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tpm: Require a digest source when extending the PCR

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This feature is used for measured boot, so we can add a log entry to the
TCPA with some information about where the digest comes from. It is not
currently supported in the TPM drivers, but add it to the API so that
code which expects it can signal its request.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
This commit is contained in:
Simon Glass 2022-08-30 21:05:32 -06:00 committed by Ilias Apalodimas
parent 67fe8cc001
commit a557d258c6
5 changed files with 18 additions and 10 deletions
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3
cmd/tpm-v1.c
View File

@ -131,7 +131,8 @@ static int do_tpm_extend(struct cmd_tbl *cmdtp, int flag, int argc,
return CMD_RET_FAILURE;
}
rc = tpm_pcr_extend(dev, index, in_digest, out_digest);
rc = tpm_pcr_extend(dev, index, in_digest, sizeof(in_digest),
out_digest, "cmd");
if (!rc) {
puts("PCR value after execution of the command:\n");
print_byte_string(out_digest, sizeof(out_digest));

5
cmd/tpm_test.c
View File

@ -91,7 +91,8 @@ static int test_early_extend(struct udevice *dev)
tpm_init(dev);
TPM_CHECK(tpm_startup(dev, TPM_ST_CLEAR));
TPM_CHECK(tpm_continue_self_test(dev));
TPM_CHECK(tpm_pcr_extend(dev, 1, value_in, value_out));
TPM_CHECK(tpm_pcr_extend(dev, 1, value_in, sizeof(value_in), value_out,
"test"));
printf("done\n");
return 0;
}
@ -438,7 +439,7 @@ static int test_timing(struct udevice *dev)
100);
TTPM_CHECK(tpm_nv_read_value(dev, INDEX0, (uint8_t *)&x, sizeof(x)),
100);
TTPM_CHECK(tpm_pcr_extend(dev, 0, in, out), 200);
TTPM_CHECK(tpm_pcr_extend(dev, 0, in, sizeof(in), out, "test"), 200);
TTPM_CHECK(tpm_set_global_lock(dev), 50);
TTPM_CHECK(tpm_tsc_physical_presence(dev, PHYS_PRESENCE), 100);
printf("done\n");

8
include/tpm_api.h
View File

@ -81,14 +81,16 @@ u32 tpm_nv_write_value(struct udevice *dev, u32 index, const void *data,
*
* @param dev TPM device
* @param index index of the PCR
* @param in_digest 160-bit value representing the event to be
* @param in_digest 160/256-bit value representing the event to be
* recorded
* @param out_digest 160-bit PCR value after execution of the
* @param size size of digest in bytes
* @param out_digest 160/256-bit PCR value after execution of the
* command
* @param name digest source, used for log output
* Return: return code of the operation
*/
u32 tpm_pcr_extend(struct udevice *dev, u32 index, const void *in_digest,
void *out_digest);
uint size, void *out_digest, const char *name);
/**
* Issue a TPM_PCRRead command.

2
lib/tpm-v2.c
View File

@ -157,6 +157,8 @@ u32 tpm2_pcr_extend(struct udevice *dev, u32 index, u32 algorithm,
};
int ret;
if (!digest)
return -EINVAL;
/*
* Fill the command structure starting from the first buffer:
* - the digest

10
lib/tpm_api.c
View File

@ -140,15 +140,17 @@ u32 tpm_write_lock(struct udevice *dev, u32 index)
}
u32 tpm_pcr_extend(struct udevice *dev, u32 index, const void *in_digest,
void *out_digest)
uint size, void *out_digest, const char *name)
{
if (tpm_is_v1(dev))
if (tpm_is_v1(dev)) {
return tpm1_extend(dev, index, in_digest, out_digest);
else if (tpm_is_v2(dev))
} else if (tpm_is_v2(dev)) {
return tpm2_pcr_extend(dev, index, TPM2_ALG_SHA256, in_digest,
TPM2_DIGEST_LEN);
else
/* @name is ignored as we do not support the TPM log here */
} else {
return -ENOSYS;
}
}
u32 tpm_pcr_read(struct udevice *dev, u32 index, void *data, size_t count)