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openssl/ssl/record/rec_layer_d1.c
Matt Caswell 732435026b Resolve a TODO in ssl3_dispatch_alert 
Properly handle the case where there is pending write data and we want
to send an alert.

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19550)
2022-11-14 10:14:41 +01:00

676 lines
21 KiB
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/*
* Copyright 2005-2021 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <stdio.h>
#include <errno.h>
#include "../ssl_local.h"
#include <openssl/evp.h>
#include <openssl/buffer.h>
#include "record_local.h"
#include "internal/packet.h"
#include "internal/cryptlib.h"
int DTLS_RECORD_LAYER_new(RECORD_LAYER *rl)
{
DTLS_RECORD_LAYER *d;
if ((d = OPENSSL_malloc(sizeof(*d))) == NULL)
return 0;
rl->d = d;
d->buffered_app_data.q = pqueue_new();
if (d->buffered_app_data.q == NULL) {
OPENSSL_free(d);
rl->d = NULL;
return 0;
}
return 1;
}
void DTLS_RECORD_LAYER_free(RECORD_LAYER *rl)
{
if (rl->d == NULL)
return;
DTLS_RECORD_LAYER_clear(rl);
pqueue_free(rl->d->buffered_app_data.q);
OPENSSL_free(rl->d);
rl->d = NULL;
}
void DTLS_RECORD_LAYER_clear(RECORD_LAYER *rl)
{
DTLS_RECORD_LAYER *d;
pitem *item = NULL;
TLS_RECORD *rec;
pqueue *buffered_app_data;
d = rl->d;
while ((item = pqueue_pop(d->buffered_app_data.q)) != NULL) {
rec = (TLS_RECORD *)item->data;
if (rl->s->options & SSL_OP_CLEANSE_PLAINTEXT)
OPENSSL_cleanse(rec->data, rec->length);
OPENSSL_free(rec->data);
OPENSSL_free(item->data);
pitem_free(item);
}
buffered_app_data = d->buffered_app_data.q;
memset(d, 0, sizeof(*d));
d->buffered_app_data.q = buffered_app_data;
}
static int dtls_buffer_record(SSL_CONNECTION *s, TLS_RECORD *rec)
{
TLS_RECORD *rdata;
pitem *item;
record_pqueue *queue = &(s->rlayer.d->buffered_app_data);
/* Limit the size of the queue to prevent DOS attacks */
if (pqueue_size(queue->q) >= 100)
return 0;
/* We don't buffer partially read records */
if (!ossl_assert(rec->off == 0))
return -1;
rdata = OPENSSL_malloc(sizeof(*rdata));
item = pitem_new(rec->seq_num, rdata);
if (rdata == NULL || item == NULL) {
OPENSSL_free(rdata);
pitem_free(item);
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return -1;
}
*rdata = *rec;
/*
* We will release the record from the record layer soon, so we take a copy
* now. Copying data isn't good - but this should be infrequent so we
* accept it here.
*/
rdata->data = OPENSSL_memdup(rec->data, rec->length);
if (rdata->data == NULL) {
OPENSSL_free(rdata);
pitem_free(item);
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_CRYPTO_LIB);
return -1;
}
/*
* We use a NULL rechandle to indicate that the data field has been
* allocated by us.
*/
rdata->rechandle = NULL;
item->data = rdata;
#ifndef OPENSSL_NO_SCTP
/* Store bio_dgram_sctp_rcvinfo struct */
if (BIO_dgram_is_sctp(s->rbio) &&
(ossl_statem_get_state(s) == TLS_ST_SR_FINISHED
|| ossl_statem_get_state(s) == TLS_ST_CR_FINISHED)) {
BIO_ctrl(s->rbio, BIO_CTRL_DGRAM_SCTP_GET_RCVINFO,
sizeof(rdata->recordinfo), &rdata->recordinfo);
}
#endif
if (pqueue_insert(queue->q, item) == NULL) {
/* Must be a duplicate so ignore it */
OPENSSL_free(rdata->data);
OPENSSL_free(rdata);
pitem_free(item);
}
return 1;
}
/* Unbuffer a previously buffered TLS_RECORD structure if any */
static void dtls_unbuffer_record(SSL_CONNECTION *s)
{
TLS_RECORD *rdata;
pitem *item;
/* If we already have records to handle then do nothing */
if (s->rlayer.curr_rec < s->rlayer.num_recs)
return;
item = pqueue_pop(s->rlayer.d->buffered_app_data.q);
if (item != NULL) {
rdata = (TLS_RECORD *)item->data;
s->rlayer.tlsrecs[0] = *rdata;
s->rlayer.num_recs = 1;
s->rlayer.curr_rec = 0;
#ifndef OPENSSL_NO_SCTP
/* Restore bio_dgram_sctp_rcvinfo struct */
if (BIO_dgram_is_sctp(s->rbio)) {
BIO_ctrl(s->rbio, BIO_CTRL_DGRAM_SCTP_SET_RCVINFO,
sizeof(rdata->recordinfo), &rdata->recordinfo);
}
#endif
OPENSSL_free(item->data);
pitem_free(item);
}
}
/*-
* 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) or renegotiation requests. ChangeCipherSpec
* messages are treated as if they were handshake messages *if* the |recd_type|
* argument is non NULL.
* 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 dtls1_read_bytes(SSL *s, int type, int *recvd_type, unsigned char *buf,
size_t len, int peek, size_t *readbytes)
{
int i, j, ret;
size_t n;
TLS_RECORD *rr;
void (*cb) (const SSL *ssl, int type2, int val) = NULL;
SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL(s);
if (sc == NULL)
return -1;
if ((type && (type != SSL3_RT_APPLICATION_DATA) &&
(type != SSL3_RT_HANDSHAKE)) ||
(peek && (type != SSL3_RT_APPLICATION_DATA))) {
SSLfatal(sc, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return -1;
}
if (!ossl_statem_get_in_handshake(sc) && SSL_in_init(s)) {
/* type == SSL3_RT_APPLICATION_DATA */
i = sc->handshake_func(s);
/* SSLfatal() already called if appropriate */
if (i < 0)
return i;
if (i == 0)
return -1;
}
start:
sc->rwstate = SSL_NOTHING;
/*
* We are not handshaking and have no data yet, so process data buffered
* during the last handshake in advance, if any.
*/
if (SSL_is_init_finished(s))
dtls_unbuffer_record(sc);
/* Check for timeout */
if (dtls1_handle_timeout(sc) > 0) {
goto start;
} else if (ossl_statem_in_error(sc)) {
/* dtls1_handle_timeout() has failed with a fatal error */
return -1;
}
/* get new packet if necessary */
if (sc->rlayer.curr_rec >= sc->rlayer.num_recs) {
sc->rlayer.curr_rec = sc->rlayer.num_recs = 0;
do {
rr = &sc->rlayer.tlsrecs[sc->rlayer.num_recs];
ret = HANDLE_RLAYER_READ_RETURN(sc,
sc->rlayer.rrlmethod->read_record(sc->rlayer.rrl,
&rr->rechandle,
&rr->version, &rr->type,
&rr->data, &rr->length,
&rr->epoch, rr->seq_num));
if (ret <= 0) {
ret = dtls1_read_failed(sc, ret);
/*
* Anything other than a timeout is an error. SSLfatal() already
* called if appropriate.
*/
if (ret <= 0)
return ret;
else
goto start;
}
rr->off = 0;
sc->rlayer.num_recs++;
} while (sc->rlayer.rrlmethod->processed_read_pending(sc->rlayer.rrl)
&& sc->rlayer.num_recs < SSL_MAX_PIPELINES);
}
rr = &sc->rlayer.tlsrecs[sc->rlayer.curr_rec];
/*
* Reset the count of consecutive warning alerts if we've got a non-empty
* record that isn't an alert.
*/
if (rr->type != SSL3_RT_ALERT && rr->length != 0)
sc->rlayer.alert_count = 0;
/* we now have a packet which can be read and processed */
if (sc->s3.change_cipher_spec /* set when we receive ChangeCipherSpec,
* reset by ssl3_get_finished */
&& (rr->type != SSL3_RT_HANDSHAKE)) {
/*
* We now have application data between CCS and Finished. Most likely
* the packets were reordered on their way, so buffer the application
* data for later processing rather than dropping the connection.
*/
if (dtls_buffer_record(sc, rr) < 0) {
/* SSLfatal() already called */
return -1;
}
ssl_release_record(sc, rr);
goto start;
}
/*
* If the other end has shut down, throw anything we read away (even in
* 'peek' mode)
*/
if (sc->shutdown & SSL_RECEIVED_SHUTDOWN) {
ssl_release_record(sc, rr);
sc->rwstate = SSL_NOTHING;
return 0;
}
if (type == rr->type
|| (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC
&& type == SSL3_RT_HANDSHAKE && recvd_type != NULL)) {
/*
* SSL3_RT_APPLICATION_DATA or
* SSL3_RT_HANDSHAKE or
* SSL3_RT_CHANGE_CIPHER_SPEC
*/
/*
* 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)
&& (SSL_IS_FIRST_HANDSHAKE(sc))) {
SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE,
SSL_R_APP_DATA_IN_HANDSHAKE);
return -1;
}
if (recvd_type != NULL)
*recvd_type = rr->type;
if (len == 0) {
/*
* Release a zero length record. This ensures multiple calls to
* SSL_read() with a zero length buffer will eventually cause
* SSL_pending() to report data as being available.
*/
if (rr->length == 0)
ssl_release_record(sc, rr);
return 0;
}
if (len > rr->length)
n = rr->length;
else
n = len;
memcpy(buf, &(rr->data[rr->off]), n);
if (peek) {
if (rr->length == 0)
ssl_release_record(sc, rr);
} else {
if (sc->options & SSL_OP_CLEANSE_PLAINTEXT)
OPENSSL_cleanse(&(rr->data[rr->off]), n);
rr->length -= n;
rr->off += n;
if (rr->length == 0)
ssl_release_record(sc, rr);
}
#ifndef OPENSSL_NO_SCTP
/*
* We might had to delay a close_notify alert because of reordered
* app data. If there was an alert and there is no message to read
* anymore, finally set shutdown.
*/
if (BIO_dgram_is_sctp(SSL_get_rbio(s)) &&
sc->d1->shutdown_received
&& BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s)) <= 0) {
sc->shutdown |= SSL_RECEIVED_SHUTDOWN;
return 0;
}
#endif
*readbytes = n;
return 1;
}
/*
* If we get here, then type != rr->type; if we have a handshake message,
* then it was unexpected (Hello Request or Client Hello).
*/
if (rr->type == SSL3_RT_ALERT) {
unsigned int alert_level, alert_descr;
unsigned char *alert_bytes = rr->data + rr->off;
PACKET alert;
if (!PACKET_buf_init(&alert, alert_bytes, rr->length)
|| !PACKET_get_1(&alert, &alert_level)
|| !PACKET_get_1(&alert, &alert_descr)
|| PACKET_remaining(&alert) != 0) {
SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_INVALID_ALERT);
return -1;
}
if (sc->msg_callback)
sc->msg_callback(0, sc->version, SSL3_RT_ALERT, alert_bytes, 2, s,
sc->msg_callback_arg);
if (sc->info_callback != NULL)
cb = sc->info_callback;
else if (s->ctx->info_callback != NULL)
cb = s->ctx->info_callback;
if (cb != NULL) {
j = (alert_level << 8) | alert_descr;
cb(s, SSL_CB_READ_ALERT, j);
}
if (alert_level == SSL3_AL_WARNING) {
sc->s3.warn_alert = alert_descr;
ssl_release_record(sc, rr);
sc->rlayer.alert_count++;
if (sc->rlayer.alert_count == MAX_WARN_ALERT_COUNT) {
SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE,
SSL_R_TOO_MANY_WARN_ALERTS);
return -1;
}
if (alert_descr == SSL_AD_CLOSE_NOTIFY) {
#ifndef OPENSSL_NO_SCTP
/*
* With SCTP and streams the socket may deliver app data
* after a close_notify alert. We have to check this first so
* that nothing gets discarded.
*/
if (BIO_dgram_is_sctp(SSL_get_rbio(s)) &&
BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s)) > 0) {
sc->d1->shutdown_received = 1;
sc->rwstate = SSL_READING;
BIO_clear_retry_flags(SSL_get_rbio(s));
BIO_set_retry_read(SSL_get_rbio(s));
return -1;
}
#endif
sc->shutdown |= SSL_RECEIVED_SHUTDOWN;
return 0;
}
} else if (alert_level == SSL3_AL_FATAL) {
sc->rwstate = SSL_NOTHING;
sc->s3.fatal_alert = alert_descr;
SSLfatal_data(sc, SSL_AD_NO_ALERT,
SSL_AD_REASON_OFFSET + alert_descr,
"SSL alert number %d", alert_descr);
sc->shutdown |= SSL_RECEIVED_SHUTDOWN;
ssl_release_record(sc, rr);
SSL_CTX_remove_session(sc->session_ctx, sc->session);
return 0;
} else {
SSLfatal(sc, SSL_AD_ILLEGAL_PARAMETER, SSL_R_UNKNOWN_ALERT_TYPE);
return -1;
}
goto start;
}
if (sc->shutdown & SSL_SENT_SHUTDOWN) { /* but we have not received a
* shutdown */
sc->rwstate = SSL_NOTHING;
ssl_release_record(sc, rr);
return 0;
}
if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC) {
/*
* We can't process a CCS now, because previous handshake messages
* are still missing, so just drop it.
*/
ssl_release_record(sc, rr);
goto start;
}
/*
* Unexpected handshake message (Client Hello, or protocol violation)
*/
if (rr->type == SSL3_RT_HANDSHAKE && !ossl_statem_get_in_handshake(sc)) {
struct hm_header_st msg_hdr;
/*
* This may just be a stale retransmit. Also sanity check that we have
* at least enough record bytes for a message header
*/
if (rr->epoch != sc->rlayer.d->r_epoch
|| rr->length < DTLS1_HM_HEADER_LENGTH) {
ssl_release_record(sc, rr);
goto start;
}
dtls1_get_message_header(rr->data, &msg_hdr);
/*
* If we are server, we may have a repeated FINISHED of the client
* here, then retransmit our CCS and FINISHED.
*/
if (msg_hdr.type == SSL3_MT_FINISHED) {
if (dtls1_check_timeout_num(sc) < 0) {
/* SSLfatal) already called */
return -1;
}
if (dtls1_retransmit_buffered_messages(sc) <= 0) {
/* Fail if we encountered a fatal error */
if (ossl_statem_in_error(sc))
return -1;
}
ssl_release_record(sc, rr);
if (!(sc->mode & SSL_MODE_AUTO_RETRY)) {
if (!sc->rlayer.rrlmethod->unprocessed_read_pending(sc->rlayer.rrl)) {
/* no read-ahead left? */
BIO *bio;
sc->rwstate = SSL_READING;
bio = SSL_get_rbio(s);
BIO_clear_retry_flags(bio);
BIO_set_retry_read(bio);
return -1;
}
}
goto start;
}
/*
* To get here we must be trying to read app data but found handshake
* data. But if we're trying to read app data, and we're not in init
* (which is tested for at the top of this function) then init must be
* finished
*/
if (!ossl_assert(SSL_is_init_finished(s))) {
SSLfatal(sc, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return -1;
}
/* We found handshake data, so we're going back into init */
ossl_statem_set_in_init(sc, 1);
i = sc->handshake_func(s);
/* SSLfatal() called if appropriate */
if (i < 0)
return i;
if (i == 0)
return -1;
if (!(sc->mode & SSL_MODE_AUTO_RETRY)) {
if (!sc->rlayer.rrlmethod->unprocessed_read_pending(sc->rlayer.rrl)) {
/* no read-ahead left? */
BIO *bio;
/*
* In the case where we try to read application data, but we
* trigger an SSL handshake, we return -1 with the retry
* option set. Otherwise renegotiation may cause nasty
* problems in the blocking world
*/
sc->rwstate = SSL_READING;
bio = SSL_get_rbio(s);
BIO_clear_retry_flags(bio);
BIO_set_retry_read(bio);
return -1;
}
}
goto start;
}
switch (rr->type) {
default:
SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_UNEXPECTED_RECORD);
return -1;
case SSL3_RT_CHANGE_CIPHER_SPEC:
case SSL3_RT_ALERT:
case SSL3_RT_HANDSHAKE:
/*
* we already handled all of these, with the possible exception of
* SSL3_RT_HANDSHAKE when ossl_statem_get_in_handshake(s) is true, but
* that should not happen when type != rr->type
*/
SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE, ERR_R_INTERNAL_ERROR);
return -1;
case SSL3_RT_APPLICATION_DATA:
/*
* At this point, we were expecting handshake data, but have
* application data. If the library was running inside ssl3_read()
* (i.e. in_read_app_data is set) and it makes sense to read
* application data at this point (session renegotiation not yet
* started), we will indulge it.
*/
if (sc->s3.in_read_app_data &&
(sc->s3.total_renegotiations != 0) &&
ossl_statem_app_data_allowed(sc)) {
sc->s3.in_read_app_data = 2;
return -1;
} else {
SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_UNEXPECTED_RECORD);
return -1;
}
}
/* not reached */
}
/*
* 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 dtls1_write_bytes(SSL_CONNECTION *s, int type, const void *buf,
size_t len, size_t *written)
{
int i;
if (!ossl_assert(len <= SSL3_RT_MAX_PLAIN_LENGTH)) {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return -1;
}
s->rwstate = SSL_NOTHING;
i = do_dtls1_write(s, type, buf, len, written);
return i;
}
int do_dtls1_write(SSL_CONNECTION *sc, int type, const unsigned char *buf,
size_t len, size_t *written)
{
int i;
OSSL_RECORD_TEMPLATE tmpl;
SSL *s = SSL_CONNECTION_GET_SSL(sc);
int ret;
/* If we have an alert to send, lets send it */
if (sc->s3.alert_dispatch > 0) {
i = s->method->ssl_dispatch_alert(s);
if (i <= 0)
return i;
/* if it went, fall through and send more stuff */
}
if (len == 0)
return 0;
if (len > ssl_get_max_send_fragment(sc)) {
SSLfatal(sc, SSL_AD_INTERNAL_ERROR, SSL_R_EXCEEDS_MAX_FRAGMENT_SIZE);
return 0;
}
tmpl.type = type;
/*
* Special case: for hello verify request, client version 1.0 and we
* haven't decided which version to use yet send back using version 1.0
* header: otherwise some clients will ignore it.
*/
if (s->method->version == DTLS_ANY_VERSION
&& sc->max_proto_version != DTLS1_BAD_VER)
tmpl.version = DTLS1_VERSION;
else
tmpl.version = sc->version;
tmpl.buf = buf;
tmpl.buflen = len;
ret = HANDLE_RLAYER_WRITE_RETURN(sc,
sc->rlayer.wrlmethod->write_records(sc->rlayer.wrl, &tmpl, 1));
if (ret > 0)
*written = (int)len;
return ret;
}
void dtls1_increment_epoch(SSL_CONNECTION *s, int rw)
{
if (rw & SSL3_CC_READ) {
s->rlayer.d->r_epoch++;
/*
* We must not use any buffered messages received from the previous
* epoch
*/
dtls1_clear_received_buffer(s);
} else {
s->rlayer.d->w_epoch++;
}
}
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