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Bluetooth: controller: Use entropy driver directly in bt_rand

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Use entropy driver directly in bt_rand instead of stitching together
calls to sys_rand32_get to improve efficiency. The use of
sys_rand32_get could also leak timestamps into keys.

Signed-off-by: Wolfgang Puffitsch <wopu@demant.com>
This commit is contained in:
Wolfgang Puffitsch 2019-09-19 10:28:43 +02:00 • committed by Alberto Escolar
commit 799b46e35e
1 changed files with 15 additions and 15 deletions
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30
subsys/bluetooth/controller/crypto/crypto.c
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@ -4,7 +4,7 @@
* SPDX-License-Identifier: Apache-2.0 * SPDX-License-Identifier: Apache-2.0
*/ */
#include <soc.h> #include <drivers/entropy.h>
#define BT_DBG_ENABLED IS_ENABLED(CONFIG_BT_DEBUG_HCI_DRIVER) #define BT_DBG_ENABLED IS_ENABLED(CONFIG_BT_DEBUG_HCI_DRIVER)
#define LOG_MODULE_NAME bt_ctlr_crypto #define LOG_MODULE_NAME bt_ctlr_crypto
@ -12,25 +12,25 @@
#include "hal/ecb.h" #include "hal/ecb.h"
static struct device *entropy_driver;
int bt_rand(void *buf, size_t len) int bt_rand(void *buf, size_t len)
{ {
u8_t *buf8 = buf; struct device *dev = entropy_driver;
while (len) { if (unlikely(!dev)) {
u32_t v = sys_rand32_get(); /* Only one entropy device exists, so this is safe even
* if the whole operation isn't atomic.
if (len >= sizeof(v)) { */
memcpy(buf8, &v, sizeof(v)); dev = device_get_binding(CONFIG_ENTROPY_NAME);
__ASSERT((dev != NULL),
buf8 += sizeof(v); "Device driver for %s (CONFIG_ENTROPY_NAME) not found. "
len -= sizeof(v); "Check your build configuration!",
} else { CONFIG_ENTROPY_NAME);
memcpy(buf8, &v, len); entropy_driver = dev;
break;
}
} }
return 0; return entropy_get_entropy(dev, (u8_t *)buf, len);
} }
int bt_encrypt_le(const u8_t key[16], const u8_t plaintext[16], int bt_encrypt_le(const u8_t key[16], const u8_t plaintext[16],