zeroing struct before memcpy in U2F init

src/u2f/u2f.h

@@ -46,14 +46,14 @@ typedef struct {
     uint8_t appId[U2F_APPID_SIZE];
 } U2F_REGISTER_REQ;
 
+
 typedef struct {
     uint8_t registerId;// U2F_REGISTER_ID_V2
     U2F_EC_POINT pubKey;
     uint8_t keyHandleLen;
     uint8_t keyHandleCertSig[U2F_MAX_KH_SIZE + U2F_MAX_ATT_CERT_SIZE + U2F_MAX_EC_SIG_SIZE];
 } U2F_REGISTER_RESP;
 
-
 // U2F_AUTHENTICATE instruction defines
 #define U2F_AUTH_ENFORCE        0x03// Enforce user presence and sign
 #define U2F_AUTH_CHECK_ONLY     0x07

src/u2f/u2f_hid.h

@@ -66,15 +66,21 @@ typedef struct {
 } U2FHID_INIT_REQ;
 
 
-typedef struct {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpacked"
+#pragma GCC diagnostic ignored "-Wattributes"
+typedef struct __attribute__((__packed__))
+{
     uint8_t nonce[U2FHID_INIT_NONCE_SIZE];
     uint32_t cid;
     uint8_t versionInterface;
     uint8_t versionMajor;
     uint8_t versionMinor;
     uint8_t versionBuild;
     uint8_t capFlags;// Capabilities flags
-} U2FHID_INIT_RESP;
+}
+U2FHID_INIT_RESP;
+#pragma GCC diagnostic pop
 
 #define U2FHID_INIT_RESP_SIZE 17
 

src/u2f_device.c

@@ -52,7 +52,7 @@
 #define APDU_LEN(A)              (uint32_t)(((A).lc1 << 16) + ((A).lc2 << 8) + ((A).lc3))
 #define U2F_TIMEOUT              500// [msec]
 #define U2F_KEYHANDLE_LEN        (U2F_NONCE_LENGTH + SHA256_DIGEST_LENGTH)
-#define U2F_READBUF_MAX_LEN      COMMANDER_REPORT_SIZE// Max allowed by U2F specification = (57 + 128 * 59) = 7609. 
+#define U2F_READBUF_MAX_LEN      COMMANDER_REPORT_SIZE// Max allowed by U2F specification = (57 + 128 * 59) = 7609.
 // In practice, U2F commands do not need this much space.
 // Therefore, reduce to save MCU memory.
 
@@ -452,6 +452,7 @@ static void u2f_device_init(const USB_FRAME *in)
     f.init.bcnth = 0;
     f.init.bcntl = U2FHID_INIT_RESP_SIZE;
 
+    utils_zero(&resp, sizeof(resp));
     memcpy(resp.nonce, init_req->nonce, sizeof(init_req->nonce));
     resp.cid = in->cid == U2FHID_CID_BROADCAST ? next_cid() : in->cid;
     resp.versionInterface = U2FHID_IF_VERSION;