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Merge pull request #9872 from rojer/tls_hs_defrag_in

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Defragment incoming TLS handshake messages
This commit is contained in:
Manuel Pégourié-Gonnard
2025-02-24 09:28:11 +01:00
committed by GitHub
parent 03e704018a dd14c0a11e
commit 28f8e205eb
6 changed files with 110 additions and 41 deletions
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5
library/ssl_misc.h
View File

@ -1756,10 +1756,11 @@ void mbedtls_ssl_set_timer(mbedtls_ssl_context *ssl, uint32_t millisecs);
MBEDTLS_CHECK_RETURN_CRITICAL
int mbedtls_ssl_check_timer(mbedtls_ssl_context *ssl);
void mbedtls_ssl_reset_in_out_pointers(mbedtls_ssl_context *ssl);
void mbedtls_ssl_reset_in_pointers(mbedtls_ssl_context *ssl);
void mbedtls_ssl_update_in_pointers(mbedtls_ssl_context *ssl);
void mbedtls_ssl_reset_out_pointers(mbedtls_ssl_context *ssl);
void mbedtls_ssl_update_out_pointers(mbedtls_ssl_context *ssl,
mbedtls_ssl_transform *transform);
void mbedtls_ssl_update_in_pointers(mbedtls_ssl_context *ssl);
MBEDTLS_CHECK_RETURN_CRITICAL
int mbedtls_ssl_session_reset_int(mbedtls_ssl_context *ssl, int partial);

102
library/ssl_msg.c
View File

@ -2962,13 +2962,17 @@ static uint32_t ssl_get_hs_total_len(mbedtls_ssl_context const *ssl)
int mbedtls_ssl_prepare_handshake_record(mbedtls_ssl_context *ssl)
{
if (ssl->in_msglen < mbedtls_ssl_hs_hdr_len(ssl)) {
/* First handshake fragment must at least include the header. */
if (ssl->in_msglen < mbedtls_ssl_hs_hdr_len(ssl) && ssl->in_hslen == 0) {
MBEDTLS_SSL_DEBUG_MSG(1, ("handshake message too short: %" MBEDTLS_PRINTF_SIZET,
ssl->in_msglen));
return MBEDTLS_ERR_SSL_INVALID_RECORD;
}
ssl->in_hslen = mbedtls_ssl_hs_hdr_len(ssl) + ssl_get_hs_total_len(ssl);
if (ssl->in_hslen == 0) {
ssl->in_hslen = mbedtls_ssl_hs_hdr_len(ssl) + ssl_get_hs_total_len(ssl);
ssl->in_hsfraglen = 0;
}
MBEDTLS_SSL_DEBUG_MSG(3, ("handshake message: msglen ="
" %" MBEDTLS_PRINTF_SIZET ", type = %u, hslen = %"
@ -3034,10 +3038,60 @@ int mbedtls_ssl_prepare_handshake_record(mbedtls_ssl_context *ssl)
}
} else
#endif /* MBEDTLS_SSL_PROTO_DTLS */
/* With TLS we don't handle fragmentation (for now) */
if (ssl->in_msglen < ssl->in_hslen) {
MBEDTLS_SSL_DEBUG_MSG(1, ("TLS handshake fragmentation not supported"));
return MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
if (ssl->in_hsfraglen <= ssl->in_hslen) {
int ret;
const size_t hs_remain = ssl->in_hslen - ssl->in_hsfraglen;
MBEDTLS_SSL_DEBUG_MSG(3,
("handshake fragment: %" MBEDTLS_PRINTF_SIZET " .. %"
MBEDTLS_PRINTF_SIZET " of %"
MBEDTLS_PRINTF_SIZET " msglen %" MBEDTLS_PRINTF_SIZET,
ssl->in_hsfraglen,
ssl->in_hsfraglen +
(hs_remain <= ssl->in_msglen ? hs_remain : ssl->in_msglen),
ssl->in_hslen, ssl->in_msglen));
if (ssl->in_msglen < hs_remain) {
ssl->in_hsfraglen += ssl->in_msglen;
ssl->in_hdr = ssl->in_msg + ssl->in_msglen;
ssl->in_msglen = 0;
mbedtls_ssl_update_in_pointers(ssl);
return MBEDTLS_ERR_SSL_CONTINUE_PROCESSING;
}
if (ssl->in_hsfraglen > 0) {
/*
* At in_first_hdr we have a sequence of records that cover the next handshake
* record, each with its own record header that we need to remove.
* Note that the reassembled record size may not equal the size of the message,
* there may be more messages after it, complete or partial.
*/
unsigned char *in_first_hdr = ssl->in_buf + MBEDTLS_SSL_SEQUENCE_NUMBER_LEN;
unsigned char *p = in_first_hdr, *q = NULL;
size_t merged_rec_len = 0;
do {
mbedtls_record rec;
ret = ssl_parse_record_header(ssl, p, mbedtls_ssl_in_hdr_len(ssl), &rec);
if (ret != 0) {
return ret;
}
merged_rec_len += rec.data_len;
p = rec.buf + rec.buf_len;
if (q != NULL) {
memmove(q, rec.buf + rec.data_offset, rec.data_len);
q += rec.data_len;
} else {
q = p;
}
} while (merged_rec_len < ssl->in_hslen);
ssl->in_hdr = in_first_hdr;
mbedtls_ssl_update_in_pointers(ssl);
ssl->in_msglen = merged_rec_len;
/* Adjust message length. */
MBEDTLS_PUT_UINT16_BE(merged_rec_len, ssl->in_len, 0);
ssl->in_hsfraglen = 0;
MBEDTLS_SSL_DEBUG_BUF(4, "reassembled record",
ssl->in_hdr, mbedtls_ssl_in_hdr_len(ssl) + merged_rec_len);
}
} else {
return MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
}
return 0;
@ -4382,6 +4436,16 @@ static int ssl_consume_current_message(mbedtls_ssl_context *ssl)
return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
}
if (ssl->in_hsfraglen != 0) {
/* Not all handshake fragments have arrived, do not consume. */
MBEDTLS_SSL_DEBUG_MSG(3,
("waiting for more fragments (%" MBEDTLS_PRINTF_SIZET " of %"
MBEDTLS_PRINTF_SIZET ", %" MBEDTLS_PRINTF_SIZET " left)",
ssl->in_hsfraglen, ssl->in_hslen,
ssl->in_hslen - ssl->in_hsfraglen));
return 0;
}
/*
* Get next Handshake message in the current record
*/
@ -4407,6 +4471,7 @@ static int ssl_consume_current_message(mbedtls_ssl_context *ssl)
ssl->in_msglen -= ssl->in_hslen;
memmove(ssl->in_msg, ssl->in_msg + ssl->in_hslen,
ssl->in_msglen);
MBEDTLS_PUT_UINT16_BE(ssl->in_msglen, ssl->in_len, 0);
MBEDTLS_SSL_DEBUG_BUF(4, "remaining content in record",
ssl->in_msg, ssl->in_msglen);
@ -5081,7 +5146,7 @@ void mbedtls_ssl_update_in_pointers(mbedtls_ssl_context *ssl)
} else
#endif
{
ssl->in_ctr = ssl->in_hdr - MBEDTLS_SSL_SEQUENCE_NUMBER_LEN;
ssl->in_ctr = ssl->in_buf;
ssl->in_len = ssl->in_hdr + 3;
#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
ssl->in_cid = ssl->in_len;
@ -5097,24 +5162,35 @@ void mbedtls_ssl_update_in_pointers(mbedtls_ssl_context *ssl)
* Setup an SSL context
*/
void mbedtls_ssl_reset_in_out_pointers(mbedtls_ssl_context *ssl)
void mbedtls_ssl_reset_in_pointers(mbedtls_ssl_context *ssl)
{
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) {
ssl->in_hdr = ssl->in_buf;
} else
#endif /* MBEDTLS_SSL_PROTO_DTLS */
{
ssl->in_hdr = ssl->in_buf + MBEDTLS_SSL_SEQUENCE_NUMBER_LEN;
}
/* Derive other internal pointers. */
mbedtls_ssl_update_in_pointers(ssl);
}
void mbedtls_ssl_reset_out_pointers(mbedtls_ssl_context *ssl)
{
/* Set the incoming and outgoing record pointers. */
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) {
ssl->out_hdr = ssl->out_buf;
ssl->in_hdr = ssl->in_buf;
} else
#endif /* MBEDTLS_SSL_PROTO_DTLS */
{
ssl->out_ctr = ssl->out_buf;
ssl->out_hdr = ssl->out_buf + 8;
ssl->in_hdr = ssl->in_buf + 8;
ssl->out_hdr = ssl->out_buf + MBEDTLS_SSL_SEQUENCE_NUMBER_LEN;
}
/* Derive other internal pointers. */
mbedtls_ssl_update_out_pointers(ssl, NULL /* no transform enabled */);
mbedtls_ssl_update_in_pointers(ssl);
}
/*

15
library/ssl_tls.c
View File

@ -339,12 +339,13 @@ static void handle_buffer_resizing(mbedtls_ssl_context *ssl, int downsizing,
size_t out_buf_new_len)
{
int modified = 0;
size_t written_in = 0, iv_offset_in = 0, len_offset_in = 0;
size_t written_in = 0, iv_offset_in = 0, len_offset_in = 0, hdr_in = 0;
size_t written_out = 0, iv_offset_out = 0, len_offset_out = 0;
if (ssl->in_buf != NULL) {
written_in = ssl->in_msg - ssl->in_buf;
iv_offset_in = ssl->in_iv - ssl->in_buf;
len_offset_in = ssl->in_len - ssl->in_buf;
hdr_in = ssl->in_hdr - ssl->in_buf;
if (downsizing ?
ssl->in_buf_len > in_buf_new_len && ssl->in_left < in_buf_new_len :
ssl->in_buf_len < in_buf_new_len) {
@ -376,7 +377,10 @@ static void handle_buffer_resizing(mbedtls_ssl_context *ssl, int downsizing,
}
if (modified) {
/* Update pointers here to avoid doing it twice. */
mbedtls_ssl_reset_in_out_pointers(ssl);
ssl->in_hdr = ssl->in_buf + hdr_in;
mbedtls_ssl_update_in_pointers(ssl);
mbedtls_ssl_reset_out_pointers(ssl);
/* Fields below might not be properly updated with record
* splitting or with CID, so they are manually updated here. */
ssl->out_msg = ssl->out_buf + written_out;
@ -1277,7 +1281,8 @@ int mbedtls_ssl_setup(mbedtls_ssl_context *ssl,
goto error;
}
mbedtls_ssl_reset_in_out_pointers(ssl);
mbedtls_ssl_reset_in_pointers(ssl);
mbedtls_ssl_reset_out_pointers(ssl);
#if defined(MBEDTLS_SSL_DTLS_SRTP)
memset(&ssl->dtls_srtp_info, 0, sizeof(ssl->dtls_srtp_info));
@ -1342,7 +1347,8 @@ void mbedtls_ssl_session_reset_msg_layer(mbedtls_ssl_context *ssl,
/* Cancel any possibly running timer */
mbedtls_ssl_set_timer(ssl, 0);
mbedtls_ssl_reset_in_out_pointers(ssl);
mbedtls_ssl_reset_in_pointers(ssl);
mbedtls_ssl_reset_out_pointers(ssl);
/* Reset incoming message parsing */
ssl->in_offt = NULL;
@ -1350,6 +1356,7 @@ void mbedtls_ssl_session_reset_msg_layer(mbedtls_ssl_context *ssl,
ssl->in_msgtype = 0;
ssl->in_msglen = 0;
ssl->in_hslen = 0;
ssl->in_hsfraglen = 0;
ssl->keep_current_message = 0;
ssl->transform_in = NULL;

22
library/ssl_tls12_server.c
View File

@ -1015,28 +1015,6 @@ read_record_header:
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
return MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE;
}
{
size_t handshake_len = MBEDTLS_GET_UINT24_BE(buf, 1);
MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v3, handshake len.: %u",
(unsigned) handshake_len));
/* The record layer has a record size limit of 2^14 - 1 and
* fragmentation is not supported, so buf[1] should be zero. */
if (buf[1] != 0) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message: %u != 0",
(unsigned) buf[1]));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
/* We don't support fragmentation of ClientHello (yet?) */
if (msg_len != mbedtls_ssl_hs_hdr_len(ssl) + handshake_len) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message: %u != %u + %u",
(unsigned) msg_len,
(unsigned) mbedtls_ssl_hs_hdr_len(ssl),
(unsigned) handshake_len));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
}
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) {