[U-Boot] [PATCH v4 18/32] tpm: add TPM2_Clear command support

Miquel Raynal
2018-05-15T09:57:14Z

Add support for the TPM2_Clear command.

Change the command file and the help accordingly.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
---
cmd/tpm-v2.c | 29 +++++++++++++++++++++++++++++
include/tpm-v2.h | 11 +++++++++++
lib/tpm-v2.c | 35 +++++++++++++++++++++++++++++++++++
3 files changed, 75 insertions(+)

diff --git a/cmd/tpm-v2.c b/cmd/tpm-v2.c
index 1e746a7f09..9f6a8fc0b6 100644
--- a/cmd/tpm-v2.c
+++ b/cmd/tpm-v2.c
@@ -51,11 +51,35 @@ static int do_tpm2_self_test(cmd_tbl_t *cmdtp, int flag, int argc,
return report_return_code(tpm2_self_test(full_test));
}

+static int do_tpm2_clear(cmd_tbl_t *cmdtp, int flag, int argc,
+ char * const argv[])
+{
+ u32 handle = 0;
+ const char *pw = (argc < 3) ? NULL : argv[2];
+ const ssize_t pw_sz = pw ? strlen(pw) : 0;
+
+ if (argc < 2 || argc > 3)
+ return CMD_RET_USAGE;
+
+ if (pw_sz > TPM2_DIGEST_LEN)
+ return -EINVAL;
+
+ if (!strcasecmp("TPM2_RH_LOCKOUT", argv[1]))
+ handle = TPM2_RH_LOCKOUT;
+ else if (!strcasecmp("TPM2_RH_PLATFORM", argv[1]))
+ handle = TPM2_RH_PLATFORM;
+ else
+ return CMD_RET_USAGE;
+
+ return report_return_code(tpm2_clear(handle, pw, pw_sz));
+}
+
static cmd_tbl_t tpm2_commands[] = {
U_BOOT_CMD_MKENT(info, 0, 1, do_tpm_info, "", ""),
U_BOOT_CMD_MKENT(init, 0, 1, do_tpm_init, "", ""),
U_BOOT_CMD_MKENT(startup, 0, 1, do_tpm2_startup, "", ""),
U_BOOT_CMD_MKENT(self_test, 0, 1, do_tpm2_self_test, "", ""),
+ U_BOOT_CMD_MKENT(clear, 0, 1, do_tpm2_clear, "", ""),
};

cmd_tbl_t *get_tpm_commands(unsigned int *size)
@@ -82,4 +106,9 @@ U_BOOT_CMD(tpm, CONFIG_SYS_MAXARGS, 1, do_tpm, "Issue a TPMv2.x command",
" <type> is one of:\n"
" * full (perform all tests)\n"
" * continue (only check untested tests)\n"
+"clear <hierarchy>\n"
+" Issue a TPM2_Clear command.\n"
+" <hierarchy> is one of:\n"
+" * TPM2_RH_LOCKOUT\n"
+" * TPM2_RH_PLATFORM\n"
);
diff --git a/include/tpm-v2.h b/include/tpm-v2.h
index f6d50a3a0b..0d02e4a89b 100644
--- a/include/tpm-v2.h
+++ b/include/tpm-v2.h
@@ -143,4 +143,15 @@ u32 tpm2_startup(enum tpm2_startup_types mode);
*/
u32 tpm2_self_test(enum tpm2_yes_no full_test);

+/**
+ * Issue a TPM2_Clear command.
+ *
+ * @handle Handle
+ * @pw Password
+ * @pw_sz Length of the password
+ *
+ * @return code of the operation
+ */
+u32 tpm2_clear(u32 handle, const char *pw, const ssize_t pw_sz);
+
#endif /* __TPM_V2_H */
diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
index c7156e569b..e3bfec5082 100644
--- a/lib/tpm-v2.c
+++ b/lib/tpm-v2.c
@@ -42,3 +42,38 @@ u32 tpm2_self_test(enum tpm2_yes_no full_test)

return tpm_sendrecv_command(command_v2, NULL, NULL);
}
+
+u32 tpm2_clear(u32 handle, const char *pw, const ssize_t pw_sz)
+{
+ u8 command_v2[COMMAND_BUFFER_SIZE] = {
+ tpm_u16(TPM2_ST_SESSIONS), /* TAG */
+ tpm_u32(27 + pw_sz), /* Length */
+ tpm_u32(TPM2_CC_CLEAR), /* Command code */
+
+ /* HANDLE */
+ tpm_u32(handle), /* TPM resource handle */
+
+ /* 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) */
+ };
+ unsigned int offset = 27;
+ int ret;
+
+ /*
+ * Fill the command structure starting from the first buffer:
+ * - the password (if any)
+ */
+ ret = pack_byte_string(command_v2, sizeof(command_v2), "s",
+ offset, pw, pw_sz);
+ offset += pw_sz;
+ if (ret)
+ return TPM_LIB_ERROR;
+
+ return tpm_sendrecv_command(command_v2, NULL, NULL);
+}
--
2.14.1