Convert tls_construct_client_hello() to use PACKETW
Reviewed-by: Rich Salz <rsalz@openssl.org>
diff --git a/ssl/statem/statem_clnt.c b/ssl/statem/statem_clnt.c
index ff42858..0fdcfa2 100644
--- a/ssl/statem/statem_clnt.c
+++ b/ssl/statem/statem_clnt.c
@@ -63,7 +63,7 @@
static int key_exchange_expected(SSL *s);
static int ca_dn_cmp(const X509_NAME *const *a, const X509_NAME *const *b);
static int ssl_cipher_list_to_bytes(SSL *s, STACK_OF(SSL_CIPHER) *sk,
- unsigned char *p);
+ PACKETW *pkt);
/*
* Is a CertificateRequest message allowed at the moment or not?
@@ -689,19 +689,22 @@
int tls_construct_client_hello(SSL *s)
{
- unsigned char *buf;
- unsigned char *p, *d;
+ unsigned char *p;
int i;
int protverr;
- unsigned long l;
- int al = 0;
+ int al = SSL_AD_HANDSHAKE_FAILURE;
#ifndef OPENSSL_NO_COMP
- int j;
SSL_COMP *comp;
#endif
SSL_SESSION *sess = s->session;
+ PACKETW pkt, body, spkt;
- buf = (unsigned char *)s->init_buf->data;
+ if (!PACKETW_init(&pkt, s->init_buf)
+ || !PACKETW_set_max_size(&pkt, SSL3_RT_MAX_PLAIN_LENGTH)) {
+ /* Should not happen */
+ SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
/* Work out what SSL/TLS/DTLS version to use */
protverr = ssl_set_client_hello_version(s);
@@ -743,8 +746,11 @@
if (i && ssl_fill_hello_random(s, 0, p, sizeof(s->s3->client_random)) <= 0)
goto err;
- /* Do the message type and length last */
- d = p = ssl_handshake_start(s);
+ if (!ssl_set_handshake_header2(s, &pkt, &body, SSL3_MT_CLIENT_HELLO)) {
+ ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
+ SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
/*-
* version indicates the negotiated version: for example from
@@ -776,90 +782,92 @@
* client_version in client hello and not resetting it to
* the negotiated version.
*/
- *(p++) = s->client_version >> 8;
- *(p++) = s->client_version & 0xff;
-
- /* Random stuff */
- memcpy(p, s->s3->client_random, SSL3_RANDOM_SIZE);
- p += SSL3_RANDOM_SIZE;
+ if (!PACKETW_put_bytes(&body, s->client_version, 2)
+ || !PACKETW_memcpy(&body, s->s3->client_random, SSL3_RANDOM_SIZE)) {
+ SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
/* Session ID */
if (s->new_session)
i = 0;
else
i = s->session->session_id_length;
- *(p++) = i;
- if (i != 0) {
- if (i > (int)sizeof(s->session->session_id)) {
- SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
- goto err;
- }
- memcpy(p, s->session->session_id, i);
- p += i;
+ if (i > (int)sizeof(s->session->session_id)
+ || !PACKETW_get_sub_packet_len(&body, &spkt, 1)
+ || (i != 0 && !PACKETW_memcpy(&spkt, s->session->session_id, i))
+ || !PACKETW_close(&spkt)) {
+ SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+ goto err;
}
/* cookie stuff for DTLS */
if (SSL_IS_DTLS(s)) {
- if (s->d1->cookie_len > sizeof(s->d1->cookie)) {
+ if (s->d1->cookie_len > sizeof(s->d1->cookie)
+ || !PACKETW_get_sub_packet_len(&body, &spkt, 1)
+ || !PACKETW_memcpy(&spkt, s->d1->cookie, s->d1->cookie_len)
+ || !PACKETW_close(&spkt)) {
SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
goto err;
}
- *(p++) = s->d1->cookie_len;
- memcpy(p, s->d1->cookie, s->d1->cookie_len);
- p += s->d1->cookie_len;
}
/* Ciphers supported */
- i = ssl_cipher_list_to_bytes(s, SSL_get_ciphers(s), &(p[2]));
- if (i == 0) {
- SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, SSL_R_NO_CIPHERS_AVAILABLE);
+ if (!PACKETW_get_sub_packet_len(&body, &spkt, 2)) {
+ SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
goto err;
}
-#ifdef OPENSSL_MAX_TLS1_2_CIPHER_LENGTH
- /*
- * Some servers hang if client hello > 256 bytes as hack workaround
- * chop number of supported ciphers to keep it well below this if we
- * use TLS v1.2
- */
- if (TLS1_get_version(s) >= TLS1_2_VERSION
- && i > OPENSSL_MAX_TLS1_2_CIPHER_LENGTH)
- i = OPENSSL_MAX_TLS1_2_CIPHER_LENGTH & ~1;
-#endif
- s2n(i, p);
- p += i;
+ /* ssl_cipher_list_to_bytes() raises SSLerr if appropriate */
+ if (!ssl_cipher_list_to_bytes(s, SSL_get_ciphers(s), &spkt))
+ goto err;
+ if (!PACKETW_close(&spkt)) {
+ SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
/* COMPRESSION */
-#ifdef OPENSSL_NO_COMP
- *(p++) = 1;
-#else
-
- if (!ssl_allow_compression(s) || !s->ctx->comp_methods)
- j = 0;
- else
- j = sk_SSL_COMP_num(s->ctx->comp_methods);
- *(p++) = 1 + j;
- for (i = 0; i < j; i++) {
- comp = sk_SSL_COMP_value(s->ctx->comp_methods, i);
- *(p++) = comp->id;
+ if (!PACKETW_get_sub_packet_len(&body, &spkt, 1)) {
+ SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
+#ifndef OPENSSL_NO_COMP
+ if (ssl_allow_compression(s) && s->ctx->comp_methods) {
+ int compnum = sk_SSL_COMP_num(s->ctx->comp_methods);
+ for (i = 0; i < compnum; i++) {
+ comp = sk_SSL_COMP_value(s->ctx->comp_methods, i);
+ if (!PACKETW_put_bytes(&spkt, comp->id, 1)) {
+ SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
+ }
}
#endif
- *(p++) = 0; /* Add the NULL method */
+ /* Add the NULL method */
+ if (!PACKETW_put_bytes(&spkt, 0, 1) || !PACKETW_close(&spkt)) {
+ SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
/* TLS extensions */
if (ssl_prepare_clienthello_tlsext(s) <= 0) {
SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, SSL_R_CLIENTHELLO_TLSEXT);
goto err;
}
- if ((p =
- ssl_add_clienthello_tlsext(s, p, buf + SSL3_RT_MAX_PLAIN_LENGTH,
- &al)) == NULL) {
+ if (!PACKETW_get_sub_packet_len(&body, &spkt, 2)
+ /*
+ * If extensions are of zero length then we don't even add the
+ * extensions length bytes
+ */
+ || !PACKETW_set_flags(&spkt,
+ OPENSSL_PACKETW_FLAGS_ABANDON_ON_ZERO_LENGTH)
+ || !ssl_add_clienthello_tlsext(s, &spkt, &al)
+ || !PACKETW_close(&spkt)) {
ssl3_send_alert(s, SSL3_AL_FATAL, al);
SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
goto err;
}
- l = p - d;
- if (!ssl_set_handshake_header(s, SSL3_MT_CLIENT_HELLO, l)) {
+ if (!PACKETW_close(&body) || !ssl_close_construct_packet(s, &pkt)) {
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
goto err;
@@ -2909,47 +2917,79 @@
return i;
}
-int ssl_cipher_list_to_bytes(SSL *s, STACK_OF(SSL_CIPHER) *sk, unsigned char *p)
+int ssl_cipher_list_to_bytes(SSL *s, STACK_OF(SSL_CIPHER) *sk, PACKETW *pkt)
{
- int i, j = 0;
- const SSL_CIPHER *c;
- unsigned char *q;
+ int i;
+ size_t totlen = 0, len, maxlen;
int empty_reneg_info_scsv = !s->renegotiate;
/* Set disabled masks for this session */
ssl_set_client_disabled(s);
if (sk == NULL)
return (0);
- q = p;
- for (i = 0; i < sk_SSL_CIPHER_num(sk); i++) {
+#ifdef OPENSSL_MAX_TLS1_2_CIPHER_LENGTH
+# if OPENSSL_MAX_TLS1_2_CIPHER_LENGTH < 6
+# error Max cipher length too short
+# endif
+ /*
+ * Some servers hang if client hello > 256 bytes as hack workaround
+ * chop number of supported ciphers to keep it well below this if we
+ * use TLS v1.2
+ */
+ if (TLS1_get_version(s) >= TLS1_2_VERSION)
+ maxlen = OPENSSL_MAX_TLS1_2_CIPHER_LENGTH & ~1;
+ else
+#endif
+ /* Maximum length that can be stored in 2 bytes. Length must be even */
+ maxlen = 0xfffe;
+
+ if (empty_reneg_info_scsv)
+ maxlen -= 2;
+ if (s->mode & SSL_MODE_SEND_FALLBACK_SCSV)
+ maxlen -= 2;
+
+ for (i = 0; i < sk_SSL_CIPHER_num(sk) && totlen < maxlen; i++) {
+ const SSL_CIPHER *c;
+
c = sk_SSL_CIPHER_value(sk, i);
/* Skip disabled ciphers */
if (ssl_cipher_disabled(s, c, SSL_SECOP_CIPHER_SUPPORTED))
continue;
- j = s->method->put_cipher_by_char(c, p);
- p += j;
+
+ if (!s->method->put_cipher_by_char(c, pkt, &len)) {
+ SSLerr(SSL_F_SSL_CIPHER_LIST_TO_BYTES, ERR_R_INTERNAL_ERROR);
+ return 0;
+ }
+
+ totlen += len;
}
- /*
- * If p == q, no ciphers; caller indicates an error. Otherwise, add
- * applicable SCSVs.
- */
- if (p != q) {
+
+ if (totlen == 0) {
+ SSLerr(SSL_F_SSL_CIPHER_LIST_TO_BYTES, SSL_R_NO_CIPHERS_AVAILABLE);
+ return 0;
+ }
+
+ if (totlen != 0) {
if (empty_reneg_info_scsv) {
static SSL_CIPHER scsv = {
0, NULL, SSL3_CK_SCSV, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
- j = s->method->put_cipher_by_char(&scsv, p);
- p += j;
+ if (!s->method->put_cipher_by_char(&scsv, pkt, &len)) {
+ SSLerr(SSL_F_SSL_CIPHER_LIST_TO_BYTES, ERR_R_INTERNAL_ERROR);
+ return 0;
+ }
}
if (s->mode & SSL_MODE_SEND_FALLBACK_SCSV) {
static SSL_CIPHER scsv = {
0, NULL, SSL3_CK_FALLBACK_SCSV, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
- j = s->method->put_cipher_by_char(&scsv, p);
- p += j;
+ if (!s->method->put_cipher_by_char(&scsv, pkt, &len)) {
+ SSLerr(SSL_F_SSL_CIPHER_LIST_TO_BYTES, ERR_R_INTERNAL_ERROR);
+ return 0;
+ }
}
}
- return (p - q);
+ return 1;
}
