Signed Integer Overflow in HMAC

[CindyZhouYH]

Hello.
It seems that there is a signed integer overflow in bitops.h:54 :

static inline uint32_t read32_be(const uint8_t buf[4])
{
*  return (buf[0] << 24) |
         (buf[1] << 16) |
         (buf[2] << 8) |
         (buf[3]);
}

It could be triggered by:

const uint8_t key[] =   {0xd9, 0x63, 0xca, 0xf9} ;
const uint8_t msg[] =  {0xb8, 0x02, 0x6b, 0xa9};
cf_hmac_init(&ctx, &cf_sha256, key, sizeof(key));
cf_hmac_update(&ctx, msg, sizeof(msg));