Add buffer and context clearing upon suspected FI

Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/library/aes.c b/library/aes.c
index 8cfb4ba..e49f74f 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -822,6 +822,7 @@
         }
     }
 
+    mbedtls_platform_memset( RK, 0, ( keybits >> 5 ) * 4 );
     return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
 }
 #endif /* !MBEDTLS_AES_SETKEY_ENC_ALT */
@@ -1176,6 +1177,8 @@
         }
     }
 
+    // Clear the output in case of a FI
+    mbedtls_platform_memset( output, 0, 16 );
     return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
 }
 
@@ -1460,6 +1463,8 @@
         }
     }
 
+    // Clear the output in case of a FI
+    mbedtls_platform_memset( output, 0, 16 );
     return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
 }