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boringssl/ssl/d1_both.c
David Benjamin bcb2d91e10 Actually check that the message has the expected type in DTLS. 
That might be a reasonable check to make, maybe.

DTLS handshake message reading has a ton of other bugs and needs a complete
rewrite. But let's fix this and get a test in now.

Change-Id: I4981fc302feb9125908bb6161ed1a18288c39e2b
Reviewed-on: https://boringssl-review.googlesource.com/3600
Reviewed-by: Adam Langley <agl@google.com>
2015-02-25 21:23:48 +00:00

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/*
* DTLS implementation written by Nagendra Modadugu
* (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
*/
/* ====================================================================
* Copyright (c) 1998-2005 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
*
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* openssl-core@openssl.org.
*
* 5. Products derived from this software may not be called "OpenSSL"
* nor may "OpenSSL" appear in their names without prior written
* permission of the OpenSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*
* This product includes cryptographic software written by Eric Young
* (eay@cryptsoft.com). This product includes software written by Tim
* Hudson (tjh@cryptsoft.com).
*
*/
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.] */
#include <assert.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>
#include <openssl/buf.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/mem.h>
#include <openssl/obj.h>
#include <openssl/rand.h>
#include <openssl/x509.h>
#include "ssl_locl.h"
#define RSMBLY_BITMASK_SIZE(msg_len) (((msg_len) + 7) / 8)
#define RSMBLY_BITMASK_MARK(bitmask, start, end) \
{ \
if ((end) - (start) <= 8) { \
long ii; \
for (ii = (start); ii < (end); ii++) \
bitmask[((ii) >> 3)] |= (1 << ((ii)&7)); \
} else { \
long ii; \
bitmask[((start) >> 3)] |= bitmask_start_values[((start)&7)]; \
for (ii = (((start) >> 3) + 1); ii < ((((end)-1)) >> 3); ii++) \
bitmask[ii] = 0xff; \
bitmask[(((end)-1) >> 3)] |= bitmask_end_values[((end)&7)]; \
} \
}
#define RSMBLY_BITMASK_IS_COMPLETE(bitmask, msg_len, is_complete) \
{ \
long ii; \
assert((msg_len) > 0); \
is_complete = 1; \
if (bitmask[(((msg_len)-1) >> 3)] != bitmask_end_values[((msg_len)&7)]) \
is_complete = 0; \
if (is_complete) \
for (ii = (((msg_len)-1) >> 3) - 1; ii >= 0; ii--) \
if (bitmask[ii] != 0xff) { \
is_complete = 0; \
break; \
} \
}
static const uint8_t bitmask_start_values[] = {0xff, 0xfe, 0xfc, 0xf8,
0xf0, 0xe0, 0xc0, 0x80};
static const uint8_t bitmask_end_values[] = {0xff, 0x01, 0x03, 0x07,
0x0f, 0x1f, 0x3f, 0x7f};
/* TODO(davidben): 28 comes from the size of IP + UDP header. Is this reasonable
* for these values? Notably, why is kMinMTU a function of the transport
* protocol's overhead rather than, say, what's needed to hold a minimally-sized
* handshake fragment plus protocol overhead. */
/* kMinMTU is the minimum acceptable MTU value. */
static const unsigned int kMinMTU = 256 - 28;
/* kDefaultMTU is the default MTU value to use if neither the user nor
* the underlying BIO supplies one. */
static const unsigned int kDefaultMTU = 1500 - 28;
static void dtls1_fix_message_header(SSL *s, unsigned long frag_off,
unsigned long frag_len);
static unsigned char *dtls1_write_message_header(SSL *s, unsigned char *p);
static long dtls1_get_message_fragment(SSL *s, int stn, long max, int *ok);
static hm_fragment *dtls1_hm_fragment_new(unsigned long frag_len,
int reassembly) {
hm_fragment *frag = NULL;
unsigned char *buf = NULL;
unsigned char *bitmask = NULL;
frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment));
if (frag == NULL) {
return NULL;
}
if (frag_len) {
buf = (unsigned char *)OPENSSL_malloc(frag_len);
if (buf == NULL) {
OPENSSL_free(frag);
return NULL;
}
}
/* zero length fragment gets zero frag->fragment */
frag->fragment = buf;
/* Initialize reassembly bitmask if necessary */
if (reassembly) {
bitmask = (unsigned char *)OPENSSL_malloc(RSMBLY_BITMASK_SIZE(frag_len));
if (bitmask == NULL) {
if (buf != NULL) {
OPENSSL_free(buf);
}
OPENSSL_free(frag);
return NULL;
}
memset(bitmask, 0, RSMBLY_BITMASK_SIZE(frag_len));
}
frag->reassembly = bitmask;
return frag;
}
void dtls1_hm_fragment_free(hm_fragment *frag) {
if (frag->fragment) {
OPENSSL_free(frag->fragment);
}
if (frag->reassembly) {
OPENSSL_free(frag->reassembly);
}
OPENSSL_free(frag);
}
/* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or
* SSL3_RT_CHANGE_CIPHER_SPEC) */
int dtls1_do_write(SSL *s, int type) {
int ret;
int curr_mtu;
unsigned int len, frag_off;
size_t max_overhead = 0;
/* AHA! Figure out the MTU, and stick to the right size */
if (s->d1->mtu < dtls1_min_mtu() &&
!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
long mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
if (mtu >= 0 && mtu <= (1 << 30) && (unsigned)mtu >= dtls1_min_mtu()) {
s->d1->mtu = (unsigned)mtu;
} else {
s->d1->mtu = kDefaultMTU;
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU, s->d1->mtu, NULL);
}
}
/* should have something reasonable now */
assert(s->d1->mtu >= dtls1_min_mtu());
if (s->init_off == 0 && type == SSL3_RT_HANDSHAKE) {
assert(s->init_num ==
(int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);
}
/* Determine the maximum overhead of the current cipher. */
if (s->aead_write_ctx != NULL) {
max_overhead = EVP_AEAD_max_overhead(s->aead_write_ctx->ctx.aead);
if (s->aead_write_ctx->variable_nonce_included_in_record) {
max_overhead += s->aead_write_ctx->variable_nonce_len;
}
}
frag_off = 0;
while (s->init_num) {
/* Account for data in the buffering BIO; multiple records may be packed
* into a single packet during the handshake.
*
* TODO(davidben): This is buggy; if the MTU is larger than the buffer size,
* the large record will be split across two packets. Moreover, in that
* case, the |dtls1_write_bytes| call may not return synchronously. This
* will break on retry as the |s->init_off| and |s->init_num| adjustment
* will run a second time. */
curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) -
DTLS1_RT_HEADER_LENGTH - max_overhead;
if (curr_mtu <= DTLS1_HM_HEADER_LENGTH) {
/* Flush the buffer and continue with a fresh packet.
*
* TODO(davidben): If |BIO_flush| is not synchronous and requires multiple
* calls to |dtls1_do_write|, |frag_off| will be wrong. */
ret = BIO_flush(SSL_get_wbio(s));
if (ret <= 0) {
return ret;
}
assert(BIO_wpending(SSL_get_wbio(s)) == 0);
curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH - max_overhead;
}
/* XDTLS: this function is too long. split out the CCS part */
if (type == SSL3_RT_HANDSHAKE) {
/* If this isn't the first fragment, reserve space to prepend a new
* fragment header. This will override the body of a previous fragment. */
if (s->init_off != 0) {
assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
s->init_off -= DTLS1_HM_HEADER_LENGTH;
s->init_num += DTLS1_HM_HEADER_LENGTH;
}
if (curr_mtu <= DTLS1_HM_HEADER_LENGTH) {
/* To make forward progress, the MTU must, at minimum, fit the handshake
* header and one byte of handshake body. */
OPENSSL_PUT_ERROR(SSL, dtls1_do_write, SSL_R_MTU_TOO_SMALL);
return -1;
}
if (s->init_num > curr_mtu) {
len = curr_mtu;
} else {
len = s->init_num;
}
assert(len >= DTLS1_HM_HEADER_LENGTH);
dtls1_fix_message_header(s, frag_off, len - DTLS1_HM_HEADER_LENGTH);
dtls1_write_message_header(
s, (uint8_t *)&s->init_buf->data[s->init_off]);
} else {
assert(type == SSL3_RT_CHANGE_CIPHER_SPEC);
/* ChangeCipherSpec cannot be fragmented. */
if (s->init_num > curr_mtu) {
OPENSSL_PUT_ERROR(SSL, dtls1_do_write, SSL_R_MTU_TOO_SMALL);
return -1;
}
len = s->init_num;
}
ret = dtls1_write_bytes(s, type, &s->init_buf->data[s->init_off], len);
if (ret < 0) {
return -1;
}
/* bad if this assert fails, only part of the handshake message got sent.
* But why would this happen? */
assert(len == (unsigned int)ret);
if (ret == s->init_num) {
if (s->msg_callback) {
s->msg_callback(1, s->version, type, s->init_buf->data,
(size_t)(s->init_off + s->init_num), s,
s->msg_callback_arg);
}
s->init_off = 0; /* done writing this message */
s->init_num = 0;
return 1;
}
s->init_off += ret;
s->init_num -= ret;
frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
}
return 0;
}
/* dtls1_get_message reads a handshake message of message type |msg_type| (any
* if |msg_type| == -1), maximum acceptable body length |max|. Read an entire
* handshake message. Handshake messages arrive in fragments. */
long dtls1_get_message(SSL *s, int st1, int stn, int msg_type, long max,
int hash_message, int *ok) {
int i, al;
struct hm_header_st *msg_hdr;
uint8_t *p;
unsigned long msg_len;
/* s3->tmp is used to store messages that are unexpected, caused
* by the absence of an optional handshake message */
if (s->s3->tmp.reuse_message) {
/* A SSL_GET_MESSAGE_DONT_HASH_MESSAGE call cannot be combined
* with reuse_message; the SSL_GET_MESSAGE_DONT_HASH_MESSAGE
* would have to have been applied to the previous call. */
assert(hash_message != SSL_GET_MESSAGE_DONT_HASH_MESSAGE);
s->s3->tmp.reuse_message = 0;
if (msg_type >= 0 && s->s3->tmp.message_type != msg_type) {
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, dtls1_get_message, SSL_R_UNEXPECTED_MESSAGE);
goto f_err;
}
*ok = 1;
s->init_msg = (uint8_t *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
s->init_num = (int)s->s3->tmp.message_size;
return s->init_num;
}
msg_hdr = &s->d1->r_msg_hdr;
memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
again:
i = dtls1_get_message_fragment(s, stn, max, ok);
if (i == DTLS1_HM_BAD_FRAGMENT ||
i == DTLS1_HM_FRAGMENT_RETRY) {
/* bad fragment received */
goto again;
} else if (i <= 0 && !*ok) {
return i;
}
if (msg_type >= 0 && msg_hdr->type != msg_type) {
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, dtls1_get_message, SSL_R_UNEXPECTED_MESSAGE);
goto f_err;
}
p = (uint8_t *)s->init_buf->data;
msg_len = msg_hdr->msg_len;
/* reconstruct message header */
*(p++) = msg_hdr->type;
l2n3(msg_len, p);
s2n(msg_hdr->seq, p);
l2n3(0, p);
l2n3(msg_len, p);
p -= DTLS1_HM_HEADER_LENGTH;
msg_len += DTLS1_HM_HEADER_LENGTH;
s->init_msg = (uint8_t *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
if (hash_message != SSL_GET_MESSAGE_DONT_HASH_MESSAGE &&
!ssl3_hash_current_message(s)) {
goto err;
}
if (s->msg_callback) {
s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, p, msg_len, s,
s->msg_callback_arg);
}
memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
s->d1->handshake_read_seq++;
return s->init_num;
f_err:
ssl3_send_alert(s, SSL3_AL_FATAL, al);
err:
*ok = 0;
return -1;
}
static int dtls1_preprocess_fragment(SSL *s, struct hm_header_st *msg_hdr,
int max) {
size_t frag_off, frag_len, msg_len;
msg_len = msg_hdr->msg_len;
frag_off = msg_hdr->frag_off;
frag_len = msg_hdr->frag_len;
/* sanity checking */
if ((frag_off + frag_len) > msg_len) {
OPENSSL_PUT_ERROR(SSL, dtls1_preprocess_fragment,
SSL_R_EXCESSIVE_MESSAGE_SIZE);
return SSL_AD_ILLEGAL_PARAMETER;
}
if ((frag_off + frag_len) > (unsigned long)max) {
OPENSSL_PUT_ERROR(SSL, dtls1_preprocess_fragment,
SSL_R_EXCESSIVE_MESSAGE_SIZE);
return SSL_AD_ILLEGAL_PARAMETER;
}
if (s->d1->r_msg_hdr.frag_off == 0) {
/* first fragment */
/* msg_len is limited to 2^24, but is effectively checked
* against max above */
if (!BUF_MEM_grow_clean(s->init_buf, msg_len + DTLS1_HM_HEADER_LENGTH)) {
OPENSSL_PUT_ERROR(SSL, dtls1_preprocess_fragment, ERR_R_BUF_LIB);
return SSL_AD_INTERNAL_ERROR;
}
s->s3->tmp.message_size = msg_len;
s->d1->r_msg_hdr.msg_len = msg_len;
s->s3->tmp.message_type = msg_hdr->type;
s->d1->r_msg_hdr.type = msg_hdr->type;
s->d1->r_msg_hdr.seq = msg_hdr->seq;
} else if (msg_len != s->d1->r_msg_hdr.msg_len) {
/* They must be playing with us! BTW, failure to enforce
* upper limit would open possibility for buffer overrun. */
OPENSSL_PUT_ERROR(SSL, dtls1_preprocess_fragment,
SSL_R_EXCESSIVE_MESSAGE_SIZE);
return SSL_AD_ILLEGAL_PARAMETER;
}
return 0; /* no error */
}
static int dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok) {
/* (0) check whether the desired fragment is available
* if so:
* (1) copy over the fragment to s->init_buf->data[]
* (2) update s->init_num */
pitem *item;
hm_fragment *frag;
int al;
unsigned long frag_len;
*ok = 0;
item = pqueue_peek(s->d1->buffered_messages);
if (item == NULL) {
return 0;
}
frag = (hm_fragment *)item->data;
/* Don't return if reassembly still in progress */
if (frag->reassembly != NULL) {
return 0;
}
if (s->d1->handshake_read_seq != frag->msg_header.seq) {
return 0;
}
frag_len = frag->msg_header.frag_len;
pqueue_pop(s->d1->buffered_messages);
al = dtls1_preprocess_fragment(s, &frag->msg_header, max);
if (al == 0) {
/* no alert */
uint8_t *p = (uint8_t *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
memcpy(&p[frag->msg_header.frag_off], frag->fragment,
frag->msg_header.frag_len);
}
dtls1_hm_fragment_free(frag);
pitem_free(item);
if (al == 0) {
*ok = 1;
return frag_len;
}
ssl3_send_alert(s, SSL3_AL_FATAL, al);
s->init_num = 0;
*ok = 0;
return -1;
}
/* dtls1_max_handshake_message_len returns the maximum number of bytes
* permitted in a DTLS handshake message for |s|. The minimum is 16KB, but may
* be greater if the maximum certificate list size requires it. */
static unsigned long dtls1_max_handshake_message_len(const SSL *s) {
unsigned long max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
if (max_len < (unsigned long)s->max_cert_list) {
return s->max_cert_list;
}
return max_len;
}
static int dtls1_reassemble_fragment(SSL *s, const struct hm_header_st *msg_hdr,
int *ok) {
hm_fragment *frag = NULL;
pitem *item = NULL;
int i = -1, is_complete;
uint8_t seq64be[8];
unsigned long frag_len = msg_hdr->frag_len;
if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len ||
msg_hdr->msg_len > dtls1_max_handshake_message_len(s)) {
goto err;
}
if (frag_len == 0) {
return DTLS1_HM_FRAGMENT_RETRY;
}
/* Try to find item in queue */
memset(seq64be, 0, sizeof(seq64be));
seq64be[6] = (uint8_t)(msg_hdr->seq >> 8);
seq64be[7] = (uint8_t)msg_hdr->seq;
item = pqueue_find(s->d1->buffered_messages, seq64be);
if (item == NULL) {
frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
if (frag == NULL) {
goto err;
}
memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
frag->msg_header.frag_len = frag->msg_header.msg_len;
frag->msg_header.frag_off = 0;
} else {
frag = (hm_fragment *)item->data;
if (frag->msg_header.msg_len != msg_hdr->msg_len) {
item = NULL;
frag = NULL;
goto err;
}
}
/* If message is already reassembled, this must be a
* retransmit and can be dropped. In this case item != NULL and so frag
* does not need to be freed. */
if (frag->reassembly == NULL) {
uint8_t devnull[256];
assert(item != NULL);
while (frag_len) {
i = s->method->ssl_read_bytes(
s, SSL3_RT_HANDSHAKE, devnull,
frag_len > sizeof(devnull) ? sizeof(devnull) : frag_len, 0);
if (i <= 0) {
goto err;
}
frag_len -= i;
}
return DTLS1_HM_FRAGMENT_RETRY;
}
/* read the body of the fragment (header has already been read */
i = s->method->ssl_read_bytes(
s, SSL3_RT_HANDSHAKE, frag->fragment + msg_hdr->frag_off, frag_len, 0);
if ((unsigned long)i != frag_len) {
i = -1;
}
if (i <= 0) {
goto err;
}
RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
(long)(msg_hdr->frag_off + frag_len));
RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
is_complete);
if (is_complete) {
OPENSSL_free(frag->reassembly);
frag->reassembly = NULL;
}
if (item == NULL) {
item = pitem_new(seq64be, frag);
if (item == NULL) {
i = -1;
goto err;
}
item = pqueue_insert(s->d1->buffered_messages, item);
/* pqueue_insert fails iff a duplicate item is inserted.
* However, |item| cannot be a duplicate. If it were,
* |pqueue_find|, above, would have returned it and control
* would never have reached this branch. */
assert(item != NULL);
}
return DTLS1_HM_FRAGMENT_RETRY;
err:
if (frag != NULL && item == NULL) {
dtls1_hm_fragment_free(frag);
}
*ok = 0;
return i;
}
static int dtls1_process_out_of_seq_message(SSL *s,
const struct hm_header_st *msg_hdr,
int *ok) {
int i = -1;
hm_fragment *frag = NULL;
pitem *item = NULL;
uint8_t seq64be[8];
unsigned long frag_len = msg_hdr->frag_len;
if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len) {
goto err;
}
/* Try to find item in queue, to prevent duplicate entries */
memset(seq64be, 0, sizeof(seq64be));
seq64be[6] = (uint8_t)(msg_hdr->seq >> 8);
seq64be[7] = (uint8_t)msg_hdr->seq;
item = pqueue_find(s->d1->buffered_messages, seq64be);
/* If we already have an entry and this one is a fragment,
* don't discard it and rather try to reassemble it. */
if (item != NULL && frag_len != msg_hdr->msg_len) {
item = NULL;
}
/* Discard the message if sequence number was already there, is
* too far in the future, or already in the queue. */
if (msg_hdr->seq <= s->d1->handshake_read_seq ||
msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL) {
uint8_t devnull[256];
while (frag_len) {
i = s->method->ssl_read_bytes(
s, SSL3_RT_HANDSHAKE, devnull,
frag_len > sizeof(devnull) ? sizeof(devnull) : frag_len, 0);
if (i <= 0) {
goto err;
}
frag_len -= i;
}
} else {
if (frag_len != msg_hdr->msg_len) {
return dtls1_reassemble_fragment(s, msg_hdr, ok);
}
if (frag_len > dtls1_max_handshake_message_len(s)) {
goto err;
}
frag = dtls1_hm_fragment_new(frag_len, 0);
if (frag == NULL) {
goto err;
}
memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
if (frag_len) {
/* read the body of the fragment (header has already been read */
i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, frag->fragment,
frag_len, 0);
if ((unsigned long)i != frag_len) {
i = -1;
}
if (i <= 0) {
goto err;
}
}
item = pitem_new(seq64be, frag);
if (item == NULL) {
goto err;
}
item = pqueue_insert(s->d1->buffered_messages, item);
/* pqueue_insert fails iff a duplicate item is inserted.
* However, |item| cannot be a duplicate. If it were,
* |pqueue_find|, above, would have returned it. Then, either
* |frag_len| != |msg_hdr->msg_len| in which case |item| is set
* to NULL and it will have been processed with
* |dtls1_reassemble_fragment|, above, or the record will have
* been discarded. */
assert(item != NULL);
}
return DTLS1_HM_FRAGMENT_RETRY;
err:
if (frag != NULL && item == NULL) {
dtls1_hm_fragment_free(frag);
}
*ok = 0;
return i;
}
static long dtls1_get_message_fragment(SSL *s, int stn, long max, int *ok) {
uint8_t wire[DTLS1_HM_HEADER_LENGTH];
unsigned long len, frag_off, frag_len;
int i, al;
struct hm_header_st msg_hdr;
redo:
/* see if we have the required fragment already */
if ((frag_len = dtls1_retrieve_buffered_fragment(s, max, ok)) || *ok) {
if (*ok) {
s->init_num = frag_len;
}
return frag_len;
}
/* read handshake message header */
i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, wire,
DTLS1_HM_HEADER_LENGTH, 0);
if (i <= 0) {
/* nbio, or an error */
s->rwstate = SSL_READING;
*ok = 0;
return i;
}
/* Handshake fails if message header is incomplete */
if (i != DTLS1_HM_HEADER_LENGTH) {
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, dtls1_get_message_fragment,
SSL_R_UNEXPECTED_MESSAGE);
goto f_err;
}
/* parse the message fragment header */
dtls1_get_message_header(wire, &msg_hdr);
/* if this is a future (or stale) message it gets buffered
* (or dropped)--no further processing at this time. */
if (msg_hdr.seq != s->d1->handshake_read_seq) {
return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
}
len = msg_hdr.msg_len;
frag_off = msg_hdr.frag_off;
frag_len = msg_hdr.frag_len;
if (frag_len && frag_len < len) {
return dtls1_reassemble_fragment(s, &msg_hdr, ok);
}
if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
wire[0] == SSL3_MT_HELLO_REQUEST) {
/* The server may always send 'Hello Request' messages --
* we are doing a handshake anyway now, so ignore them
* if their format is correct. Does not count for
* 'Finished' MAC. */
if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0) {
if (s->msg_callback) {
s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, wire,
DTLS1_HM_HEADER_LENGTH, s, s->msg_callback_arg);
}
s->init_num = 0;
goto redo;
} else {
/* Incorrectly formated Hello request */
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, dtls1_get_message_fragment,
SSL_R_UNEXPECTED_MESSAGE);
goto f_err;
}
}
if ((al = dtls1_preprocess_fragment(s, &msg_hdr, max))) {
goto f_err;
}
/* XDTLS: ressurect this when restart is in place */
s->state = stn;
if (frag_len > 0) {
uint8_t *p = (uint8_t *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, &p[frag_off], frag_len,
0);
/* XDTLS: fix this--message fragments cannot span multiple packets */
if (i <= 0) {
s->rwstate = SSL_READING;
*ok = 0;
return i;
}
} else {
i = 0;
}
/* XDTLS: an incorrectly formatted fragment should cause the
* handshake to fail */
if (i != (int)frag_len) {
al = SSL3_AD_ILLEGAL_PARAMETER;
OPENSSL_PUT_ERROR(SSL, dtls1_get_message_fragment,
SSL3_AD_ILLEGAL_PARAMETER);
goto f_err;
}
*ok = 1;
/* Note that s->init_num is *not* used as current offset in
* s->init_buf->data, but as a counter summing up fragments'
* lengths: as soon as they sum up to handshake packet
* length, we assume we have got all the fragments. */
s->init_num = frag_len;
return frag_len;
f_err:
ssl3_send_alert(s, SSL3_AL_FATAL, al);
s->init_num = 0;
*ok = 0;
return -1;
}
/* for these 2 messages, we need to
* ssl->enc_read_ctx re-init
* ssl->s3->read_sequence zero
* ssl->s3->read_mac_secret re-init
* ssl->session->read_sym_enc assign
* ssl->session->read_compression assign
* ssl->session->read_hash assign */
int dtls1_send_change_cipher_spec(SSL *s, int a, int b) {
uint8_t *p;
if (s->state == a) {
p = (uint8_t *)s->init_buf->data;
*p++ = SSL3_MT_CCS;
s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
s->init_num = DTLS1_CCS_HEADER_LENGTH;
s->init_off = 0;
dtls1_set_message_header(s, SSL3_MT_CCS, 0, s->d1->handshake_write_seq, 0,
0);
/* buffer the message to handle re-xmits */
dtls1_buffer_message(s, 1);
s->state = b;
}
/* SSL3_ST_CW_CHANGE_B */
return dtls1_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC);
}
int dtls1_read_failed(SSL *s, int code) {
if (code > 0) {
assert(0);
return 1;
}
if (!dtls1_is_timer_expired(s)) {
/* not a timeout, none of our business, let higher layers handle this. In
* fact, it's probably an error */
return code;
}
if (!SSL_in_init(s)) {
/* done, no need to send a retransmit */
BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
return code;
}
return dtls1_handle_timeout(s);
}
int dtls1_get_queue_priority(unsigned short seq, int is_ccs) {
/* The index of the retransmission queue actually is the message sequence
* number, since the queue only contains messages of a single handshake.
* However, the ChangeCipherSpec has no message sequence number and so using
* only the sequence will result in the CCS and Finished having the same
* index. To prevent this, the sequence number is multiplied by 2. In case of
* a CCS 1 is subtracted. This does not only differ CSS and Finished, it also
* maintains the order of the index (important for priority queues) and fits
* in the unsigned short variable. */
return seq * 2 - is_ccs;
}
static int dtls1_retransmit_message(SSL *s, hm_fragment *frag) {
int ret;
/* XDTLS: for now assuming that read/writes are blocking */
unsigned long header_length;
uint8_t save_write_sequence[8];
/* assert(s->init_num == 0);
assert(s->init_off == 0); */
if (frag->msg_header.is_ccs) {
header_length = DTLS1_CCS_HEADER_LENGTH;
} else {
header_length = DTLS1_HM_HEADER_LENGTH;
}
memcpy(s->init_buf->data, frag->fragment,
frag->msg_header.msg_len + header_length);
s->init_num = frag->msg_header.msg_len + header_length;
dtls1_set_message_header(s, frag->msg_header.type,
frag->msg_header.msg_len, frag->msg_header.seq,
0, frag->msg_header.frag_len);
/* Save current state. */
SSL_AEAD_CTX *aead_write_ctx = s->aead_write_ctx;
uint16_t epoch = s->d1->w_epoch;
/* DTLS renegotiation is unsupported, so only epochs 0 (NULL cipher) and 1
* (negotiated cipher) exist. */
assert(epoch == 0 || epoch == 1);
assert(frag->msg_header.epoch <= epoch);
const int fragment_from_previous_epoch = (epoch == 1 &&
frag->msg_header.epoch == 0);
if (fragment_from_previous_epoch) {
/* Rewind to the previous epoch.
*
* TODO(davidben): Instead of swapping out connection-global state, this
* logic should pass a "use previous epoch" parameter down to lower-level
* functions. */
s->d1->w_epoch = frag->msg_header.epoch;
s->aead_write_ctx = NULL;
memcpy(save_write_sequence, s->s3->write_sequence,
sizeof(s->s3->write_sequence));
memcpy(s->s3->write_sequence, s->d1->last_write_sequence,
sizeof(s->s3->write_sequence));
} else {
/* Otherwise the messages must be from the same epoch. */
assert(frag->msg_header.epoch == epoch);
}
ret = dtls1_do_write(s, frag->msg_header.is_ccs ? SSL3_RT_CHANGE_CIPHER_SPEC
: SSL3_RT_HANDSHAKE);
if (fragment_from_previous_epoch) {
/* Restore the current epoch. */
s->aead_write_ctx = aead_write_ctx;
s->d1->w_epoch = epoch;
memcpy(s->d1->last_write_sequence, s->s3->write_sequence,
sizeof(s->s3->write_sequence));
memcpy(s->s3->write_sequence, save_write_sequence,
sizeof(s->s3->write_sequence));
}
(void)BIO_flush(SSL_get_wbio(s));
return ret;
}
int dtls1_retransmit_buffered_messages(SSL *s) {
pqueue sent = s->d1->sent_messages;
piterator iter = pqueue_iterator(sent);
pitem *item;
for (item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter)) {
hm_fragment *frag = (hm_fragment *)item->data;
if (dtls1_retransmit_message(s, frag) <= 0) {
return -1;
}
}
return 1;
}
int dtls1_buffer_message(SSL *s, int is_ccs) {
pitem *item;
hm_fragment *frag;
uint8_t seq64be[8];
/* this function is called immediately after a message has
* been serialized */
assert(s->init_off == 0);
frag = dtls1_hm_fragment_new(s->init_num, 0);
if (!frag) {
return 0;
}
memcpy(frag->fragment, s->init_buf->data, s->init_num);
if (is_ccs) {
assert(s->d1->w_msg_hdr.msg_len + DTLS1_CCS_HEADER_LENGTH ==
(unsigned int)s->init_num);
} else {
assert(s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH ==
(unsigned int)s->init_num);
}
frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
frag->msg_header.seq = s->d1->w_msg_hdr.seq;
frag->msg_header.type = s->d1->w_msg_hdr.type;
frag->msg_header.frag_off = 0;
frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
frag->msg_header.is_ccs = is_ccs;
frag->msg_header.epoch = s->d1->w_epoch;
memset(seq64be, 0, sizeof(seq64be));
seq64be[6] = (uint8_t)(
dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs) >>
8);
seq64be[7] = (uint8_t)(
dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs));
item = pitem_new(seq64be, frag);
if (item == NULL) {
dtls1_hm_fragment_free(frag);
return 0;
}
pqueue_insert(s->d1->sent_messages, item);
return 1;
}
/* call this function when the buffered messages are no longer needed */
void dtls1_clear_record_buffer(SSL *s) {
pitem *item;
for (item = pqueue_pop(s->d1->sent_messages); item != NULL;
item = pqueue_pop(s->d1->sent_messages)) {
dtls1_hm_fragment_free((hm_fragment *)item->data);
pitem_free(item);
}
}
/* don't actually do the writing, wait till the MTU has been retrieved */
void dtls1_set_message_header(SSL *s, uint8_t mt, unsigned long len,
unsigned short seq_num, unsigned long frag_off,
unsigned long frag_len) {
struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
msg_hdr->type = mt;
msg_hdr->msg_len = len;
msg_hdr->seq = seq_num;
msg_hdr->frag_off = frag_off;
msg_hdr->frag_len = frag_len;
}
static void dtls1_fix_message_header(SSL *s, unsigned long frag_off,
unsigned long frag_len) {
struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
msg_hdr->frag_off = frag_off;
msg_hdr->frag_len = frag_len;
}
static uint8_t *dtls1_write_message_header(SSL *s, uint8_t *p) {
struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
*p++ = msg_hdr->type;
l2n3(msg_hdr->msg_len, p);
s2n(msg_hdr->seq, p);
l2n3(msg_hdr->frag_off, p);
l2n3(msg_hdr->frag_len, p);
return p;
}
unsigned int dtls1_min_mtu(void) {
return kMinMTU;
}
void dtls1_get_message_header(uint8_t *data,
struct hm_header_st *msg_hdr) {
memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
msg_hdr->type = *(data++);
n2l3(data, msg_hdr->msg_len);
n2s(data, msg_hdr->seq);
n2l3(data, msg_hdr->frag_off);
n2l3(data, msg_hdr->frag_len);
}
void dtls1_get_ccs_header(uint8_t *data, struct ccs_header_st *ccs_hdr) {
memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
ccs_hdr->type = *(data++);
}
int dtls1_shutdown(SSL *s) {
int ret;
ret = ssl3_shutdown(s);
return ret;
}
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