Messages in this thread Patch in this message | | | From | Jarkko Sakkinen <> | Subject | [PATCH 3/4] tpm: seal/unseal for TPM 2.0 | Date | Fri, 3 Jul 2015 18:36:35 +0300 |
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Added tpm_trusted_seal() and tpm_trusted_unseal() API for sealing trusted keys.
This patch implements basic sealing and unsealing functionality for TPM 2.0:
* Seal with a parent key using a 20 byte auth value. * Unseal with a parent key using a 20 byte auth value.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> --- drivers/char/tpm/tpm-interface.c | 75 ++++++++++++++++ drivers/char/tpm/tpm.h | 13 +++ drivers/char/tpm/tpm2-cmd.c | 182 +++++++++++++++++++++++++++++++++++++++ include/linux/tpm.h | 26 ++++++ 4 files changed, 296 insertions(+)
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index e85d341..6dd4c74 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -666,6 +666,29 @@ int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf) } /** + * tpm_is_tpm2 - is the chip a TPM2 chip? + * @chip_num: tpm idx # or ANY + * + * Returns 1 if the chip is a TPM2 chip. + */ +int tpm_is_tpm2(u32 chip_num) +{ + struct tpm_chip *chip; + int rc; + + chip = tpm_chip_find_get(chip_num); + if (chip == NULL) + return -ENODEV; + + rc = (chip->flags & TPM_CHIP_FLAG_TPM2) != 0; + + tpm_chip_put(chip); + + return rc; +} +EXPORT_SYMBOL_GPL(tpm_is_tpm2); + +/** * tpm_pcr_read - read a pcr value * @chip_num: tpm idx # or ANY * @pcr_idx: pcr idx to retrieve @@ -1021,6 +1044,58 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max) } EXPORT_SYMBOL_GPL(tpm_get_random); +/** + * tpm_seal_trusted() - seal a trusted key + * @chip_num: A specific chip number for the request or TPM_ANY_NUM + * @options: authentication values and other options + * @payload: the key data in clear and encrypted form + * + * Returns < 0 on error and 0 on success. At the moment, only TPM 2.0 chips + * are supported. + */ +int tpm_seal_trusted(u32 chip_num, struct trusted_key_payload *payload, + struct trusted_key_options *options) +{ + struct tpm_chip *chip; + int rc; + + chip = tpm_chip_find_get(chip_num); + if (chip == NULL || !(chip->flags & TPM_CHIP_FLAG_TPM2)) + return -ENODEV; + + rc = tpm2_seal_trusted(chip, payload, options); + + tpm_chip_put(chip); + return rc; +} +EXPORT_SYMBOL_GPL(tpm_seal_trusted); + +/** + * tpm_unseal_trusted() - unseal a trusted key + * @chip_num: A specific chip number for the request or TPM_ANY_NUM + * @options: authentication values and other options + * @payload: the key data in clear and encrypted form + * + * Returns < 0 on error and 0 on success. At the moment, only TPM 2.0 chips + * are supported. + */ +int tpm_unseal_trusted(u32 chip_num, struct trusted_key_payload *payload, + struct trusted_key_options *options) +{ + struct tpm_chip *chip; + int rc; + + chip = tpm_chip_find_get(chip_num); + if (chip == NULL || !(chip->flags & TPM_CHIP_FLAG_TPM2)) + return -ENODEV; + + rc = tpm2_unseal_trusted(chip, payload, options); + + tpm_chip_put(chip); + return rc; +} +EXPORT_SYMBOL_GPL(tpm_unseal_trusted); + static int __init tpm_init(void) { int rc; diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index f04afb7..0fa179a 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -88,6 +88,8 @@ enum tpm2_return_codes { enum tpm2_algorithms { TPM2_ALG_SHA1 = 0x0004, + TPM2_ALG_KEYEDHASH = 0x0008, + TPM2_ALG_NULL = 0x0010 }; enum tpm2_command_codes { @@ -95,6 +97,10 @@ enum tpm2_command_codes { TPM2_CC_SELF_TEST = 0x0143, TPM2_CC_STARTUP = 0x0144, TPM2_CC_SHUTDOWN = 0x0145, + TPM2_CC_CREATE = 0x0153, + TPM2_CC_LOAD = 0x0157, + TPM2_CC_UNSEAL = 0x015E, + TPM2_CC_FLUSH_CONTEXT = 0x0165, TPM2_CC_GET_CAPABILITY = 0x017A, TPM2_CC_GET_RANDOM = 0x017B, TPM2_CC_PCR_READ = 0x017E, @@ -492,6 +498,13 @@ static inline void tpm_remove_ppi(struct tpm_chip *chip) int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf); int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash); int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max); +int tpm2_seal_trusted(struct tpm_chip *chip, + struct trusted_key_payload *payload, + struct trusted_key_options *options); +int tpm2_unseal_trusted(struct tpm_chip *chip, + struct trusted_key_payload *payload, + struct trusted_key_options *options); + ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id, u32 *value, const char *desc); diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c index edf474f..d404e5f 100644 --- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -16,6 +16,11 @@ */ #include "tpm.h" +#include <keys/trusted-type.h> + +enum tpm2_object_attributes { + TPM2_ATTR_USER_WITH_AUTH = BIT(6), +}; struct tpm2_pcr_read_in { __be32 pcr_selects_cnt; @@ -322,6 +327,183 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *res_buf, size_t max) } /** + * tpm2_seal_trusted() - seal a trusted key + * @chip_num: A specific chip number for the request or TPM_ANY_NUM + * @options: authentication values and other options + * @payload: the key data in clear and encrypted form + * + * Returns < 0 on error and 0 on success. + */ +int tpm2_seal_trusted(struct tpm_chip *chip, + struct trusted_key_payload *payload, + struct trusted_key_options *options) +{ + unsigned int blob_len; + struct tpm_buf buf; + int rc; + + tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE); + tpm_buf_append_u32(&buf, options->keyhandle); + tpm2_buf_append_auth(&buf, TPM2_RS_PW, NULL /* nonce */, 0, + 0 /* session_attributes */, NULL /* hmac */, 0); + + /* sensitive */ + tpm_buf_append_u16(&buf, 4 + TPM_DIGEST_SIZE + payload->key_len); + + tpm_buf_append_u16(&buf, TPM_DIGEST_SIZE); + tpm_buf_append(&buf, options->blobauth, TPM_DIGEST_SIZE); + tpm_buf_append_u16(&buf, payload->key_len); + tpm_buf_append(&buf, payload->key, payload->key_len); + + /* public */ + tpm_buf_append_u16(&buf, 14); + + tpm_buf_append_u16(&buf, TPM2_ALG_KEYEDHASH); + tpm_buf_append_u16(&buf, TPM2_ALG_SHA1); + tpm_buf_append_u32(&buf, TPM2_ATTR_USER_WITH_AUTH); + tpm_buf_append_u16(&buf, 0); /* policy digest size */ + tpm_buf_append_u16(&buf, TPM2_ALG_NULL); + tpm_buf_append_u16(&buf, 0); + + /* outside info */ + tpm_buf_append_u16(&buf, 0); + + /* creation PCR */ + tpm_buf_append_u32(&buf, 0); + + rc = tpm_transmit_cmd(chip, buf.data, TPM_BUF_SIZE, "sealing data"); + if (rc) + goto out; + + blob_len = be32_to_cpup((__be32 *) &buf.data[TPM_HEADER_SIZE]); + if (blob_len > MAX_BLOB_SIZE) { + rc = -E2BIG; + goto out; + } + + memcpy(payload->blob, &buf.data[TPM_HEADER_SIZE + 4], blob_len); + payload->blob_len = blob_len; + +out: + if (rc > 0) + rc = -EPERM; + + return rc; +} + +static int tpm2_load(struct tpm_chip *chip, + struct trusted_key_payload *payload, + struct trusted_key_options *options, + u32 *blob_handle) +{ + struct tpm_buf buf; + unsigned int private_len; + unsigned int public_len; + unsigned int blob_len; + int rc; + + private_len = be16_to_cpup((__be16 *) &payload->blob[0]); + if (private_len > (payload->blob_len - 2)) + return -E2BIG; + + pr_info("private_len=%u\n", private_len); + + public_len = be16_to_cpup((__be16 *) &payload->blob[2 + private_len]); + blob_len = private_len + public_len + 4; + if (blob_len > payload->blob_len) + return -E2BIG; + + pr_info("public_len=%u\n", public_len); + + tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD); + tpm_buf_append_u32(&buf, options->keyhandle); + tpm2_buf_append_auth(&buf, TPM2_RS_PW, NULL /* nonce */, 0, + 0 /* session_attributes */, NULL /* hmac */, 0); + + tpm_buf_append(&buf, payload->blob, payload->blob_len); + + rc = tpm_transmit_cmd(chip, buf.data, TPM_BUF_SIZE, "loading blob"); + if (!rc) + *blob_handle = be32_to_cpup( + (__be32 *) &buf.data[TPM_HEADER_SIZE]); + + if (rc > 0) + rc = -EPERM; + + return rc; +} + +static void tpm2_flush_context(struct tpm_chip *chip, u32 handle) +{ + struct tpm_buf buf; + int rc; + + tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_FLUSH_CONTEXT); + tpm_buf_append_u32(&buf, handle); + + rc = tpm_transmit_cmd(chip, buf.data, TPM_BUF_SIZE, "flushing context"); + if (rc) + dev_warn(chip->pdev, "0x%08x was not flushed\n", handle); +} + +static int tpm2_unseal(struct tpm_chip *chip, + struct trusted_key_payload *payload, + struct trusted_key_options *options, + u32 blob_handle) +{ + struct tpm_buf buf; + int rc; + + tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL); + tpm_buf_append_u32(&buf, blob_handle); + tpm2_buf_append_auth(&buf, TPM2_RS_PW, + NULL /* nonce */, 0, + 0 /* session_attributes */, + options->blobauth /* hmac */, + TPM_DIGEST_SIZE); + + rc = tpm_transmit_cmd(chip, buf.data, TPM_BUF_SIZE, "unsealing"); + if (rc > 0) + rc = -EPERM; + + if (!rc) { + payload->key_len = be16_to_cpup( + (__be16 *) &buf.data[TPM_HEADER_SIZE + 4]); + + memcpy(payload->key, &buf.data[TPM_HEADER_SIZE + 6], + payload->key_len); + } + + return rc; +} + +/** + * tpm_unseal_trusted() - unseal a trusted key + * @chip_num: A specific chip number for the request or TPM_ANY_NUM + * @options: authentication values and other options + * @payload: the key data in clear and encrypted form + * + * Returns < 0 on error and 0 on success. + */ +int tpm2_unseal_trusted(struct tpm_chip *chip, + struct trusted_key_payload *payload, + struct trusted_key_options *options) +{ + u32 blob_handle; + int rc; + + rc = tpm2_load(chip, payload, options, &blob_handle); + if (rc) + return rc; + + rc = tpm2_unseal(chip, payload, options, blob_handle); + + tpm2_flush_context(chip, blob_handle); + + return rc; +} + +/** * tpm2_get_tpm_pt() - get value of a TPM_CAP_TPM_PROPERTIES type property * @chip: TPM chip to use. * @property_id: property ID. diff --git a/include/linux/tpm.h b/include/linux/tpm.h index 8350c53..706e63e 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -30,6 +30,8 @@ #define TPM_ANY_NUM 0xFFFF struct tpm_chip; +struct trusted_key_payload; +struct trusted_key_options; struct tpm_class_ops { const u8 req_complete_mask; @@ -46,11 +48,22 @@ struct tpm_class_ops { #if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE) +extern int tpm_is_tpm2(u32 chip_num); extern int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf); extern int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash); extern int tpm_send(u32 chip_num, void *cmd, size_t buflen); extern int tpm_get_random(u32 chip_num, u8 *data, size_t max); +extern int tpm_seal_trusted(u32 chip_num, + struct trusted_key_payload *payload, + struct trusted_key_options *options); +extern int tpm_unseal_trusted(u32 chip_num, + struct trusted_key_payload *payload, + struct trusted_key_options *options); #else +static inline int tpm_is_tpm2(u32 chip_num) +{ + return -ENODEV; +} static inline int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf) { return -ENODEV; } @@ -63,5 +76,18 @@ static inline int tpm_send(u32 chip_num, void *cmd, size_t buflen) { static inline int tpm_get_random(u32 chip_num, u8 *data, size_t max) { return -ENODEV; } + +static inline int tpm_seal_trusted(u32 chip_num, + struct trusted_key_payload *payload, + struct trusted_key_options *options) +{ + return -ENODEV; +} +static inline int tpm_unseal_trusted(u32 chip_num, + struct trusted_key_payload *payload, + struct trusted_key_options *options) +{ + return -ENODEV; +} #endif #endif -- 2.1.4
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