Merge pull request #5579 from SiliconLabs/erase_secret_before_free
Erase secrets in allocated memory before freeing said memory
diff --git a/ChangeLog.d/zeroize_key_buffers_before_free.txt b/ChangeLog.d/zeroize_key_buffers_before_free.txt
new file mode 100644
index 0000000..ba5bae1
--- /dev/null
+++ b/ChangeLog.d/zeroize_key_buffers_before_free.txt
@@ -0,0 +1,4 @@
+Security
+ * Zeroize dynamically-allocated buffers used by the PSA Crypto key storage
+ module before freeing them. These buffers contain secret key material, and
+ could thus potentially leak the key through freed heap.
diff --git a/library/psa_crypto_storage.c b/library/psa_crypto_storage.c
index c6660b9..db7786d 100644
--- a/library/psa_crypto_storage.c
+++ b/library/psa_crypto_storage.c
@@ -349,6 +349,7 @@
status = psa_crypto_storage_store( attr->id,
storage_data, storage_data_length );
+ mbedtls_platform_zeroize( storage_data, storage_data_length );
mbedtls_free( storage_data );
return( status );
@@ -394,6 +395,7 @@
status = PSA_ERROR_STORAGE_FAILURE;
exit:
+ mbedtls_platform_zeroize( loaded_data, storage_data_length );
mbedtls_free( loaded_data );
return( status );
}