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Fixed issues in the PSK implementation #386

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Merged
fdesbiens merged 2 commits into from
May 28, 2026
Merged

Fixed issues in the PSK implementation #386

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f054fad
Fixed server PSK identity selection for ECDHE-PSK
fdesbiens May 12, 2026
69dd226
Fixed selected client PSK identity preservation
fdesbiens May 13, 2026
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46 changes: 36 additions & 10 deletions nx_secure/src/nx_secure_generate_client_key_exchange.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,8 @@
* SPDX-License-Identifier: MIT
**************************************************************************/

// Some portions generated by Codex gpt-5.5.


/**************************************************************************/
/**************************************************************************/
Expand Down Expand Up @@ -124,15 +126,40 @@ NX_CRYPTO_EXTENDED_OUTPUT extended_output;
{
data_size = (UINT)(1 + tls_key_material -> nx_secure_tls_new_key_material_data[0]);

if ((data_size > sizeof(tls_key_material -> nx_secure_tls_new_key_material_data)) ||
(data_size > buffer_length))
#ifdef NX_SECURE_ENABLE_PSK_CIPHERSUITES
if (ciphersuite -> nx_secure_tls_public_auth -> nx_crypto_algorithm == NX_CRYPTO_KEY_EXCHANGE_PSK)
{
if ((tls_credentials -> nx_secure_tls_client_psk.nx_secure_tls_psk_id_size >
sizeof(tls_credentials -> nx_secure_tls_client_psk.nx_secure_tls_psk_id)) ||
(data_size > sizeof(tls_key_material -> nx_secure_tls_new_key_material_data)) ||
(((ULONG)data_size + 2u + tls_credentials -> nx_secure_tls_client_psk.nx_secure_tls_psk_id_size) > buffer_length))
{

/* Packet buffer too small. */
return(NX_SECURE_TLS_PACKET_BUFFER_TOO_SMALL);
/* Packet buffer too small. */
return(NX_SECURE_TLS_PACKET_BUFFER_TOO_SMALL);
}

data_buffer[0] = (UCHAR)((tls_credentials -> nx_secure_tls_client_psk.nx_secure_tls_psk_id_size & 0xFF00) >> 8);
data_buffer[1] = (UCHAR)(tls_credentials -> nx_secure_tls_client_psk.nx_secure_tls_psk_id_size & 0x00FF);
NX_SECURE_MEMCPY(&data_buffer[2], tls_credentials -> nx_secure_tls_client_psk.nx_secure_tls_psk_id,
tls_credentials -> nx_secure_tls_client_psk.nx_secure_tls_psk_id_size); /* Use case of memcpy is verified. */
NX_SECURE_MEMCPY(&data_buffer[2 + tls_credentials -> nx_secure_tls_client_psk.nx_secure_tls_psk_id_size],
tls_key_material -> nx_secure_tls_new_key_material_data, data_size); /* Use case of memcpy is verified. */
data_size += 2 + tls_credentials -> nx_secure_tls_client_psk.nx_secure_tls_psk_id_size;
}
else
#endif /* NX_SECURE_ENABLE_PSK_CIPHERSUITES */
{
if ((data_size > sizeof(tls_key_material -> nx_secure_tls_new_key_material_data)) ||
(data_size > buffer_length))
{

NX_SECURE_MEMCPY(data_buffer, tls_key_material -> nx_secure_tls_new_key_material_data, data_size); /* Use case of memcpy is verified. */
/* Packet buffer too small. */
return(NX_SECURE_TLS_PACKET_BUFFER_TOO_SMALL);
}

NX_SECURE_MEMCPY(data_buffer, tls_key_material -> nx_secure_tls_new_key_material_data, data_size); /* Use case of memcpy is verified. */
}
}
else
#endif /* NX_SECURE_ENABLE_ECC_CIPHERSUITE */
Expand All @@ -145,10 +172,10 @@ NX_CRYPTO_EXTENDED_OUTPUT extended_output;
/* Check for PSK ciphersuites. */
if (ciphersuite -> nx_secure_tls_public_auth -> nx_crypto_algorithm == NX_CRYPTO_KEY_EXCHANGE_PSK)
{
if ((tls_credentials -> nx_secure_tls_client_psk.nx_secure_tls_psk_id_hint_size >
sizeof(tls_credentials -> nx_secure_tls_client_psk.nx_secure_tls_psk_id_hint)) ||
(tls_credentials -> nx_secure_tls_client_psk.nx_secure_tls_psk_id_hint_size >
(buffer_length - 2)))
if ((tls_credentials -> nx_secure_tls_client_psk.nx_secure_tls_psk_id_size >
sizeof(tls_credentials -> nx_secure_tls_client_psk.nx_secure_tls_psk_id)) ||
((buffer_length < 2u) || (tls_credentials -> nx_secure_tls_client_psk.nx_secure_tls_psk_id_size >
(buffer_length - 2u))))
{

/* Packet buffer too small. */
Expand Down Expand Up @@ -327,4 +354,3 @@ NX_CRYPTO_EXTENDED_OUTPUT extended_output;

return(NX_SECURE_TLS_SUCCESS);
}

180 changes: 172 additions & 8 deletions nx_secure/src/nx_secure_generate_premaster_secret.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,8 @@
* SPDX-License-Identifier: MIT
**************************************************************************/

// Some portions generated by Codex gpt-5.5.


/**************************************************************************/
/**************************************************************************/
Expand All @@ -24,6 +26,141 @@

#include "nx_secure_tls.h"

#ifdef NX_SECURE_ENABLE_PSK_CIPHERSUITES
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_tls_psk_identity_lookup PORTABLE C */
/* 6.x */
/* AUTHOR */
/* */
/* Eclipse ThreadX Contributors */
/* */
/* DESCRIPTION */
/* */
/* This function searches the PSK store for an entry matching a peer */
/* PSK identity. */
/* */
/* INPUT */
/* */
/* tls_credentials TLS credentials */
/* psk_data Destination for PSK data */
/* psk_length Destination for PSK length */
/* psk_identity PSK identity data */
/* identity_length PSK identity length */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* tx_mutex_get Get TLS protection */
/* tx_mutex_put Release TLS protection */
/* */
/* CALLED BY */
/* */
/* _nx_secure_generate_premaster_secret Generate pre-master secret */
/* */
/**************************************************************************/
static UINT _nx_secure_tls_psk_identity_lookup(NX_SECURE_TLS_CREDENTIALS *tls_credentials, UCHAR **psk_data, UINT *psk_length,
UCHAR *psk_identity, UINT identity_length)
{
UINT psk_list_size;
UINT i;

/* Get the protection. */
tx_mutex_get(&_nx_secure_tls_protection, TX_WAIT_FOREVER);

psk_list_size = tls_credentials -> nx_secure_tls_psk_count;

/* Loop through all PSKs, looking for a matching identity string. */
for (i = 0; i < psk_list_size; ++i)
{
if (identity_length == tls_credentials -> nx_secure_tls_psk_store[i].nx_secure_tls_psk_id_size)
{
if (NX_SECURE_MEMCMP(tls_credentials -> nx_secure_tls_psk_store[i].nx_secure_tls_psk_id,
psk_identity, identity_length) == 0)
{
*psk_data = tls_credentials -> nx_secure_tls_psk_store[i].nx_secure_tls_psk_data;
*psk_length = tls_credentials -> nx_secure_tls_psk_store[i].nx_secure_tls_psk_data_size;

/* Release the protection. */
tx_mutex_put(&_nx_secure_tls_protection);

return(NX_SUCCESS);
}
}
}

/* Release the protection. */
tx_mutex_put(&_nx_secure_tls_protection);

return(NX_SECURE_TLS_NO_MATCHING_PSK);
}

/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_tls_client_psk_save PORTABLE C */
/* 6.x */
/* AUTHOR */
/* */
/* Eclipse ThreadX Contributors */
/* */
/* DESCRIPTION */
/* */
/* This function saves the PSK store entry selected by the server */
/* identity hint so the client sends the matching identity in */
/* ClientKeyExchange. */
/* */
/* INPUT */
/* */
/* tls_credentials TLS credentials */
/* psk_store_index Selected PSK store index */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* tx_mutex_get Get TLS protection */
/* tx_mutex_put Release TLS protection */
/* */
/* CALLED BY */
/* */
/* _nx_secure_generate_premaster_secret Generate pre-master secret */
/* */
/**************************************************************************/
static UINT _nx_secure_tls_client_psk_save(NX_SECURE_TLS_CREDENTIALS *tls_credentials, UINT psk_store_index)
{
UINT status;

/* Get the protection. */
tx_mutex_get(&_nx_secure_tls_protection, TX_WAIT_FOREVER);

if (psk_store_index < tls_credentials -> nx_secure_tls_psk_count)
{
NX_SECURE_MEMCPY(&tls_credentials -> nx_secure_tls_client_psk,
&tls_credentials -> nx_secure_tls_psk_store[psk_store_index],
sizeof(NX_SECURE_TLS_PSK_STORE)); /* Use case of memcpy is verified. */
status = NX_SUCCESS;
}
else
{
status = NX_SECURE_TLS_NO_MATCHING_PSK;
}

/* Release the protection. */
tx_mutex_put(&_nx_secure_tls_protection);

return(status);
}
#endif

/**************************************************************************/
/* */
/* FUNCTION RELEASE */
Expand Down Expand Up @@ -80,6 +217,7 @@ UINT status = NX_SECURE_TLS_SUCCESS;
UCHAR *psk_data;
UINT psk_length;
UINT index;
UINT psk_store_index;
#endif
#if defined(NX_SECURE_ENABLE_ECC_CIPHERSUITE) && !defined(NX_SECURE_DISABLE_X509)
NX_SECURE_X509_CERT *server_certificate;
Expand Down Expand Up @@ -125,9 +263,24 @@ UINT pre_master_secret_size;
containing the length of the PSK (in octets), and the PSK itself.
*/

/* Client has to search for the PSK based on the identity hint. */
status = _nx_secure_tls_psk_find(tls_credentials, &psk_data, &psk_length, tls_credentials -> nx_secure_tls_remote_psk_id,
tls_credentials -> nx_secure_tls_remote_psk_id_size, NX_NULL);
if (session_type == NX_SECURE_TLS_SESSION_TYPE_SERVER)
{
/* Server searches for the PSK based on the identity requested by the client. */
status = _nx_secure_tls_psk_identity_lookup(tls_credentials, &psk_data, &psk_length,
tls_credentials -> nx_secure_tls_remote_psk_id,
tls_credentials -> nx_secure_tls_remote_psk_id_size);
}
else
{
/* Client has to search for the PSK based on the identity hint. */
status = _nx_secure_tls_psk_find(tls_credentials, &psk_data, &psk_length,
tls_credentials -> nx_secure_tls_remote_psk_id,
tls_credentials -> nx_secure_tls_remote_psk_id_size, &psk_store_index);
if (status == NX_SUCCESS)
{
status = _nx_secure_tls_client_psk_save(tls_credentials, psk_store_index);
}
}

if (status != NX_SUCCESS)
{
Expand Down Expand Up @@ -280,20 +433,32 @@ UINT pre_master_secret_size;
/* Now, using the identity as a key, find the PSK in our PSK store. */
if (session_type == NX_SECURE_TLS_SESSION_TYPE_SERVER)
{
/* Server just uses its PSK. */
psk_data = tls_credentials -> nx_secure_tls_psk_store[0].nx_secure_tls_psk_data;
psk_length = tls_credentials -> nx_secure_tls_psk_store[0].nx_secure_tls_psk_data_size;
/* Server searches for the PSK based on the identity requested by the client. */
status = _nx_secure_tls_psk_identity_lookup(tls_credentials, &psk_data, &psk_length,
tls_credentials -> nx_secure_tls_remote_psk_id,
tls_credentials -> nx_secure_tls_remote_psk_id_size);

if (status != NX_SUCCESS)
{
return(status);
}
}
else
{
/* Client has to search for the PSK based on the identity hint. */
status = _nx_secure_tls_psk_find(tls_credentials, &psk_data, &psk_length, tls_credentials -> nx_secure_tls_remote_psk_id,
tls_credentials -> nx_secure_tls_remote_psk_id_size, NX_NULL);
tls_credentials -> nx_secure_tls_remote_psk_id_size, &psk_store_index);

if (status != NX_SUCCESS)
{
return(status);
}

status = _nx_secure_tls_client_psk_save(tls_credentials, psk_store_index);
if (status != NX_SUCCESS)
{
return(status);
}
}

/* From RFC 4279:
Expand Down Expand Up @@ -369,4 +534,3 @@ UINT pre_master_secret_size;

return(status);
}

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