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); + } 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;