tpm: add TPM2_GetRandom command support

Add support for TPM2 GetRandom command

Signed-off-by: Dhananjay Phadke <dphadke@linux.microsoft.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Dhananjay Phadke 2020-06-04 16:43:59 -07:00 committed by Tom Rini
parent 78cc3fcf08
commit 06bea49809
2 changed files with 57 additions and 0 deletions

View File

@ -70,6 +70,7 @@ enum tpm2_handles {
* @TPM2_CC_DAM_RESET: TPM2_DictionaryAttackLockReset().
* @TPM2_CC_DAM_PARAMETERS: TPM2_DictionaryAttackParameters().
* @TPM2_CC_GET_CAPABILITY: TPM2_GetCapibility().
* @TPM2_CC_GET_RANDOM: TPM2_GetRandom().
* @TPM2_CC_PCR_READ: TPM2_PCR_Read().
* @TPM2_CC_PCR_EXTEND: TPM2_PCR_Extend().
* @TPM2_CC_PCR_SETAUTHVAL: TPM2_PCR_SetAuthValue().
@ -85,6 +86,7 @@ enum tpm2_command_codes {
TPM2_CC_DAM_PARAMETERS = 0x013A,
TPM2_CC_NV_READ = 0x014E,
TPM2_CC_GET_CAPABILITY = 0x017A,
TPM2_CC_GET_RANDOM = 0x017B,
TPM2_CC_PCR_READ = 0x017E,
TPM2_CC_PCR_EXTEND = 0x0182,
TPM2_CC_PCR_SETAUTHVAL = 0x0183,
@ -339,4 +341,15 @@ u32 tpm2_pcr_setauthvalue(struct udevice *dev, const char *pw,
const ssize_t pw_sz, u32 index, const char *key,
const ssize_t key_sz);
/**
* Issue a TPM2_GetRandom command.
*
* @dev TPM device
* @param data output buffer for the random bytes
* @param count size of output buffer
*
* @return return code of the operation
*/
u32 tpm2_get_random(struct udevice *dev, void *data, u32 count);
#endif /* __TPM_V2_H */

View File

@ -422,3 +422,47 @@ u32 tpm2_pcr_setauthvalue(struct udevice *dev, const char *pw,
return tpm_sendrecv_command(dev, command_v2, NULL, NULL);
}
u32 tpm2_get_random(struct udevice *dev, void *data, u32 count)
{
const u8 command_v2[10] = {
tpm_u16(TPM2_ST_NO_SESSIONS),
tpm_u32(12),
tpm_u32(TPM2_CC_GET_RANDOM),
};
u8 buf[COMMAND_BUFFER_SIZE], response[COMMAND_BUFFER_SIZE];
const size_t data_size_offset = 10;
const size_t data_offset = 12;
size_t response_length = sizeof(response);
u32 data_size;
u8 *out = data;
while (count > 0) {
u32 this_bytes = min((size_t)count,
sizeof(response) - data_offset);
u32 err;
if (pack_byte_string(buf, sizeof(buf), "sw",
0, command_v2, sizeof(command_v2),
sizeof(command_v2), this_bytes))
return TPM_LIB_ERROR;
err = tpm_sendrecv_command(dev, buf, response,
&response_length);
if (err)
return err;
if (unpack_byte_string(response, response_length, "w",
data_size_offset, &data_size))
return TPM_LIB_ERROR;
if (data_size > this_bytes)
return TPM_LIB_ERROR;
if (unpack_byte_string(response, response_length, "s",
data_offset, out, data_size))
return TPM_LIB_ERROR;
count -= data_size;
out += data_size;
}
return 0;
}