hs_descriptor: CID 1440368: Incorrect expression (SIZEOF_MISMATCH)

*** CID 1440368:  Incorrect expression  (SIZEOF_MISMATCH)
/src/feature/hs/hs_descriptor.c: 2954 in hs_desc_build_authorized_client()
2948                                                   HS_DESC_COOKIE_KEY_BIT_SIZE);
2949       /* This can't fail. */
2950       crypto_cipher_encrypt(cipher, (char *) client_out->encrypted_cookie,
2951                             (const char *) descriptor_cookie,
2952                             HS_DESC_DESCRIPTOR_COOKIE_LEN);
2953     
>>>     CID 1440368:  Incorrect expression  (SIZEOF_MISMATCH)
>>>     Passing argument "keystream" of type "uint8_t *" and argument "8UL /* sizeof (keystream) */" to function "memwipe" is suspicious.
2954       memwipe(keystream, 0, sizeof(keystream));
2955       tor_free(keystream);