[PATCH 2/6] tmp: add TPM2_PCR_Allocate command
Raymond Mao
raymond.mao at linaro.org
Wed Jan 15 21:01:36 CET 2025
TPM2_PCR_Allocate command is required to re-configurate a TPM device
to enable or disable algorithms in run-time, thus this patch introduces
the implementation of PCR allocate APIs and adds related cmd functions
for testing.
To test the feature, ensure that TPM is started up.
Run pcr_allocate command to turn on/off an algorithm, multiple calls
are supported and all changes will be cached:
`tpm2 pcr_allocate <algorithm_name> <on|off>`
Run startup command with argument 'off' to shutdown the TPM.
`tpm2 startup TPM2_SU_CLEAR off`
Reboot the board via `reset` to activate the changes.
Signed-off-by: Raymond Mao <raymond.mao at linaro.org>
---
cmd/tpm-v2.c | 94 +++++++++++++++++++++++++++++++++++
include/tpm-v2.h | 29 +++++++++++
lib/tpm-v2.c | 124 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 247 insertions(+)
diff --git a/cmd/tpm-v2.c b/cmd/tpm-v2.c
index a6d57ee7c4..2302e8e94c 100644
--- a/cmd/tpm-v2.c
+++ b/cmd/tpm-v2.c
@@ -232,6 +232,86 @@ unmap_data:
return report_return_code(rc);
}
+static u32 select_mask(u32 mask, enum tpm2_algorithms algo, bool select)
+{
+ size_t i;
+
+ for (i = 0; i < ARRAY_SIZE(hash_algo_list); i++) {
+ if (hash_algo_list[i].hash_alg != algo)
+ continue;
+
+ if (select)
+ mask |= hash_algo_list[i].hash_mask;
+ else
+ mask &= ~hash_algo_list[i].hash_mask;
+
+ break;
+ }
+
+ return mask;
+}
+
+static int do_tpm2_pcrallocate(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ struct udevice *dev;
+ int ret;
+ enum tpm2_algorithms algo;
+ const char *pw = (argc < 4) ? NULL : argv[3];
+ const ssize_t pw_sz = pw ? strlen(pw) : 0;
+ static struct tpml_pcr_selection pcr = { 0 };
+ u32 pcr_len = 0;
+ bool bon = false;
+ static u32 mask;
+ int i;
+
+ /* argv[1]: algorithm (bank), argv[2]: on/off */
+ if (argc < 3 || argc > 4)
+ return CMD_RET_USAGE;
+
+ if (!strcasecmp("on", argv[2]))
+ bon = true;
+ else if (strcasecmp("off", argv[2]))
+ return CMD_RET_USAGE;
+
+ algo = tpm2_name_to_algorithm(argv[1]);
+ if (algo == -EINVAL)
+ return CMD_RET_USAGE;
+
+ ret = get_tpm(&dev);
+ if (ret)
+ return ret;
+
+ if (!pcr.count) {
+ /*
+ * Get current in-use algorithms (banks), PCRs and mask via the
+ * first call
+ */
+ ret = tpm2_get_pcr_info(dev, &pcr);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < pcr.count; i++) {
+ struct tpms_pcr_selection *sel = &pcr.selection[i];
+
+ if (!tpm2_is_active_bank(sel))
+ continue;
+
+ mask = select_mask(mask, sel->hash, true);
+ printf("Active bank[%d] with algo[%#x]\n", i,
+ sel->hash);
+ }
+ }
+
+ mask = select_mask(mask, algo, bon);
+ ret = tpm2_pcr_config_algo(dev, mask, &pcr, &pcr_len);
+ if (ret)
+ return ret;
+
+ return report_return_code(tpm2_send_pcr_allocate(dev, pw, pw_sz, &pcr,
+ pcr_len));
+}
+
static int do_tpm_dam_reset(struct cmd_tbl *cmdtp, int flag, int argc,
char *const argv[])
{
@@ -401,6 +481,7 @@ static struct cmd_tbl tpm2_commands[] = {
do_tpm_pcr_setauthpolicy, "", ""),
U_BOOT_CMD_MKENT(pcr_setauthvalue, 0, 1,
do_tpm_pcr_setauthvalue, "", ""),
+ U_BOOT_CMD_MKENT(pcr_allocate, 0, 1, do_tpm2_pcrallocate, "", ""),
};
struct cmd_tbl *get_tpm2_commands(unsigned int *size)
@@ -481,4 +562,17 @@ U_BOOT_CMD(tpm2, CONFIG_SYS_MAXARGS, 1, do_tpm, "Issue a TPMv2.x command",
" <pcr>: index of the PCR\n"
" <key>: secret to protect the access of PCR #<pcr>\n"
" <password>: optional password of the PLATFORM hierarchy\n"
+"pcr_allocate <algorithm> <on/off> [<password>]\n"
+" Issue a TPM2_PCR_Allocate Command to reconfig PCR bank algorithm.\n"
+" <algorithm> is one of:\n"
+" * sha1\n"
+" * sha256\n"
+" * sha384\n"
+" * sha512\n"
+" <on|off> is one of:\n"
+" * on - Select all available PCRs associated with the specified\n"
+" algorithm (bank)\n"
+" * off - Clear all available PCRs associated with the specified\n"
+" algorithm (bank)\n"
+" <password>: optional password\n"
);
diff --git a/include/tpm-v2.h b/include/tpm-v2.h
index f66a8e1bf4..af3158f6e4 100644
--- a/include/tpm-v2.h
+++ b/include/tpm-v2.h
@@ -230,6 +230,7 @@ enum tpm2_command_codes {
TPM2_CC_PCR_READ = 0x017E,
TPM2_CC_PCR_EXTEND = 0x0182,
TPM2_CC_PCR_SETAUTHVAL = 0x0183,
+ TPM2_CC_PCR_ALLOCATE = 0x012B,
TPM2_CC_SHUTDOWN = 0x0145,
};
@@ -702,6 +703,34 @@ u32 tpm2_report_state(struct udevice *dev, uint vendor_cmd, uint vendor_subcmd,
u32 tpm2_enable_nvcommits(struct udevice *dev, uint vendor_cmd,
uint vendor_subcmd);
+/**
+ * tpm2_pcr_config_algo() - Allocate the active PCRs. Requires reboot
+ *
+ * @dev TPM device
+ * @algo_mask Mask of the algorithms
+ * @pcr PCR structure for allocation
+ * @pcr_len Actual PCR data length
+ *
+ * Return: code of the operation
+ */
+u32 tpm2_pcr_config_algo(struct udevice *dev, u32 algo_mask,
+ struct tpml_pcr_selection *pcr, u32 *pcr_len);
+
+/**
+ * tpm2_send_pcr_allocate() - Send PCR allocate command. Requires reboot
+ *
+ * @dev TPM device
+ * @pw Platform password
+ * @pw_sz Length of the password
+ * @pcr PCR structure for allocation
+ * @pcr_len Actual PCR data length
+ *
+ * Return: code of the operation
+ */
+u32 tpm2_send_pcr_allocate(struct udevice *dev, const char *pw,
+ const ssize_t pw_sz, struct tpml_pcr_selection *pcr,
+ u32 pcr_len);
+
/**
* tpm2_auto_start() - start up the TPM and perform selftests.
* If a testable function has not been tested and is
diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
index 3946ac2dbb..045b5dd9eb 100644
--- a/lib/tpm-v2.c
+++ b/lib/tpm-v2.c
@@ -400,6 +400,130 @@ u32 tpm2_get_capability(struct udevice *dev, u32 capability, u32 property,
return 0;
}
+u32 tpm2_pcr_config_algo(struct udevice *dev, u32 algo_mask,
+ struct tpml_pcr_selection *pcr, u32 *pcr_len)
+{
+ int i;
+
+ if (pcr->count > TPM2_NUM_PCR_BANKS)
+ return TPM_LIB_ERROR;
+
+ *pcr_len = sizeof(pcr->count);
+
+ for (i = 0; i < pcr->count; i++) {
+ struct tpms_pcr_selection *sel = &pcr->selection[i];
+ u8 pad = 0;
+ int j;
+
+ if (sel->size_of_select > TPM2_PCR_SELECT_MAX)
+ return TPM_LIB_ERROR;
+
+ /*
+ * Found the algorithm (bank) that matches, and enable all PCR
+ * bits.
+ * TODO: only select the bits needed
+ */
+ for (j = 0; j < ARRAY_SIZE(hash_algo_list); j++) {
+ if (hash_algo_list[j].hash_alg != sel->hash)
+ continue;
+
+ if (algo_mask & hash_algo_list[j].hash_mask)
+ pad = 0xff;
+ }
+
+ for (j = 0; j < sel->size_of_select; j++)
+ sel->pcr_select[j] = pad;
+
+ log_info("set bank[%d] %s %s\n", i,
+ tpm2_algorithm_name(sel->hash),
+ tpm2_is_active_bank(sel) ? "on" : "off");
+
+ *pcr_len += sizeof(sel->hash) + sizeof(sel->size_of_select) +
+ sel->size_of_select;
+ }
+
+ return 0;
+}
+
+u32 tpm2_send_pcr_allocate(struct udevice *dev, const char *pw,
+ const ssize_t pw_sz, struct tpml_pcr_selection *pcr,
+ u32 pcr_len)
+{
+ /* Length of the message header, up to start of password */
+ uint offset = 27;
+ u8 command_v2[COMMAND_BUFFER_SIZE] = {
+ tpm_u16(TPM2_ST_SESSIONS), /* TAG */
+ tpm_u32(offset + pw_sz + pcr_len), /* Length */
+ tpm_u32(TPM2_CC_PCR_ALLOCATE), /* Command code */
+
+ /* handles 4 bytes */
+ tpm_u32(TPM2_RH_PLATFORM), /* Primary platform seed */
+
+ /* AUTH_SESSION */
+ tpm_u32(9 + pw_sz), /* Authorization size */
+ tpm_u32(TPM2_RS_PW), /* Session handle */
+ tpm_u16(0), /* Size of <nonce> */
+ /* <nonce> (if any) */
+ 0, /* Attributes: Cont/Excl/Rst */
+ tpm_u16(pw_sz), /* Size of <hmac/password> */
+ /* STRING(pw) <hmac/password> (if any) */
+
+ /* TPML_PCR_SELECTION */
+ };
+ u8 response[COMMAND_BUFFER_SIZE];
+ size_t response_len = COMMAND_BUFFER_SIZE;
+ u32 i;
+ int ret;
+
+ /*
+ * Fill the command structure starting from the first buffer:
+ * the password (if any)
+ */
+ if (pack_byte_string(command_v2, sizeof(command_v2), "s", offset, pw,
+ pw_sz))
+ return TPM_LIB_ERROR;
+
+ offset += pw_sz;
+
+ /* Pack the count field */
+ if (pack_byte_string(command_v2, sizeof(command_v2), "d", offset, pcr->count))
+ return TPM_LIB_ERROR;
+
+ offset += sizeof(pcr->count);
+
+ /* Pack each tpms_pcr_selection */
+ for (i = 0; i < pcr->count; i++) {
+ struct tpms_pcr_selection *sel = &pcr->selection[i];
+
+ /* Pack hash (16-bit) */
+ if (pack_byte_string(command_v2, sizeof(command_v2), "w", offset,
+ sel->hash))
+ return TPM_LIB_ERROR;
+
+ offset += sizeof(sel->hash);
+
+ /* Pack size_of_select (8-bit) */
+ if (pack_byte_string(command_v2, sizeof(command_v2), "b", offset,
+ sel->size_of_select))
+ return TPM_LIB_ERROR;
+
+ offset += sizeof(sel->size_of_select);
+
+ /* Pack pcr_select array */
+ if (pack_byte_string(command_v2, sizeof(command_v2), "s", offset,
+ sel->pcr_select, sel->size_of_select))
+ return TPM_LIB_ERROR;
+
+ offset += sel->size_of_select;
+ }
+
+ ret = tpm_sendrecv_command(dev, command_v2, response, &response_len);
+ if (!ret)
+ tpm_init(dev);
+
+ return ret;
+}
+
static int tpm2_get_num_pcr(struct udevice *dev, u32 *num_pcr)
{
u8 response[(sizeof(struct tpms_capability_data) -
--
2.25.1
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