[U-Boot] [PATCH v4 23/32] tpm: add TPM2_HierarchyChangeAuth command support

Miquel Raynal
2018-05-15T09:57:19Z

Add support for the TPM2_HierarchyChangeAuth 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 | 59 ++++++++++++++++++++++++++++++++++++++++++++------------
include/tpm-v2.h | 14 ++++++++++++++
lib/tpm-v2.c | 44 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 105 insertions(+), 12 deletions(-)

diff --git a/cmd/tpm-v2.c b/cmd/tpm-v2.c
index 5e3ebc7984..b52409846b 100644
--- a/cmd/tpm-v2.c
+++ b/cmd/tpm-v2.c
@@ -234,6 +234,36 @@ static int do_tpm_dam_parameters(cmd_tbl_t *cmdtp, int flag, int argc,
lockout_recovery));
}

+static int do_tpm_change_auth(cmd_tbl_t *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ u32 handle;
+ const char *newpw = argv[2];
+ const char *oldpw = (argc == 3) ? NULL : argv[3];
+ const ssize_t newpw_sz = strlen(newpw);
+ const ssize_t oldpw_sz = oldpw ? strlen(oldpw) : 0;
+
+ if (argc < 3 || argc > 4)
+ return CMD_RET_USAGE;
+
+ if (newpw_sz > TPM2_DIGEST_LEN || oldpw_sz > TPM2_DIGEST_LEN)
+ return -EINVAL;
+
+ if (!strcasecmp("TPM2_RH_LOCKOUT", argv[1]))
+ handle = TPM2_RH_LOCKOUT;
+ else if (!strcasecmp("TPM2_RH_ENDORSEMENT", argv[1]))
+ handle = TPM2_RH_ENDORSEMENT;
+ else if (!strcasecmp("TPM2_RH_OWNER", argv[1]))
+ handle = TPM2_RH_OWNER;
+ else if (!strcasecmp("TPM2_RH_PLATFORM", argv[1]))
+ handle = TPM2_RH_PLATFORM;
+ else
+ return CMD_RET_USAGE;
+
+ return report_return_code(tpm2_change_auth(handle, newpw, newpw_sz,
+ oldpw, oldpw_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, "", ""),
@@ -245,6 +275,7 @@ static cmd_tbl_t tpm2_commands[] = {
U_BOOT_CMD_MKENT(get_capability, 0, 1, do_tpm_get_capability, "", ""),
U_BOOT_CMD_MKENT(dam_reset, 0, 1, do_tpm_dam_reset, "", ""),
U_BOOT_CMD_MKENT(dam_parameters, 0, 1, do_tpm_dam_parameters, "", ""),
+ U_BOOT_CMD_MKENT(change_auth, 0, 1, do_tpm_change_auth, "", ""),
};

cmd_tbl_t *get_tpm_commands(unsigned int *size)
@@ -291,16 +322,20 @@ U_BOOT_CMD(tpm, CONFIG_SYS_MAXARGS, 1, do_tpm, "Issue a TPMv2.x command",
" <property>: property\n"
" <addr>: address to store <count> entries of 4 bytes\n"
" <count>: number of entries to retrieve\n"
-" dam_reset_counter [<password>]\n"
-" - If the TPM is not in a LOCKOUT state, reset the internal error\n"
-" counter (TPMv2 only)\n"
-" dam_set_parameters <maxTries> <recoveryTime> <lockoutRecovery> [<password>]\n"
-" - If the TPM is not in a LOCKOUT state, set the dictionary attack\n"
-" parameters:\n"
-" * maxTries: maximum number of failures before lockout.\n"
-" 0 means always locking.\n"
-" * recoveryTime: time before decrementation of the error counter,\n"
-" 0 means no lockout.\n"
-" * lockoutRecovery: time of a lockout (before the next try)\n"
-" 0 means a reboot is needed.\n"
+"dam_reset [<password>]\n"
+" If the TPM is not in a LOCKOUT state, reset the internal error counter.\n"
+" <password>: optional password\n"
+"dam_parameters <max_tries> <recovery_time> <lockout_recovery> [<password>]\n"
+" If the TPM is not in a LOCKOUT state, set the DAM parameters\n"
+" <maxTries>: maximum number of failures before lockout,\n"
+" 0 means always locking\n"
+" <recoveryTime>: time before decrement of the error counter,\n"
+" 0 means no lockout\n"
+" <lockoutRecovery>: time of a lockout (before the next try),\n"
+" 0 means a reboot is needed\n"
+" <password>: optional password of the LOCKOUT hierarchy\n"
+"change_auth <hierarchy> <new_pw> [<old_pw>]\n"
+" <hierarchy>: the hierarchy\n"
+" <new_pw>: new password for <hierarchy>\n"
+" <old_pw>: optional previous password of <hierarchy>\n"
);
diff --git a/include/tpm-v2.h b/include/tpm-v2.h
index 4e182cf827..19f0ecd80b 100644
--- a/include/tpm-v2.h
+++ b/include/tpm-v2.h
@@ -216,4 +216,18 @@ u32 tpm2_dam_parameters(const char *pw, const ssize_t pw_sz,
unsigned int max_tries, unsigned int recovery_time,
unsigned int lockout_recovery);

+/**
+ * Issue a TPM2_HierarchyChangeAuth command.
+ *
+ * @handle Handle
+ * @newpw New password
+ * @newpw_sz Length of the new password
+ * @oldpw Old password
+ * @oldpw_sz Length of the old password
+ *
+ * @return code of the operation
+ */
+int tpm2_change_auth(u32 handle, const char *newpw, const ssize_t newpw_sz,
+ const char *oldpw, const ssize_t oldpw_sz);
+
#endif /* __TPM_V2_H */
diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
index 5f1090eccb..219f0ee941 100644
--- a/lib/tpm-v2.c
+++ b/lib/tpm-v2.c
@@ -273,3 +273,47 @@ u32 tpm2_dam_parameters(const char *pw, const ssize_t pw_sz,

return tpm_sendrecv_command(command_v2, NULL, NULL);
}
+
+int tpm2_change_auth(u32 handle, const char *newpw, const ssize_t newpw_sz,
+ const char *oldpw, const ssize_t oldpw_sz)
+{
+ unsigned int offset = 27;
+ u8 command_v2[COMMAND_BUFFER_SIZE] = {
+ tpm_u16(TPM2_ST_SESSIONS), /* TAG */
+ tpm_u32(offset + oldpw_sz + 2 + newpw_sz), /* Length */
+ tpm_u32(TPM2_CC_HIERCHANGEAUTH), /* Command code */
+
+ /* HANDLE */
+ tpm_u32(handle), /* TPM resource handle */
+
+ /* AUTH_SESSION */
+ tpm_u32(9 + oldpw_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(oldpw_sz) /* Size of <hmac/password> */
+ /* STRING(oldpw) <hmac/password> (if any) */
+
+ /* TPM2B_AUTH (TPM2B_DIGEST) */
+ /* tpm_u16(newpw_sz) Digest size, new pw length */
+ /* STRING(newpw) Digest buffer, new pw */
+ };
+ int ret;
+
+ /*
+ * Fill the command structure starting from the first buffer:
+ * - the old password (if any)
+ * - size of the new password
+ * - new password
+ */
+ ret = pack_byte_string(command_v2, sizeof(command_v2), "sws",
+ offset, oldpw, oldpw_sz,
+ offset + oldpw_sz, newpw_sz,
+ offset + oldpw_sz + 2, newpw, newpw_sz);
+ offset += oldpw_sz + 2 + newpw_sz;
+ if (ret)
+ return TPM_LIB_ERROR;
+
+ return tpm_sendrecv_command(command_v2, NULL, NULL);
+}
--
2.14.1