pineapple-src/externals/libressl/ssl/ssl_packet.c
2022-04-24 22:29:35 +02:00

292 lines
7.8 KiB
C
Executable file

/* $OpenBSD: ssl_packet.c,v 1.13 2022/02/05 14:54:10 jsing Exp $ */
/*
* Copyright (c) 2016, 2017 Joel Sing <jsing@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "bytestring.h"
#include "ssl_locl.h"
static int
ssl_is_sslv2_client_hello(CBS *header)
{
uint16_t record_length;
uint8_t message_type;
CBS cbs;
CBS_dup(header, &cbs);
if (!CBS_get_u16(&cbs, &record_length) ||
!CBS_get_u8(&cbs, &message_type))
return 0;
/*
* The SSLv2 record length field uses variable length (2 or 3 byte)
* encoding. Given the size of a client hello, we expect/require the
* 2-byte form which is indicated by a one in the most significant bit.
*/
if ((record_length & 0x8000) == 0)
return 0;
if ((record_length & ~0x8000) < 3)
return 0;
if (message_type != SSL2_MT_CLIENT_HELLO)
return 0;
return 1;
}
static int
ssl_is_sslv3_handshake(CBS *header)
{
uint16_t record_version;
uint8_t record_type;
CBS cbs;
CBS_dup(header, &cbs);
if (!CBS_get_u8(&cbs, &record_type) ||
!CBS_get_u16(&cbs, &record_version))
return 0;
if (record_type != SSL3_RT_HANDSHAKE)
return 0;
if ((record_version >> 8) != SSL3_VERSION_MAJOR)
return 0;
return 1;
}
static int
ssl_convert_sslv2_client_hello(SSL *s)
{
CBB cbb, handshake, client_hello, cipher_suites, compression, session_id;
CBS cbs, challenge, cipher_specs, session;
uint16_t record_length, client_version, cipher_specs_length;
uint16_t session_id_length, challenge_length;
unsigned char *client_random = NULL, *data = NULL;
size_t data_len, pad_len, len;
uint32_t cipher_spec;
uint8_t message_type;
unsigned char *pad;
int ret = -1;
int n;
memset(&cbb, 0, sizeof(cbb));
CBS_init(&cbs, s->internal->packet, SSL3_RT_HEADER_LENGTH);
if (!CBS_get_u16(&cbs, &record_length) ||
!CBS_get_u8(&cbs, &message_type) ||
!CBS_get_u16(&cbs, &client_version))
return -1;
/*
* The SSLv2 record length field uses variable length (2 or 3 byte)
* encoding. Given the size of a client hello, we expect/require the
* 2-byte form which is indicated by a one in the most significant bit.
* Also note that the record length value does not include the bytes
* used for the record length field.
*/
if ((record_length & 0x8000) == 0)
return -1;
record_length &= ~0x8000;
if (record_length < SSL3_RT_HEADER_LENGTH - 2)
return -1;
if (message_type != SSL2_MT_CLIENT_HELLO)
return -1;
if (record_length < 9) {
SSLerror(s, SSL_R_RECORD_LENGTH_MISMATCH);
return -1;
}
if (record_length > 4096) {
SSLerror(s, SSL_R_RECORD_TOO_LARGE);
return -1;
}
n = ssl3_packet_extend(s, record_length + 2);
if (n != record_length + 2)
return n;
tls1_transcript_record(s, s->internal->packet + 2,
s->internal->packet_length - 2);
s->internal->mac_packet = 0;
if (s->internal->msg_callback)
s->internal->msg_callback(0, SSL2_VERSION, 0,
s->internal->packet + 2, s->internal->packet_length - 2, s,
s->internal->msg_callback_arg);
/* Decode the SSLv2 record containing the client hello. */
CBS_init(&cbs, s->internal->packet, s->internal->packet_length);
if (!CBS_get_u16(&cbs, &record_length))
return -1;
if (!CBS_get_u8(&cbs, &message_type))
return -1;
if (!CBS_get_u16(&cbs, &client_version))
return -1;
if (!CBS_get_u16(&cbs, &cipher_specs_length))
return -1;
if (!CBS_get_u16(&cbs, &session_id_length))
return -1;
if (!CBS_get_u16(&cbs, &challenge_length))
return -1;
if (!CBS_get_bytes(&cbs, &cipher_specs, cipher_specs_length))
return -1;
if (!CBS_get_bytes(&cbs, &session, session_id_length))
return -1;
if (!CBS_get_bytes(&cbs, &challenge, challenge_length))
return -1;
if (CBS_len(&cbs) != 0) {
SSLerror(s, SSL_R_RECORD_LENGTH_MISMATCH);
return -1;
}
/*
* Convert SSLv2 challenge to SSLv3/TLS client random, by truncating or
* left-padding with zero bytes.
*/
if ((client_random = malloc(SSL3_RANDOM_SIZE)) == NULL)
goto err;
if (!CBB_init_fixed(&cbb, client_random, SSL3_RANDOM_SIZE))
goto err;
if ((len = CBS_len(&challenge)) > SSL3_RANDOM_SIZE)
len = SSL3_RANDOM_SIZE;
pad_len = SSL3_RANDOM_SIZE - len;
if (!CBB_add_space(&cbb, &pad, pad_len))
goto err;
memset(pad, 0, pad_len);
if (!CBB_add_bytes(&cbb, CBS_data(&challenge), len))
goto err;
if (!CBB_finish(&cbb, NULL, NULL))
goto err;
/* Build SSLv3/TLS record with client hello. */
if (!CBB_init(&cbb, SSL3_RT_MAX_PLAIN_LENGTH))
goto err;
if (!CBB_add_u8(&cbb, SSL3_RT_HANDSHAKE))
goto err;
if (!CBB_add_u16(&cbb, 0x0301))
goto err;
if (!CBB_add_u16_length_prefixed(&cbb, &handshake))
goto err;
if (!CBB_add_u8(&handshake, SSL3_MT_CLIENT_HELLO))
goto err;
if (!CBB_add_u24_length_prefixed(&handshake, &client_hello))
goto err;
if (!CBB_add_u16(&client_hello, client_version))
goto err;
if (!CBB_add_bytes(&client_hello, client_random, SSL3_RANDOM_SIZE))
goto err;
if (!CBB_add_u8_length_prefixed(&client_hello, &session_id))
goto err;
if (!CBB_add_u16_length_prefixed(&client_hello, &cipher_suites))
goto err;
while (CBS_len(&cipher_specs) > 0) {
if (!CBS_get_u24(&cipher_specs, &cipher_spec))
goto err;
if ((cipher_spec & 0xff0000) != 0)
continue;
if (!CBB_add_u16(&cipher_suites, cipher_spec & 0xffff))
goto err;
}
if (!CBB_add_u8_length_prefixed(&client_hello, &compression))
goto err;
if (!CBB_add_u8(&compression, 0))
goto err;
if (!CBB_finish(&cbb, &data, &data_len))
goto err;
if (data_len > s->s3->rbuf.len)
goto err;
s->internal->packet = s->s3->rbuf.buf;
s->internal->packet_length = data_len;
memcpy(s->internal->packet, data, data_len);
ret = 1;
err:
CBB_cleanup(&cbb);
free(client_random);
free(data);
return (ret);
}
/*
* Potentially do legacy processing on the first packet received by a TLS
* server. We return 1 if we want SSLv3/TLS record processing to continue
* normally, otherwise we must set an SSLerr and return -1.
*/
int
ssl_server_legacy_first_packet(SSL *s)
{
uint16_t min_version;
const char *data;
CBS header;
if (SSL_is_dtls(s))
return 1;
CBS_init(&header, s->internal->packet, SSL3_RT_HEADER_LENGTH);
if (ssl_is_sslv3_handshake(&header) == 1)
return 1;
/* Only continue if this is not a version locked method. */
if (s->method->min_tls_version == s->method->max_tls_version)
return 1;
if (ssl_is_sslv2_client_hello(&header) == 1) {
/* Only permit SSLv2 client hellos if TLSv1.0 is enabled. */
if (ssl_enabled_tls_version_range(s, &min_version, NULL) != 1) {
SSLerror(s, SSL_R_NO_PROTOCOLS_AVAILABLE);
return -1;
}
if (min_version > TLS1_VERSION)
return 1;
if (ssl_convert_sslv2_client_hello(s) != 1) {
SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
return -1;
}
return 1;
}
/* Ensure that we have SSL3_RT_HEADER_LENGTH (5 bytes) of the packet. */
if (CBS_len(&header) != SSL3_RT_HEADER_LENGTH) {
SSLerror(s, ERR_R_INTERNAL_ERROR);
return -1;
}
data = (const char *)CBS_data(&header);
/* Is this a cleartext protocol? */
if (strncmp("GET ", data, 4) == 0 ||
strncmp("POST ", data, 5) == 0 ||
strncmp("HEAD ", data, 5) == 0 ||
strncmp("PUT ", data, 4) == 0) {
SSLerror(s, SSL_R_HTTP_REQUEST);
return -1;
}
if (strncmp("CONNE", data, 5) == 0) {
SSLerror(s, SSL_R_HTTPS_PROXY_REQUEST);
return -1;
}
SSLerror(s, SSL_R_UNKNOWN_PROTOCOL);
return -1;
}