On Thu, 15 Jul 2021 at 22:04, Ilias Apalodimas ilias.apalodimas@linaro.org wrote:
On Mon, Jul 05, 2021 at 09:48:49AM -0600, Simon Glass wrote:
It is fairly easy to handle this case and it makes the emulator more useful, since PCRs are commonly extended several times.
Add support for this, using U-Boot's sha256 support.
Signed-off-by: Simon Glass sjg@chromium.org
drivers/tpm/tpm2_tis_sandbox.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-)
diff --git a/drivers/tpm/tpm2_tis_sandbox.c b/drivers/tpm/tpm2_tis_sandbox.c index ed9c9a0bc9f..e84bcc7c4c8 100644 --- a/drivers/tpm/tpm2_tis_sandbox.c +++ b/drivers/tpm/tpm2_tis_sandbox.c @@ -11,6 +11,7 @@ #include <asm/unaligned.h> #include <linux/bitops.h> #include <u-boot/crc.h> +#include <u-boot/sha256.h> #include "sandbox_common.h"
/* Hierarchies */ @@ -407,15 +408,19 @@ static int sandbox_tpm2_extend(struct udevice *dev, int pcr_index, const u8 *extension) { struct sandbox_tpm2 *tpm = dev_get_priv(dev);
int i;/* Only simulate the first extensions from all '0' with only '0' */for (i = 0; i < TPM2_DIGEST_LEN; i++)if (tpm->pcr[pcr_index][i] || extension[i])return TPM2_RC_FAILURE;
if (!pcr_index) {memcpy(tpm->pcr[pcr_index], sandbox_extended_once_pcr,TPM2_DIGEST_LEN);Why do we have to treat pcr 0 specially? Can't we just get rid of sandbox_extended_once_pcr and just extend all the PCRs with the value wee get?
Also looking at the entire series, SANDBOX_TPM_PCR_NB doesn't seem to change. I don't know too much about the tpm sandbox, but that effectively limits us to a single PCR?
} else {sha256_context ctx;sha256_starts(&ctx);sha256_update(&ctx, tpm->pcr[pcr_index], TPM2_DIGEST_LEN);sha256_update(&ctx, extension, TPM2_DIGEST_LEN);sha256_finish(&ctx, tpm->pcr[pcr_index]);}
memcpy(tpm->pcr[pcr_index], sandbox_extended_once_pcr,TPM2_DIGEST_LEN); tpm->pcr_extensions[pcr_index]++; return 0;-- 2.32.0.93.g670b81a890-goog