#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>
#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)
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)
{
}
#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;
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)
{
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;
* (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))
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;
#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;
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;
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
(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;
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;
}
* 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;
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 */
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
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))
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))
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 */
#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)
{
n=i;
}
- i=RSA_private_decrypt((int)n,p,p,rsa,RSA_PKCS1_PADDING);
+ /* 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 */
- 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); */
-
- /* 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,
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);
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;
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)
{
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);
projects / openssl.git / blobdiff