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lib: bluetooth: peer_manager: LESC DHkey computation request fixes #857

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Merged
eivindj-nordic merged 2 commits into from
Sep 22, 2026
Merged

lib: bluetooth: peer_manager: LESC DHkey computation request fixes #857

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1a30bc2
lib: peer_manager: lesc dhkey reply, treat invalid conn handle as ok
anhmolt Sep 9, 2026
c642fda
lib: peer_manager: fix DHkey computation requested state
anhmolt Sep 9, 2026
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35 changes: 25 additions & 10 deletions lib/bluetooth/peer_manager/modules/nrf_ble_lesc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@
#include <bm/softdevice_handler/nrf_sdh_ble.h>
#include <psa/crypto.h>
#include <zephyr/logging/log.h>
#include <zephyr/sys/atomic.h>
#include <zephyr/sys/byteorder.h>
#include <zephyr/sys/util.h>
#include <zephyr/sys/printk.h>
Expand All @@ -20,14 +21,20 @@

LOG_MODULE_DECLARE(peer_manager, CONFIG_PEER_MANAGER_LOG_LEVEL);

#define STATE_IDLE 0
#define STATE_REQUESTED 1
#define STATE_PROCESSING 2

/** @brief Descriptor of the peer public key. */
struct lesc_peer_pub_key {
/** @brief Peer public key. Stored in little-endian. */
uint8_t value[BLE_GAP_LESC_P256_PK_LEN];
/** @brief Peer connection handle. */
uint16_t conn_handle;
/** @brief Flag indicating that the public key has been requested to compute DH key. */
bool is_requested;
/** @brief State variable indicating whether the DH key computation have been requested
* or is currently being processed.
*/
atomic_t state;
};

/**
Expand Down Expand Up @@ -103,7 +110,7 @@ uint32_t nrf_ble_lesc_keypair_generate(void)

/* Check if any DH computation is pending */
for (uint16_t i = 0; i < ARRAY_SIZE(peer_keys); i++) {
if (peer_keys[i].is_requested) {
if (atomic_get(&peer_keys[i].state) != STATE_IDLE) {
return NRF_ERROR_BUSY;
}
}
Expand Down Expand Up @@ -284,6 +291,13 @@ static uint32_t compute_and_give_dhkey(struct lesc_peer_pub_key *peer_public_key
/* Discard the key immediately after handing it over to the SoftDevice. */
memset(lesc_dh_key.key, 0, sizeof(lesc_dh_key.key));

if (nrf_err == BLE_ERROR_INVALID_CONN_HANDLE) {
/* The peer disconnected before the SoftDevice was handed the LESC DHKey.
* The LESC DHKey is no longer needed by SoftDevice, so treat this as a success.
*/
nrf_err = NRF_SUCCESS;
}

return nrf_err;
}

Expand All @@ -297,9 +311,9 @@ uint32_t nrf_ble_lesc_request_handler(void)
}

for (uint16_t i = 0; i < NRF_BLE_LESC_LINK_COUNT; i++) {
if (peer_keys[i].is_requested) {
if (atomic_cas(&peer_keys[i].state, STATE_REQUESTED, STATE_PROCESSING)) {
nrf_err = compute_and_give_dhkey(&peer_keys[i]);
peer_keys[i].is_requested = false;
(void)atomic_set(&peer_keys[i].state, STATE_IDLE);

if (nrf_err) {
return nrf_err;
Expand All @@ -322,9 +336,11 @@ static void on_dhkey_request(uint16_t conn_handle, int idx,
{
const uint8_t *const public_raw = dhkey_request->p_pk_peer->pk;

memcpy(peer_keys[idx].value, public_raw, BLE_GAP_LESC_P256_PK_LEN);
peer_keys[idx].conn_handle = conn_handle;
peer_keys[idx].is_requested = true;
if (atomic_get(&peer_keys[idx].state) == STATE_IDLE) {
memcpy(peer_keys[idx].value, public_raw, BLE_GAP_LESC_P256_PK_LEN);
peer_keys[idx].conn_handle = conn_handle;
atomic_set(&peer_keys[idx].state, STATE_REQUESTED);
}
}

/**
Expand Down Expand Up @@ -360,8 +376,7 @@ void nrf_ble_lesc_on_ble_evt(const ble_evt_t *ble_evt)

switch (ble_evt->header.evt_id) {
case BLE_GAP_EVT_DISCONNECTED:
peer_keys[idx].is_requested = false;

(void)atomic_cas(&peer_keys[idx].state, STATE_REQUESTED, STATE_IDLE);
break;

case BLE_GAP_EVT_LESC_DHKEY_REQUEST:
Expand Down
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