[Telink]: Fix entropy source failed crash on boot

src/platform/Zephyr/PlatformManagerImpl.cpp

@@ -21,6 +21,10 @@
  *          for Zephyr platforms.
  */
 
+#if !CONFIG_NORDIC_SECURITY_BACKEND
+#include <crypto/CHIPCryptoPAL.h> // nogncheck
+#endif                            // !CONFIG_NORDIC_SECURITY_BACKEND
+
 #include <platform/internal/CHIPDeviceLayerInternal.h>
 
 #include <platform/PlatformManager.h>
@@ -37,19 +41,43 @@ static K_THREAD_STACK_DEFINE(sChipThreadStack, CHIP_DEVICE_CONFIG_CHIP_TASK_STAC
 
 PlatformManagerImpl PlatformManagerImpl::sInstance{ sChipThreadStack };
 
+#if !CONFIG_NORDIC_SECURITY_BACKEND
+static int app_entropy_source(void * data, unsigned char * output, size_t len, size_t * olen)
+{
+    const struct device * entropy = device_get_binding(DT_CHOSEN_ZEPHYR_ENTROPY_LABEL);
+    int ret                       = entropy_get_entropy(entropy, output, len);
+
+    if (ret == 0)
+    {
+        *olen = len;
+    }
+    else
+    {
+        *olen = 0;
+    }
+
+    return ret;
+}
+#endif // !CONFIG_NORDIC_SECURITY_BACKEND
+
 CHIP_ERROR PlatformManagerImpl::_InitChipStack(void)
 {
     CHIP_ERROR err;
-    const struct device * entropy = device_get_binding(DT_CHOSEN_ZEPHYR_ENTROPY_LABEL);
-    unsigned int seed;
+
+#if !CONFIG_NORDIC_SECURITY_BACKEND
+    // Minimum required from source before entropy is released ( with mbedtls_entropy_func() ) (in bytes)
+    const size_t kThreshold = 16;
+#endif // !CONFIG_NORDIC_SECURITY_BACKEND
 
     // Initialize the configuration system.
     err = Internal::ZephyrConfig::Init();
     SuccessOrExit(err);
 
-    // Get entropy to initialize seed for pseudorandom operations.
-    SuccessOrExit(entropy_get_entropy(entropy, reinterpret_cast<uint8_t *>(&seed), sizeof(seed)));
-    srand(seed);
+#if !CONFIG_NORDIC_SECURITY_BACKEND
+    // Add entropy source based on Zephyr entropy driver
+    err = chip::Crypto::add_entropy_source(app_entropy_source, NULL, kThreshold);
+    SuccessOrExit(err);
+#endif // !CONFIG_NORDIC_SECURITY_BACKEND
 
     // Call _InitChipStack() on the generic implementation base class to finish the initialization process.
     err = Internal::GenericPlatformManagerImpl_Zephyr<PlatformManagerImpl>::_InitChipStack();

src/platform/telink/BUILD.gn

@@ -58,4 +58,6 @@ static_library("telink") {
       deps += [ "${chip_root}/src/lib/mdns:platform_header" ]
     }
   }
+
+  public_deps += [ "${chip_root}/src/crypto" ]
 }