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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** NetX Secure Component */
/** */
/** Transport Layer Security (TLS) */
/** */
/**************************************************************************/
/**************************************************************************/
#define NX_SECURE_SOURCE_CODE
#include "nx_secure_tls.h"
static UINT _nx_secure_tls_record_data_encrypt_init(NX_SECURE_TLS_SESSION *tls_session, NX_PACKET *send_packet,
ULONG sequence_num[NX_SECURE_TLS_SEQUENCE_NUMBER_SIZE],
UCHAR record_type, UINT *data_offset,
const NX_CRYPTO_METHOD *session_cipher_method);
UCHAR _nx_secure_tls_record_block_buffer[NX_SECURE_TLS_MAX_CIPHER_BLOCK_SIZE];
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_tls_record_payload_encrypt PORTABLE C */
/* 6.1.8 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function encrypts the payload of an outgoing TLS record using */
/* the session keys generated and ciphersuite determined during the */
/* TLS handshake. */
/* */
/* INPUT */
/* */
/* tls_session TLS control block */
/* send_packet Pointer to packet data */
/* sequence_num Current TLS/DTLS message num */
/* record_type TLS record type */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* [nx_crypto_operation] Decryption ciphers */
/* */
/* CALLED BY */
/* */
/* _nx_secure_dtls_send_record Send DTLS encrypted record */
/* _nx_secure_tls_send_record Send TLS encrypted record */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* verified memcpy use cases, */
/* fixed data copy in chained */
/* packet, */
/* resulting in version 6.1 */
/* 08-02-2021 Timothy Stapko Modified comment(s), called */
/* NX_CRYPTO_ENCRYPT_CALCULATE */
/* to finalize the encryption */
/* of this record, resulting */
/* in version 6.1.8 */
/* */
/**************************************************************************/
UINT _nx_secure_tls_record_payload_encrypt(NX_SECURE_TLS_SESSION *tls_session, NX_PACKET *send_packet,
ULONG sequence_num[NX_SECURE_TLS_SEQUENCE_NUMBER_SIZE],
UCHAR record_type)
{
UINT status;
UCHAR *iv;
const NX_CRYPTO_METHOD *session_cipher_method;
UINT block_size;
USHORT iv_size;
NX_PACKET *current_packet;
ULONG current_length;
ULONG rounded_length;
ULONG copy_length;
ULONG remainder_length;
UINT data_offset = 0;
VOID *handler = NX_NULL;
VOID *crypto_method_metadata;
UINT icv_size = 0;
UCHAR *icv_ptr = NX_NULL;
if (tls_session -> nx_secure_tls_session_ciphersuite == NX_NULL)
{
/* Likely internal error since at this point ciphersuite negotiation was theoretically completed. */
return(NX_SECURE_TLS_UNKNOWN_CIPHERSUITE);
}
/* Select metadata based on the current mode. */
if (tls_session -> nx_secure_tls_socket_type == NX_SECURE_TLS_SESSION_TYPE_SERVER)
{
/* The socket is a TLS server, so use the server cipher to encrypt. */
iv = tls_session -> nx_secure_tls_key_material.nx_secure_tls_server_iv;
handler = tls_session -> nx_secure_session_cipher_handler_server;
crypto_method_metadata = tls_session -> nx_secure_session_cipher_metadata_area_server;
}
else
{
/* The socket is a TLS client, so use the client cipher to encrypt. */
iv = tls_session -> nx_secure_tls_key_material.nx_secure_tls_client_iv;
handler = tls_session -> nx_secure_session_cipher_handler_client;
crypto_method_metadata = tls_session -> nx_secure_session_cipher_metadata_area_client;
}
/* Select the encryption algorithm based on the ciphersuite. Then, using the session keys and the chosen
cipher, encrypt the data in place. */
session_cipher_method = tls_session -> nx_secure_tls_session_ciphersuite -> nx_secure_tls_session_cipher;
if (session_cipher_method -> nx_crypto_operation == NX_NULL)
{
/* No encryption needed. */
return(NX_SUCCESS);
}
block_size = session_cipher_method -> nx_crypto_block_size_in_bytes;
/* Get the size of the IV used by the session cipher. */
iv_size = session_cipher_method -> nx_crypto_IV_size_in_bits >> 3;
/* Make sure our block size is small enough to fit into our buffer. */
NX_ASSERT((iv_size <= NX_SECURE_TLS_MAX_CIPHER_BLOCK_SIZE) &&
(block_size <= NX_SECURE_TLS_MAX_CIPHER_BLOCK_SIZE));
status = _nx_secure_tls_record_data_encrypt_init(tls_session, send_packet, sequence_num,
record_type, &data_offset, session_cipher_method);
if (status)
{
return(status);
}
/* Iterate through the packet chain using a temporary pointer. */
current_packet = send_packet;
/* Loop through all packets in the chain. */
do
{
/* Get our current packet length. Use the data_offset from any previous iterations. */
current_length = (ULONG)(current_packet -> nx_packet_append_ptr -
current_packet -> nx_packet_prepend_ptr) - data_offset;
/* See if there are more packets in the chain. */
if (current_packet -> nx_packet_next == NX_NULL)
{
if (current_length)
{
/* Encrypt any remaining data in the current packet since it is our last. */
/* Offset should be such that the remaining data in the packet is remainder_length bytes. Add the block-boundary
length to the previous offset to get this new offset. Also, add padding as this is the last bit of data to
be encrypted (all previous packets should have been encrypted without padding). */
status = session_cipher_method -> nx_crypto_operation(NX_CRYPTO_ENCRYPT_UPDATE,
handler,
(NX_CRYPTO_METHOD *)session_cipher_method,
NX_NULL,
0,
¤t_packet -> nx_packet_prepend_ptr[data_offset],
current_length,
NX_NULL,
¤t_packet -> nx_packet_prepend_ptr[data_offset],
current_length,
crypto_method_metadata,
tls_session -> nx_secure_session_cipher_metadata_size,
NX_NULL, NX_NULL);
if (status != NX_SUCCESS)
{
return(status);
}
/* CBC-mode ciphers need to have their IV's updated after encryption. */
if (session_cipher_method -> nx_crypto_algorithm == NX_CRYPTO_ENCRYPTION_AES_CBC)
{
/* New IV is the last encrypted block of the output. */
NX_SECURE_MEMCPY(iv, ¤t_packet -> nx_packet_prepend_ptr[current_length + data_offset - iv_size],
iv_size); /* Use case of memcpy is verified. */
}
}
}
else
{
/* Figure out how much we can encrypt. Get an evenly-divisible
block of data and the remainder. */
if (block_size == 0)
{
remainder_length = 0;
}
else
{
remainder_length = (ULONG)((current_length % block_size));
}
rounded_length = current_length - remainder_length;
if (rounded_length > 0)
{
/* Encrypt remaining data in the current packet from our previous offset to evenly-divisible block boundary. */
status = session_cipher_method -> nx_crypto_operation(NX_CRYPTO_ENCRYPT_UPDATE,
handler,
(NX_CRYPTO_METHOD *)session_cipher_method,
NX_NULL,
0,
¤t_packet -> nx_packet_prepend_ptr[data_offset],
rounded_length,
NX_NULL,
¤t_packet -> nx_packet_prepend_ptr[data_offset],
rounded_length,
crypto_method_metadata,
tls_session -> nx_secure_session_cipher_metadata_size,
NX_NULL, NX_NULL);
if (status != NX_SUCCESS)
{
#ifdef NX_SECURE_KEY_CLEAR
NX_SECURE_MEMSET(_nx_secure_tls_record_block_buffer, 0, block_size);
#endif /* NX_SECURE_KEY_CLEAR */
return(status);
}
}
if (remainder_length)
{
/* Copy data into temporary buffer for encryption.
Pointers: packet2->prepend_ptr[data_offset]---v
Lengths: | current length | remainder | block size - remainder | packet 2 remainder |
Data: |**Packet 1 data***************|**Packet 2 data*************************************|
Temporary: | record block buffer [block size] |
*/
/* Offset for remainder bytes is rounded_length + data_offset. */
NX_SECURE_MEMCPY(&_nx_secure_tls_record_block_buffer[0],
¤t_packet -> nx_packet_prepend_ptr[rounded_length + data_offset],
remainder_length); /* Use case of memcpy is verified. */
copy_length = (ULONG)(current_packet -> nx_packet_next -> nx_packet_append_ptr -
current_packet -> nx_packet_next -> nx_packet_prepend_ptr);
if (copy_length > (ULONG)(block_size - remainder_length))
{
copy_length = (ULONG)(block_size - remainder_length);
}
NX_SECURE_MEMCPY(&_nx_secure_tls_record_block_buffer[remainder_length],
current_packet -> nx_packet_next -> nx_packet_prepend_ptr,
copy_length); /* Use case of memcpy is verified. */
/* Encrypt the remainder block. */
status = session_cipher_method -> nx_crypto_operation(NX_CRYPTO_ENCRYPT_UPDATE,
handler,
(NX_CRYPTO_METHOD *)session_cipher_method,
NX_NULL,
0,
_nx_secure_tls_record_block_buffer,
(remainder_length + copy_length),
NX_NULL,
_nx_secure_tls_record_block_buffer,
(remainder_length + copy_length),
crypto_method_metadata,
tls_session -> nx_secure_session_cipher_metadata_size,
NX_NULL, NX_NULL);
if (status != NX_SUCCESS)
{
#ifdef NX_SECURE_KEY_CLEAR
NX_SECURE_MEMSET(_nx_secure_tls_record_block_buffer, 0, block_size);
#endif /* NX_SECURE_KEY_CLEAR */
return(status);
}
/* Copy data from temporary buffer back into packets. */
NX_SECURE_MEMCPY(¤t_packet -> nx_packet_prepend_ptr[rounded_length + data_offset],
&_nx_secure_tls_record_block_buffer[0], remainder_length); /* Use case of memcpy is verified. */
NX_SECURE_MEMCPY(current_packet -> nx_packet_next -> nx_packet_prepend_ptr,
&_nx_secure_tls_record_block_buffer[remainder_length],
copy_length); /* Use case of memcpy is verified. */
/* CBC-mode ciphers need to have their IV's updated after encryption. */
if (session_cipher_method -> nx_crypto_algorithm == NX_CRYPTO_ENCRYPTION_AES_CBC)
{
/* New IV is the last encrypted block of the output. */
NX_SECURE_MEMCPY(iv, &_nx_secure_tls_record_block_buffer, iv_size); /* Use case of memcpy is verified. */
}
#ifdef NX_SECURE_KEY_CLEAR
NX_SECURE_MEMSET(_nx_secure_tls_record_block_buffer, 0, block_size);
#endif /* NX_SECURE_KEY_CLEAR */
/* Finally, our new offset for the next round is the number of bytes we already
encrypted (along with the remainder bytes) in the next packet. */
data_offset = copy_length;
}
else
{
data_offset = 0;
}
}
/* Move to the next packet. */
current_packet = current_packet -> nx_packet_next;
} while (current_packet != NX_NULL);
if (session_cipher_method -> nx_crypto_ICV_size_in_bits > 0)
{
/* Get icv_size and icv_ptr for AEAD cipher */
if ((session_cipher_method -> nx_crypto_ICV_size_in_bits >> 3) >
sizeof(_nx_secure_tls_record_block_buffer))
{
return(NX_SIZE_ERROR);
}
icv_size = session_cipher_method -> nx_crypto_ICV_size_in_bits >> 3;
icv_ptr = _nx_secure_tls_record_block_buffer;
}
/* Call NX_CRYPTO_ENCRYPT_CALCULATE to finalize the encryption of this record. */
status = session_cipher_method -> nx_crypto_operation(NX_CRYPTO_ENCRYPT_CALCULATE,
handler,
(NX_CRYPTO_METHOD*)session_cipher_method,
NX_NULL,
NX_NULL,
NX_NULL,
0,
NX_NULL,
icv_ptr,
icv_size,
crypto_method_metadata,
tls_session -> nx_secure_session_cipher_metadata_size,
NX_NULL, NX_NULL);
if (status)
{
return(status);
}
if (icv_ptr && icv_size)
{
/* Append data for AEAD cipher */
status = nx_packet_data_append(send_packet, icv_ptr, icv_size,
tls_session -> nx_secure_tls_packet_pool, NX_WAIT_FOREVER);
if (status)
{
return(status);
}
}
return(NX_SUCCESS);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_tls_record_data_encrypt_init PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function is a static helper function used to initialize */
/* metadata for encryption. */
/* */
/* INPUT */
/* */
/* tls_session TLS control block */
/* send_packet Pointer to packet data */
/* sequence_num Current TLS/DTLS message num */
/* record_type TLS record type */
/* data_offset Data offset for Initial Vector*/
/* session_cipher_method Pointer to cipher method */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* [nx_crypto_operation] Decryption ciphers */
/* */
/* CALLED BY */
/* */
/* _nx_secure_tls_record_payload_encrypt Encrypt payload */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* verified memcpy use cases, */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
static UINT _nx_secure_tls_record_data_encrypt_init(NX_SECURE_TLS_SESSION *tls_session, NX_PACKET *send_packet,
ULONG sequence_num[NX_SECURE_TLS_SEQUENCE_NUMBER_SIZE],
UCHAR record_type, UINT *data_offset,
const NX_CRYPTO_METHOD *session_cipher_method)
{
UINT status;
UCHAR *iv;
VOID *handler = NX_NULL;
VOID *crypto_method_metadata;
UINT block_size;
USHORT iv_size;
UCHAR padding_length;
#ifdef NX_SECURE_ENABLE_AEAD_CIPHER
UCHAR additional_data[13];
UINT additional_data_size = 0;
UCHAR nonce[13];
#if (NX_SECURE_TLS_TLS_1_3_ENABLED)
UINT record_length;
#endif
UINT message_length;
#else
NX_PARAMETER_NOT_USED(sequence_num);
NX_PARAMETER_NOT_USED(record_type);
#endif /* NX_SECURE_ENABLE_AEAD_CIPHER */
/* Select IV based on the current mode. */
if (tls_session -> nx_secure_tls_socket_type == NX_SECURE_TLS_SESSION_TYPE_SERVER)
{
/* The socket is a TLS server, so use the server cipher to encrypt. */
iv = tls_session -> nx_secure_tls_key_material.nx_secure_tls_server_iv;
handler = tls_session -> nx_secure_session_cipher_handler_server;
crypto_method_metadata = tls_session -> nx_secure_session_cipher_metadata_area_server;
}
else
{
/* The socket is a TLS client, so use the client cipher to encrypt. */
iv = tls_session -> nx_secure_tls_key_material.nx_secure_tls_client_iv;
handler = tls_session -> nx_secure_session_cipher_handler_client;
crypto_method_metadata = tls_session -> nx_secure_session_cipher_metadata_area_client;
}
/* Offset into current packet data. */
*data_offset = 0;
/* See if we need to add any data to the beginning of the payload such as an IV (e.g. for AES-CBC mode). */
/* !!! NOTE: This relies on nx_secure_tls_packet_allocate reserving block_size bytes between NX_PACKET.nx_packet_prepend_ptr
and nx_packet_append_ptr !!! */
#ifdef NX_SECURE_ENABLE_AEAD_CIPHER
if ((session_cipher_method -> nx_crypto_algorithm == NX_CRYPTO_ENCRYPTION_AES_CCM_8) ||
(session_cipher_method -> nx_crypto_algorithm == NX_CRYPTO_ENCRYPTION_AES_CCM_12) ||
(session_cipher_method -> nx_crypto_algorithm == NX_CRYPTO_ENCRYPTION_AES_CCM_16) ||
(session_cipher_method -> nx_crypto_algorithm == NX_CRYPTO_ENCRYPTION_AES_GCM_16) ||
NX_SECURE_AEAD_CIPHER_CHECK(session_cipher_method -> nx_crypto_algorithm))
{
#if (NX_SECURE_TLS_TLS_1_3_ENABLED)
if (tls_session -> nx_secure_tls_1_3)
{
/*
Each AEAD algorithm will specify a range of possible lengths for the
per-record nonce, from N_MIN bytes to N_MAX bytes of input [RFC5116].
The length of the TLS per-record nonce (iv_length) is set to the
larger of 8 bytes and N_MIN for the AEAD algorithm (see [RFC5116],
Section 4). An AEAD algorithm where N_MAX is less than 8 bytes
MUST NOT be used with TLS. The per-record nonce for the AEAD
construction is formed as follows:
1. The 64-bit record sequence number is encoded in network byte
order and padded to the left with zeros to iv_length.
2. The padded sequence number is XORed with either the static
client_write_iv or server_write_iv (depending on the role).
The resulting quantity (of length iv_length) is used as the
per-record nonce.
Note: This is a different construction from that in TLS 1.2, which
specified a partially explicit nonce.
*/
/* The length of the nonce is 12 bytes. */
nonce[0] = 12;
/* Copy client_write_IV or server_write_IV. */
NX_SECURE_MEMCPY(&nonce[1], iv, 12); /* Use case of memcpy is verified. */
/* Correct the endianness of our sequence number and XOR with
* the IV. Pad to the left with zeroes. */
nonce[1] = (UCHAR)(nonce[1] ^ 0);
nonce[2] = (UCHAR)(nonce[2] ^ 0);
nonce[3] = (UCHAR)(nonce[3] ^ 0);
nonce[4] = (UCHAR)(nonce[4] ^ 0);
nonce[5] = (UCHAR)(nonce[5] ^ (sequence_num[1] >> 24));
nonce[6] = (UCHAR)(nonce[6] ^ (sequence_num[1] >> 16));
nonce[7] = (UCHAR)(nonce[7] ^ (sequence_num[1] >> 8));
nonce[8] = (UCHAR)(nonce[8] ^ (sequence_num[1]));
nonce[9] = (UCHAR)(nonce[9] ^ (sequence_num[0] >> 24));
nonce[10] = (UCHAR)(nonce[10] ^ (sequence_num[0] >> 16));
nonce[11] = (UCHAR)(nonce[11] ^ (sequence_num[0] >> 8));
nonce[12] = (UCHAR)(nonce[12] ^ (sequence_num[0]));
/* additional_data = record header
* record header = TLSCiphertext.opaque_type ||
TLSCiphertext.legacy_record_version ||
TLSCiphertext.length
*/
/* There is no explicit ICV in TLS 1.3 AEAD. */
record_length = send_packet -> nx_packet_length + (session_cipher_method -> nx_crypto_ICV_size_in_bits >> 3);
message_length = send_packet -> nx_packet_length;
additional_data[0] = record_type;
additional_data[1] = (UCHAR)(0x03);
additional_data[2] = (UCHAR)(0x03);
additional_data[3] = (UCHAR)((record_length) >> 8);
additional_data[4] = (UCHAR)(record_length);
/* We have 5 bytes of additional data. */
additional_data_size = 5;
}
else
#endif
{
/* AEAD ciphers structure:
struct {
opaque nonce_explicit[SecurityParameters.record_iv_length];
aead-ciphered struct {
opaque content[TLSCompressed.length];
};
} GenericAEADCipher;
*/
/* The nonce of the CCM cipher is passed into crypto method using iv_ptr.
struct {
uint32 client_write_IV; // low order 32-bits
uint64 seq_num; // TLS sequence number
} CCMClientNonce.
struct {
uint32 server_write_IV; // low order 32-bits
uint64 seq_num; // TLS sequence number
} CCMServerNonce.
*/
/* The length of CCMClientNonce or CCMServerNonce is 12 bytes. */
nonce[0] = 12;
/* Copy client_write_IV or server_write_IV. */
NX_SECURE_MEMCPY(&nonce[1], iv, 4); /* Use case of memcpy is verified. */
/* Correct the endianness of our sequence number before hashing. */
nonce[5] = (UCHAR)(sequence_num[1] >> 24);
nonce[6] = (UCHAR)(sequence_num[1] >> 16);
nonce[7] = (UCHAR)(sequence_num[1] >> 8);
nonce[8] = (UCHAR)(sequence_num[1]);
nonce[9] = (UCHAR)(sequence_num[0] >> 24);
nonce[10] = (UCHAR)(sequence_num[0] >> 16);
nonce[11] = (UCHAR)(sequence_num[0] >> 8);
nonce[12] = (UCHAR)(sequence_num[0]);
/* additional_data = seq_num + TLSCompressed.type +
TLSCompressed.version + TLSCompressed.length;
*/
message_length = send_packet -> nx_packet_length - 8;
NX_SECURE_MEMCPY(additional_data, &nonce[5], 8); /* Use case of memcpy is verified. */
additional_data[8] = record_type;
additional_data[9] = (UCHAR)(tls_session -> nx_secure_tls_protocol_version >> 8);
additional_data[10] = (UCHAR)(tls_session -> nx_secure_tls_protocol_version);
additional_data[11] = (UCHAR)(message_length >> 8);
additional_data[12] = (UCHAR)(message_length);
/* We have 13 bytes of additional data (8 bytes seq num + 5 bytes header). */
additional_data_size = 13;
/* Copy our IV into our data buffer at the head of the payload. */
NX_SECURE_MEMCPY(send_packet -> nx_packet_prepend_ptr, &nonce[5], 8); /* Use case of memcpy is verified. */
*data_offset = 8;
}
/* Initialize crypto algorithm. */
status = session_cipher_method -> nx_crypto_operation(NX_CRYPTO_ENCRYPT_INITIALIZE,
handler,
(NX_CRYPTO_METHOD*)session_cipher_method,
NX_NULL,
0,
additional_data,
additional_data_size,
nonce,
NX_NULL,
message_length,
crypto_method_metadata,
tls_session -> nx_secure_session_cipher_metadata_size,
NX_NULL, NX_NULL);
return(status);
}
#endif /* NX_SECURE_ENABLE_AEAD_CIPHER */
block_size = session_cipher_method -> nx_crypto_block_size_in_bytes;
/* Get the size of the IV used by the session cipher. */
iv_size = session_cipher_method -> nx_crypto_IV_size_in_bits >> 3;
if (session_cipher_method -> nx_crypto_algorithm == NX_CRYPTO_ENCRYPTION_AES_CBC)
{
/* CBC mode has a specific structure for encrypted data, so handle that here:
block-ciphered struct {
opaque IV[CipherSpec.block_length];
opaque content[TLSCompressed.length];
opaque MAC[CipherSpec.hash_size];
uint8 padding[GenericBlockCipher.padding_length];
uint8 padding_length;
} GenericBlockCipher;
*/
/* TLS 1.0 does not use an explicit IV in CBC-mode ciphers, so don't include it
in the record. */
if (tls_session -> nx_secure_tls_protocol_version != NX_SECURE_TLS_VERSION_TLS_1_0)
{
if (iv_size > ((ULONG)(send_packet -> nx_packet_data_end) - (ULONG)(send_packet -> nx_packet_prepend_ptr)))
{
/* Packet buffer too small. */
return(NX_SECURE_TLS_PACKET_BUFFER_TOO_SMALL);
}
/* IV size is equal to the AES block size. Copy our IV into our data buffer
at the head of the payload. */
NX_SECURE_MEMCPY(send_packet -> nx_packet_prepend_ptr, iv, iv_size); /* Use case of memcpy is verified. */
*data_offset = iv_size;
}
if (iv_size != block_size)
{
/* Invalid size. */
return(NX_SECURE_TLS_INVALID_STATE);
}
/* Initialize crypto algorithm. */
status = session_cipher_method -> nx_crypto_operation(NX_CRYPTO_ENCRYPT_INITIALIZE,
handler,
(NX_CRYPTO_METHOD*)session_cipher_method,
NX_NULL,
0,
NX_NULL,
0,
iv,
NX_NULL,
0,
crypto_method_metadata,
tls_session -> nx_secure_session_cipher_metadata_size,
NX_NULL, NX_NULL);
if (status)
{
return(status);
}
}
/* Padding - final output must be an integral multiple of the block size (16 bytes for AES
* modes used in TLS). If the data is not a multiple, the padding consists of bytes each
* with the value of the length of the padding (e.g. for 3 bytes, the padding would be 0x03,
* 0x03, 0x03).
*/
if (block_size > 0)
{
padding_length = (UCHAR)(block_size -
(send_packet -> nx_packet_length % block_size));
NX_SECURE_MEMSET(_nx_secure_tls_record_block_buffer, padding_length - 1, padding_length);
status = nx_packet_data_append(send_packet, _nx_secure_tls_record_block_buffer,
padding_length, tls_session -> nx_secure_tls_packet_pool,
NX_WAIT_FOREVER);
#ifdef NX_SECURE_KEY_CLEAR
NX_SECURE_MEMSET(_nx_secure_tls_record_block_buffer, 0, block_size);
#endif /* NX_SECURE_KEY_CLEAR */
if (status)
{
return(status);
}
}
return(NX_SUCCESS);
}