X-Git-Url: https://git.openssl.org/?a=blobdiff_plain;f=ssl%2Fs3_srvr.c;h=3bf6cfec52a8c11357095e1adc73d82802c799b0;hb=0b3c13092ca47b43c9af85ea88bac3e23a2feb6f;hp=8d0e54315f680dfa913356744ccd902a8d20a4f0;hpb=aa10982c49c941799b4229cc9b081dcc738f6ee8;p=openssl.git diff --git a/ssl/s3_srvr.c b/ssl/s3_srvr.c index 8d0e54315f..3bf6cfec52 100644 --- a/ssl/s3_srvr.c +++ b/ssl/s3_srvr.c @@ -154,6 +154,7 @@ #include #include "ssl_locl.h" #include "kssl_lcl.h" +#include "../crypto/constant_time_locl.h" #include #include #include @@ -169,6 +170,7 @@ #endif #include +#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; @@ -298,6 +301,9 @@ int ssl3_accept(SSL *s) s->init_num=0; s->s3->flags &= ~SSL3_FLAGS_SGC_RESTART_DONE; s->s3->flags &= ~TLS1_FLAGS_SKIP_CERT_VERIFY; + 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) { @@ -402,32 +408,16 @@ int ssl3_accept(SSL *s) s->state=SSL3_ST_SW_CHANGE_A; #endif else -#ifndef OPENSSL_NO_TLSEXT - s->state = SSL3_ST_SW_SUPPLEMENTAL_DATA_A; -#else - s->state = SSL3_ST_SW_CERT_A; -#endif - s->init_num = 0; - break; - -#ifndef OPENSSL_NO_TLSEXT - case SSL3_ST_SW_SUPPLEMENTAL_DATA_A: - case SSL3_ST_SW_SUPPLEMENTAL_DATA_B: - ret = tls1_send_server_supplemental_data(s, &skip); - if (ret <= 0) goto end; - - s->state = SSL3_ST_SW_CERT_A; + s->state = SSL3_ST_SW_CERT_A; s->init_num = 0; break; -#endif case SSL3_ST_SW_CERT_A: 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; @@ -530,7 +520,9 @@ 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)) @@ -589,16 +581,7 @@ int ssl3_accept(SSL *s) s->state=s->s3->tmp.next_state; break; -#ifndef OPENSSL_NO_TLSEXT - case SSL3_ST_SR_SUPPLEMENTAL_DATA_A: - case SSL3_ST_SR_SUPPLEMENTAL_DATA_B: - ret=tls1_get_client_supplemental_data(s); - if (ret <= 0) goto end; - s->s3->tmp.next_state=SSL3_ST_SR_CERT_A; - s->state=SSL3_ST_SW_FLUSH; - s->init_num=0; - break; -#endif + case SSL3_ST_SR_CERT_A: case SSL3_ST_SR_CERT_B: /* Check for second client hello (MS SGC) */ @@ -607,10 +590,6 @@ int ssl3_accept(SSL *s) goto end; if (ret == 2) s->state = SSL3_ST_SR_CLNT_HELLO_C; -#ifndef OPENSSL_NO_TLSEXT - else if (ret == 3) - s->state = SSL3_ST_SR_SUPPLEMENTAL_DATA_A; -#endif else { if (s->s3->tmp.cert_request) { @@ -700,7 +679,14 @@ int ssl3_accept(SSL *s) case SSL3_ST_SR_CERT_VRFY_A: case SSL3_ST_SR_CERT_VRFY_B: - + /* + * 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; @@ -719,6 +705,19 @@ 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; @@ -728,6 +727,18 @@ int ssl3_accept(SSL *s) case SSL3_ST_SR_FINISHED_A: case SSL3_ST_SR_FINISHED_B: + /* + * 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; @@ -798,7 +809,9 @@ int ssl3_accept(SSL *s) s->s3->tmp.next_state=SSL3_ST_SR_FINISHED_A; #else if (s->s3->next_proto_neg_seen) + { s->s3->tmp.next_state=SSL3_ST_SR_NEXT_PROTO_A; + } else s->s3->tmp.next_state=SSL3_ST_SR_FINISHED_A; #endif @@ -901,10 +914,6 @@ int ssl3_check_client_hello(SSL *s) &ok); if (!ok) return((int)n); s->s3->tmp.reuse_message = 1; -#ifndef OPENSSL_NO_TLSEXT - if (s->s3->tmp.message_type == SSL3_MT_SUPPLEMENTAL_DATA) - return 3; -#endif if (s->s3->tmp.message_type == SSL3_MT_CLIENT_HELLO) { /* We only allow the client to restart the handshake once per @@ -1038,7 +1047,16 @@ 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; } @@ -1396,6 +1414,11 @@ int ssl3_get_client_hello(SSL *s) goto f_err; } ciphers=NULL; + if (!tls1_set_server_sigalgs(s)) + { + SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_CLIENTHELLO_TLSEXT); + goto err; + } /* Let cert callback update server certificates if required */ retry_cert: if (s->cert->cert_cb) @@ -1902,7 +1925,7 @@ 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)) @@ -2146,6 +2169,11 @@ int ssl3_send_certificate_request(SSL *s) #ifdef NETSCAPE_HANG_BUG if (!SSL_IS_DTLS(s)) { + 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 */ *(p++)=SSL3_MT_SERVER_DONE; @@ -2205,6 +2233,10 @@ 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; + /* FIX THIS UP EAY EAY EAY EAY */ if (s->s3->tmp.use_rsa_tmp) { @@ -2252,54 +2284,61 @@ 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) - { - al=SSL_AD_DECODE_ERROR; - /* SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,SSL_R_BAD_RSA_DECRYPT); */ - } - - 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); */ + /* 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 */ - /* 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. */ - } + /* 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 p using + * decrypt_good_mask. */ + for (i = 0; i < (int) sizeof(rand_premaster_secret); i++) + { + p[i] = constant_time_select_8(decrypt_good, p[i], + rand_premaster_secret[i]); } - if (al != -1) - { - /* 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; - } - s->session->master_key_length= s->method->ssl3_enc->generate_master_secret(s, s->session->master_key, @@ -2869,6 +2908,13 @@ int ssl3_get_client_key_exchange(SSL *s) SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,ERR_R_BN_LIB); goto err; } + if (BN_ucmp(s->srp_ctx.A, s->srp_ctx.N) >= 0 + || BN_is_zero(s->srp_ctx.A)) + { + al=SSL_AD_ILLEGAL_PARAMETER; + SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,SSL_R_BAD_SRP_PARAMETERS); + goto f_err; + } if (s->session->srp_username != NULL) OPENSSL_free(s->session->srp_username); s->session->srp_username = BUF_strdup(s->srp_ctx.login); @@ -2897,6 +2943,8 @@ 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; @@ -2918,26 +2966,15 @@ 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) { @@ -3001,7 +3038,7 @@ 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); @@ -3652,156 +3689,4 @@ int ssl3_get_next_proto(SSL *s) } # endif -int tls1_send_server_supplemental_data(SSL *s, int *skip) - { - int al = 0; - if (s->ctx->srv_supp_data_records_count) - { - unsigned char *p = NULL; - unsigned char *size_loc = NULL; - srv_supp_data_record *record = NULL; - size_t length = 0; - size_t i = 0; - - for (i = 0; i < s->ctx->srv_supp_data_records_count; i++) - { - const unsigned char *out = NULL; - unsigned short outlen = 0; - int cb_retval = 0; - record = &s->ctx->srv_supp_data_records[i]; - - /* NULL callback or -1 omits supp data entry */ - if (!record->fn1) - continue; - cb_retval = record->fn1(s, record->supp_data_type, - &out, &outlen, &al, record->arg); - if (cb_retval == -1) - continue; /* skip this supp data entry */ - if (cb_retval == 0) - { - SSLerr(SSL_F_TLS1_SEND_SERVER_SUPPLEMENTAL_DATA,ERR_R_BUF_LIB); - goto f_err; - } - if (outlen == 0 || TLSEXT_MAXLEN_supplemental_data < outlen + 4 + length) - { - SSLerr(SSL_F_TLS1_SEND_SERVER_SUPPLEMENTAL_DATA,ERR_R_BUF_LIB); - return 0; - } - /* write supp data entry... - * if first entry, write handshake message type - * jump back to write length at end */ - if (length == 0) - { - /* 1 byte message type + 3 bytes for - * message length */ - if (!BUF_MEM_grow_clean(s->init_buf, 4)) - { - SSLerr(SSL_F_TLS1_SEND_SERVER_SUPPLEMENTAL_DATA,ERR_R_BUF_LIB); - return 0; - } - p = (unsigned char *)s->init_buf->data; - *(p++) = SSL3_MT_SUPPLEMENTAL_DATA; - /* hold on to length field to update later */ - size_loc = p; - /* skip over handshake length field (3 - * bytes) and supp_data length field - * (3 bytes) */ - p += 3 + 3; - length += 1 +3 +3; - } - /* 2 byte supp data type + 2 byte length + outlen */ - if (!BUF_MEM_grow(s->init_buf, outlen + 4)) - { - SSLerr(SSL_F_TLS1_SEND_SERVER_SUPPLEMENTAL_DATA,ERR_R_BUF_LIB); - return 0; - } - s2n(record->supp_data_type, p); - s2n(outlen, p); - memcpy(p, out, outlen); - /* update length to supp data type (2 bytes) + - * supp data length (2 bytes) + supp data */ - length += (outlen + 4); - p += outlen; - } - if (length > 0) - { - /* write handshake length */ - l2n3(length - 4, size_loc); - /* supp_data length */ - l2n3(length - 7, size_loc); - s->state = SSL3_ST_SW_SUPPLEMENTAL_DATA_B; - s->init_num = length; - s->init_off = 0; - - return ssl3_do_write(s, SSL3_RT_HANDSHAKE); - } - } - - /* no supp data message sent */ - *skip = 1; - s->init_num = 0; - s->init_off = 0; - return 1; -f_err: - ssl3_send_alert(s,SSL3_AL_FATAL,al); - return 0; - } - -int tls1_get_client_supplemental_data(SSL *s) - { - int al = 0; - int cb_retval = 0; - int ok; - long n; - const unsigned char *p, *d; - unsigned short supp_data_entry_type = 0; - unsigned short supp_data_entry_len = 0; - unsigned long supp_data_len = 0; - size_t i = 0; - - n=s->method->ssl_get_message(s, - SSL3_ST_SR_SUPPLEMENTAL_DATA_A, - SSL3_ST_SR_SUPPLEMENTAL_DATA_B, - SSL3_MT_SUPPLEMENTAL_DATA, - /* use default limit */ - TLSEXT_MAXLEN_supplemental_data, - &ok); - - if (!ok) return((int)n); - - p = (unsigned char *)s->init_msg; - d = p; - - /* The message cannot be empty */ - if (n < 3) - { - al = SSL_AD_DECODE_ERROR; - SSLerr(SSL_F_TLS1_GET_CLIENT_SUPPLEMENTAL_DATA,SSL_R_LENGTH_MISMATCH); - goto f_err; - } - n2l3(p, supp_data_len); - while (pctx->srv_supp_data_records_count; i++) - { - if (s->ctx->srv_supp_data_records[i].supp_data_type == supp_data_entry_type && s->ctx->srv_supp_data_records[i].fn2) - { - cb_retval = s->ctx->srv_supp_data_records[i].fn2(s, supp_data_entry_type, p, supp_data_entry_len, &al, s->ctx->srv_supp_data_records[i].arg); - if (cb_retval == 0) - { - SSLerr(SSL_F_TLS1_GET_CLIENT_SUPPLEMENTAL_DATA, ERR_R_SSL_LIB); - goto f_err; - } - } - } - p+=supp_data_entry_len; - } - return 1; -f_err: - ssl3_send_alert(s,SSL3_AL_FATAL,al); - return -1; - } #endif