Implement the V2ClientHello sniff in version-locked methods.
Tested manually by replacing SSLv23_method() with TLSv1_2_method() in
bssl_shim. This is a large chunk of code which is not run in SSLv23_method(),
but it will be run after unification. It's split out separately to ease review.
Change-Id: I6bd241daca17aa0f9b3e36e51864a29755a41097
diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h
index 1bc9604..e5d7a51 100644
--- a/include/openssl/ssl.h
+++ b/include/openssl/ssl.h
@@ -2444,6 +2444,8 @@
#define SSL_F_SSL_SESSION_to_bytes_full 292
#define SSL_F_SSL_accept 293
#define SSL_F_SSL_connect 294
+#define SSL_F_ssl3_get_v2_client_hello 295
+#define SSL_F_ssl3_get_initial_bytes 296
#define SSL_R_UNABLE_TO_FIND_ECDH_PARAMETERS 100
#define SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC 101
#define SSL_R_INVALID_NULL_CMD_NAME 102
diff --git a/include/openssl/ssl3.h b/include/openssl/ssl3.h
index 7c30d9b..34c483e 100644
--- a/include/openssl/ssl3.h
+++ b/include/openssl/ssl3.h
@@ -369,6 +369,12 @@
* known. Otherwise the version has not been negotiated yet. */
char have_version;
+ /* sniff_buffer is used by the server in the initial handshake
+ * to read a V2ClientHello before the record layer is
+ * initialized. */
+ BUF_MEM *sniff_buffer;
+ size_t sniff_buffer_len;
+
SSL3_BUFFER rbuf; /* read IO goes into here */
SSL3_BUFFER wbuf; /* write IO goes into here */
@@ -589,6 +595,8 @@
/* extra state */
#define SSL3_ST_SW_FLUSH (0x100|SSL_ST_ACCEPT)
/* read from client */
+#define SSL3_ST_SR_INITIAL_BYTES (0x240|SSL_ST_ACCEPT)
+#define SSL3_ST_SR_V2_CLIENT_HELLO (0x241|SSL_ST_ACCEPT)
/* Do not change the number values, they do matter */
#define SSL3_ST_SR_CLNT_HELLO_A (0x110|SSL_ST_ACCEPT)
#define SSL3_ST_SR_CLNT_HELLO_B (0x111|SSL_ST_ACCEPT)
@@ -624,6 +632,7 @@
#define SSL3_ST_SR_CHANNEL_ID_B (0x231|SSL_ST_ACCEPT)
#define SSL3_ST_SR_FINISHED_A (0x1C0|SSL_ST_ACCEPT)
#define SSL3_ST_SR_FINISHED_B (0x1C1|SSL_ST_ACCEPT)
+
/* write to client */
#define SSL3_ST_SW_CHANGE_A (0x1D0|SSL_ST_ACCEPT)
#define SSL3_ST_SW_CHANGE_B (0x1D1|SSL_ST_ACCEPT)
diff --git a/ssl/s3_lib.c b/ssl/s3_lib.c
index 8176b2a..f4d4775 100644
--- a/ssl/s3_lib.c
+++ b/ssl/s3_lib.c
@@ -1011,6 +1011,9 @@
if(s == NULL)
return;
+ if (s->s3->sniff_buffer != NULL)
+ BUF_MEM_free(s->s3->sniff_buffer);
+
ssl3_cleanup_key_block(s);
if (s->s3->rbuf.buf != NULL)
ssl3_release_read_buffer(s);
@@ -1053,6 +1056,10 @@
* ssl3_new. rbuf, wbuf, and init_extra are preserved, but
* this may not serve anything more than saving a malloc. */
+ if (s->s3->sniff_buffer != NULL)
+ BUF_MEM_free(s->s3->sniff_buffer);
+ s->s3->sniff_buffer = NULL;
+
ssl3_cleanup_key_block(s);
if (s->s3->tmp.ca_names != NULL)
sk_X509_NAME_pop_free(s->s3->tmp.ca_names,X509_NAME_free);
diff --git a/ssl/s3_srvr.c b/ssl/s3_srvr.c
index 1d3285d..b320140 100644
--- a/ssl/s3_srvr.c
+++ b/ssl/s3_srvr.c
@@ -172,6 +172,10 @@
#include "../crypto/internal.h"
#include "../crypto/dh/internal.h"
+/* INITIAL_SNIFF_BUFFER_SIZE is the number of bytes read in the initial sniff
+ * buffer. */
+#define INITIAL_SNIFF_BUFFER_SIZE 8
+
int ssl3_accept(SSL *s)
{
BUF_MEM *buf = NULL;
@@ -207,55 +211,33 @@
switch (s->state)
{
case SSL_ST_RENEGOTIATE:
- s->renegotiate=1;
- /* s->state=SSL_ST_ACCEPT; */
+ /* This state is the renegotiate entry point. It sends a
+ * HelloRequest and nothing else. */
+ s->renegotiate = 1;
- case SSL_ST_ACCEPT:
- case SSL_ST_BEFORE|SSL_ST_ACCEPT:
-
- if (cb != NULL) cb(s,SSL_CB_HANDSHAKE_START,1);
+ if (cb != NULL)
+ cb(s, SSL_CB_HANDSHAKE_START, 1);
if (s->init_buf == NULL)
{
- if ((buf=BUF_MEM_new()) == NULL)
+ buf = BUF_MEM_new();
+ if (!buf || !BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH))
{
- ret= -1;
- goto end;
- }
- if (!BUF_MEM_grow(buf,SSL3_RT_MAX_PLAIN_LENGTH))
- {
- ret= -1;
- goto end;
- }
- s->init_buf=buf;
- buf = NULL;
- }
-
- if (!ssl3_setup_buffers(s))
- {
- ret= -1;
- goto end;
- }
-
- s->init_num=0;
-
- if (s->state != SSL_ST_RENEGOTIATE)
- {
- /* Ok, we now need to push on a buffering BIO so that
- * the output is sent in a way that TCP likes :-)
- */
- if (!ssl_init_wbio_buffer(s,1)) { ret= -1; goto end; }
-
- if (!ssl3_init_finished_mac(s))
- {
- OPENSSL_PUT_ERROR(SSL, ssl3_accept, ERR_R_INTERNAL_ERROR);
ret = -1;
goto end;
}
- s->state=SSL3_ST_SR_CLNT_HELLO_A;
- s->ctx->stats.sess_accept++;
+ s->init_buf = buf;
+ buf = NULL;
}
- else if (!s->s3->send_connection_binding &&
+ s->init_num = 0;
+
+ if (!ssl3_setup_buffers(s))
+ {
+ ret = -1;
+ goto end;
+ }
+
+ if (!s->s3->send_connection_binding &&
!(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION))
{
/* Server attempting to renegotiate with
@@ -267,13 +249,9 @@
ret = -1;
goto end;
}
- else
- {
- /* s->state == SSL_ST_RENEGOTIATE,
- * we will just send a HelloRequest */
- s->ctx->stats.sess_accept_renegotiate++;
- s->state=SSL3_ST_SW_HELLO_REQ_A;
- }
+
+ s->ctx->stats.sess_accept_renegotiate++;
+ s->state = SSL3_ST_SW_HELLO_REQ_A;
break;
case SSL3_ST_SW_HELLO_REQ_A:
@@ -298,6 +276,75 @@
s->state=SSL_ST_OK;
break;
+ case SSL_ST_ACCEPT:
+ case SSL_ST_BEFORE|SSL_ST_ACCEPT:
+ /* This state is the entry point for the handshake
+ * itself (initial and renegotiation). */
+ if (cb != NULL)
+ cb(s, SSL_CB_HANDSHAKE_START, 1);
+
+ if (s->init_buf == NULL)
+ {
+ buf = BUF_MEM_new();
+ if (!buf || !BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH))
+ {
+ ret = -1;
+ goto end;
+ }
+ s->init_buf = buf;
+ buf = NULL;
+ }
+ s->init_num = 0;
+
+ if (!ssl3_init_finished_mac(s))
+ {
+ OPENSSL_PUT_ERROR(SSL, ssl3_accept, ERR_R_INTERNAL_ERROR);
+ ret = -1;
+ goto end;
+ }
+
+ if (!s->s3->have_version)
+ {
+ /* This is the initial handshake. The record
+ * layer has not been initialized yet. Sniff for
+ * a V2ClientHello before reading a ClientHello
+ * normally. */
+ assert(s->s3->rbuf.buf == NULL);
+ assert(s->s3->wbuf.buf == NULL);
+ s->state = SSL3_ST_SR_INITIAL_BYTES;
+ }
+ else
+ {
+ /* Enable a write buffer. This groups handshake
+ * messages within a flight into a single
+ * write. */
+ if (!ssl3_setup_buffers(s) ||
+ !ssl_init_wbio_buffer(s, 1))
+ {
+ ret = -1;
+ goto end;
+ }
+ s->state = SSL3_ST_SR_CLNT_HELLO_A;
+ }
+ s->ctx->stats.sess_accept++;
+ break;
+
+ case SSL3_ST_SR_INITIAL_BYTES:
+ ret = ssl3_get_initial_bytes(s);
+ if (ret <= 0)
+ goto end;
+ /* ssl3_get_initial_bytes sets s->state to one of
+ * SSL3_ST_SR_V2_CLIENT_HELLO or SSL3_ST_SR_CLNT_HELLO_A
+ * on success. */
+ break;
+
+ case SSL3_ST_SR_V2_CLIENT_HELLO:
+ ret = ssl3_get_v2_client_hello(s);
+ if (ret <= 0)
+ goto end;
+ s->state = SSL3_ST_SR_CLNT_HELLO_A;
+ break;
+
case SSL3_ST_SR_CLNT_HELLO_A:
case SSL3_ST_SR_CLNT_HELLO_B:
case SSL3_ST_SR_CLNT_HELLO_C:
@@ -674,6 +721,242 @@
return(ret);
}
+static int ssl3_read_sniff_buffer(SSL *s, size_t n)
+ {
+ if (s->s3->sniff_buffer == NULL)
+ {
+ s->s3->sniff_buffer = BUF_MEM_new();
+ }
+ if (s->s3->sniff_buffer == NULL ||
+ !BUF_MEM_grow(s->s3->sniff_buffer, n))
+ {
+ return -1;
+ }
+
+ while (s->s3->sniff_buffer_len < n)
+ {
+ int ret;
+
+ s->rwstate = SSL_READING;
+ ret = BIO_read(s->rbio,
+ s->s3->sniff_buffer->data + s->s3->sniff_buffer_len,
+ n - s->s3->sniff_buffer_len);
+ if (ret <= 0)
+ return ret;
+ s->rwstate = SSL_NOTHING;
+ s->s3->sniff_buffer_len += ret;
+ }
+ return 1;
+ }
+
+int ssl3_get_initial_bytes(SSL *s)
+ {
+ int ret;
+ const uint8_t *p;
+
+ /* Read the first 8 bytes. To recognize a ClientHello or V2ClientHello
+ * only needs the first 6 bytes, but 8 is needed to recognize CONNECT
+ * below. */
+ ret = ssl3_read_sniff_buffer(s, INITIAL_SNIFF_BUFFER_SIZE);
+ if (ret <= 0)
+ return ret;
+ assert(s->s3->sniff_buffer_len >= INITIAL_SNIFF_BUFFER_SIZE);
+ p = (const uint8_t *)s->s3->sniff_buffer->data;
+
+ /* Some dedicated error codes for protocol mixups should the application
+ * wish to interpret them differently. (These do not overlap with
+ * ClientHello or V2ClientHello.) */
+ if (strncmp("GET ", (const char *)p, 4) == 0 ||
+ strncmp("POST ", (const char *)p, 5) == 0 ||
+ strncmp("HEAD ", (const char *)p, 5) == 0 ||
+ strncmp("PUT ", (const char *)p, 4) == 0)
+ {
+ OPENSSL_PUT_ERROR(SSL, ssl3_get_initial_bytes, SSL_R_HTTP_REQUEST);
+ return -1;
+ }
+ if (strncmp("CONNECT ", (const char *)p, 8) == 0)
+ {
+ OPENSSL_PUT_ERROR(SSL, ssl3_get_initial_bytes, SSL_R_HTTPS_PROXY_REQUEST);
+ return -1;
+ }
+
+ /* Determine if this is a ClientHello or V2ClientHello. */
+
+ if (p[0] & 0x80 && p[2] == SSL2_MT_CLIENT_HELLO &&
+ p[3] >= SSL3_VERSION_MAJOR)
+ {
+ /* This is a V2ClientHello. */
+ s->state = SSL3_ST_SR_V2_CLIENT_HELLO;
+ return 1;
+ }
+ if (p[0] == SSL3_RT_HANDSHAKE && p[1] >= SSL3_VERSION_MAJOR &&
+ p[5] == SSL3_MT_CLIENT_HELLO)
+ {
+ /* This is a ClientHello. Initialize the record layer with the
+ * already consumed data and continue the handshake. */
+ if (!ssl3_setup_buffers(s) || !ssl_init_wbio_buffer(s, 1))
+ {
+ return -1;
+ }
+ assert(s->rstate == SSL_ST_READ_HEADER);
+ memcpy(s->s3->rbuf.buf, p, s->s3->sniff_buffer_len);
+ s->s3->rbuf.offset = 0;
+ s->s3->rbuf.left = s->s3->sniff_buffer_len;
+ s->packet_length = 0;
+
+ BUF_MEM_free(s->s3->sniff_buffer);
+ s->s3->sniff_buffer = NULL;
+ s->s3->sniff_buffer_len = 0;
+
+ s->state = SSL3_ST_SR_CLNT_HELLO_A;
+ return 1;
+ }
+
+ OPENSSL_PUT_ERROR(SSL, ssl3_get_initial_bytes, SSL_R_UNKNOWN_PROTOCOL);
+ return -1;
+ }
+
+int ssl3_get_v2_client_hello(SSL *s)
+ {
+ const uint8_t *p;
+ int ret;
+ CBS v2_client_hello, cipher_specs, session_id, challenge;
+ size_t msg_length, rand_len, len;
+ uint8_t msg_type;
+ uint16_t version, cipher_spec_length, session_id_length, challenge_length;
+ CBB client_hello, hello_body, cipher_suites;
+ uint8_t random[SSL3_RANDOM_SIZE];
+
+ /* Read the remainder of the V2ClientHello. We have previously read 8
+ * bytes in ssl3_get_initial_bytes. */
+ assert(s->s3->sniff_buffer_len >= INITIAL_SNIFF_BUFFER_SIZE);
+ p = (const uint8_t *)s->s3->sniff_buffer->data;
+ msg_length = ((p[0] & 0x7f) << 8) | p[1];
+ if (msg_length > (1024 * 4))
+ {
+ OPENSSL_PUT_ERROR(SSL, ssl3_get_v2_client_hello, SSL_R_RECORD_TOO_LARGE);
+ return -1;
+ }
+ if (msg_length < INITIAL_SNIFF_BUFFER_SIZE - 2)
+ {
+ /* Reject lengths that are too short early. We have already read
+ * 8 bytes, so we should not attempt to process an (invalid)
+ * V2ClientHello which would be shorter than that. */
+ OPENSSL_PUT_ERROR(SSL, ssl3_get_v2_client_hello, SSL_R_RECORD_LENGTH_MISMATCH);
+ return -1;
+ }
+
+ ret = ssl3_read_sniff_buffer(s, msg_length + 2);
+ if (ret <= 0)
+ return ret;
+ assert(s->s3->sniff_buffer_len == msg_length + 2);
+ CBS_init(&v2_client_hello,
+ (const uint8_t *)s->s3->sniff_buffer->data + 2, msg_length);
+
+ /* The V2ClientHello without the length is incorporated into the
+ * Finished hash. */
+ ssl3_finish_mac(s, CBS_data(&v2_client_hello), CBS_len(&v2_client_hello));
+ if (s->msg_callback)
+ s->msg_callback(0, SSL2_VERSION, 0, CBS_data(&v2_client_hello),
+ CBS_len(&v2_client_hello), s, s->msg_callback_arg);
+
+ if (!CBS_get_u8(&v2_client_hello, &msg_type) ||
+ !CBS_get_u16(&v2_client_hello, &version) ||
+ !CBS_get_u16(&v2_client_hello, &cipher_spec_length) ||
+ !CBS_get_u16(&v2_client_hello, &session_id_length) ||
+ !CBS_get_u16(&v2_client_hello, &challenge_length) ||
+ !CBS_get_bytes(&v2_client_hello, &cipher_specs, cipher_spec_length) ||
+ !CBS_get_bytes(&v2_client_hello, &session_id, session_id_length) ||
+ !CBS_get_bytes(&v2_client_hello, &challenge, challenge_length) ||
+ CBS_len(&v2_client_hello) != 0)
+ {
+ OPENSSL_PUT_ERROR(SSL, ssl3_get_v2_client_hello, SSL_R_DECODE_ERROR);
+ return -1;
+ }
+
+ /* msg_type has already been checked. */
+ assert(msg_type == SSL2_MT_CLIENT_HELLO);
+
+ /* The client_random is the V2ClientHello challenge. Truncate or
+ * left-pad with zeros as needed. */
+ memset(random, 0, SSL3_RANDOM_SIZE);
+ rand_len = CBS_len(&challenge);
+ if (rand_len > SSL3_RANDOM_SIZE)
+ rand_len = SSL3_RANDOM_SIZE;
+ memcpy(random + (SSL3_RANDOM_SIZE - rand_len), CBS_data(&challenge), rand_len);
+
+ /* Write out an equivalent SSLv3 ClientHello. */
+ if (!CBB_init_fixed(&client_hello, (uint8_t *)s->init_buf->data, s->init_buf->max))
+ {
+ OPENSSL_PUT_ERROR(SSL, ssl3_get_v2_client_hello, ERR_R_MALLOC_FAILURE);
+ return -1;
+ }
+ if (!CBB_add_u8(&client_hello, SSL3_MT_CLIENT_HELLO) ||
+ !CBB_add_u24_length_prefixed(&client_hello, &hello_body) ||
+ !CBB_add_u16(&hello_body, version) ||
+ !CBB_add_bytes(&hello_body, random, SSL3_RANDOM_SIZE) ||
+ /* No session id. */
+ !CBB_add_u8(&hello_body, 0) ||
+ !CBB_add_u16_length_prefixed(&hello_body, &cipher_suites))
+ {
+ CBB_cleanup(&client_hello);
+ OPENSSL_PUT_ERROR(SSL, ssl3_get_v2_client_hello, ERR_R_INTERNAL_ERROR);
+ return -1;
+ }
+
+ /* Copy the cipher suites. */
+ while (CBS_len(&cipher_specs) > 0)
+ {
+ uint32_t cipher_spec;
+ if (!CBS_get_u24(&cipher_specs, &cipher_spec))
+ {
+ CBB_cleanup(&client_hello);
+ OPENSSL_PUT_ERROR(SSL, ssl3_get_v2_client_hello, SSL_R_DECODE_ERROR);
+ return -1;
+ }
+
+ /* Skip SSLv2 ciphers. */
+ if ((cipher_spec & 0xff0000) != 0)
+ continue;
+ if (!CBB_add_u16(&cipher_suites, cipher_spec))
+ {
+ CBB_cleanup(&client_hello);
+ OPENSSL_PUT_ERROR(SSL, ssl3_get_v2_client_hello, ERR_R_INTERNAL_ERROR);
+ return -1;
+ }
+ }
+
+ /* Add the null compression scheme and finish. */
+ if (!CBB_add_u8(&hello_body, 1) ||
+ !CBB_add_u8(&hello_body, 0) ||
+ !CBB_finish(&client_hello, NULL, &len))
+ {
+ CBB_cleanup(&client_hello);
+ OPENSSL_PUT_ERROR(SSL, ssl3_get_v2_client_hello, ERR_R_INTERNAL_ERROR);
+ return -1;
+ }
+
+ /* Mark the message for "re"-use by the version-specific
+ * method. */
+ s->s3->tmp.reuse_message = 1;
+ s->s3->tmp.message_type = SSL3_MT_CLIENT_HELLO;
+ /* The handshake message header is 4 bytes. */
+ s->s3->tmp.message_size = len - 4;
+
+ /* Initialize the record layer. */
+ if (!ssl3_setup_buffers(s) || !ssl_init_wbio_buffer(s, 1))
+ {
+ return -1;
+ }
+
+ /* Drop the sniff buffer. */
+ BUF_MEM_free(s->s3->sniff_buffer);
+ s->s3->sniff_buffer = NULL;
+ s->s3->sniff_buffer_len = 0;
+
+ return 1;
+ }
+
int ssl3_send_hello_request(SSL *s)
{
diff --git a/ssl/ssl_error.c b/ssl/ssl_error.c
index 4d09ee4..f9be633 100644
--- a/ssl/ssl_error.c
+++ b/ssl/ssl_error.c
@@ -126,6 +126,7 @@
{ERR_PACK(ERR_LIB_SSL, SSL_F_ssl3_get_client_hello, 0), "ssl3_get_client_hello"},
{ERR_PACK(ERR_LIB_SSL, SSL_F_ssl3_get_client_key_exchange, 0), "ssl3_get_client_key_exchange"},
{ERR_PACK(ERR_LIB_SSL, SSL_F_ssl3_get_finished, 0), "ssl3_get_finished"},
+ {ERR_PACK(ERR_LIB_SSL, SSL_F_ssl3_get_initial_bytes, 0), "ssl3_get_initial_bytes"},
{ERR_PACK(ERR_LIB_SSL, SSL_F_ssl3_get_message, 0), "ssl3_get_message"},
{ERR_PACK(ERR_LIB_SSL, SSL_F_ssl3_get_new_session_ticket, 0), "ssl3_get_new_session_ticket"},
{ERR_PACK(ERR_LIB_SSL, SSL_F_ssl3_get_next_proto, 0), "ssl3_get_next_proto"},
@@ -134,6 +135,7 @@
{ERR_PACK(ERR_LIB_SSL, SSL_F_ssl3_get_server_done, 0), "ssl3_get_server_done"},
{ERR_PACK(ERR_LIB_SSL, SSL_F_ssl3_get_server_hello, 0), "ssl3_get_server_hello"},
{ERR_PACK(ERR_LIB_SSL, SSL_F_ssl3_get_server_key_exchange, 0), "ssl3_get_server_key_exchange"},
+ {ERR_PACK(ERR_LIB_SSL, SSL_F_ssl3_get_v2_client_hello, 0), "ssl3_get_v2_client_hello"},
{ERR_PACK(ERR_LIB_SSL, SSL_F_ssl3_handshake_mac, 0), "ssl3_handshake_mac"},
{ERR_PACK(ERR_LIB_SSL, SSL_F_ssl3_read_bytes, 0), "ssl3_read_bytes"},
{ERR_PACK(ERR_LIB_SSL, SSL_F_ssl3_read_n, 0), "ssl3_read_n"},
diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index fdc06f7..7ca8e14 100644
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -945,6 +945,8 @@
int dtls1_client_hello(SSL *s);
/* some server-only functions */
+int ssl3_get_initial_bytes(SSL *s);
+int ssl3_get_v2_client_hello(SSL *s);
int ssl3_get_client_hello(SSL *s);
int ssl3_send_server_hello(SSL *s);
int ssl3_send_hello_request(SSL *s);
