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boringssl/ssl/s3_pkt.c
David Benjamin 897e5e0013 Default renegotiations to off. 
As of crbug.com/484543, Chromium's SSLClientSocket is not sensitive to whether
renegotiation is enabled or not. Disable it by default and require consumers to
opt into enabling this protocol mistake.

BUG=429450

Change-Id: I2329068284dbb851da010ff1fd398df3d663bcc3
Reviewed-on: https://boringssl-review.googlesource.com/4723
Reviewed-by: Adam Langley <agl@google.com>
2015-05-13 17:02:14 +00:00

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/* 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.]
*/
/* ====================================================================
* Copyright (c) 1998-2002 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). */
#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/rand.h>
#include "internal.h"
static int do_ssl3_write(SSL *s, int type, const uint8_t *buf, unsigned int len,
char fragment);
static int ssl3_get_record(SSL *s);
int ssl3_read_n(SSL *s, int n, int extend) {
/* If |extend| is 0, obtain new n-byte packet;
* if |extend| is 1, increase packet by another n bytes.
*
* The packet will be in the sub-array of |s->s3->rbuf.buf| specified by
* |s->packet| and |s->packet_length|. (If |s->read_ahead| is set and |extend|
* is 0, additional bytes may be read into |rbuf|, up to the size of the
* buffer.) */
int i, len, left;
uintptr_t align = 0;
uint8_t *pkt;
SSL3_BUFFER *rb;
if (n <= 0) {
return n;
}
rb = &s->s3->rbuf;
if (rb->buf == NULL && !ssl3_setup_read_buffer(s)) {
return -1;
}
left = rb->left;
align = (uintptr_t)rb->buf + SSL3_RT_HEADER_LENGTH;
align = (0 - align) & (SSL3_ALIGN_PAYLOAD - 1);
if (!extend) {
/* start with empty packet ... */
if (left == 0) {
rb->offset = align;
} else if (align != 0 && left >= SSL3_RT_HEADER_LENGTH) {
/* check if next packet length is large enough to justify payload
* alignment... */
pkt = rb->buf + rb->offset;
if (pkt[0] == SSL3_RT_APPLICATION_DATA && (pkt[3] << 8 | pkt[4]) >= 128) {
/* Note that even if packet is corrupted and its length field is
* insane, we can only be led to wrong decision about whether memmove
* will occur or not. Header values has no effect on memmove arguments
* and therefore no buffer overrun can be triggered. */
memmove(rb->buf + align, pkt, left);
rb->offset = align;
}
}
s->packet = rb->buf + rb->offset;
s->packet_length = 0;
/* ... now we can act as if 'extend' was set */
}
/* For DTLS/UDP reads should not span multiple packets because the read
* operation returns the whole packet at once (as long as it fits into the
* buffer). */
if (SSL_IS_DTLS(s) && left > 0 && n > left) {
n = left;
}
/* if there is enough in the buffer from a previous read, take some */
if (left >= n) {
s->packet_length += n;
rb->left = left - n;
rb->offset += n;
return n;
}
/* else we need to read more data */
len = s->packet_length;
pkt = rb->buf + align;
/* Move any available bytes to front of buffer: |len| bytes already pointed
* to by |packet|, |left| extra ones at the end. */
if (s->packet != pkt) {
/* len > 0 */
memmove(pkt, s->packet, len + left);
s->packet = pkt;
rb->offset = len + align;
}
if (n > (int)(rb->len - rb->offset)) {
OPENSSL_PUT_ERROR(SSL, ssl3_read_n, ERR_R_INTERNAL_ERROR);
return -1;
}
int max = n;
if (s->read_ahead && !extend) {
max = rb->len - rb->offset;
}
while (left < n) {
/* Now we have len+left bytes at the front of s->s3->rbuf.buf and need to
* read in more until we have len+n (up to len+max if possible). */
ERR_clear_system_error();
if (s->rbio != NULL) {
s->rwstate = SSL_READING;
i = BIO_read(s->rbio, pkt + len + left, max - left);
} else {
OPENSSL_PUT_ERROR(SSL, ssl3_read_n, SSL_R_READ_BIO_NOT_SET);
i = -1;
}
if (i <= 0) {
rb->left = left;
if (len + left == 0) {
ssl3_release_read_buffer(s);
}
return i;
}
left += i;
/* reads should *never* span multiple packets for DTLS because the
* underlying transport protocol is message oriented as opposed to byte
* oriented as in the TLS case. */
if (SSL_IS_DTLS(s) && n > left) {
n = left; /* makes the while condition false */
}
}
/* done reading, now the book-keeping */
rb->offset += n;
rb->left = left - n;
s->packet_length += n;
s->rwstate = SSL_NOTHING;
return n;
}
/* MAX_EMPTY_RECORDS defines the number of consecutive, empty records that will
* be processed per call to ssl3_get_record. Without this limit an attacker
* could send empty records at a faster rate than we can process and cause
* ssl3_get_record to loop forever. */
#define MAX_EMPTY_RECORDS 32
/* Call this to get a new input record. It will return <= 0 if more data is
* needed, normally due to an error or non-blocking IO. When it finishes, one
* packet has been decoded and can be found in
* ssl->s3->rrec.type - is the type of record
* ssl->s3->rrec.data - data
* ssl->s3->rrec.length - number of bytes */
/* used only by ssl3_read_bytes */
static int ssl3_get_record(SSL *s) {
int ssl_major, ssl_minor, al;
int n, i, ret = -1;
SSL3_RECORD *rr;
uint8_t *p;
short version;
size_t extra;
unsigned empty_record_count = 0;
rr = &s->s3->rrec;
again:
/* check if we have the header */
if (s->rstate != SSL_ST_READ_BODY ||
s->packet_length < SSL3_RT_HEADER_LENGTH) {
n = ssl3_read_n(s, SSL3_RT_HEADER_LENGTH, 0);
if (n <= 0) {
return n; /* error or non-blocking */
}
s->rstate = SSL_ST_READ_BODY;
/* Some bytes were read, so the read buffer must be existant and
* |s->s3->init_extra| is defined. */
assert(s->s3->rbuf.buf != NULL);
extra = s->s3->init_extra ? SSL3_RT_MAX_EXTRA : 0;
p = s->packet;
if (s->msg_callback) {
s->msg_callback(0, 0, SSL3_RT_HEADER, p, 5, s, s->msg_callback_arg);
}
/* Pull apart the header into the SSL3_RECORD */
rr->type = *(p++);
ssl_major = *(p++);
ssl_minor = *(p++);
version = (ssl_major << 8) | ssl_minor;
n2s(p, rr->length);
if (s->s3->have_version && version != s->version) {
OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_WRONG_VERSION_NUMBER);
al = SSL_AD_PROTOCOL_VERSION;
goto f_err;
}
if ((version >> 8) != SSL3_VERSION_MAJOR) {
OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_WRONG_VERSION_NUMBER);
goto err;
}
if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH + extra) {
al = SSL_AD_RECORD_OVERFLOW;
OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
goto f_err;
}
/* now s->rstate == SSL_ST_READ_BODY */
} else {
/* |packet_length| is non-zero and |s->rstate| is |SSL_ST_READ_BODY|. The
* read buffer must be existant and |s->s3->init_extra| is defined. */
assert(s->s3->rbuf.buf != NULL);
extra = s->s3->init_extra ? SSL3_RT_MAX_EXTRA : 0;
}
/* s->rstate == SSL_ST_READ_BODY, get and decode the data */
if (rr->length > s->packet_length - SSL3_RT_HEADER_LENGTH) {
/* now s->packet_length == SSL3_RT_HEADER_LENGTH */
i = rr->length;
n = ssl3_read_n(s, i, 1);
if (n <= 0) {
/* Error or non-blocking IO. Now |n| == |rr->length|, and
* |s->packet_length| == |SSL3_RT_HEADER_LENGTH| + |rr->length|. */
return n;
}
}
s->rstate = SSL_ST_READ_HEADER; /* set state for later operations */
/* At this point, s->packet_length == SSL3_RT_HEADER_LNGTH + rr->length, and
* we have that many bytes in s->packet. */
rr->input = &s->packet[SSL3_RT_HEADER_LENGTH];
/* ok, we can now read from |s->packet| data into |rr|. |rr->input| points at
* |rr->length| bytes, which need to be copied into |rr->data| by decryption.
* When the data is 'copied' into the |rr->data| buffer, |rr->input| will be
* pointed at the new buffer. */
/* We now have - encrypted [ MAC [ compressed [ plain ] ] ]
* rr->length bytes of encrypted compressed stuff. */
/* decrypt in place in 'rr->input' */
rr->data = rr->input;
if (!s->enc_method->enc(s, 0)) {
al = SSL_AD_BAD_RECORD_MAC;
OPENSSL_PUT_ERROR(SSL, ssl3_get_record,
SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
goto f_err;
}
if (rr->length > SSL3_RT_MAX_PLAIN_LENGTH + extra) {
al = SSL_AD_RECORD_OVERFLOW;
OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_DATA_LENGTH_TOO_LONG);
goto f_err;
}
rr->off = 0;
/* So at this point the following is true:
* ssl->s3->rrec.type is the type of record;
* ssl->s3->rrec.length is the number of bytes in the record;
* ssl->s3->rrec.off is the offset to first valid byte;
* ssl->s3->rrec.data is where to take bytes from (increment after use). */
/* we have pulled in a full packet so zero things */
s->packet_length = 0;
/* just read a 0 length packet */
if (rr->length == 0) {
empty_record_count++;
if (empty_record_count > MAX_EMPTY_RECORDS) {
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_TOO_MANY_EMPTY_FRAGMENTS);
goto f_err;
}
goto again;
}
return 1;
f_err:
ssl3_send_alert(s, SSL3_AL_FATAL, al);
err:
return ret;
}
/* Call this to write data in records of type |type|. It will return <= 0 if
* not all data has been sent or non-blocking IO. */
int ssl3_write_bytes(SSL *s, int type, const void *buf_, int len) {
const uint8_t *buf = buf_;
unsigned int tot, n, nw;
int i;
s->rwstate = SSL_NOTHING;
assert(s->s3->wnum <= INT_MAX);
tot = s->s3->wnum;
s->s3->wnum = 0;
if (!s->in_handshake && SSL_in_init(s) && !SSL_in_false_start(s)) {
i = s->handshake_func(s);
if (i < 0) {
return i;
}
if (i == 0) {
OPENSSL_PUT_ERROR(SSL, ssl3_write_bytes, SSL_R_SSL_HANDSHAKE_FAILURE);
return -1;
}
}
/* Ensure that if we end up with a smaller value of data to write out than
* the the original len from a write which didn't complete for non-blocking
* I/O and also somehow ended up avoiding the check for this in
* ssl3_write_pending/SSL_R_BAD_WRITE_RETRY as it must never be possible to
* end up with (len-tot) as a large number that will then promptly send
* beyond the end of the users buffer ... so we trap and report the error in
* a way the user will notice. */
if (len < 0 || (size_t)len < tot) {
OPENSSL_PUT_ERROR(SSL, ssl3_write_bytes, SSL_R_BAD_LENGTH);
return -1;
}
int record_split_done = 0;
n = (len - tot);
for (;;) {
/* max contains the maximum number of bytes that we can put into a
* record. */
unsigned max = s->max_send_fragment;
/* fragment is true if do_ssl3_write should send the first byte in its own
* record in order to randomise a CBC IV. */
int fragment = 0;
if (!record_split_done && s->s3->need_record_splitting &&
type == SSL3_RT_APPLICATION_DATA) {
/* Only the the first record per write call needs to be split. The
* remaining plaintext was determined before the IV was randomized. */
fragment = 1;
record_split_done = 1;
}
if (n > max) {
nw = max;
} else {
nw = n;
}
i = do_ssl3_write(s, type, &buf[tot], nw, fragment);
if (i <= 0) {
s->s3->wnum = tot;
return i;
}
if (i == (int)n || (type == SSL3_RT_APPLICATION_DATA &&
(s->mode & SSL_MODE_ENABLE_PARTIAL_WRITE))) {
return tot + i;
}
n -= i;
tot += i;
}
}
/* ssl3_seal_record seals a new record of type |type| and plaintext |in| and
* writes it to |out|. At most |max_out| bytes will be written. It returns one
* on success and zero on error. On success, |s->s3->wrec| is updated to include
* the new record. */
static int ssl3_seal_record(SSL *s, uint8_t *out, size_t *out_len,
size_t max_out, uint8_t type, const uint8_t *in,
size_t in_len) {
if (max_out < SSL3_RT_HEADER_LENGTH) {
OPENSSL_PUT_ERROR(SSL, ssl3_seal_record, SSL_R_BUFFER_TOO_SMALL);
return 0;
}
out[0] = type;
/* Some servers hang if initial ClientHello is larger than 256 bytes and
* record version number > TLS 1.0. */
if (!s->s3->have_version && s->version > SSL3_VERSION) {
out[1] = TLS1_VERSION >> 8;
out[2] = TLS1_VERSION & 0xff;
} else {
out[1] = s->version >> 8;
out[2] = s->version & 0xff;
}
size_t explicit_nonce_len = 0;
if (s->aead_write_ctx != NULL &&
s->aead_write_ctx->variable_nonce_included_in_record) {
explicit_nonce_len = s->aead_write_ctx->variable_nonce_len;
}
size_t max_overhead = 0;
if (s->aead_write_ctx != NULL) {
max_overhead = s->aead_write_ctx->tag_len;
}
/* Assemble the input for |s->enc_method->enc|. The input is the plaintext
* with |explicit_nonce_len| bytes of space prepended for the explicit
* nonce. The input is copied into |out| and then encrypted in-place to take
* advantage of alignment.
*
* TODO(davidben): |tls1_enc| should accept its inputs and outputs directly
* rather than looking up in |wrec| and friends. The |max_overhead| bounds
* check would also be unnecessary if |max_out| were passed down. */
SSL3_RECORD *wr = &s->s3->wrec;
size_t plaintext_len = in_len + explicit_nonce_len;
if (plaintext_len < in_len || plaintext_len > INT_MAX ||
plaintext_len + max_overhead < plaintext_len) {
OPENSSL_PUT_ERROR(SSL, ssl3_seal_record, ERR_R_OVERFLOW);
return 0;
}
if (max_out - SSL3_RT_HEADER_LENGTH < plaintext_len + max_overhead) {
OPENSSL_PUT_ERROR(SSL, ssl3_seal_record, SSL_R_BUFFER_TOO_SMALL);
return 0;
}
wr->type = type;
wr->input = out + SSL3_RT_HEADER_LENGTH;
wr->data = wr->input;
wr->length = plaintext_len;
memcpy(wr->input + explicit_nonce_len, in, in_len);
if (!s->enc_method->enc(s, 1)) {
return 0;
}
/* |wr->length| has now been set to the ciphertext length. */
if (wr->length >= 1 << 16) {
OPENSSL_PUT_ERROR(SSL, ssl3_seal_record, ERR_R_OVERFLOW);
return 0;
}
out[3] = wr->length >> 8;
out[4] = wr->length & 0xff;
*out_len = SSL3_RT_HEADER_LENGTH + (size_t)wr->length;
if (s->msg_callback) {
s->msg_callback(1 /* write */, 0, SSL3_RT_HEADER, out, SSL3_RT_HEADER_LENGTH,
s, s->msg_callback_arg);
}
return 1;
}
/* do_ssl3_write writes an SSL record of the given type. If |fragment| is 1
* then it splits the record into a one byte record and a record with the rest
* of the data in order to randomise a CBC IV. */
static int do_ssl3_write(SSL *s, int type, const uint8_t *buf, unsigned int len,
char fragment) {
SSL3_BUFFER *wb = &s->s3->wbuf;
/* first check if there is a SSL3_BUFFER still being written out. This will
* happen with non blocking IO */
if (wb->left != 0) {
return ssl3_write_pending(s, type, buf, len);
}
/* If we have an alert to send, lets send it */
if (s->s3->alert_dispatch) {
int ret = s->method->ssl_dispatch_alert(s);
if (ret <= 0) {
return ret;
}
/* if it went, fall through and send more stuff */
}
if (wb->buf == NULL && !ssl3_setup_write_buffer(s)) {
return -1;
}
if (len == 0) {
return 0;
}
if (len == 1) {
/* No sense in fragmenting a one-byte record. */
fragment = 0;
}
/* Align the output so the ciphertext is aligned to |SSL3_ALIGN_PAYLOAD|. */
uintptr_t align;
if (fragment) {
/* Only CBC-mode ciphers require fragmenting. CBC-mode ciphertext is a
* multiple of the block size which we may assume is aligned. Thus we only
* need to account for a second copy of the record header. */
align = (uintptr_t)wb->buf + 2 * SSL3_RT_HEADER_LENGTH;
} else {
align = (uintptr_t)wb->buf + SSL3_RT_HEADER_LENGTH;
}
align = (0 - align) & (SSL3_ALIGN_PAYLOAD - 1);
uint8_t *out = wb->buf + align;
wb->offset = align;
size_t max_out = wb->len - wb->offset;
const uint8_t *orig_buf = buf;
unsigned int orig_len = len;
size_t fragment_len = 0;
if (fragment) {
/* Write the first byte in its own record as a countermeasure against
* known-IV weaknesses in CBC ciphersuites. (See
* http://www.openssl.org/~bodo/tls-cbc.txt.) */
if (!ssl3_seal_record(s, out, &fragment_len, max_out, type, buf, 1)) {
return -1;
}
out += fragment_len;
max_out -= fragment_len;
buf++;
len--;
}
assert((((uintptr_t)out + SSL3_RT_HEADER_LENGTH) & (SSL3_ALIGN_PAYLOAD - 1))
== 0);
size_t ciphertext_len;
if (!ssl3_seal_record(s, out, &ciphertext_len, max_out, type, buf, len)) {
return -1;
}
ciphertext_len += fragment_len;
/* now let's set up wb */
wb->left = ciphertext_len;
/* memorize arguments so that ssl3_write_pending can detect bad write retries
* later */
s->s3->wpend_tot = orig_len;
s->s3->wpend_buf = orig_buf;
s->s3->wpend_type = type;
s->s3->wpend_ret = orig_len;
/* we now just need to write the buffer */
return ssl3_write_pending(s, type, orig_buf, orig_len);
}
/* if s->s3->wbuf.left != 0, we need to call this */
int ssl3_write_pending(SSL *s, int type, const uint8_t *buf, unsigned int len) {
int i;
SSL3_BUFFER *wb = &(s->s3->wbuf);
if (s->s3->wpend_tot > (int)len ||
(s->s3->wpend_buf != buf &&
!(s->mode & SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER)) ||
s->s3->wpend_type != type) {
OPENSSL_PUT_ERROR(SSL, ssl3_write_pending, SSL_R_BAD_WRITE_RETRY);
return -1;
}
for (;;) {
ERR_clear_system_error();
if (s->wbio != NULL) {
s->rwstate = SSL_WRITING;
i = BIO_write(s->wbio, (char *)&(wb->buf[wb->offset]),
(unsigned int)wb->left);
} else {
OPENSSL_PUT_ERROR(SSL, ssl3_write_pending, SSL_R_BIO_NOT_SET);
i = -1;
}
if (i == wb->left) {
wb->left = 0;
wb->offset += i;
ssl3_release_write_buffer(s);
s->rwstate = SSL_NOTHING;
return s->s3->wpend_ret;
} else if (i <= 0) {
if (SSL_IS_DTLS(s)) {
/* For DTLS, just drop it. That's kind of the whole point in
* using a datagram service */
wb->left = 0;
}
return i;
}
/* TODO(davidben): This codepath is used in DTLS, but the write
* payload may not split across packets. */
wb->offset += i;
wb->left -= i;
}
}
/* ssl3_expect_change_cipher_spec informs the record layer that a
* ChangeCipherSpec record is required at this point. If a Handshake record is
* received before ChangeCipherSpec, the connection will fail. Moreover, if
* there are unprocessed handshake bytes, the handshake will also fail and the
* function returns zero. Otherwise, the function returns one. */
int ssl3_expect_change_cipher_spec(SSL *s) {
if (s->s3->handshake_fragment_len > 0 || s->s3->tmp.reuse_message) {
OPENSSL_PUT_ERROR(SSL, ssl3_expect_change_cipher_spec,
SSL_R_UNPROCESSED_HANDSHAKE_DATA);
return 0;
}
s->s3->flags |= SSL3_FLAGS_EXPECT_CCS;
return 1;
}
/* Return up to 'len' payload bytes received in 'type' records.
* 'type' is one of the following:
*
* - SSL3_RT_HANDSHAKE (when ssl3_get_message calls us)
* - SSL3_RT_APPLICATION_DATA (when ssl3_read calls us)
* - 0 (during a shutdown, no data has to be returned)
*
* If we don't have stored data to work from, read a SSL/TLS record first
* (possibly multiple records if we still don't have anything to return).
*
* This function must handle any surprises the peer may have for us, such as
* Alert records (e.g. close_notify), ChangeCipherSpec records (not really
* a surprise, but handled as if it were), or renegotiation requests.
* Also if record payloads contain fragments too small to process, we store
* them until there is enough for the respective protocol (the record protocol
* may use arbitrary fragmentation and even interleaving):
* Change cipher spec protocol
* just 1 byte needed, no need for keeping anything stored
* Alert protocol
* 2 bytes needed (AlertLevel, AlertDescription)
* Handshake protocol
* 4 bytes needed (HandshakeType, uint24 length) -- we just have
* to detect unexpected Client Hello and Hello Request messages
* here, anything else is handled by higher layers
* Application data protocol
* none of our business
*/
int ssl3_read_bytes(SSL *s, int type, uint8_t *buf, int len, int peek) {
int al, i, ret;
unsigned int n;
SSL3_RECORD *rr;
void (*cb)(const SSL *ssl, int type2, int val) = NULL;
if ((type && type != SSL3_RT_APPLICATION_DATA && type != SSL3_RT_HANDSHAKE) ||
(peek && type != SSL3_RT_APPLICATION_DATA)) {
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, ERR_R_INTERNAL_ERROR);
return -1;
}
if (type == SSL3_RT_HANDSHAKE && s->s3->handshake_fragment_len > 0) {
/* (partially) satisfy request from storage */
uint8_t *src = s->s3->handshake_fragment;
uint8_t *dst = buf;
unsigned int k;
/* peek == 0 */
n = 0;
while (len > 0 && s->s3->handshake_fragment_len > 0) {
*dst++ = *src++;
len--;
s->s3->handshake_fragment_len--;
n++;
}
/* move any remaining fragment bytes: */
for (k = 0; k < s->s3->handshake_fragment_len; k++) {
s->s3->handshake_fragment[k] = *src++;
}
return n;
}
/* Now s->s3->handshake_fragment_len == 0 if type == SSL3_RT_HANDSHAKE. */
/* This may require multiple iterations. False Start will cause
* |s->handshake_func| to signal success one step early, but the handshake
* must be completely finished before other modes are accepted.
*
* TODO(davidben): Move this check up to a higher level. */
while (!s->in_handshake && SSL_in_init(s)) {
assert(type == SSL3_RT_APPLICATION_DATA);
i = s->handshake_func(s);
if (i < 0) {
return i;
}
if (i == 0) {
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_SSL_HANDSHAKE_FAILURE);
return -1;
}
}
start:
s->rwstate = SSL_NOTHING;
/* s->s3->rrec.type - is the type of record
* s->s3->rrec.data - data
* s->s3->rrec.off - offset into 'data' for next read
* s->s3->rrec.length - number of bytes. */
rr = &s->s3->rrec;
/* get new packet if necessary */
if (rr->length == 0 || s->rstate == SSL_ST_READ_BODY) {
ret = ssl3_get_record(s);
if (ret <= 0) {
return ret;
}
}
/* we now have a packet which can be read and processed */
/* |change_cipher_spec is set when we receive a ChangeCipherSpec and reset by
* ssl3_get_finished. */
if (s->s3->change_cipher_spec && rr->type != SSL3_RT_HANDSHAKE &&
rr->type != SSL3_RT_ALERT) {
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes,
SSL_R_DATA_BETWEEN_CCS_AND_FINISHED);
goto f_err;
}
/* If we are expecting a ChangeCipherSpec, it is illegal to receive a
* Handshake record. */
if (rr->type == SSL3_RT_HANDSHAKE && (s->s3->flags & SSL3_FLAGS_EXPECT_CCS)) {
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_HANDSHAKE_RECORD_BEFORE_CCS);
goto f_err;
}
/* If the other end has shut down, throw anything we read away (even in
* 'peek' mode) */
if (s->shutdown & SSL_RECEIVED_SHUTDOWN) {
rr->length = 0;
s->rwstate = SSL_NOTHING;
return 0;
}
if (type == rr->type) {
/* SSL3_RT_APPLICATION_DATA or SSL3_RT_HANDSHAKE */
/* make sure that we are not getting application data when we are doing a
* handshake for the first time */
if (SSL_in_init(s) && type == SSL3_RT_APPLICATION_DATA &&
s->aead_read_ctx == NULL) {
/* TODO(davidben): Is this check redundant with the handshake_func
* check? */
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_APP_DATA_IN_HANDSHAKE);
goto f_err;
}
if (len <= 0) {
return len;
}
if ((unsigned int)len > rr->length) {
n = rr->length;
} else {
n = (unsigned int)len;
}
memcpy(buf, &(rr->data[rr->off]), n);
if (!peek) {
rr->length -= n;
rr->off += n;
if (rr->length == 0) {
s->rstate = SSL_ST_READ_HEADER;
rr->off = 0;
if (s->s3->rbuf.left == 0) {
ssl3_release_read_buffer(s);
}
}
}
return n;
}
/* If we get here, then type != rr->type; if we have a handshake message,
* then it was unexpected (Hello Request or Client Hello). */
/* In case of record types for which we have 'fragment' storage, fill that so
* that we can process the data at a fixed place. */
if (rr->type == SSL3_RT_HANDSHAKE) {
/* If peer renegotiations are disabled, all out-of-order handshake records
* are fatal. */
if (!s->accept_peer_renegotiations) {
al = SSL_AD_NO_RENEGOTIATION;
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_NO_RENEGOTIATION);
goto f_err;
}
const size_t size = sizeof(s->s3->handshake_fragment);
const size_t avail = size - s->s3->handshake_fragment_len;
const size_t todo = (rr->length < avail) ? rr->length : avail;
memcpy(s->s3->handshake_fragment + s->s3->handshake_fragment_len,
&rr->data[rr->off], todo);
rr->off += todo;
rr->length -= todo;
s->s3->handshake_fragment_len += todo;
if (s->s3->handshake_fragment_len < size) {
goto start; /* fragment was too small */
}
}
/* s->s3->handshake_fragment_len == 4 iff rr->type == SSL3_RT_HANDSHAKE;
* (Possibly rr is 'empty' now, i.e. rr->length may be 0.) */
/* If we are a client, check for an incoming 'Hello Request': */
if (!s->server && s->s3->handshake_fragment_len >= 4 &&
s->s3->handshake_fragment[0] == SSL3_MT_HELLO_REQUEST &&
s->session != NULL && s->session->cipher != NULL) {
s->s3->handshake_fragment_len = 0;
if (s->s3->handshake_fragment[1] != 0 ||
s->s3->handshake_fragment[2] != 0 ||
s->s3->handshake_fragment[3] != 0) {
al = SSL_AD_DECODE_ERROR;
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_BAD_HELLO_REQUEST);
goto f_err;
}
if (s->msg_callback) {
s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
s->s3->handshake_fragment, 4, s, s->msg_callback_arg);
}
if (SSL_is_init_finished(s) && !s->s3->renegotiate) {
ssl3_renegotiate(s);
if (ssl3_renegotiate_check(s)) {
i = s->handshake_func(s);
if (i < 0) {
return i;
}
if (i == 0) {
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_SSL_HANDSHAKE_FAILURE);
return -1;
}
}
}
/* we either finished a handshake or ignored the request, now try again to
* obtain the (application) data we were asked for */
goto start;
}
/* If an alert record, process one alert out of the record. Note that we allow
* a single record to contain multiple alerts. */
if (rr->type == SSL3_RT_ALERT) {
/* Alerts may not be fragmented. */
if (rr->length < 2) {
al = SSL_AD_DECODE_ERROR;
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_BAD_ALERT);
goto f_err;
}
if (s->msg_callback) {
s->msg_callback(0, s->version, SSL3_RT_ALERT, &rr->data[rr->off], 2, s,
s->msg_callback_arg);
}
const uint8_t alert_level = rr->data[rr->off++];
const uint8_t alert_descr = rr->data[rr->off++];
rr->length -= 2;
if (s->info_callback != NULL) {
cb = s->info_callback;
} else if (s->ctx->info_callback != NULL) {
cb = s->ctx->info_callback;
}
if (cb != NULL) {
uint16_t alert = (alert_level << 8) | alert_descr;
cb(s, SSL_CB_READ_ALERT, alert);
}
if (alert_level == SSL3_AL_WARNING) {
s->s3->warn_alert = alert_descr;
if (alert_descr == SSL_AD_CLOSE_NOTIFY) {
s->shutdown |= SSL_RECEIVED_SHUTDOWN;
return 0;
}
/* This is a warning but we receive it if we requested renegotiation and
* the peer denied it. Terminate with a fatal alert because if
* application tried to renegotiatie it presumably had a good reason and
* expects it to succeed.
*
* In future we might have a renegotiation where we don't care if the
* peer refused it where we carry on. */
else if (alert_descr == SSL_AD_NO_RENEGOTIATION) {
al = SSL_AD_HANDSHAKE_FAILURE;
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_NO_RENEGOTIATION);
goto f_err;
}
} else if (alert_level == SSL3_AL_FATAL) {
char tmp[16];
s->rwstate = SSL_NOTHING;
s->s3->fatal_alert = alert_descr;
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes,
SSL_AD_REASON_OFFSET + alert_descr);
BIO_snprintf(tmp, sizeof(tmp), "%d", alert_descr);
ERR_add_error_data(2, "SSL alert number ", tmp);
s->shutdown |= SSL_RECEIVED_SHUTDOWN;
SSL_CTX_remove_session(s->ctx, s->session);
return 0;
} else {
al = SSL_AD_ILLEGAL_PARAMETER;
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_UNKNOWN_ALERT_TYPE);
goto f_err;
}
goto start;
}
if (s->shutdown & SSL_SENT_SHUTDOWN) {
/* but we have not received a shutdown */
s->rwstate = SSL_NOTHING;
rr->length = 0;
return 0;
}
if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC) {
/* 'Change Cipher Spec' is just a single byte, so we know exactly what the
* record payload has to look like */
if (rr->length != 1 || rr->off != 0 || rr->data[0] != SSL3_MT_CCS) {
al = SSL_AD_ILLEGAL_PARAMETER;
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_BAD_CHANGE_CIPHER_SPEC);
goto f_err;
}
/* Check we have a cipher to change to */
if (s->s3->tmp.new_cipher == NULL) {
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_CCS_RECEIVED_EARLY);
goto f_err;
}
if (!(s->s3->flags & SSL3_FLAGS_EXPECT_CCS)) {
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_CCS_RECEIVED_EARLY);
goto f_err;
}
s->s3->flags &= ~SSL3_FLAGS_EXPECT_CCS;
rr->length = 0;
if (s->msg_callback) {
s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC, rr->data, 1, s,
s->msg_callback_arg);
}
s->s3->change_cipher_spec = 1;
if (!ssl3_do_change_cipher_spec(s)) {
goto err;
} else {
goto start;
}
}
/* Unexpected handshake message (Client Hello, or protocol violation) */
if (s->s3->handshake_fragment_len >= 4 && !s->in_handshake) {
if ((s->state & SSL_ST_MASK) == SSL_ST_OK) {
s->state = s->server ? SSL_ST_ACCEPT : SSL_ST_CONNECT;
s->renegotiate = 1;
s->new_session = 1;
}
i = s->handshake_func(s);
if (i < 0) {
return i;
}
if (i == 0) {
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_SSL_HANDSHAKE_FAILURE);
return -1;
}
goto start;
}
/* We already handled these. */
assert(rr->type != SSL3_RT_CHANGE_CIPHER_SPEC && rr->type != SSL3_RT_ALERT &&
rr->type != SSL3_RT_HANDSHAKE);
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_UNEXPECTED_RECORD);
f_err:
ssl3_send_alert(s, SSL3_AL_FATAL, al);
err:
return -1;
}
int ssl3_do_change_cipher_spec(SSL *s) {
int i;
if (s->state & SSL_ST_ACCEPT) {
i = SSL3_CHANGE_CIPHER_SERVER_READ;
} else {
i = SSL3_CHANGE_CIPHER_CLIENT_READ;
}
if (s->s3->tmp.key_block == NULL) {
if (s->session == NULL || s->session->master_key_length == 0) {
/* might happen if dtls1_read_bytes() calls this */
OPENSSL_PUT_ERROR(SSL, ssl3_do_change_cipher_spec,
SSL_R_CCS_RECEIVED_EARLY);
return 0;
}
s->session->cipher = s->s3->tmp.new_cipher;
if (!s->enc_method->setup_key_block(s)) {
return 0;
}
}
if (!s->enc_method->change_cipher_state(s, i)) {
return 0;
}
return 1;
}
int ssl3_send_alert(SSL *s, int level, int desc) {
/* Map tls/ssl alert value to correct one */
desc = s->enc_method->alert_value(desc);
if (s->version == SSL3_VERSION && desc == SSL_AD_PROTOCOL_VERSION) {
/* SSL 3.0 does not have protocol_version alerts */
desc = SSL_AD_HANDSHAKE_FAILURE;
}
if (desc < 0) {
return -1;
}
/* If a fatal one, remove from cache */
if (level == 2 && s->session != NULL) {
SSL_CTX_remove_session(s->ctx, s->session);
}
s->s3->alert_dispatch = 1;
s->s3->send_alert[0] = level;
s->s3->send_alert[1] = desc;
if (s->s3->wbuf.left == 0) {
/* data is still being written out. */
return s->method->ssl_dispatch_alert(s);
}
/* else data is still being written out, we will get written some time in the
* future */
return -1;
}
int ssl3_dispatch_alert(SSL *s) {
int i, j;
void (*cb)(const SSL *ssl, int type, int val) = NULL;
s->s3->alert_dispatch = 0;
i = do_ssl3_write(s, SSL3_RT_ALERT, &s->s3->send_alert[0], 2, 0);
if (i <= 0) {
s->s3->alert_dispatch = 1;
} else {
/* Alert sent to BIO. If it is important, flush it now. If the message
* does not get sent due to non-blocking IO, we will not worry too much. */
if (s->s3->send_alert[0] == SSL3_AL_FATAL) {
BIO_flush(s->wbio);
}
if (s->msg_callback) {
s->msg_callback(1, s->version, SSL3_RT_ALERT, s->s3->send_alert, 2, s,
s->msg_callback_arg);
}
if (s->info_callback != NULL) {
cb = s->info_callback;
} else if (s->ctx->info_callback != NULL) {
cb = s->ctx->info_callback;
}
if (cb != NULL) {
j = (s->s3->send_alert[0] << 8) | s->s3->send_alert[1];
cb(s, SSL_CB_WRITE_ALERT, j);
}
}
return i;
}
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