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Convert dtls_write_records to use standard record layer functions
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We have standard functions for most of the work that dtls_write_records
does - so we convert it to use those functions instead.

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Hugo Landau <hlandau@openssl.org>
(Merged from #19424)
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@mattcaswell
mattcaswell committed Oct 20, 2022
1 parent 248a9bf commit b9e37f8
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Showing 8 changed files with 120 additions and 164 deletions.
182 changes: 62 additions & 120 deletions ssl/record/methods/dtls_meth.c
View file
Expand Up @@ -689,36 +689,52 @@ dtls_new_record_layer(OSSL_LIB_CTX *libctx, const char *propq, int vers,
return ret;
}

int dtls_prepare_record_header(OSSL_RECORD_LAYER *rl,
WPACKET *thispkt,
OSSL_RECORD_TEMPLATE *templ,
unsigned int rectype,
unsigned char **recdata)
{
size_t maxcomplen;

*recdata = NULL;

maxcomplen = templ->buflen;
if (rl->compctx != NULL)
maxcomplen += SSL3_RT_MAX_COMPRESSED_OVERHEAD;

if (!WPACKET_put_bytes_u8(thispkt, rectype)
|| !WPACKET_put_bytes_u16(thispkt, templ->version)
|| !WPACKET_put_bytes_u16(thispkt, rl->epoch)
|| !WPACKET_memcpy(thispkt, &(rl->sequence[2]), 6)
|| !WPACKET_start_sub_packet_u16(thispkt)
|| (rl->eivlen > 0
&& !WPACKET_allocate_bytes(thispkt, rl->eivlen, NULL))
|| (maxcomplen > 0
&& !WPACKET_reserve_bytes(thispkt, maxcomplen,
recdata))) {
RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return 0;
}

return 1;
}

int dtls_write_records(OSSL_RECORD_LAYER *rl, OSSL_RECORD_TEMPLATE *templates,
size_t numtempl)
{
/* TODO(RECLAYER): Remove me */
SSL_CONNECTION *sc = (SSL_CONNECTION *)rl->cbarg;
unsigned char *p, *pseq;
int mac_size, clear = 0;
int eivlen;
int mac_size = 0;
SSL3_RECORD wr;
SSL3_BUFFER *wb;
SSL_SESSION *sess;
SSL *s = SSL_CONNECTION_GET_SSL(sc);
WPACKET pkt, *thispkt = &pkt;
size_t wpinited = 0;
int ret = 0;
unsigned char *compressdata = NULL;

sess = sc->session;

if ((sess == NULL)
|| (sc->enc_write_ctx == NULL)
|| (EVP_MD_CTX_get0_md(sc->write_hash) == NULL))
clear = 1;

if (clear)
mac_size = 0;
else {
mac_size = EVP_MD_CTX_get_size(sc->write_hash);
if (rl->md_ctx != NULL && EVP_MD_CTX_get0_md(rl->md_ctx) != NULL) {
mac_size = EVP_MD_CTX_get_size(rl->md_ctx);
if (mac_size < 0) {
RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR,
SSL_R_EXCEEDS_MAX_FRAGMENT_SIZE);
RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return 0;
}
}
Expand All @@ -741,45 +757,19 @@ int dtls_write_records(OSSL_RECORD_LAYER *rl, OSSL_RECORD_TEMPLATE *templates,
return 0;
}


wb = rl->wbuf;
p = SSL3_BUFFER_get_buf(wb);

/* write the header */

*(p++) = templates->type & 0xff;
SSL3_RECORD_set_type(&wr, templates->type);
*(p++) = templates->version >> 8;
*(p++) = templates->version & 0xff;

/* field where we are to write out packet epoch, seq num and len */
pseq = p;
p += 10;

/* Explicit IV length, block ciphers appropriate version flag */
if (sc->enc_write_ctx) {
int mode = EVP_CIPHER_CTX_get_mode(sc->enc_write_ctx);
if (mode == EVP_CIPH_CBC_MODE) {
eivlen = EVP_CIPHER_CTX_get_iv_length(sc->enc_write_ctx);
if (eivlen < 0) {
RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, SSL_R_LIBRARY_BUG);
goto err;
}
if (eivlen <= 1)
eivlen = 0;
}
/* Need explicit part of IV for GCM mode */
else if (mode == EVP_CIPH_GCM_MODE)
eivlen = EVP_GCM_TLS_EXPLICIT_IV_LEN;
else if (mode == EVP_CIPH_CCM_MODE)
eivlen = EVP_CCM_TLS_EXPLICIT_IV_LEN;
else
eivlen = 0;
} else
eivlen = 0;
SSL3_RECORD_set_rec_version(&wr, templates->version);

if (!rl->funcs->prepare_record_header(rl, thispkt, templates,
templates->type, &compressdata)) {
/* RLAYERfatal() already called */
goto err;
}

/* lets setup the record stuff. */
SSL3_RECORD_set_data(&wr, p + eivlen); /* make room for IV in case of CBC */
SSL3_RECORD_set_data(&wr, compressdata);
SSL3_RECORD_set_length(&wr, templates->buflen);
SSL3_RECORD_set_input(&wr, (unsigned char *)templates->buf);

Expand All @@ -788,91 +778,43 @@ int dtls_write_records(OSSL_RECORD_LAYER *rl, OSSL_RECORD_TEMPLATE *templates,
*/

/* first we compress */
if (sc->compress != NULL) {
if (!ssl3_do_compress(sc, &wr)) {
if (rl->compctx != NULL) {
if (!tls_do_compress(rl, &wr)
|| !WPACKET_allocate_bytes(thispkt, wr.length, NULL)) {
RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, SSL_R_COMPRESSION_FAILURE);
goto err;
}
} else {
memcpy(SSL3_RECORD_get_data(&wr), SSL3_RECORD_get_input(&wr),
SSL3_RECORD_get_length(&wr));
SSL3_RECORD_reset_input(&wr);
}

/*
* we should still have the output to wr.data and the input from
* wr.input. Length should be wr.length. wr.data still points in the
* wb->buf
*/

if (!SSL_WRITE_ETM(sc) && mac_size != 0) {
if (!s->method->ssl3_enc->mac(sc, &wr,
&(p[SSL3_RECORD_get_length(&wr) + eivlen]),
1)) {
} else if (compressdata != NULL) {
if (!WPACKET_memcpy(thispkt, wr.input, wr.length)) {
RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
goto err;
}
SSL3_RECORD_add_length(&wr, mac_size);
SSL3_RECORD_reset_input(&wr);
}

/* this is true regardless of mac size */
SSL3_RECORD_set_data(&wr, p);
SSL3_RECORD_reset_input(&wr);

if (eivlen)
SSL3_RECORD_add_length(&wr, eivlen);

if (s->method->ssl3_enc->enc(sc, &wr, 1, 1, NULL, mac_size) < 1) {
if (!ossl_statem_in_error(sc)) {
RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
}
if (!rl->funcs->prepare_for_encryption(rl, mac_size, thispkt, &wr)) {
/* RLAYERfatal() already called */
goto err;
}

if (SSL_WRITE_ETM(sc) && mac_size != 0) {
if (!s->method->ssl3_enc->mac(sc, &wr,
&(p[SSL3_RECORD_get_length(&wr)]), 1)) {
if (rl->funcs->cipher(rl, &wr, 1, 1, NULL, mac_size) < 1) {
if (rl->alert == SSL_AD_NO_ALERT) {
RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
goto err;
}
SSL3_RECORD_add_length(&wr, mac_size);
goto err;
}

/* record length after mac and block padding */

/* there's only one epoch between handshake and app data */

s2n(sc->rlayer.d->w_epoch, pseq);

memcpy(pseq, &(sc->rlayer.write_sequence[2]), 6);
pseq += 6;
s2n(SSL3_RECORD_get_length(&wr), pseq);

if (sc->msg_callback)
sc->msg_callback(1, 0, SSL3_RT_HEADER, pseq - DTLS1_RT_HEADER_LENGTH,
DTLS1_RT_HEADER_LENGTH, s, sc->msg_callback_arg);

/*
* we should now have wr.data pointing to the encrypted data, which is
* wr->length long
*/
SSL3_RECORD_set_type(&wr, templates->type); /* not needed but helps for debugging */
SSL3_RECORD_add_length(&wr, DTLS1_RT_HEADER_LENGTH);
if (!rl->funcs->post_encryption_processing(rl, mac_size, templates,
thispkt, &wr)) {
/* RLAYERfatal() already called */
goto err;
}

ssl3_record_sequence_update(&(sc->rlayer.write_sequence[0]));
/* TODO(RECLAYER): FIXME */
ssl3_record_sequence_update(rl->sequence);

/* now let's set up wb */
SSL3_BUFFER_set_left(wb, SSL3_RECORD_get_length(&wr));
SSL3_BUFFER_set_offset(wb, 0);

/*
* memorize arguments so that ssl3_write_pending can detect bad write
* retries later
*/
sc->rlayer.wpend_tot = templates->buflen;
sc->rlayer.wpend_buf = templates->buf;
sc->rlayer.wpend_type = templates->type;
sc->rlayer.wpend_ret = templates->buflen;

ret = 1;
err:
Expand Down
6 changes: 6 additions & 0 deletions ssl/record/methods/recmethod_local.h
View file
Expand Up @@ -349,11 +349,17 @@ int tls_default_read_n(OSSL_RECORD_LAYER *rl, size_t n, size_t max, int extend,
int tls_get_more_records(OSSL_RECORD_LAYER *rl);
int dtls_get_more_records(OSSL_RECORD_LAYER *rl);

int dtls_prepare_record_header(OSSL_RECORD_LAYER *rl,
WPACKET *thispkt,
OSSL_RECORD_TEMPLATE *templ,
unsigned int rectype,
unsigned char **recdata);
int dtls_write_records(OSSL_RECORD_LAYER *rl, OSSL_RECORD_TEMPLATE *templates,
size_t numtempl);

int tls_default_set_protocol_version(OSSL_RECORD_LAYER *rl, int version);
int tls_default_validate_record_header(OSSL_RECORD_LAYER *rl, SSL3_RECORD *re);
int tls_do_compress(OSSL_RECORD_LAYER *rl, SSL3_RECORD *wr);
int tls_do_uncompress(OSSL_RECORD_LAYER *rl, SSL3_RECORD *rec);
int tls_default_post_process_record(OSSL_RECORD_LAYER *rl, SSL3_RECORD *rec);
int tls13_common_post_process_record(OSSL_RECORD_LAYER *rl, SSL3_RECORD *rec);
Expand Down
5 changes: 3 additions & 2 deletions ssl/record/methods/tls1_meth.c
View file
Expand Up @@ -683,8 +683,9 @@ struct record_functions_st dtls_1_funcs = {
/* Don't use tls1_initialise_write_packets for same reason as above */
tls_initialise_write_packets_default,
NULL,
dtls_prepare_record_header,
NULL,
NULL,
NULL,
tls_prepare_for_encryption_default,
tls_post_encryption_processing_default,
NULL
};
13 changes: 8 additions & 5 deletions ssl/record/methods/tls_common.c
View file
Expand Up @@ -962,7 +962,7 @@ int tls_default_validate_record_header(OSSL_RECORD_LAYER *rl, SSL3_RECORD *rec)
return 1;
}

static int tls_do_compress(OSSL_RECORD_LAYER *rl, SSL3_RECORD *wr)
int tls_do_compress(OSSL_RECORD_LAYER *rl, SSL3_RECORD *wr)
{
#ifndef OPENSSL_NO_COMP
int i;
Expand Down Expand Up @@ -1514,7 +1514,8 @@ int tls_initialise_write_packets_default(OSSL_RECORD_LAYER *rl,
wb->type = templates[j].type;

#if defined(SSL3_ALIGN_PAYLOAD) && SSL3_ALIGN_PAYLOAD != 0
align = (size_t)SSL3_BUFFER_get_buf(wb) + SSL3_RT_HEADER_LENGTH;
align = (size_t)SSL3_BUFFER_get_buf(wb);
align += rl->isdtls ? DTLS1_RT_HEADER_LENGTH : SSL3_RT_HEADER_LENGTH;
align = SSL3_ALIGN_PAYLOAD - 1
- ((align - 1) % SSL3_ALIGN_PAYLOAD);
#endif
Expand Down Expand Up @@ -1621,6 +1622,8 @@ int tls_post_encryption_processing_default(OSSL_RECORD_LAYER *rl,
SSL3_RECORD *thiswr)
{
size_t origlen, len;
size_t headerlen = rl->isdtls ? DTLS1_RT_HEADER_LENGTH
: SSL3_RT_HEADER_LENGTH;

/* Allocate bytes for the encryption overhead */
if (!WPACKET_get_length(thispkt, &origlen)
Expand Down Expand Up @@ -1654,9 +1657,9 @@ int tls_post_encryption_processing_default(OSSL_RECORD_LAYER *rl,
if (rl->msg_callback != NULL) {
unsigned char *recordstart;

recordstart = WPACKET_get_curr(thispkt) - len - SSL3_RT_HEADER_LENGTH;
recordstart = WPACKET_get_curr(thispkt) - len - headerlen;
rl->msg_callback(1, thiswr->rec_version, SSL3_RT_HEADER, recordstart,
SSL3_RT_HEADER_LENGTH, rl->cbarg);
headerlen, rl->cbarg);

if (rl->version == TLS1_3_VERSION && rl->enc_ctx != NULL) {
unsigned char ctype = thistempl->type;
Expand All @@ -1671,7 +1674,7 @@ int tls_post_encryption_processing_default(OSSL_RECORD_LAYER *rl,
return 0;
}

SSL3_RECORD_add_length(thiswr, SSL3_RT_HEADER_LENGTH);
SSL3_RECORD_add_length(thiswr, headerlen);

return 1;
}
Expand Down
6 changes: 3 additions & 3 deletions ssl/record/methods/tlsany_meth.c
View file
Expand Up @@ -187,9 +187,9 @@ struct record_functions_st dtls_any_funcs = {
tls_allocate_write_buffers_default,
tls_initialise_write_packets_default,
NULL,
dtls_prepare_record_header,
NULL,
NULL,
NULL,
NULL,
tls_prepare_for_encryption_default,
tls_post_encryption_processing_default,
NULL
};
18 changes: 15 additions & 3 deletions ssl/record/rec_layer_s3.c
View file
Expand Up @@ -1267,6 +1267,10 @@ int ssl_set_new_record_layer(SSL_CONNECTION *s, int version,
return 0;
}
s->rlayer.rrlnext = next;
} else {
if (SSL_CONNECTION_IS_DTLS(s)
&& level != OSSL_RECORD_PROTECTION_LEVEL_NONE)
epoch = DTLS_RECORD_LAYER_get_w_epoch(&s->rlayer) + 1; /* new epoch */
}

/*
Expand Down Expand Up @@ -1325,9 +1329,17 @@ int ssl_set_new_record_layer(SSL_CONNECTION *s, int version,
break;
}

if (*thismethod != NULL && !(*thismethod)->free(*thisrl)) {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return 0;
/*
* Free the old record layer if we have one except in the case of DTLS when
* writing. In that case the record layer is still referenced by buffered
* messages for potential retransmit. Only when those buffered messages get
* freed do we free the record layer object (see dtls1_hm_fragment_free)
*/
if (!SSL_CONNECTION_IS_DTLS(s) || direction == OSSL_RECORD_DIRECTION_READ) {
if (*thismethod != NULL && !(*thismethod)->free(*thisrl)) {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return 0;
}
}

*thisrl = newrl;
Expand Down
7 changes: 2 additions & 5 deletions ssl/ssl_local.h
View file
Expand Up @@ -1915,11 +1915,8 @@ typedef struct {
# define DTLS1_SKIP_RECORD_HEADER 2

struct dtls1_retransmit_state {
EVP_CIPHER_CTX *enc_write_ctx; /* cryptographic state */
EVP_MD_CTX *write_hash; /* used for mac generation */
COMP_CTX *compress; /* compression */
SSL_SESSION *session;
uint16_t epoch;
const OSSL_RECORD_METHOD *wrlmethod;
OSSL_RECORD_LAYER *wrl;
};

struct hm_header_st {
Expand Down

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