == TLSEXT_TYPE_status_request && s->version != DTLS1_VERSION && s->ctx->tlsext_status_cb) @@ -2354,18 +2357,6 @@ static int tls12_find_id(int nid, tls12_lookup *table, size_t tlen) } return -1; } -#if 0 -static int tls12_find_nid(int id, tls12_lookup *table, size_t tlen) - { - size_t i; - for (i = 0; i < tlen; i++) - { - if (table[i].id == id) - return table[i].nid; - } - return -1; - } -#endif int tls12_get_sigandhash(unsigned char *p, const EVP_PKEY *pk, const EVP_MD *md) { @@ -2384,6 +2375,8 @@ int tls12_get_sigandhash(unsigned char *p, const EVP_PKEY *pk, const EVP_MD *md) return 1; } +/* tls12_get_sigid returns the TLS 1.2 SignatureAlgorithm value corresponding + * to the given public key, or -1 if not known. */ int tls12_get_sigid(const EVP_PKEY *pk) { return tls12_find_id(pk->type, tls12_sig, @@ -2403,47 +2396,49 @@ const EVP_MD *tls12_get_hash(unsigned char hash_alg) return EVP_md5(); #endif #ifndef OPENSSL_NO_SHA - case TLSEXT_hash_sha1: + case TLSEXT_hash_sha1: return EVP_sha1(); #endif #ifndef OPENSSL_NO_SHA256 - case TLSEXT_hash_sha224: + case TLSEXT_hash_sha224: return EVP_sha224(); - case TLSEXT_hash_sha256: + case TLSEXT_hash_sha256: return EVP_sha256(); #endif #ifndef OPENSSL_NO_SHA512 - case TLSEXT_hash_sha384: + case TLSEXT_hash_sha384: return EVP_sha384(); - case TLSEXT_hash_sha512: + case TLSEXT_hash_sha512: return EVP_sha512(); #endif - default: + default: return NULL; } } -/* Set preferred digest for each key type */ - -int tls1_process_sigalgs(SSL *s, const unsigned char *data, int dsize) +/* tls1_process_sigalgs processes a signature_algorithms extension and sets the + * digest functions accordingly for each key type. + * + * See RFC 5246, section 7.4.1.4.1. + * + * data: points to the content of the extension, not including type and length + * headers. + * dsize: the number of bytes of |data|. Must be even. + */ +void tls1_process_sigalgs(SSL *s, const unsigned char *data, int dsize) { - int i, idx; - const EVP_MD *md; - CERT *c = s->cert; + int i; + const EVP_MD *md, **digest_ptr; /* Extension ignored for TLS versions below 1.2 */ if (TLS1_get_version(s) < TLS1_2_VERSION) - return 1; - /* Should never happen */ - if (!c) - return 0; + return; - c->pkeys[SSL_PKEY_DSA_SIGN].digest = NULL; - c->pkeys[SSL_PKEY_RSA_SIGN].digest = NULL; - c->pkeys[SSL_PKEY_RSA_ENC].digest = NULL; - c->pkeys[SSL_PKEY_ECC].digest = NULL; + s->s3->digest_rsa = NULL; + s->s3->digest_dsa = NULL; + s->s3->digest_ecdsa = NULL; for (i = 0; i < dsize; i += 2) { @@ -2453,56 +2448,31 @@ int tls1_process_sigalgs(SSL *s, const unsigned char *data, int dsize) { #ifndef OPENSSL_NO_RSA case TLSEXT_signature_rsa: - idx = SSL_PKEY_RSA_SIGN; + digest_ptr = &s->s3->digest_rsa; break; #endif #ifndef OPENSSL_NO_DSA case TLSEXT_signature_dsa: - idx = SSL_PKEY_DSA_SIGN; + digest_ptr = &s->s3->digest_dsa; break; #endif #ifndef OPENSSL_NO_ECDSA case TLSEXT_signature_ecdsa: - idx = SSL_PKEY_ECC; + digest_ptr = &s->s3->digest_ecdsa; break; #endif default: continue; } - if (c->pkeys[idx].digest == NULL) + if (*digest_ptr == NULL) { md = tls12_get_hash(hash_alg); if (md) - { - c->pkeys[idx].digest = md; - if (idx == SSL_PKEY_RSA_SIGN) - c->pkeys[SSL_PKEY_RSA_ENC].digest = md; - } + *digest_ptr = md; } } - - - /* Set any remaining keys to default values. NOTE: if alg is not - * supported it stays as NULL. - */ -#ifndef OPENSSL_NO_DSA - if (!c->pkeys[SSL_PKEY_DSA_SIGN].digest) - c->pkeys[SSL_PKEY_DSA_SIGN].digest = EVP_sha1(); -#endif -#ifndef OPENSSL_NO_RSA - if (!c->pkeys[SSL_PKEY_RSA_SIGN].digest) - { - c->pkeys[SSL_PKEY_RSA_SIGN].digest = EVP_sha1(); - c->pkeys[SSL_PKEY_RSA_ENC].digest = EVP_sha1(); - } -#endif -#ifndef OPENSSL_NO_ECDSA - if (!c->pkeys[SSL_PKEY_ECC].digest) - c->pkeys[SSL_PKEY_ECC].digest = EVP_sha1(); -#endif - return 1; } #endif -- 1.8.2.1