On Tue, Oct 15, 2019 at 02:04:50PM -0300, Jason Gunthorpe wrote: > On Tue, Oct 15, 2019 at 03:47:02PM +0300, Jarkko Sakkinen wrote: > > Salt the result that comes from the TPM RNG with random bytes from the > > kernel RNG. This will allow to use tpm_get_random() as a substitute for > > get_random_bytes(). TPM could have a bug (making results predicatable), > > backdoor or even an inteposer in the bus. Salting gives protections > > against these concerns. > > Seems like a dangerous use case, why would any kernel user that cared > about quality of randomness ever call a tpm_* API to get quality > random data? This is related to this discussion: https://lore.kernel.org/linux-integrity/CAE=NcrY3BTvD-L2XP6bsO=9oAJLtSD0wYpUymVkAGAnYObsPzQ@xxxxxxxxxxxxxx/T/#t I could also move this to the call site. /Jarkko
