diff options
Diffstat (limited to 'crypto/openssl/ssl/s3_srvr.c')
| -rw-r--r-- | crypto/openssl/ssl/s3_srvr.c | 267 |
1 files changed, 169 insertions, 98 deletions
diff --git a/crypto/openssl/ssl/s3_srvr.c b/crypto/openssl/ssl/s3_srvr.c index 5cb1a4b17cb5..fadca74ec269 100644 --- a/crypto/openssl/ssl/s3_srvr.c +++ b/crypto/openssl/ssl/s3_srvr.c @@ -154,6 +154,7 @@ #include <stdio.h> #include "ssl_locl.h" #include "kssl_lcl.h" +#include "../crypto/constant_time_locl.h" #include <openssl/buffer.h> #include <openssl/rand.h> #include <openssl/objects.h> @@ -169,6 +170,7 @@ #endif #include <openssl/md5.h> +#ifndef OPENSSL_NO_SSL3_METHOD static const SSL_METHOD *ssl3_get_server_method(int ver); static const SSL_METHOD *ssl3_get_server_method(int ver) @@ -179,6 +181,12 @@ static const SSL_METHOD *ssl3_get_server_method(int ver) return(NULL); } +IMPLEMENT_ssl3_meth_func(SSLv3_server_method, + ssl3_accept, + ssl_undefined_function, + ssl3_get_server_method) +#endif + #ifndef OPENSSL_NO_SRP static int ssl_check_srp_ext_ClientHello(SSL *s, int *al) { @@ -205,11 +213,6 @@ static int ssl_check_srp_ext_ClientHello(SSL *s, int *al) } #endif -IMPLEMENT_ssl3_meth_func(SSLv3_server_method, - ssl3_accept, - ssl_undefined_function, - ssl3_get_server_method) - int ssl3_accept(SSL *s) { BUF_MEM *buf; @@ -283,6 +286,7 @@ int ssl3_accept(SSL *s) } if (!BUF_MEM_grow(buf,SSL3_RT_MAX_PLAIN_LENGTH)) { + BUF_MEM_free(buf); ret= -1; goto end; } @@ -297,6 +301,9 @@ int ssl3_accept(SSL *s) s->init_num=0; s->s3->flags &= ~SSL3_FLAGS_SGC_RESTART_DONE; + s->s3->flags &= ~SSL3_FLAGS_CCS_OK; + /* Should have been reset by ssl3_get_finished, too. */ + s->s3->change_cipher_spec = 0; if (s->state != SSL_ST_RENEGOTIATE) { @@ -410,9 +417,8 @@ int ssl3_accept(SSL *s) case SSL3_ST_SW_CERT_B: /* Check if it is anon DH or anon ECDH, */ /* normal PSK or KRB5 or SRP */ - if (!(s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL) - && !(s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK) - && !(s->s3->tmp.new_cipher->algorithm_auth & SSL_aKRB5)) + if (!(s->s3->tmp.new_cipher->algorithm_auth & (SSL_aNULL|SSL_aKRB5|SSL_aSRP)) + && !(s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK)) { ret=ssl3_send_server_certificate(s); if (ret <= 0) goto end; @@ -506,7 +512,9 @@ int ssl3_accept(SSL *s) * (against the specs, but s3_clnt.c accepts this for SSL 3) */ !(s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) || /* never request cert in Kerberos ciphersuites */ - (s->s3->tmp.new_cipher->algorithm_auth & SSL_aKRB5) + (s->s3->tmp.new_cipher->algorithm_auth & SSL_aKRB5) || + /* don't request certificate for SRP auth */ + (s->s3->tmp.new_cipher->algorithm_auth & SSL_aSRP) /* With normal PSK Certificates and * Certificate Requests are omitted */ || (s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK)) @@ -663,8 +671,14 @@ int ssl3_accept(SSL *s) case SSL3_ST_SR_CERT_VRFY_A: case SSL3_ST_SR_CERT_VRFY_B: - - s->s3->flags |= SSL3_FLAGS_CCS_OK; + /* + * This *should* be the first time we enable CCS, but be + * extra careful about surrounding code changes. We need + * to set this here because we don't know if we're + * expecting a CertificateVerify or not. + */ + if (!s->s3->change_cipher_spec) + s->s3->flags |= SSL3_FLAGS_CCS_OK; /* we should decide if we expected this one */ ret=ssl3_get_cert_verify(s); if (ret <= 0) goto end; @@ -683,6 +697,19 @@ int ssl3_accept(SSL *s) #if !defined(OPENSSL_NO_TLSEXT) && !defined(OPENSSL_NO_NEXTPROTONEG) case SSL3_ST_SR_NEXT_PROTO_A: case SSL3_ST_SR_NEXT_PROTO_B: + /* + * Enable CCS for resumed handshakes with NPN. + * In a full handshake with NPN, we end up here through + * SSL3_ST_SR_CERT_VRFY_B, where SSL3_FLAGS_CCS_OK was + * already set. Receiving a CCS clears the flag, so make + * sure not to re-enable it to ban duplicates. + * s->s3->change_cipher_spec is set when a CCS is + * processed in s3_pkt.c, and remains set until + * the client's Finished message is read. + */ + if (!s->s3->change_cipher_spec) + s->s3->flags |= SSL3_FLAGS_CCS_OK; + ret=ssl3_get_next_proto(s); if (ret <= 0) goto end; s->init_num = 0; @@ -692,7 +719,18 @@ int ssl3_accept(SSL *s) case SSL3_ST_SR_FINISHED_A: case SSL3_ST_SR_FINISHED_B: - s->s3->flags |= SSL3_FLAGS_CCS_OK; + /* + * Enable CCS for resumed handshakes without NPN. + * In a full handshake, we end up here through + * SSL3_ST_SR_CERT_VRFY_B, where SSL3_FLAGS_CCS_OK was + * already set. Receiving a CCS clears the flag, so make + * sure not to re-enable it to ban duplicates. + * s->s3->change_cipher_spec is set when a CCS is + * processed in s3_pkt.c, and remains set until + * the client's Finished message is read. + */ + if (!s->s3->change_cipher_spec) + s->s3->flags |= SSL3_FLAGS_CCS_OK; ret=ssl3_get_finished(s,SSL3_ST_SR_FINISHED_A, SSL3_ST_SR_FINISHED_B); if (ret <= 0) goto end; @@ -764,7 +802,6 @@ int ssl3_accept(SSL *s) #else if (s->s3->next_proto_neg_seen) { - s->s3->flags |= SSL3_FLAGS_CCS_OK; s->s3->tmp.next_state=SSL3_ST_SR_NEXT_PROTO_A; } else @@ -954,7 +991,8 @@ int ssl3_get_client_hello(SSL *s) (s->version != DTLS1_VERSION && s->client_version < s->version)) { SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_WRONG_VERSION_NUMBER); - if ((s->client_version>>8) == SSL3_VERSION_MAJOR) + if ((s->client_version>>8) == SSL3_VERSION_MAJOR && + !s->enc_write_ctx && !s->write_hash) { /* similar to ssl3_get_record, send alert using remote version number */ s->version = s->client_version; @@ -1005,7 +1043,16 @@ int ssl3_get_client_hello(SSL *s) else { i=ssl_get_prev_session(s, p, j, d + n); - if (i == 1) + /* + * Only resume if the session's version matches the negotiated + * version. + * RFC 5246 does not provide much useful advice on resumption + * with a different protocol version. It doesn't forbid it but + * the sanity of such behaviour would be questionable. + * In practice, clients do not accept a version mismatch and + * will abort the handshake with an error. + */ + if (i == 1 && s->version == s->session->ssl_version) { /* previous session */ s->hit=1; } @@ -1100,14 +1147,15 @@ int ssl3_get_client_hello(SSL *s) id=s->session->cipher->id; #ifdef CIPHER_DEBUG - printf("client sent %d ciphers\n",sk_num(ciphers)); + fprintf(stderr,"client sent %d ciphers\n",sk_SSL_CIPHER_num(ciphers)); #endif for (i=0; i<sk_SSL_CIPHER_num(ciphers); i++) { c=sk_SSL_CIPHER_value(ciphers,i); #ifdef CIPHER_DEBUG - printf("client [%2d of %2d]:%s\n", - i,sk_num(ciphers),SSL_CIPHER_get_name(c)); + fprintf(stderr,"client [%2d of %2d]:%s\n", + i,sk_SSL_CIPHER_num(ciphers), + SSL_CIPHER_get_name(c)); #endif if (c->id == id) { @@ -1189,12 +1237,9 @@ int ssl3_get_client_hello(SSL *s) * server_random before calling tls_session_secret_cb in order to allow * SessionTicket processing to use it in key derivation. */ { - unsigned long Time; unsigned char *pos; - Time=(unsigned long)time(NULL); /* Time */ pos=s->s3->server_random; - l2n(Time,pos); - if (RAND_pseudo_bytes(pos,SSL3_RANDOM_SIZE-4) <= 0) + if (ssl_fill_hello_random(s, 1, pos, SSL3_RANDOM_SIZE) <= 0) { al=SSL_AD_INTERNAL_ERROR; goto f_err; @@ -1431,19 +1476,13 @@ int ssl3_send_server_hello(SSL *s) unsigned char *p,*d; int i,sl; unsigned long l; -#ifdef OPENSSL_NO_TLSEXT - unsigned long Time; -#endif if (s->state == SSL3_ST_SW_SRVR_HELLO_A) { buf=(unsigned char *)s->init_buf->data; #ifdef OPENSSL_NO_TLSEXT p=s->s3->server_random; - /* Generate server_random if it was not needed previously */ - Time=(unsigned long)time(NULL); /* Time */ - l2n(Time,p); - if (RAND_pseudo_bytes(p,SSL3_RANDOM_SIZE-4) <= 0) + if (ssl_fill_hello_random(s, 1, p, SSL3_RANDOM_SIZE) <= 0) return -1; #endif /* Do the message type and length last */ @@ -1834,7 +1873,7 @@ int ssl3_send_server_key_exchange(SSL *s) SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,SSL_R_UNKNOWN_KEY_EXCHANGE_TYPE); goto f_err; } - for (i=0; r[i] != NULL && i<4; i++) + for (i=0; i < 4 && r[i] != NULL; i++) { nr[i]=BN_num_bytes(r[i]); #ifndef OPENSSL_NO_SRP @@ -1845,7 +1884,7 @@ int ssl3_send_server_key_exchange(SSL *s) n+=2+nr[i]; } - if (!(s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL) + if (!(s->s3->tmp.new_cipher->algorithm_auth & (SSL_aNULL|SSL_aSRP)) && !(s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK)) { if ((pkey=ssl_get_sign_pkey(s,s->s3->tmp.new_cipher,&md)) @@ -1870,7 +1909,7 @@ int ssl3_send_server_key_exchange(SSL *s) d=(unsigned char *)s->init_buf->data; p= &(d[4]); - for (i=0; r[i] != NULL && i<4; i++) + for (i=0; i < 4 && r[i] != NULL; i++) { #ifndef OPENSSL_NO_SRP if ((i == 2) && (type & SSL_kSRP)) @@ -2101,6 +2140,11 @@ int ssl3_send_certificate_request(SSL *s) s->init_num=n+4; s->init_off=0; #ifdef NETSCAPE_HANG_BUG + if (!BUF_MEM_grow_clean(buf, s->init_num + 4)) + { + SSLerr(SSL_F_SSL3_SEND_CERTIFICATE_REQUEST,ERR_R_BUF_LIB); + goto err; + } p=(unsigned char *)s->init_buf->data + s->init_num; /* do the header */ @@ -2160,6 +2204,11 @@ int ssl3_get_client_key_exchange(SSL *s) #ifndef OPENSSL_NO_RSA if (alg_k & SSL_kRSA) { + unsigned char rand_premaster_secret[SSL_MAX_MASTER_KEY_LENGTH]; + int decrypt_len; + unsigned char decrypt_good, version_good; + size_t j; + /* FIX THIS UP EAY EAY EAY EAY */ if (s->s3->tmp.use_rsa_tmp) { @@ -2197,8 +2246,9 @@ int ssl3_get_client_key_exchange(SSL *s) { if (!(s->options & SSL_OP_TLS_D5_BUG)) { + al = SSL_AD_DECODE_ERROR; SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,SSL_R_TLS_RSA_ENCRYPTED_VALUE_LENGTH_IS_WRONG); - goto err; + goto f_err; } else p-=2; @@ -2207,59 +2257,84 @@ int ssl3_get_client_key_exchange(SSL *s) n=i; } - i=RSA_private_decrypt((int)n,p,p,rsa,RSA_PKCS1_PADDING); - - al = -1; - - if (i != SSL_MAX_MASTER_KEY_LENGTH) + /* + * Reject overly short RSA ciphertext because we want to be sure + * that the buffer size makes it safe to iterate over the entire + * size of a premaster secret (SSL_MAX_MASTER_KEY_LENGTH). The + * actual expected size is larger due to RSA padding, but the + * bound is sufficient to be safe. + */ + if (n < SSL_MAX_MASTER_KEY_LENGTH) { - al=SSL_AD_DECODE_ERROR; - /* SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,SSL_R_BAD_RSA_DECRYPT); */ + al = SSL_AD_DECRYPT_ERROR; + SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, SSL_R_TLS_RSA_ENCRYPTED_VALUE_LENGTH_IS_WRONG); + goto f_err; } - if ((al == -1) && !((p[0] == (s->client_version>>8)) && (p[1] == (s->client_version & 0xff)))) - { - /* The premaster secret must contain the same version number as the - * ClientHello to detect version rollback attacks (strangely, the - * protocol does not offer such protection for DH ciphersuites). - * However, buggy clients exist that send the negotiated protocol - * version instead if the server does not support the requested - * protocol version. - * If SSL_OP_TLS_ROLLBACK_BUG is set, tolerate such clients. */ - if (!((s->options & SSL_OP_TLS_ROLLBACK_BUG) && - (p[0] == (s->version>>8)) && (p[1] == (s->version & 0xff)))) - { - al=SSL_AD_DECODE_ERROR; - /* SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,SSL_R_BAD_PROTOCOL_VERSION_NUMBER); */ - - /* The Klima-Pokorny-Rosa extension of Bleichenbacher's attack - * (http://eprint.iacr.org/2003/052/) exploits the version - * number check as a "bad version oracle" -- an alert would - * reveal that the plaintext corresponding to some ciphertext - * made up by the adversary is properly formatted except - * that the version number is wrong. To avoid such attacks, - * we should treat this just like any other decryption error. */ - } - } + /* We must not leak whether a decryption failure occurs because + * of Bleichenbacher's attack on PKCS #1 v1.5 RSA padding (see + * RFC 2246, section 7.4.7.1). The code follows that advice of + * the TLS RFC and generates a random premaster secret for the + * case that the decrypt fails. See + * https://tools.ietf.org/html/rfc5246#section-7.4.7.1 */ - if (al != -1) + /* should be RAND_bytes, but we cannot work around a failure. */ + if (RAND_pseudo_bytes(rand_premaster_secret, + sizeof(rand_premaster_secret)) <= 0) + goto err; + decrypt_len = RSA_private_decrypt((int)n,p,p,rsa,RSA_PKCS1_PADDING); + ERR_clear_error(); + + /* decrypt_len should be SSL_MAX_MASTER_KEY_LENGTH. + * decrypt_good will be 0xff if so and zero otherwise. */ + decrypt_good = constant_time_eq_int_8(decrypt_len, SSL_MAX_MASTER_KEY_LENGTH); + + /* If the version in the decrypted pre-master secret is correct + * then version_good will be 0xff, otherwise it'll be zero. + * The Klima-Pokorny-Rosa extension of Bleichenbacher's attack + * (http://eprint.iacr.org/2003/052/) exploits the version + * number check as a "bad version oracle". Thus version checks + * are done in constant time and are treated like any other + * decryption error. */ + version_good = constant_time_eq_8(p[0], (unsigned)(s->client_version>>8)); + version_good &= constant_time_eq_8(p[1], (unsigned)(s->client_version&0xff)); + + /* The premaster secret must contain the same version number as + * the ClientHello to detect version rollback attacks + * (strangely, the protocol does not offer such protection for + * DH ciphersuites). However, buggy clients exist that send the + * negotiated protocol version instead if the server does not + * support the requested protocol version. If + * SSL_OP_TLS_ROLLBACK_BUG is set, tolerate such clients. */ + if (s->options & SSL_OP_TLS_ROLLBACK_BUG) + { + unsigned char workaround_good; + workaround_good = constant_time_eq_8(p[0], (unsigned)(s->version>>8)); + workaround_good &= constant_time_eq_8(p[1], (unsigned)(s->version&0xff)); + version_good |= workaround_good; + } + + /* Both decryption and version must be good for decrypt_good + * to remain non-zero (0xff). */ + decrypt_good &= version_good; + + /* + * Now copy rand_premaster_secret over from p using + * decrypt_good_mask. If decryption failed, then p does not + * contain valid plaintext, however, a check above guarantees + * it is still sufficiently large to read from. + */ + for (j = 0; j < sizeof(rand_premaster_secret); j++) { - /* Some decryption failure -- use random value instead as countermeasure - * against Bleichenbacher's attack on PKCS #1 v1.5 RSA padding - * (see RFC 2246, section 7.4.7.1). */ - ERR_clear_error(); - i = SSL_MAX_MASTER_KEY_LENGTH; - p[0] = s->client_version >> 8; - p[1] = s->client_version & 0xff; - if (RAND_pseudo_bytes(p+2, i-2) <= 0) /* should be RAND_bytes, but we cannot work around a failure */ - goto err; + p[j] = constant_time_select_8(decrypt_good, p[j], + rand_premaster_secret[j]); } - + s->session->master_key_length= s->method->ssl3_enc->generate_master_secret(s, s->session->master_key, - p,i); - OPENSSL_cleanse(p,i); + p,sizeof(rand_premaster_secret)); + OPENSSL_cleanse(p,sizeof(rand_premaster_secret)); } else #endif @@ -2401,10 +2476,10 @@ int ssl3_get_client_key_exchange(SSL *s) &kssl_err)) != 0) { #ifdef KSSL_DEBUG - printf("kssl_sget_tkt rtn %d [%d]\n", + fprintf(stderr,"kssl_sget_tkt rtn %d [%d]\n", krb5rc, kssl_err.reason); if (kssl_err.text) - printf("kssl_err text= %s\n", kssl_err.text); + fprintf(stderr,"kssl_err text= %s\n", kssl_err.text); #endif /* KSSL_DEBUG */ SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, kssl_err.reason); @@ -2418,10 +2493,10 @@ int ssl3_get_client_key_exchange(SSL *s) &authtime, &kssl_err)) != 0) { #ifdef KSSL_DEBUG - printf("kssl_check_authent rtn %d [%d]\n", + fprintf(stderr,"kssl_check_authent rtn %d [%d]\n", krb5rc, kssl_err.reason); if (kssl_err.text) - printf("kssl_err text= %s\n", kssl_err.text); + fprintf(stderr,"kssl_err text= %s\n", kssl_err.text); #endif /* KSSL_DEBUG */ SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, kssl_err.reason); @@ -2824,6 +2899,8 @@ int ssl3_get_client_key_exchange(SSL *s) unsigned char premaster_secret[32], *start; size_t outlen=32, inlen; unsigned long alg_a; + int Ttag, Tclass; + long Tlen; /* Get our certificate private key*/ alg_a = s->s3->tmp.new_cipher->algorithm_auth; @@ -2845,26 +2922,15 @@ int ssl3_get_client_key_exchange(SSL *s) ERR_clear_error(); } /* Decrypt session key */ - if ((*p!=( V_ASN1_SEQUENCE| V_ASN1_CONSTRUCTED))) - { - SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,SSL_R_DECRYPTION_FAILED); - goto gerr; - } - if (p[1] == 0x81) - { - start = p+3; - inlen = p[2]; - } - else if (p[1] < 0x80) - { - start = p+2; - inlen = p[1]; - } - else + if (ASN1_get_object((const unsigned char **)&p, &Tlen, &Ttag, &Tclass, n) != V_ASN1_CONSTRUCTED || + Ttag != V_ASN1_SEQUENCE || + Tclass != V_ASN1_UNIVERSAL) { SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,SSL_R_DECRYPTION_FAILED); goto gerr; } + start = p; + inlen = Tlen; if (EVP_PKEY_decrypt(pkey_ctx,premaster_secret,&outlen,start,inlen) <=0) { @@ -2928,7 +2994,7 @@ int ssl3_get_cert_verify(SSL *s) SSL3_ST_SR_CERT_VRFY_A, SSL3_ST_SR_CERT_VRFY_B, -1, - 516, /* Enough for 4096 bit RSA key with TLS v1.2 */ + SSL3_RT_MAX_PLAIN_LENGTH, &ok); if (!ok) return((int)n); @@ -3352,6 +3418,11 @@ int ssl3_send_server_certificate(SSL *s) } l=ssl3_output_cert_chain(s,x); + if (!l) + { + SSLerr(SSL_F_SSL3_SEND_SERVER_CERTIFICATE,ERR_R_INTERNAL_ERROR); + return(0); + } s->state=SSL3_ST_SW_CERT_B; s->init_num=(int)l; s->init_off=0; |