On Wed, 2010-11-24 at 08:59 -0600, Serge Hallyn wrote: > Quoting David Safford (safford@xxxxxxxxxxxxxx): > > On Tue, 2010-11-23 at 20:32 -0600, Serge Hallyn wrote: > > > Quoting Mimi Zohar (zohar@xxxxxxxxxxxxxxxxxx): > > > > Add internal kernel tpm_send() command used to seal/unseal keys. > > ... > > > > +int tpm_send(u32 chip_num, void *cmd, size_t buflen) > > > > > > Hate to nit-pick, but any particular reason you're not following the > > > rest of the file and using 'struct tpm_cmd_t *cmd' here? > > > > > > Acked-by: Serge E. Hallyn <serge.hallyn@xxxxxxxxxxxxx> > > > > We put some thought into this one. TPM command packets are > > binary blobs with lots of optional and variable length fields, > > and there are at least three common approaches to creating them: > > structures (as used in tpm.c), load/store (as used in trousers > > and trusted-keys), and an sprintf like format string (as used > > in the original libtpm.) Each has its advantages and disadvantages. > > Structures are nice for the simple TPM commands, but they become > > unwieldy for the complex commands like seal and unseal. Load/store > > is much more readable for the complex seal and unseal commands. > > Format strings are nice for creating the most complex commands > > in the fewest lines of code, but are way overkill for simple ones. > > > > With the void *cmd, we are allowing the other modules to pick > > whichever method most suits their needs. > > Jinkeys, that's complicated :) > > But doesn't that mean that the transmit_cmd() parameters are lying? > Should the second argument for transmit_cmd() be a union? > > (If only to help out the lamentable reader) > > thanks, > -serge ah. transmit_cmd() takes a struct tpm_cmd_t * and immediately casts it to u8 * for tpm_transmit(). So sending in a u8 * isn't so much lying as recognizing that tpm_cmd_t * and u8 * are equivalent :-) I suppose a union would be more correct, although I'm not sure it would be easier for the lamentable reader... dave -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
