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Merge pull request #7455 from KloolK/record-size-limit/comply-with-limit

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Comply with the received Record Size Limit extension
This commit is contained in:
Tom Cosgrove
2024-01-09 15:22:17 +00:00
committed by GitHub
parent 454ab28be5 e2d3db5cfc
commit 3a6059beca
11 changed files with 293 additions and 57 deletions
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68
library/ssl_tls.c
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@ -2455,6 +2455,7 @@ mbedtls_ssl_mode_t mbedtls_ssl_get_mode_from_ciphersuite(
* uint8 ticket_flags;
* opaque resumption_key<0..255>;
* uint32 max_early_data_size;
* uint16 record_size_limit;
* select ( endpoint ) {
* case client: ClientOnlyData;
* case server: uint64 ticket_creation_time;
@ -2490,6 +2491,9 @@ static int ssl_tls13_session_save(const mbedtls_ssl_session *session,
#if defined(MBEDTLS_SSL_EARLY_DATA)
needed += 4; /* max_early_data_size */
#endif
#if defined(MBEDTLS_SSL_RECORD_SIZE_LIMIT)
needed += 2; /* record_size_limit */
#endif /* MBEDTLS_SSL_RECORD_SIZE_LIMIT */
#if defined(MBEDTLS_HAVE_TIME)
needed += 8; /* ticket_creation_time or ticket_reception_time */
@ -2534,6 +2538,10 @@ static int ssl_tls13_session_save(const mbedtls_ssl_session *session,
MBEDTLS_PUT_UINT32_BE(session->max_early_data_size, p, 0);
p += 4;
#endif
#if defined(MBEDTLS_SSL_RECORD_SIZE_LIMIT)
MBEDTLS_PUT_UINT16_BE(session->record_size_limit, p, 0);
p += 2;
#endif /* MBEDTLS_SSL_RECORD_SIZE_LIMIT */
#if defined(MBEDTLS_HAVE_TIME) && defined(MBEDTLS_SSL_SRV_C)
if (session->endpoint == MBEDTLS_SSL_IS_SERVER) {
@ -2610,6 +2618,13 @@ static int ssl_tls13_session_load(mbedtls_ssl_session *session,
session->max_early_data_size = MBEDTLS_GET_UINT32_BE(p, 0);
p += 4;
#endif
#if defined(MBEDTLS_SSL_RECORD_SIZE_LIMIT)
if (end - p < 2) {
return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
}
session->record_size_limit = MBEDTLS_GET_UINT16_BE(p, 0);
p += 2;
#endif /* MBEDTLS_SSL_RECORD_SIZE_LIMIT */
#if defined(MBEDTLS_HAVE_TIME) && defined(MBEDTLS_SSL_SRV_C)
if (session->endpoint == MBEDTLS_SSL_IS_SERVER) {
@ -3372,6 +3387,31 @@ const char *mbedtls_ssl_get_version(const mbedtls_ssl_context *ssl)
}
}
#if defined(MBEDTLS_SSL_RECORD_SIZE_LIMIT)
size_t mbedtls_ssl_get_output_record_size_limit(const mbedtls_ssl_context *ssl)
{
const size_t max_len = MBEDTLS_SSL_OUT_CONTENT_LEN;
size_t record_size_limit = max_len;
if (ssl->session != NULL &&
ssl->session->record_size_limit >= MBEDTLS_SSL_RECORD_SIZE_LIMIT_MIN &&
ssl->session->record_size_limit < max_len) {
record_size_limit = ssl->session->record_size_limit;
}
// TODO: this is currently untested
/* During a handshake, use the value being negotiated */
if (ssl->session_negotiate != NULL &&
ssl->session_negotiate->record_size_limit >= MBEDTLS_SSL_RECORD_SIZE_LIMIT_MIN &&
ssl->session_negotiate->record_size_limit < max_len) {
record_size_limit = ssl->session_negotiate->record_size_limit;
}
return record_size_limit;
}
#endif /* MBEDTLS_SSL_RECORD_SIZE_LIMIT */
#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
size_t mbedtls_ssl_get_input_max_frag_len(const mbedtls_ssl_context *ssl)
{
@ -3458,6 +3498,7 @@ int mbedtls_ssl_get_max_out_record_payload(const mbedtls_ssl_context *ssl)
size_t max_len = MBEDTLS_SSL_OUT_CONTENT_LEN;
#if !defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH) && \
!defined(MBEDTLS_SSL_RECORD_SIZE_LIMIT) && \
!defined(MBEDTLS_SSL_PROTO_DTLS)
(void) ssl;
#endif
@ -3470,6 +3511,30 @@ int mbedtls_ssl_get_max_out_record_payload(const mbedtls_ssl_context *ssl)
}
#endif
#if defined(MBEDTLS_SSL_RECORD_SIZE_LIMIT)
const size_t record_size_limit = mbedtls_ssl_get_output_record_size_limit(ssl);
if (max_len > record_size_limit) {
max_len = record_size_limit;
}
#endif
if (ssl->transform_out != NULL &&
ssl->transform_out->tls_version == MBEDTLS_SSL_VERSION_TLS1_3) {
/* RFC 8449, section 4:
*
* This value [record_size_limit] is the length of the plaintext
* of a protected record.
* The value includes the content type and padding added in TLS 1.3
* (that is, the complete length of TLSInnerPlaintext).
*
* Thus, round down to a multiple of MBEDTLS_SSL_CID_TLS1_3_PADDING_GRANULARITY
* and subtract 1 (for the content type that will be added later)
*/
max_len = ((max_len / MBEDTLS_SSL_CID_TLS1_3_PADDING_GRANULARITY) *
MBEDTLS_SSL_CID_TLS1_3_PADDING_GRANULARITY) - 1;
}
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if (mbedtls_ssl_get_current_mtu(ssl) != 0) {
const size_t mtu = mbedtls_ssl_get_current_mtu(ssl);
@ -3492,7 +3557,8 @@ int mbedtls_ssl_get_max_out_record_payload(const mbedtls_ssl_context *ssl)
#endif /* MBEDTLS_SSL_PROTO_DTLS */
#if !defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH) && \
!defined(MBEDTLS_SSL_PROTO_DTLS)
!defined(MBEDTLS_SSL_PROTO_DTLS) && \
!defined(MBEDTLS_SSL_RECORD_SIZE_LIMIT)
((void) ssl);
#endif