[PATCH] implement policy_pcr commands to lock NV-indexes behind a PCR
Ilias Apalodimas
ilias.apalodimas at linaro.org
Tue Mar 5 11:47:28 CET 2024
On Tue, 20 Feb 2024 at 07:59, niek.nooijens at omron.com
<niek.nooijens at omron.com> wrote:
>
> Hi there
>
> After the NV-memory read/write code I'm here again for another patch.
> This time I implemented code to allow an NV-index to be locked behind a PCR value.
> This can be used together with the new measured-boot code allowing you to store encryption keys inside the TPM and locking them behind PCR's.
> To do that you:
>
> set the PCR's to some value
> start an auth session
> create a policy_pcr
> get that policy's digest
> use NV_define together with the policy digest.
> use nv_write together with the session handle in which the policy_digest was generated.
>
> After another PCR extend, the NV index will be locked and cannot be read.
> At next boot, when the PCR's are in the correct state again, you can read the NV_index by authenticating with a PCR value.
> To do that you:
>
> set the PCR's to the correct value
> start an auth session
> create a policy_pcr
> nv_read whilst providing the session handle in which the policy was created.
>
>
> It might not be perfect yet, but at least it vastly extends the TPM capabilities of uboot.
> I generated the patch against latest github master.
> Feedback is welcome.
>
> Niek
>
> =================START PATCH========================
> From 8d3ea3130794d9db51d95056eb42044a2c5d9f4f Mon Sep 17 00:00:00 2001
> From: Niek Nooijens <niek.nooijens at omron.com>
> Date: Tue, 20 Feb 2024 13:42:57 +0900
> Subject: [PATCH] implement policy_pcr commands to lock NV-indexes behind a PCR
> policy
>
> Signed-off-by: Niek Nooijens <niek.nooijens at omron.com>
> ---
> cmd/tpm-v2.c | 258 +++++++++++++++++++++++++++++++
> include/tpm-common.h | 2 +
> include/tpm-v2.h | 126 ++++++++++++---
> lib/tpm-v2.c | 355 +++++++++++++++++++++++++++++++++++++------
> lib/tpm_api.c | 4 +-
> 5 files changed, 669 insertions(+), 76 deletions(-)
>
> diff --git a/cmd/tpm-v2.c b/cmd/tpm-v2.c
> index 7e479b9dfe..6b6f4629ea 100644
> --- a/cmd/tpm-v2.c
> +++ b/cmd/tpm-v2.c
> @@ -356,6 +356,222 @@ static int do_tpm_pcr_setauthvalue(struct cmd_tbl *cmdtp, int flag,
> key, key_sz));
> }
>
> +static int do_tpm_nv_define(struct cmd_tbl *cmdtp, int flag,
> + int argc, char *const argv[])
> +{
> + struct udevice *dev;
> + struct tpm_chip_priv *priv;
> + u32 nv_addr, nv_size, rc;
> + void *policy_addr = NULL;
> + size_t policy_size = 0;
> + int ret;
> +
> + u32 nv_attributes = TPMA_NV_PLATFORMCREATE | TPMA_NV_OWNERWRITE | TPMA_NV_OWNERREAD | TPMA_NV_PPWRITE | TPMA_NV_PPREAD;
You need to break this at 80 chars
u32 nv_attributes = TPMA_NV_PLATFORMCREATE | TPMA_NV_OWNERWRITE | \
...etc
> +
> + if (argc < 3 && argc > 7)
> + return CMD_RET_USAGE;
> +
> + ret = get_tpm(&dev);
> + if (ret)
> + return ret;
> +
> + priv = dev_get_uclass_priv(dev);
> + if (!priv)
> + return -EINVAL;
> +
> + nv_addr = simple_strtoul(argv[1], NULL, 0);
> +
> + nv_size = simple_strtoul(argv[2], NULL, 0);
> +
> + if (argc > 3)
> + nv_attributes = simple_strtoul(argv[3], NULL, 0);
> +
> + if (argc > 4) {
> + policy_addr = map_sysmem(simple_strtoul(argv[4], NULL, 0), 0);
> + nv_attributes |= (TPMA_NV_POLICYREAD | TPMA_NV_POLICYWRITE); //obligated, might as well force it
I am not sure I understand the comment
> + if (argc < 5)
> + return CMD_RET_USAGE;
> + policy_size = simple_strtoul(argv[5], NULL, 0);
> + }
> +
> + rc = tpm2_nv_define_space(dev, nv_addr, nv_size, nv_attributes, policy_addr, policy_size);
> +
You don't need an empty line here
> + if (rc)
> + printf("ERROR: nv_define #%u returns: 0x%x\n", nv_addr, rc);
> +
> + if (policy_addr)
> + unmap_sysmem(policy_addr);
Later down the code, you unconditionally call unmap_sysmem even for
NULL. I don't think we need the check here either
> +
> + return report_return_code(rc);
> +}
> +
> +static int do_tpm_nv_undefine(struct cmd_tbl *cmdtp, int flag,
> + int argc, char *const argv[])
> +{
> + struct udevice *dev;
> + u32 nv_addr, ret, rc;
> +
> + ret = get_tpm(&dev);
> + if (ret)
> + return ret;
> +
> + if (argc != 2)
> + return CMD_RET_USAGE;
> +
> + nv_addr = simple_strtoul(argv[1], NULL, 0);
> + rc = tpm2_nv_undefine_space(dev, nv_addr);
> +
> + return report_return_code(rc);
> +}
> +
> +static int do_tpm_nv_read_value(struct cmd_tbl *cmdtp, int flag,
> + int argc, char *const argv[])
> +{
> + struct udevice *dev;
> + u32 nv_addr, nv_size, rc;
> + void *session_addr = NULL;
> + int ret;
> + void *out_data;
> +
> + ret = get_tpm(&dev);
> + if (ret)
> + return ret;
> +
> + if (argc < 4)
> + return CMD_RET_USAGE;
> +
> + nv_addr = simple_strtoul(argv[1], NULL, 0);
> +
> + nv_size = simple_strtoul(argv[2], NULL, 0);
> +
> + out_data = map_sysmem(simple_strtoul(argv[3], NULL, 0), 0);
> +
Get rid of the empty lines before if() statements in the entire patch please.
> + if (argc == 5)
> + session_addr = map_sysmem(simple_strtoul(argv[4], NULL, 0), 0);
> +
> + rc = tpm2_nv_read_value(dev, nv_addr, out_data, nv_size, session_addr);
What happens if session_addr is NULL?
> +
> + if (rc)
> + printf("ERROR: nv_read #%u returns: #%u\n", nv_addr, rc);
> +
> + unmap_sysmem(out_data);
> + return report_return_code(rc);
> +}
> +
> +static int do_tpm_nv_write_value(struct cmd_tbl *cmdtp, int flag,
> + int argc, char *const argv[]) //TODO: session handle from auth session!
Please explain that TODO in more detail
> +{
> + struct udevice *dev;
> + u32 nv_addr, nv_size, rc;
> + void *session_addr = NULL;
> + int ret;
> +
> + ret = get_tpm(&dev);
> + if (ret)
> + return ret;
> +
> + if (argc < 4)
> + return CMD_RET_USAGE;
> +
> + nv_addr = simple_strtoul(argv[1], NULL, 0); //tpm_addr
> +
> + nv_size = simple_strtoul(argv[2], NULL, 0); //size
> +
> + void *data_to_write = map_sysmem(simple_strtoul(argv[3], NULL, 0), 0);
> +
> + if (argc == 5)
> + session_addr = map_sysmem(simple_strtoul(argv[4], NULL, 0), 0);
> +
> + rc = tpm2_nv_write_value(dev, nv_addr, data_to_write, nv_size, session_addr);
> +
> + if (rc)
> + printf("ERROR: nv_write #%u returns: #%u\n", nv_addr, rc);
> +
> + unmap_sysmem(session_addr);
> + unmap_sysmem(data_to_write);
> + return report_return_code(rc);
> +}
> +
> +static int do_start_auth_session(struct cmd_tbl *cmdtp, int flag,
> + int argc, char *const argv[])
> +{
> + struct udevice *dev;
> + u32 rc;
> + u8 session_type = TPM_SE_POLICY;
> + int ret;
> +
> + ret = get_tpm(&dev);
> +
> + if (argc < 2)
> + return CMD_RET_USAGE;
> +
> + void *data_to_write = map_sysmem(simple_strtoul(argv[1], NULL, 0), 0);
> +
> + if (argc > 2)
> + session_type = simple_strtoul(argv[2], NULL, 0);
> +
> + rc = tpm2_start_auth_session(dev, data_to_write, session_type);
> +
> + if (rc)
> + printf("ERROR: start_auth_session returns: #%u\n", rc);
> +
> + unmap_sysmem(data_to_write);
> + return report_return_code(rc);
> +}
> +
> +static int do_flush_context(struct cmd_tbl *cmdtp, int flag,
> + int argc, char *const argv[])
> +{
> + struct udevice *dev;
> + u32 rc;
> + int ret;
> +
> + ret = get_tpm(&dev);
> +
> + if (argc < 2)
> + return CMD_RET_USAGE;
> +
> + void *data_to_read = map_sysmem(simple_strtoul(argv[1], NULL, 0), 0);
> + u32 session_handle = *((u32 *)data_to_read);
> +
> + rc = tpm2_flush_context(dev, session_handle);
> +
> + if (rc)
> + printf("ERROR: flush_context returns: #%u\n", rc);
> +
> + unmap_sysmem(data_to_read);
> + return report_return_code(rc);
> +}
> +
> +static int do_policy_pcr(struct cmd_tbl *cmdtp, int flag,
> + int argc, char *const argv[])
> +{
> + struct udevice *dev;
> + u32 rc, pcr;
> + int ret;
> +
> + ret = get_tpm(&dev);
> +
> + if (argc != 4)
> + return CMD_RET_USAGE;
> +
> + void *data_to_read = map_sysmem(simple_strtoul(argv[1], NULL, 0), 0);
> + u32 session_handle = *((u32 *)data_to_read);
> +
> + pcr = simple_strtoul(argv[2], NULL, 0);
> +
> + void *out_digest = map_sysmem(simple_strtoul(argv[3], NULL, 0), 0);
> +
> + rc = tpm2_set_policy_pcr(dev, session_handle, pcr, out_digest);
> +
> + if (rc)
> + printf("ERROR: policy_pcr returns: #%u\n", rc);
> +
> + unmap_sysmem(data_to_read);
> + unmap_sysmem(out_digest);
> + return report_return_code(rc);
> +}
> +
> static struct cmd_tbl tpm2_commands[] = {
> U_BOOT_CMD_MKENT(device, 0, 1, do_tpm_device, "", ""),
> U_BOOT_CMD_MKENT(info, 0, 1, do_tpm_info, "", ""),
> @@ -375,6 +591,13 @@ 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(nv_define, 0, 1, do_tpm_nv_define, "", ""),
> + U_BOOT_CMD_MKENT(nv_undefine, 0, 1, do_tpm_nv_undefine, "", ""),
> + U_BOOT_CMD_MKENT(nv_read, 0, 1, do_tpm_nv_read_value, "", ""),
> + U_BOOT_CMD_MKENT(nv_write, 0, 1, do_tpm_nv_write_value, "", ""),
> + U_BOOT_CMD_MKENT(start_auth_session, 0, 1, do_start_auth_session, "", ""),
> + U_BOOT_CMD_MKENT(flush_context, 0, 1, do_flush_context, "", ""),
> + U_BOOT_CMD_MKENT(policy_pcr, 0, 1, do_policy_pcr, "", ""),
> };
>
> struct cmd_tbl *get_tpm2_commands(unsigned int *size)
> @@ -453,4 +676,40 @@ 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"
> +"\n"
> +"nv_define <tpm_addr> <size> [<attributes> <policy_digest_addr> <policy_size>]\n"
> +" Define new nv index in the TPM at <tpm_addr> with size <size>\n"
> +" <tpm_addr>: the internal address used within the TPM for the NV-index\n"
> +" <attributes>: is described in tpm-v2.h enum tpm_index_attrs. Note; Always use TPMA_NV_PLATFORMCREATE!\n"
> +" will default to: TPMA_NV_PLATFORMCREATE|TPMA_NV_OWNERWRITE|TPMA_NV_OWNERREAD|TPMA_NV_PPWRITE|TPMA_NV_PPREAD\n"
> +" <policy_digest_addr>: address to a policy digest. (e.g. a PCR value)\n"
> +" <policy_size>: size of the digest in bytes\n"
> +"nv_undefine <tpm_addr>\n"
> +" delete nv index\n"
> +"nv_read <tpm_addr> <size> <data_addr> [<session_handle_addr>]\n"
> +" Read data stored in TPM nv_memory at <tpm_addr> with size <size>\n"
> +" <tpm_addr>: the internal address used within the TPM for the NV-index\n"
> +" <size>: datasize in bytes\n"
> +" <data_addr>: memory address where to store the data read from the TPM\n"
> +" <session_handle_addr>: addr where the session handle is stored\n"
> +"nv_write <tpm_addr> <size> <data_addr> [<session_handle_addr>]\n"
> +" Write data to the TPM's nv_memory at <tpm_addr> with size <size>\n"
> +" <tpm_addr>: the internal address used within the TPM for the NV-index\n"
> +" <size>: datasize in bytes\n"
> +" <data_addr>: memory address of the data to be written to the TPM's NV-index\n"
> +" <session_handle_addr>: addr where the session handle is stored\n"
> +"start_auth_session <session_handle_addr> [<session_type>]\n"
> +" Start an authorization session and store it's handle at <session_handle_addr>\n"
> +" <session_handle_addr>: addr where to store the handle data (4 bytes)\n"
> +" <session_type>: type of session: 0x00 for HMAC, 0x01 for policy, 0x03 for trial\n"
> +" will default to 0x01 (TPM_SE_POLICY) if not provided\n"
> +" to create a policy, use TPM_SE_TRIAL (0x03), to authenticate TPM_SE_POLICY (0x01)\n"
> +"flush_context <session_handle_addr>\n"
> +" flush/terminate a session which's handle is stored at <session_handle_addr>\n"
> +" <session_handle_addr>: addr where the session handle is stored\n"
> +"policy_pcr <session_handle_addr> <pcr> <digest_addr>\n"
> +" create a policy to authorize using a PCR\n"
> +" <session_handle_addr>: addr where the session handle is stored\n"
> +" <pcr>: index of the PCR\n"
> +" <digest_addr>: addr where to store the policy digest (for nv_define/nv_read/write)\n"
> );
> diff --git a/include/tpm-common.h b/include/tpm-common.h
> index 1ba81386ce..5620454da7 100644
> --- a/include/tpm-common.h
> +++ b/include/tpm-common.h
> @@ -69,6 +69,8 @@ struct tpm_chip_priv {
> uint pcr_count;
> uint pcr_select_min;
> bool plat_hier_disabled;
> + u16 nonce_sz;
> + u8 nonce[32]; //NONCE_TPM_SIZE;
Add this on a define on the header file and use it, instead of adding a comment
> };
>
> /**
> diff --git a/include/tpm-v2.h b/include/tpm-v2.h
> index 33dd103767..5b60883777 100644
> --- a/include/tpm-v2.h
> +++ b/include/tpm-v2.h
> @@ -301,7 +301,8 @@ enum tpm2_startup_types {
> */
> enum tpm2_handles {
> TPM2_RH_OWNER = 0x40000001,
> - TPM2_RS_PW = 0x40000009,
> + TPM2_RH_NULL = 0x40000007,
> + TPM2_RS_PW = 0x40000009,
> TPM2_RH_LOCKOUT = 0x4000000A,
> TPM2_RH_ENDORSEMENT = 0x4000000B,
> TPM2_RH_PLATFORM = 0x4000000C,
> @@ -325,24 +326,30 @@ enum tpm2_handles {
> * @TPM2_CC_PCR_SETAUTHVAL: TPM2_PCR_SetAuthValue().
> */
> enum tpm2_command_codes {
> - TPM2_CC_STARTUP = 0x0144,
> - TPM2_CC_SELF_TEST = 0x0143,
> - TPM2_CC_HIER_CONTROL = 0x0121,
> - TPM2_CC_CLEAR = 0x0126,
> - TPM2_CC_CLEARCONTROL = 0x0127,
> - TPM2_CC_HIERCHANGEAUTH = 0x0129,
> - TPM2_CC_NV_DEFINE_SPACE = 0x012a,
> - TPM2_CC_PCR_SETAUTHPOL = 0x012C,
> - TPM2_CC_NV_WRITE = 0x0137,
> - TPM2_CC_NV_WRITELOCK = 0x0138,
> - TPM2_CC_DAM_RESET = 0x0139,
> - 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,
> + TPM2_CC_STARTUP = 0x0144,
> + TPM2_CC_SELF_TEST = 0x0143,
> + TPM2_CC_HIER_CONTROL = 0x0121,
> + TPM2_CC_CLEAR = 0x0126,
Some of the values you added include an extra tab, can you indent all
of these properly?
> + TPM2_CC_CLEARCONTROL = 0x0127,
> + TPM2_CC_HIERCHANGEAUTH = 0x0129,
> + TPM2_CC_NV_DEFINE_SPACE = 0x012a,
> + TPM2_CC_NV_UNDEFINE_SPACE = 0x0122,
> + TPM2_CC_PCR_SETAUTHPOL = 0x012C,
> + TPM2_CC_CREATE_PRIMARY = 0x0131,
> + TPM2_CC_NV_WRITE = 0x0137,
> + TPM2_CC_NV_WRITELOCK = 0x0138,
> + TPM2_CC_DAM_RESET = 0x0139,
> + TPM2_CC_DAM_PARAMETERS = 0x013A,
> + TPM2_CC_NV_READ = 0x014E,
> + TPM2_CC_FLUSH_CONTEXT = 0x0165,
> + TPM2_CC_START_AUTH_SESSION = 0x0176,
> + TPM2_CC_GET_CAPABILITY = 0x017A,
> + TPM2_CC_GET_RANDOM = 0x017B,
> + TPM2_CC_PCR_READ = 0x017E,
> + TPM2_CC_POLICY_PCR = 0x017F,
> + TPM2_CC_PCR_EXTEND = 0x0182,
> + TPM2_CC_PCR_SETAUTHVAL = 0x0183,
> + TPM2_CC_POLICY_GET_DIGEST = 0x0189,
> };
>
> /**
> @@ -384,6 +391,16 @@ enum tpm2_algorithms {
> TPM2_ALG_SHA512 = 0x0D,
> TPM2_ALG_NULL = 0x10,
> TPM2_ALG_SM3_256 = 0x12,
> + TPM2_ALG_ECC = 0x23,
> +};
> +
> +/**
> + * TPM2 session types.
> + */
> +enum tpm2_se {
> + TPM_SE_HMAC = 0x00,
> + TPM_SE_POLICY = 0x01,
> + TPM_SE_TRIAL = 0x03,
> };
>
> extern const enum tpm2_algorithms tpm2_supported_algorithms[4];
> @@ -700,6 +717,51 @@ u32 tpm2_self_test(struct udevice *dev, enum tpm2_yes_no full_test);
> u32 tpm2_clear(struct udevice *dev, u32 handle, const char *pw,
> const ssize_t pw_sz);
>
> +/**
> + * Issue a TPM2_StartAuthSession command. (chaining several commands together that need authorization)
> + *
> + * @dev TPM device
> + * @session_handle Pointer to memory where to store the session handle.
> + * @session_type tpm2_se value to indicate session type (usually TPM_SE_POLICY)
> + *
> + * Return: code of the operation
> + */
> +u32 tpm2_start_auth_session(struct udevice *dev, u32 *session_handle, u8 session_type);
> +/**
> + * Issue a TPM2_FlushContext command. (for ending the authorization session)
> + *
> + * @dev TPM device
> + * @session_handle Authorization session to be terminated.
> + *
> + * Return: code of the operation
> + */
> +u32 tpm2_flush_context(struct udevice *dev, u32 session_handle);
> +
> +/**
> + * Issue a TPM2_PolicyPCR command. (for authenticating using a PCR value)
> + *
> + * @dev TPM device
> + * @session_handle policy session handle started with start_auth_session.
> + * @index Index of the PCR
> + *
> + * @note For now only 1 PCR selection is supported,
> + * since the value of one PCR can be extended with the value of another.
> + * This achieves the same effect as selecting multiple PCR's
> + * @out_digest addr where to write the digest
The comments should be like this
@dev: TPM device
@session_handle: ....
etc
Please fix them on all functions
> + * Return: code of the operation
> + */
> +u32 tpm2_set_policy_pcr(struct udevice *dev, u32 session_handle, u32 index, void *out_digest);
> +
> +/**
> + * Issue a TPM2_getPolicyDigest command.
> + *
> + * @dev TPM device
> + * @session_handle policy session handle started with start_auth_session.
> + * @out_digest addr where to write the digest (size is always 0x20 / TPM2_SHA256_DIGEST_SIZE)
> + * Return: code of the operation
> + */
> +u32 tpm2_get_policy_digest(struct udevice *dev, u32 session_handle, void *out_digest);
> +
> /**
> * Issue a TPM_NV_DefineSpace command
> *
> @@ -709,6 +771,7 @@ u32 tpm2_clear(struct udevice *dev, u32 handle, const char *pw,
> * @space_index index of the area
> * @space_size size of area in bytes
> * @nv_attributes TPM_NV_ATTRIBUTES of the area
> + * @session_handle handle to a session. can be TPM2_RS_PW
> * @nv_policy policy to use
> * @nv_policy_size size of the policy
> * Return: return code of the operation
> @@ -717,6 +780,17 @@ u32 tpm2_nv_define_space(struct udevice *dev, u32 space_index,
> size_t space_size, u32 nv_attributes,
> const u8 *nv_policy, size_t nv_policy_size);
>
> +/**
> + * Issue a TPM_NV_UnDefineSpace command
> + *
> + * This allows a space to be removed. Needed because TPM_clear doesn't clear platform entries
> + *
> + * @dev TPM device
> + * @space_index index of the area
> + * Return: return code of the operation
> + */
> +u32 tpm2_nv_undefine_space(struct udevice *dev, u32 space_index);
> +
> /**
> * Issue a TPM2_PCR_Extend command.
> *
> @@ -734,13 +808,14 @@ u32 tpm2_pcr_extend(struct udevice *dev, u32 index, u32 algorithm,
> /**
> * Read data from the secure storage
> *
> - * @dev TPM device
> - * @index Index of data to read
> - * @data Place to put data
> - * @count Number of bytes of data
> + * @dev TPM device
> + * @index Index of data to read
> + * @data Place to put data
> + * @count Number of bytes of data
> + * @session_handle handle of a running authorization session. if NULL->password authorization
> * Return: code of the operation
> */
> -u32 tpm2_nv_read_value(struct udevice *dev, u32 index, void *data, u32 count);
> +u32 tpm2_nv_read_value(struct udevice *dev, u32 index, void *data, u32 count, u32 *session_handle);
>
> /**
> * Write data to the secure storage
> @@ -749,10 +824,11 @@ u32 tpm2_nv_read_value(struct udevice *dev, u32 index, void *data, u32 count);
> * @index Index of data to write
> * @data Data to write
> * @count Number of bytes of data
> + * @session_handle handle of a running authorization session. if NULL->password authorization
> * Return: code of the operation
> */
> u32 tpm2_nv_write_value(struct udevice *dev, u32 index, const void *data,
> - u32 count);
> + u32 count, u32 *session_handle);
>
> /**
> * Issue a TPM2_PCR_Read command.
> diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
> index 68eaaa639f..3d5e4e8343 100644
> --- a/lib/tpm-v2.c
> +++ b/lib/tpm-v2.c
> @@ -786,19 +787,192 @@ u32 tpm2_clear(struct udevice *dev, u32 handle, const char *pw,
> return tpm_sendrecv_command(dev, command_v2, NULL, NULL);
> }
>
> +u32 tpm2_start_auth_session(struct udevice *dev, u32 *session_handle, u8 session_type)
> +{
> + const u16 nonce_size = TPM2_SHA256_DIGEST_SIZE;
> + const int handles_len = sizeof(u32) * 2;
> + uint offset = TPM2_HDR_LEN + handles_len + 2;
> + struct tpm_chip_priv *priv;
> +
> + priv = dev_get_uclass_priv(dev);
> + if (!priv)
> + return TPM_LIB_ERROR;
> +
> + u8 command_v2[COMMAND_BUFFER_SIZE] = {
> + /* header 10 bytes */
> + tpm_u16(TPM2_ST_NO_SESSIONS), /* TAG */
> + tpm_u32(offset + nonce_size + 7),/* Length */
> + tpm_u32(TPM2_CC_START_AUTH_SESSION),/* Command code */
> +
> + /* handles 8 bytes */
> + tpm_u32(TPM2_RH_NULL), /* TPMI_DH_OBJECT+ */
> + tpm_u32(TPM2_RH_NULL), /* TPMI_DH_ENTITY+ */
> +
> + /* NONCE 32 bytes -> use pack_byte_string() */
> + tpm_u16(nonce_size),
> + /* message 7 bytes -> use pack_byte_string() */
> + //tpm_u16(0), // salt size
> + //session_type, // session type
> + //tpm_u16(TPM2_ALG_NULL), // symmetric key algorythm
> + //tpm_u16(TPM2_ALG_SHA256), // auth hash
> + };
> + u8 Nonce[nonce_size]; //nonce is a random number you use once. (Number ONCE)
> +
> + memset(&Nonce, 2, nonce_size); //should use TPM_get_random() to randomize
> + int ret;
> +
> + ret = pack_byte_string(command_v2, sizeof(command_v2), "swbww",
> + offset, Nonce, nonce_size,
> + offset + nonce_size, 0, //salt size
> + offset + nonce_size + 2, session_type,
> + offset + nonce_size + 3, TPM2_ALG_NULL,
> + offset + nonce_size + 5, TPM2_ALG_SHA256);
> +
> + if (ret)
> + return TPM_LIB_ERROR;
> +
> + size_t response_len = COMMAND_BUFFER_SIZE;
> + u8 response[COMMAND_BUFFER_SIZE];
> + u16 tag;
> + u32 size, code;
> +
> + ret = tpm_sendrecv_command(dev, command_v2, response, &response_len);
> +
> + if (ret)
> + return log_msg_ret("read", ret);
> +
> + if (unpack_byte_string(response, response_len, "wdddws",
> + 0, &tag, 2, &size, 6, &code, //header
> + 10, session_handle, //TPMI_SH_AUTH_SESSION
> + 14, &priv->nonce_sz,
> + 16, priv->nonce, TPM2_SHA256_DIGEST_SIZE)) //HACK: we asked for a SHA256, so that's what we'll get. if ret == 0 at least
> + return TPM_LIB_ERROR;
> +
> + return ret;
> +}
> +
> +u32 tpm2_flush_context(struct udevice *dev, u32 session_handle)
> +{
> + u8 command_v2[COMMAND_BUFFER_SIZE] = {
> + /* header 10 bytes */
> + tpm_u16(TPM2_ST_NO_SESSIONS), /* TAG */
> + tpm_u32(TPM2_HDR_LEN + sizeof(u32)),/* Length */
> + tpm_u32(TPM2_CC_FLUSH_CONTEXT),/* Command code */
> +
> + /* session handle 4 bytes */
> + tpm_u32(session_handle), /* TPMI_DH_CONTEXT+ */
> + };
> + return tpm_sendrecv_command(dev, command_v2, NULL, NULL);
> +}
> +
> +u32 tpm2_set_policy_pcr(struct udevice *dev, u32 session_handle, u32 index, void *out_digest)
> +{
> + const int offset = TPM2_HDR_LEN + 6;
> + const int message_len = offset + TPM2_SHA256_DIGEST_SIZE + 10;
> +
> + u8 pcr_sel_bit = BIT(index % 8);
> + struct tpm_chip_priv *priv;
> + struct tpml_digest_values digest_list;
> +
> + digest_list.count = 1;
> + digest_list.digests->hash_alg = TPM2_ALG_SHA256;
> + tcg2_pcr_read(dev, index, &digest_list);
> +
> + u8 pcr_sha_output[TPM2_SHA256_DIGEST_SIZE];
> + sha256_context ctx_256;
> +
> + sha256_starts(&ctx_256);
> + sha256_update(&ctx_256, digest_list.digests[0].digest.sha256, TPM2_SHA256_DIGEST_SIZE);
> + sha256_finish(&ctx_256, pcr_sha_output);
> +
> + priv = dev_get_uclass_priv(dev);
> + if (!priv)
> + return TPM_LIB_ERROR;
> +
> + u8 idx_array_sz = max(priv->pcr_select_min, DIV_ROUND_UP(index, 8));
> +
> + u8 command_v2[COMMAND_BUFFER_SIZE] = {
> + /* header 10 bytes */
> + tpm_u16(TPM2_ST_NO_SESSIONS), /* TAG -> TPM2_ST_SESSIONS only for audit or decrypt*/
> + tpm_u32(message_len),/* Length */
> + tpm_u32(TPM2_CC_POLICY_PCR),/* Command code */
> + /* session handle 4 bytes */
> + tpm_u32(session_handle), /* TPMI_SH_POLICY */
> + /* PCR Digest - 32 bytes */
> + tpm_u16(TPM2_SHA256_DIGEST_SIZE) /*hash size*/
> + /* digest - 32-bytes */
> + /* PCR selection */
> + //tpm_u32(1), /* Number of selections */
> + //tpm_u16(TPM_ALG_SHA256), /* Algorithm of the hash */
> + //idx_array_sz, /* Array size for selection */
> + /* bitmap(idx) Selected PCR bitmap */
> + };
> +
> + if (pack_byte_string(command_v2, COMMAND_BUFFER_SIZE, "sdwbbw",
> + offset, pcr_sha_output, TPM2_SHA256_DIGEST_SIZE,
> + offset + TPM2_SHA256_DIGEST_SIZE, 1, /* Number of selections */
> + offset + TPM2_SHA256_DIGEST_SIZE + 4, TPM2_ALG_SHA256, /* Algorithm of the hash */
> + offset + TPM2_SHA256_DIGEST_SIZE + 6, idx_array_sz, /* Array size for selection */
> + offset + TPM2_SHA256_DIGEST_SIZE + 7, pcr_sel_bit,/* Selected PCR bitmap */
> + offset + TPM2_SHA256_DIGEST_SIZE + 8, 0)) /*padding */
> + return TPM_LIB_ERROR;
> +
> + int ret = tpm_sendrecv_command(dev, command_v2, NULL, NULL);
> +
> + if (ret)
> + return ret;
> +
> + return tpm2_get_policy_digest(dev, session_handle, out_digest);
> +}
> +
> +u32 tpm2_get_policy_digest(struct udevice *dev, u32 session_handle, void *out_digest)
> +{
> + const int message_len = TPM2_HDR_LEN + sizeof(u32);
> +
> + u8 command_v2[COMMAND_BUFFER_SIZE] = {
> + /* header 10 bytes */
> + tpm_u16(TPM2_ST_NO_SESSIONS), /* TAG -> only audit or decrypt session uses TPM2_ST_SESSIONS */
> + tpm_u32(message_len),/* Length */
> + tpm_u32(TPM2_CC_POLICY_GET_DIGEST),/* Command code */
> + /* session handle 4 bytes */
> + tpm_u32(session_handle), /* TPMI_SH_POLICY */
> + };
> +
> + size_t response_len = COMMAND_BUFFER_SIZE;
> + u8 response[COMMAND_BUFFER_SIZE];
> + int ret;
> + u16 tag;
> + u32 size, code;
> +
> + ret = tpm_sendrecv_command(dev, command_v2, response, &response_len);
> + if (ret)
> + return log_msg_ret("read", ret);
> +
> + if (unpack_byte_string(response, response_len, "wdds",
> + 0, &tag, 2, &size, 6, &code,
> + 12, out_digest, TPM2_SHA256_DIGEST_SIZE)) //digest_size
> + return TPM_LIB_ERROR;
> +
> + return ret;
> +}
> +
> u32 tpm2_nv_define_space(struct udevice *dev, u32 space_index,
> - size_t space_size, u32 nv_attributes,
> - const u8 *nv_policy, size_t nv_policy_size)
> + size_t space_size, u32 nv_attributes,
> + const u8 *nv_policy, size_t nv_policy_size)
> {
> /*
> * Calculate the offset of the nv_policy piece by adding each of the
> * chunks below.
> */
> const int platform_len = sizeof(u32);
> - const int session_hdr_len = 13;
> + const int session_hdr_len = 15;
> const int message_len = 14;
> - uint offset = TPM2_HDR_LEN + platform_len + session_hdr_len +
> - message_len;
> + uint offset = TPM2_HDR_LEN + platform_len + session_hdr_len + message_len;
> + u8 attrs = 0;
> +
> + //if(session_handle != TPM2_RS_PW)
> + //attrs = 1; //continue_session (bit 1)
Why is this commented out?
> +
> u8 command_v2[COMMAND_BUFFER_SIZE] = {
> /* header 10 bytes */
> tpm_u16(TPM2_ST_SESSIONS), /* TAG */
> @@ -806,20 +979,24 @@ u32 tpm2_nv_define_space(struct udevice *dev, u32 space_index,
> tpm_u32(TPM2_CC_NV_DEFINE_SPACE),/* Command code */
>
> /* handles 4 bytes */
> - tpm_u32(TPM2_RH_PLATFORM), /* Primary platform seed */
> + tpm_u32(TPM2_RH_PLATFORM), /* Primary platform seed, requires TPMA_NV_PLATFORMCREATE*/
> +
>
> - /* session header 13 bytes */
> + /* session header 15 bytes */
> + /*null auth session*/
> tpm_u32(9), /* Header size */
> - tpm_u32(TPM2_RS_PW), /* Password authorisation */
> + tpm_u32(TPM2_RS_PW),/* auth session handle if it's active, otherwise TPM2_RS_PW*/
> tpm_u16(0), /* nonce_size */
> - 0, /* session_attrs */
> + attrs, /* session_attrs */
> + tpm_u16(0), /* HMAC size */
> + /*end auth area*/
> tpm_u16(0), /* auth_size */
>
> /* message 14 bytes + policy */
> tpm_u16(message_len + nv_policy_size), /* size */
> tpm_u32(space_index),
> tpm_u16(TPM2_ALG_SHA256),
> - tpm_u32(nv_attributes),
> + tpm_u32(nv_attributes | TPMA_NV_PLATFORMCREATE),
> tpm_u16(nv_policy_size),
> /*
> * nv_policy
> @@ -841,6 +1018,35 @@ u32 tpm2_nv_define_space(struct udevice *dev, u32 space_index,
> return tpm_sendrecv_command(dev, command_v2, NULL, NULL);
> }
>
> +u32 tpm2_nv_undefine_space(struct udevice *dev, u32 space_index)
> +{
> + const int platform_len = sizeof(u32);
> + const int session_hdr_len = 13;
> + const int message_len = 4;
> + u8 command_v2[COMMAND_BUFFER_SIZE] = {
> + /* header 10 bytes */
> + tpm_u16(TPM2_ST_SESSIONS), /* TAG */
> + tpm_u32(TPM2_HDR_LEN + platform_len + session_hdr_len +
> + message_len),/* Length - header + provision + index + auth area*/
> + tpm_u32(TPM2_CC_NV_UNDEFINE_SPACE),/* Command code */
> +
> + /* handles 4 bytes */
> + tpm_u32(TPM2_RH_PLATFORM), /* Primary platform seed */
> + /* nv_index */
> + tpm_u32(space_index),
> +
> + /*null auth session*/
> + tpm_u32(9), /* Header size */
> + tpm_u32(TPM2_RS_PW), /* Password authorisation*/
> + tpm_u16(0), /* nonce_size */
> + 0, /* session_attrs */
> + tpm_u16(0), /* HMAC size */
> + /*end auth area*/
> +
> + };
> + return tpm_sendrecv_command(dev, command_v2, NULL, NULL);
> +}
> +
> u32 tpm2_pcr_extend(struct udevice *dev, u32 index, u32 algorithm,
> const u8 *digest, u32 digest_len)
> {
> @@ -884,56 +1091,101 @@ u32 tpm2_pcr_extend(struct udevice *dev, u32 index, u32 algorithm,
> return tpm_sendrecv_command(dev, command_v2, NULL, NULL);
> }
>
> -u32 tpm2_nv_read_value(struct udevice *dev, u32 index, void *data, u32 count)
> +u32 tpm2_nv_read_value(struct udevice *dev, u32 index, void *data, u32 count, u32 *session_handle)
> {
> - u8 command_v2[COMMAND_BUFFER_SIZE] = {
> - /* header 10 bytes */
> - tpm_u16(TPM2_ST_SESSIONS), /* TAG */
> - tpm_u32(10 + 8 + 4 + 9 + 4), /* Length */
> - tpm_u32(TPM2_CC_NV_READ), /* Command code */
> + u32 offset = TPM2_HDR_LEN + 8 + 4 + 6;
> + struct tpm_chip_priv *priv;
>
> - /* handles 8 bytes */
> - tpm_u32(TPM2_RH_PLATFORM), /* Primary platform seed */
> - tpm_u32(HR_NV_INDEX + index), /* Password authorisation */
> + priv = dev_get_uclass_priv(dev);
>
> - /* AUTH_SESSION */
> - tpm_u32(9), /* 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(0), /* Size of <hmac/password> */
> - /* <hmac/password> (if any) */
> + if (!priv)
> + return TPM_LIB_ERROR;
> +
> + u32 nonce_size = priv->nonce_sz;
> +
> + priv->nonce[nonce_size - 1]++; //increase nonce.
> +
> + u32 authorization = TPM2_RS_PW;
>
> - tpm_u16(count), /* Number of bytes */
> - tpm_u16(0), /* Offset */
> + if (session_handle)
> + authorization = *session_handle;
> + else
> + nonce_size = 0; //cannot use nonce when using password authorization
> +
> + u8 command_v2[COMMAND_BUFFER_SIZE] = {
> + /* header 10 bytes */
> + tpm_u16(TPM2_ST_SESSIONS), /* TAG */
> + tpm_u32(offset + nonce_size + 7), /* Length */
> + tpm_u32(TPM2_CC_NV_READ), /* Command code */
> +
> + /* handles 8 bytes */
> + tpm_u32(index), /* Primary platform seed */
> + tpm_u32(index), /*nv index*/
> +
> + /* AUTH_SESSION */
> + tpm_u32(9 + nonce_size), /* Authorization size - 4 bytes*/
> + /*auth handle - 9 bytes */
> + tpm_u32(authorization),
> + tpm_u16(nonce_size), /* Size of <nonce> */
> + /* <nonce> (if any) */
> + //0, /* Attributes: Cont/Excl/Rst */
> + //tpm_u16(0), /* Size of <hmac/password> */
> + /* <hmac/password> (if any) */
> + /*end auth handle */
> + //tpm_u16(count), /* Number of bytes */
> + //tpm_u16(0), /* Offset */
I am not sure keeping the values commented out helps in readability.
> };
> +
> size_t response_len = COMMAND_BUFFER_SIZE;
> u8 response[COMMAND_BUFFER_SIZE];
> int ret;
> u16 tag;
> u32 size, code;
Those should be defined on top. IIRC we don't allow declarations here.
>
> + ret = pack_byte_string(command_v2, sizeof(command_v2), "sbwww",
> + offset, priv->nonce, nonce_size,
> + offset + nonce_size, 0,
> + offset + nonce_size + 1, 0,
> + offset + nonce_size + 3, count,
> + offset + nonce_size + 5, 0);
> +
> + if (ret)
> + return TPM_LIB_ERROR;
> +
> ret = tpm_sendrecv_command(dev, command_v2, response, &response_len);
> if (ret)
> return log_msg_ret("read", ret);
> +
> if (unpack_byte_string(response, response_len, "wdds",
> - 0, &tag, 2, &size, 6, &code,
> - 16, data, count))
> + 0, &tag, 2, &size, 6, &code,
> + 16, data, count))
> return TPM_LIB_ERROR;
>
> return 0;
> }
>
> u32 tpm2_nv_write_value(struct udevice *dev, u32 index, const void *data,
> - u32 count)
> + u32 count, u32 *session_handle)
> {
> struct tpm_chip_priv *priv = dev_get_uclass_priv(dev);
> - uint offset = 10 + 8 + 4 + 9 + 2;
> - uint len = offset + count + 2;
> - /* Use empty password auth if platform hierarchy is disabled */
> - u32 auth = priv->plat_hier_disabled ? HR_NV_INDEX + index :
> - TPM2_RH_PLATFORM;
> +
> + if (!priv)
> + return TPM_LIB_ERROR;
> +
> + u32 nonce_size = priv->nonce_sz;
> +
> + priv->nonce[nonce_size - 1]++;
> +
> + u32 authorization = TPM2_RS_PW;
> +
> + if (session_handle)
> + authorization = *session_handle;
> + else
> + nonce_size = 0; //cannot use nonce when using password authorization
> +
> + uint offset = TPM2_HDR_LEN + 8 + 4 + 6;
> + uint len = offset + nonce_size + count + 7;
This isn't a problem of your patch directly, but since you are
changing that, can we get rid of the magic values (e.g 8,4, 7 etc) and
either add a comment or a define that explains it?
> +
> u8 command_v2[COMMAND_BUFFER_SIZE] = {
> /* header 10 bytes */
> tpm_u16(TPM2_ST_SESSIONS), /* TAG */
> @@ -941,27 +1192,35 @@ u32 tpm2_nv_write_value(struct udevice *dev, u32 index, const void *data,
> tpm_u32(TPM2_CC_NV_WRITE), /* Command code */
>
> /* handles 8 bytes */
> - tpm_u32(auth), /* Primary platform seed */
> - tpm_u32(HR_NV_INDEX + index), /* Password authorisation */
> + tpm_u32(index), /* Primary platform seed */
> + tpm_u32(index), /*nv index*/
>
> /* AUTH_SESSION */
> - tpm_u32(9), /* Authorization size */
> - tpm_u32(TPM2_RS_PW), /* Session handle */
> - tpm_u16(0), /* Size of <nonce> */
> + tpm_u32(9 + nonce_size), /* Authorization size - 4 bytes */
> + /*auth handle - 9 bytes */
> + tpm_u32(authorization),
> + tpm_u16(nonce_size), /* Size of <nonce> */
> /* <nonce> (if any) */
> - 0, /* Attributes: Cont/Excl/Rst */
> - tpm_u16(0), /* Size of <hmac/password> */
> + //0, /* Attributes: Cont/Excl/Rst */
> + //tpm_u16(0), /* Size of <hmac/password> */
> /* <hmac/password> (if any) */
> -
> - tpm_u16(count),
> + /*end auth handle */
> + //tpm_u16(count),/*size of buffer - 2 bytes*/
> + /*data (buffer)*/
> + /*offset -> the octet offset into the NV Area*/
> };
> size_t response_len = COMMAND_BUFFER_SIZE;
> u8 response[COMMAND_BUFFER_SIZE];
> int ret;
>
> - ret = pack_byte_string(command_v2, sizeof(command_v2), "sw",
> - offset, data, count,
> - offset + count, 0);
> + ret = pack_byte_string(command_v2, sizeof(command_v2), "sbwwsw",
> + offset, priv->nonce, nonce_size,
> + offset + nonce_size, 0, //attrs
> + offset + nonce_size + 1, 0, //hmac sz
> + offset + nonce_size + 3, count,
> + offset + nonce_size + 5, data, count,
> + offset + nonce_size + count, 0);
> +
> if (ret)
> return TPM_LIB_ERROR;
>
> diff --git a/lib/tpm_api.c b/lib/tpm_api.c
> index 39a5121e30..5875e7b085 100644
> --- a/lib/tpm_api.c
> +++ b/lib/tpm_api.c
> @@ -128,7 +128,7 @@ u32 tpm_nv_read_value(struct udevice *dev, u32 index, void *data, u32 count)
> if (tpm_is_v1(dev))
> return tpm1_nv_read_value(dev, index, data, count);
> else if (tpm_is_v2(dev))
> - return tpm2_nv_read_value(dev, index, data, count);
> + return tpm2_nv_read_value(dev, index, data, count, NULL);
> else
> return -ENOSYS;
> }
> @@ -139,7 +139,7 @@ u32 tpm_nv_write_value(struct udevice *dev, u32 index, const void *data,
> if (tpm_is_v1(dev))
> return tpm1_nv_write_value(dev, index, data, count);
> else if (tpm_is_v2(dev))
> - return tpm2_nv_write_value(dev, index, data, count);
> + return tpm2_nv_write_value(dev, index, data, count, NULL);
> else
> return -ENOSYS;
> }
> --
> 2.34.1
> ==========================END PATCH=======================
Thanks
/Ilias
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