Add support for TEE based trusted keys where TEE provides the functionality to seal and unseal trusted keys using hardware unique key. Also, this is an alternative in case platform doesn't possess a TPM device.
This series also adds some TEE features like:
Patch #1, #2 enables support for registered kernel shared memory with TEE.
Patch #3 enables support for private kernel login method required for cases like trusted keys where we don't wan't user-space to directly access TEE service to retrieve trusted key contents.
Rest of the patches from #4 to #7 adds support for TEE based trusted keys.
This patch-set has been tested with OP-TEE based pseudo TA which can be found here [1].
[1] https://github.com/OP-TEE/optee_os/pull/3082
Changes in v3: 1. Update patch #2 to support registration of multiple kernel pages. 2. Incoporate dependency patch #4 in this patch-set: https://patchwork.kernel.org/patch/11091435/ 3. Rebased to latest tpmdd-master.
Changes in v2: 1. Add reviewed-by tags for patch #1 and #2. 2. Incorporate comments from Jens for patch #3. 3. Switch to use generic trusted keys framework.
Sumit Garg (7): tee: optee: allow kernel pages to register as shm tee: enable support to register kernel memory tee: add private login method for kernel clients KEYS: trusted: Add generic trusted keys framework KEYS: trusted: Introduce TEE based Trusted Keys doc: keys: Document usage of TEE based Trusted Keys MAINTAINERS: Add entry for TEE based Trusted Keys
Documentation/security/keys/index.rst | 1 + Documentation/security/keys/tee-trusted.rst | 93 ++++++++ MAINTAINERS | 9 + drivers/tee/optee/call.c | 7 + drivers/tee/tee_core.c | 6 + drivers/tee/tee_shm.c | 26 ++- include/keys/trusted-type.h | 48 ++++ include/keys/trusted_tee.h | 66 ++++++ include/keys/trusted_tpm.h | 15 -- include/linux/tee_drv.h | 1 + include/uapi/linux/tee.h | 8 + security/keys/Kconfig | 3 + security/keys/trusted-keys/Makefile | 2 + security/keys/trusted-keys/trusted_common.c | 346 ++++++++++++++++++++++++++++ security/keys/trusted-keys/trusted_tee.c | 282 +++++++++++++++++++++++ security/keys/trusted-keys/trusted_tpm1.c | 345 +++++---------------------- 16 files changed, 954 insertions(+), 304 deletions(-) create mode 100644 Documentation/security/keys/tee-trusted.rst create mode 100644 include/keys/trusted_tee.h create mode 100644 security/keys/trusted-keys/trusted_common.c create mode 100644 security/keys/trusted-keys/trusted_tee.c
Kernel pages are marked as normal type memory only so allow kernel pages to be registered as shared memory with OP-TEE.
Signed-off-by: Sumit Garg sumit.garg@linaro.org Reviewed-by: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com Reviewed-by: Jens Wiklander jens.wiklander@linaro.org --- drivers/tee/optee/call.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c index 13b0269..cf2367b 100644 --- a/drivers/tee/optee/call.c +++ b/drivers/tee/optee/call.c @@ -554,6 +554,13 @@ static int check_mem_type(unsigned long start, size_t num_pages) struct mm_struct *mm = current->mm; int rc;
+ /* + * Allow kernel address to register with OP-TEE as kernel + * pages are configured as normal memory only. + */ + if (virt_addr_valid(start)) + return 0; + down_read(&mm->mmap_sem); rc = __check_mem_type(find_vma(mm, start), start + num_pages * PAGE_SIZE);
Enable support to register kernel memory reference with TEE. This change will allow TEE bus drivers to register memory references.
Signed-off-by: Sumit Garg sumit.garg@linaro.org --- drivers/tee/tee_shm.c | 26 ++++++++++++++++++++++++-- include/linux/tee_drv.h | 1 + 2 files changed, 25 insertions(+), 2 deletions(-)
diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c index 09ddcd0..1ec1577 100644 --- a/drivers/tee/tee_shm.c +++ b/drivers/tee/tee_shm.c @@ -9,6 +9,7 @@ #include <linux/sched.h> #include <linux/slab.h> #include <linux/tee_drv.h> +#include <linux/uio.h> #include "tee_private.h"
static void tee_shm_release(struct tee_shm *shm) @@ -224,13 +225,14 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr, { struct tee_device *teedev = ctx->teedev; const u32 req_flags = TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED; + const u32 req_ker_flags = TEE_SHM_DMA_BUF | TEE_SHM_KERNEL_MAPPED; struct tee_shm *shm; void *ret; int rc; int num_pages; unsigned long start;
- if (flags != req_flags) + if (flags != req_flags && flags != req_ker_flags) return ERR_PTR(-ENOTSUPP);
if (!tee_device_get(teedev)) @@ -265,7 +267,27 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr, goto err; }
- rc = get_user_pages_fast(start, num_pages, FOLL_WRITE, shm->pages); + if (flags & TEE_SHM_USER_MAPPED) { + rc = get_user_pages_fast(start, num_pages, FOLL_WRITE, + shm->pages); + } else { + struct kvec *kiov; + int i; + + kiov = kcalloc(num_pages, sizeof(*kiov), GFP_KERNEL); + if (!kiov) { + ret = ERR_PTR(-ENOMEM); + goto err; + } + + for (i = 0; i < num_pages; i++) { + kiov[i].iov_base = (void *)(start + i * PAGE_SIZE); + kiov[i].iov_len = PAGE_SIZE; + } + + rc = get_kernel_pages(kiov, num_pages, 0, shm->pages); + kfree(kiov); + } if (rc > 0) shm->num_pages = rc; if (rc != num_pages) { diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h index 7a03f68..dedf8fa 100644 --- a/include/linux/tee_drv.h +++ b/include/linux/tee_drv.h @@ -26,6 +26,7 @@ #define TEE_SHM_REGISTER BIT(3) /* Memory registered in secure world */ #define TEE_SHM_USER_MAPPED BIT(4) /* Memory mapped in user space */ #define TEE_SHM_POOL BIT(5) /* Memory allocated from pool */ +#define TEE_SHM_KERNEL_MAPPED BIT(6) /* Memory mapped in kernel space */
struct device; struct tee_device;
There are use-cases where user-space shouldn't be allowed to communicate directly with a TEE device which is dedicated to provide a specific service for a kernel client. So add a private login method for kernel clients and disallow user-space to open-session using GP implementation defined login method range: (0x80000000 - 0xFFFFFFFF).
Signed-off-by: Sumit Garg sumit.garg@linaro.org --- drivers/tee/tee_core.c | 6 ++++++ include/uapi/linux/tee.h | 8 ++++++++ 2 files changed, 14 insertions(+)
diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c index 0f16d9f..2c2f646 100644 --- a/drivers/tee/tee_core.c +++ b/drivers/tee/tee_core.c @@ -334,6 +334,12 @@ static int tee_ioctl_open_session(struct tee_context *ctx, goto out; }
+ if (arg.clnt_login & TEE_IOCTL_LOGIN_MASK) { + pr_debug("login method not allowed for user-space client\n"); + rc = -EPERM; + goto out; + } + rc = ctx->teedev->desc->ops->open_session(ctx, &arg, params); if (rc) goto out; diff --git a/include/uapi/linux/tee.h b/include/uapi/linux/tee.h index 4b9eb06..a0a3d52 100644 --- a/include/uapi/linux/tee.h +++ b/include/uapi/linux/tee.h @@ -172,6 +172,14 @@ struct tee_ioctl_buf_data { #define TEE_IOCTL_LOGIN_APPLICATION 4 #define TEE_IOCTL_LOGIN_USER_APPLICATION 5 #define TEE_IOCTL_LOGIN_GROUP_APPLICATION 6 +/* + * Disallow user-space to use GP implementation specific login + * method range (0x80000000 - 0xFFFFFFFF). This range is rather + * being reserved for REE kernel clients or TEE implementation. + */ +#define TEE_IOCTL_LOGIN_MASK 0x80000000 +/* Private login method for REE kernel clients */ +#define TEE_IOCTL_LOGIN_REE_KERNEL 0x80000000
/** * struct tee_ioctl_param - parameter
Current trusted keys framework is tightly coupled to use TPM device as an underlying implementation which makes it difficult for implementations like Trusted Execution Environment (TEE) etc. to provide trusked keys support in case platform doesn't posses a TPM device.
So this patch tries to add generic trusted keys framework where underlying implemtations like TPM, TEE etc. could be easily plugged-in.
Suggested-by: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com Signed-off-by: Sumit Garg sumit.garg@linaro.org --- include/keys/trusted-type.h | 45 ++++ include/keys/trusted_tpm.h | 15 -- security/keys/trusted-keys/Makefile | 1 + security/keys/trusted-keys/trusted_common.c | 343 +++++++++++++++++++++++++++ security/keys/trusted-keys/trusted_tpm1.c | 345 +++++----------------------- 5 files changed, 447 insertions(+), 302 deletions(-) create mode 100644 security/keys/trusted-keys/trusted_common.c
diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h index a94c03a..5559010 100644 --- a/include/keys/trusted-type.h +++ b/include/keys/trusted-type.h @@ -40,6 +40,51 @@ struct trusted_key_options { uint32_t policyhandle; };
+struct trusted_key_ops { + /* + * flag to indicate if trusted key implementation supports migration + * or not. + */ + unsigned char migratable; + + /* trusted key init */ + int (*init)(void); + + /* seal a trusted key */ + int (*seal)(struct trusted_key_payload *p, char *datablob); + + /* unseal a trusted key */ + int (*unseal)(struct trusted_key_payload *p, char *datablob); + + /* get random trusted key */ + int (*get_random)(unsigned char *key, size_t key_len); + + /* trusted key cleanup */ + void (*cleanup)(void); +}; + extern struct key_type key_type_trusted; +#if defined(CONFIG_TCG_TPM) +extern struct trusted_key_ops tpm_trusted_key_ops; +#endif + +#define TRUSTED_DEBUG 0 + +#if TRUSTED_DEBUG +static inline void dump_payload(struct trusted_key_payload *p) +{ + pr_info("trusted_key: key_len %d\n", p->key_len); + print_hex_dump(KERN_INFO, "key ", DUMP_PREFIX_NONE, + 16, 1, p->key, p->key_len, 0); + pr_info("trusted_key: bloblen %d\n", p->blob_len); + print_hex_dump(KERN_INFO, "blob ", DUMP_PREFIX_NONE, + 16, 1, p->blob, p->blob_len, 0); + pr_info("trusted_key: migratable %d\n", p->migratable); +} +#else +static inline void dump_payload(struct trusted_key_payload *p) +{ +} +#endif
#endif /* _KEYS_TRUSTED_TYPE_H */ diff --git a/include/keys/trusted_tpm.h b/include/keys/trusted_tpm.h index a56d8e1..5753231 100644 --- a/include/keys/trusted_tpm.h +++ b/include/keys/trusted_tpm.h @@ -60,17 +60,6 @@ static inline void dump_options(struct trusted_key_options *o) 16, 1, o->pcrinfo, o->pcrinfo_len, 0); }
-static inline void dump_payload(struct trusted_key_payload *p) -{ - pr_info("trusted_key: key_len %d\n", p->key_len); - print_hex_dump(KERN_INFO, "key ", DUMP_PREFIX_NONE, - 16, 1, p->key, p->key_len, 0); - pr_info("trusted_key: bloblen %d\n", p->blob_len); - print_hex_dump(KERN_INFO, "blob ", DUMP_PREFIX_NONE, - 16, 1, p->blob, p->blob_len, 0); - pr_info("trusted_key: migratable %d\n", p->migratable); -} - static inline void dump_sess(struct osapsess *s) { print_hex_dump(KERN_INFO, "trusted-key: handle ", DUMP_PREFIX_NONE, @@ -96,10 +85,6 @@ static inline void dump_options(struct trusted_key_options *o) { }
-static inline void dump_payload(struct trusted_key_payload *p) -{ -} - static inline void dump_sess(struct osapsess *s) { } diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile index 7b73ceb..2b1085b 100644 --- a/security/keys/trusted-keys/Makefile +++ b/security/keys/trusted-keys/Makefile @@ -4,5 +4,6 @@ #
obj-$(CONFIG_TRUSTED_KEYS) += trusted.o +trusted-y += trusted_common.o trusted-y += trusted_tpm1.o trusted-y += trusted_tpm2.o diff --git a/security/keys/trusted-keys/trusted_common.c b/security/keys/trusted-keys/trusted_common.c new file mode 100644 index 0000000..8f00fde --- /dev/null +++ b/security/keys/trusted-keys/trusted_common.c @@ -0,0 +1,343 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2010 IBM Corporation + * Copyright (c) 2019, Linaro Limited + * + * Author: + * David Safford safford@us.ibm.com + * Added generic trusted key framework: Sumit Garg sumit.garg@linaro.org + * + * See Documentation/security/keys/trusted-encrypted.rst + */ + +#include <keys/user-type.h> +#include <keys/trusted-type.h> +#include <linux/capability.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/key-type.h> +#include <linux/module.h> +#include <linux/parser.h> +#include <linux/rcupdate.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/uaccess.h> + +static struct trusted_key_ops *available_tk_ops[] = { +#if defined(CONFIG_TCG_TPM) + &tpm_trusted_key_ops, +#endif +}; +static struct trusted_key_ops *tk_ops; + +enum { + Opt_err, + Opt_new, Opt_load, Opt_update, +}; + +static const match_table_t key_tokens = { + {Opt_new, "new"}, + {Opt_load, "load"}, + {Opt_update, "update"}, + {Opt_err, NULL} +}; + +/* + * datablob_parse - parse the keyctl data and fill in the + * payload structure + * + * On success returns 0, otherwise -EINVAL. + */ +static int datablob_parse(char *datablob, struct trusted_key_payload *p) +{ + substring_t args[MAX_OPT_ARGS]; + long keylen; + int ret = -EINVAL; + int key_cmd; + char *c; + + /* main command */ + c = strsep(&datablob, " \t"); + if (!c) + return -EINVAL; + key_cmd = match_token(c, key_tokens, args); + switch (key_cmd) { + case Opt_new: + /* first argument is key size */ + c = strsep(&datablob, " \t"); + if (!c) + return -EINVAL; + ret = kstrtol(c, 10, &keylen); + if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE) + return -EINVAL; + p->key_len = keylen; + ret = Opt_new; + break; + case Opt_load: + /* first argument is sealed blob */ + c = strsep(&datablob, " \t"); + if (!c) + return -EINVAL; + p->blob_len = strlen(c) / 2; + if (p->blob_len > MAX_BLOB_SIZE) + return -EINVAL; + ret = hex2bin(p->blob, c, p->blob_len); + if (ret < 0) + return -EINVAL; + ret = Opt_load; + break; + case Opt_update: + ret = Opt_update; + break; + case Opt_err: + return -EINVAL; + } + return ret; +} + +static struct trusted_key_payload *trusted_payload_alloc(struct key *key) +{ + struct trusted_key_payload *p = NULL; + int ret; + + ret = key_payload_reserve(key, sizeof(*p)); + if (ret < 0) + return p; + p = kzalloc(sizeof(*p), GFP_KERNEL); + + p->migratable = tk_ops->migratable; + + return p; +} + +/* + * trusted_instantiate - create a new trusted key + * + * Unseal an existing trusted blob or, for a new key, get a + * random key, then seal and create a trusted key-type key, + * adding it to the specified keyring. + * + * On success, return 0. Otherwise return errno. + */ +static int trusted_instantiate(struct key *key, + struct key_preparsed_payload *prep) +{ + struct trusted_key_payload *payload = NULL; + size_t datalen = prep->datalen; + char *datablob; + int ret = 0; + int key_cmd; + size_t key_len; + + if (datalen <= 0 || datalen > 32767 || !prep->data) + return -EINVAL; + + datablob = kmalloc(datalen + 1, GFP_KERNEL); + if (!datablob) + return -ENOMEM; + memcpy(datablob, prep->data, datalen); + datablob[datalen] = '\0'; + + payload = trusted_payload_alloc(key); + if (!payload) { + ret = -ENOMEM; + goto out; + } + + key_cmd = datablob_parse(datablob, payload); + if (key_cmd < 0) { + ret = key_cmd; + goto out; + } + + dump_payload(payload); + + switch (key_cmd) { + case Opt_load: + ret = tk_ops->unseal(payload, datablob); + dump_payload(payload); + if (ret < 0) + pr_info("trusted_key: key_unseal failed (%d)\n", ret); + break; + case Opt_new: + key_len = payload->key_len; + ret = tk_ops->get_random(payload->key, key_len); + if (ret != key_len) { + pr_info("trusted_key: key_create failed (%d)\n", ret); + goto out; + } + + ret = tk_ops->seal(payload, datablob); + if (ret < 0) + pr_info("trusted_key: key_seal failed (%d)\n", ret); + break; + default: + ret = -EINVAL; + } +out: + kzfree(datablob); + if (!ret) + rcu_assign_keypointer(key, payload); + else + kzfree(payload); + return ret; +} + +static void trusted_rcu_free(struct rcu_head *rcu) +{ + struct trusted_key_payload *p; + + p = container_of(rcu, struct trusted_key_payload, rcu); + kzfree(p); +} + +/* + * trusted_update - reseal an existing key with new PCR values + */ +static int trusted_update(struct key *key, struct key_preparsed_payload *prep) +{ + struct trusted_key_payload *p; + struct trusted_key_payload *new_p; + size_t datalen = prep->datalen; + char *datablob; + int ret = 0; + + if (key_is_negative(key)) + return -ENOKEY; + p = key->payload.data[0]; + if (!p->migratable) + return -EPERM; + if (datalen <= 0 || datalen > 32767 || !prep->data) + return -EINVAL; + + datablob = kmalloc(datalen + 1, GFP_KERNEL); + if (!datablob) + return -ENOMEM; + + new_p = trusted_payload_alloc(key); + if (!new_p) { + ret = -ENOMEM; + goto out; + } + + memcpy(datablob, prep->data, datalen); + datablob[datalen] = '\0'; + ret = datablob_parse(datablob, new_p); + if (ret != Opt_update) { + ret = -EINVAL; + kzfree(new_p); + goto out; + } + + /* copy old key values, and reseal with new pcrs */ + new_p->migratable = p->migratable; + new_p->key_len = p->key_len; + memcpy(new_p->key, p->key, p->key_len); + dump_payload(p); + dump_payload(new_p); + + ret = tk_ops->seal(new_p, datablob); + if (ret < 0) { + pr_info("trusted_key: key_seal failed (%d)\n", ret); + kzfree(new_p); + goto out; + } + + rcu_assign_keypointer(key, new_p); + call_rcu(&p->rcu, trusted_rcu_free); +out: + kzfree(datablob); + return ret; +} + +/* + * trusted_read - copy the sealed blob data to userspace in hex. + * On success, return to userspace the trusted key datablob size. + */ +static long trusted_read(const struct key *key, char __user *buffer, + size_t buflen) +{ + const struct trusted_key_payload *p; + char *ascii_buf; + char *bufp; + int i; + + p = dereference_key_locked(key); + if (!p) + return -EINVAL; + + if (buffer && buflen >= 2 * p->blob_len) { + ascii_buf = kmalloc_array(2, p->blob_len, GFP_KERNEL); + if (!ascii_buf) + return -ENOMEM; + + bufp = ascii_buf; + for (i = 0; i < p->blob_len; i++) + bufp = hex_byte_pack(bufp, p->blob[i]); + if (copy_to_user(buffer, ascii_buf, 2 * p->blob_len) != 0) { + kzfree(ascii_buf); + return -EFAULT; + } + kzfree(ascii_buf); + } + return 2 * p->blob_len; +} + +/* + * trusted_destroy - clear and free the key's payload + */ +static void trusted_destroy(struct key *key) +{ + kzfree(key->payload.data[0]); +} + +struct key_type key_type_trusted = { + .name = "trusted", + .instantiate = trusted_instantiate, + .update = trusted_update, + .destroy = trusted_destroy, + .describe = user_describe, + .read = trusted_read, +}; +EXPORT_SYMBOL_GPL(key_type_trusted); + +static int __init init_trusted(void) +{ + int i, ret = 0; + + for (i = 0; i < sizeof(available_tk_ops); i++) { + tk_ops = available_tk_ops[i]; + + if (!(tk_ops && tk_ops->init && tk_ops->seal && + tk_ops->unseal && tk_ops->get_random)) + continue; + + ret = tk_ops->init(); + if (ret) { + if (tk_ops->cleanup) + tk_ops->cleanup(); + } else { + break; + } + } + + /* + * encrypted_keys.ko depends on successful load of this module even if + * trusted key implementation is not found. + */ + if (ret == -ENODEV) + return 0; + + return ret; +} + +static void __exit cleanup_trusted(void) +{ + if (tk_ops->cleanup) + tk_ops->cleanup(); +} + +late_initcall(init_trusted); +module_exit(cleanup_trusted); + +MODULE_LICENSE("GPL"); diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c index d2c5ec1..32fd1ea 100644 --- a/security/keys/trusted-keys/trusted_tpm1.c +++ b/security/keys/trusted-keys/trusted_tpm1.c @@ -1,29 +1,26 @@ // SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2010 IBM Corporation + * Copyright (c) 2019, Linaro Limited * * Author: * David Safford safford@us.ibm.com + * Switch to generic trusted key framework: Sumit Garg sumit.garg@linaro.org * * See Documentation/security/keys/trusted-encrypted.rst */
#include <crypto/hash_info.h> -#include <linux/uaccess.h> -#include <linux/module.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/parser.h> #include <linux/string.h> #include <linux/err.h> -#include <keys/user-type.h> #include <keys/trusted-type.h> #include <linux/key-type.h> -#include <linux/rcupdate.h> #include <linux/crypto.h> #include <crypto/hash.h> #include <crypto/sha.h> -#include <linux/capability.h> #include <linux/tpm.h> #include <linux/tpm_command.h>
@@ -703,7 +700,6 @@ static int key_unseal(struct trusted_key_payload *p,
enum { Opt_err, - Opt_new, Opt_load, Opt_update, Opt_keyhandle, Opt_keyauth, Opt_blobauth, Opt_pcrinfo, Opt_pcrlock, Opt_migratable, Opt_hash, @@ -712,9 +708,6 @@ enum { };
static const match_table_t key_tokens = { - {Opt_new, "new"}, - {Opt_load, "load"}, - {Opt_update, "update"}, {Opt_keyhandle, "keyhandle=%s"}, {Opt_keyauth, "keyauth=%s"}, {Opt_blobauth, "blobauth=%s"}, @@ -841,71 +834,6 @@ static int getoptions(char *c, struct trusted_key_payload *pay, return 0; }
-/* - * datablob_parse - parse the keyctl data and fill in the - * payload and options structures - * - * On success returns 0, otherwise -EINVAL. - */ -static int datablob_parse(char *datablob, struct trusted_key_payload *p, - struct trusted_key_options *o) -{ - substring_t args[MAX_OPT_ARGS]; - long keylen; - int ret = -EINVAL; - int key_cmd; - char *c; - - /* main command */ - c = strsep(&datablob, " \t"); - if (!c) - return -EINVAL; - key_cmd = match_token(c, key_tokens, args); - switch (key_cmd) { - case Opt_new: - /* first argument is key size */ - c = strsep(&datablob, " \t"); - if (!c) - return -EINVAL; - ret = kstrtol(c, 10, &keylen); - if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE) - return -EINVAL; - p->key_len = keylen; - ret = getoptions(datablob, p, o); - if (ret < 0) - return ret; - ret = Opt_new; - break; - case Opt_load: - /* first argument is sealed blob */ - c = strsep(&datablob, " \t"); - if (!c) - return -EINVAL; - p->blob_len = strlen(c) / 2; - if (p->blob_len > MAX_BLOB_SIZE) - return -EINVAL; - ret = hex2bin(p->blob, c, p->blob_len); - if (ret < 0) - return -EINVAL; - ret = getoptions(datablob, p, o); - if (ret < 0) - return ret; - ret = Opt_load; - break; - case Opt_update: - /* all arguments are options */ - ret = getoptions(datablob, p, o); - if (ret < 0) - return ret; - ret = Opt_update; - break; - case Opt_err: - return -EINVAL; - break; - } - return ret; -} - static struct trusted_key_options *trusted_options_alloc(void) { struct trusted_key_options *options; @@ -926,258 +854,99 @@ static struct trusted_key_options *trusted_options_alloc(void) return options; }
-static struct trusted_key_payload *trusted_payload_alloc(struct key *key) +static int tpm_tk_seal(struct trusted_key_payload *p, char *datablob) { - struct trusted_key_payload *p = NULL; - int ret; - - ret = key_payload_reserve(key, sizeof *p); - if (ret < 0) - return p; - p = kzalloc(sizeof *p, GFP_KERNEL); - if (p) - p->migratable = 1; /* migratable by default */ - return p; -} - -/* - * trusted_instantiate - create a new trusted key - * - * Unseal an existing trusted blob or, for a new key, get a - * random key, then seal and create a trusted key-type key, - * adding it to the specified keyring. - * - * On success, return 0. Otherwise return errno. - */ -static int trusted_instantiate(struct key *key, - struct key_preparsed_payload *prep) -{ - struct trusted_key_payload *payload = NULL; struct trusted_key_options *options = NULL; - size_t datalen = prep->datalen; - char *datablob; int ret = 0; - int key_cmd; - size_t key_len; int tpm2;
tpm2 = tpm_is_tpm2(chip); if (tpm2 < 0) return tpm2;
- if (datalen <= 0 || datalen > 32767 || !prep->data) - return -EINVAL; - - datablob = kmalloc(datalen + 1, GFP_KERNEL); - if (!datablob) - return -ENOMEM; - memcpy(datablob, prep->data, datalen); - datablob[datalen] = '\0'; - options = trusted_options_alloc(); - if (!options) { - ret = -ENOMEM; - goto out; - } - payload = trusted_payload_alloc(key); - if (!payload) { - ret = -ENOMEM; - goto out; - } + if (!options) + return -ENOMEM;
- key_cmd = datablob_parse(datablob, payload, options); - if (key_cmd < 0) { - ret = key_cmd; + ret = getoptions(datablob, p, options); + if (ret < 0) goto out; - } + dump_options(options);
if (!options->keyhandle) { ret = -EINVAL; goto out; }
- dump_payload(payload); - dump_options(options); + if (tpm2) + ret = tpm2_seal_trusted(chip, p, options); + else + ret = key_seal(p, options); + if (ret < 0) { + pr_info("tpm_trusted_key: key_seal failed (%d)\n", ret); + goto out; + }
- switch (key_cmd) { - case Opt_load: - if (tpm2) - ret = tpm2_unseal_trusted(chip, payload, options); - else - ret = key_unseal(payload, options); - dump_payload(payload); - dump_options(options); - if (ret < 0) - pr_info("trusted_key: key_unseal failed (%d)\n", ret); - break; - case Opt_new: - key_len = payload->key_len; - ret = tpm_get_random(chip, payload->key, key_len); - if (ret != key_len) { - pr_info("trusted_key: key_create failed (%d)\n", ret); + if (options->pcrlock) { + ret = pcrlock(options->pcrlock); + if (ret < 0) { + pr_info("tpm_trusted_key: pcrlock failed (%d)\n", ret); goto out; } - if (tpm2) - ret = tpm2_seal_trusted(chip, payload, options); - else - ret = key_seal(payload, options); - if (ret < 0) - pr_info("trusted_key: key_seal failed (%d)\n", ret); - break; - default: - ret = -EINVAL; - goto out; } - if (!ret && options->pcrlock) - ret = pcrlock(options->pcrlock); out: - kzfree(datablob); kzfree(options); - if (!ret) - rcu_assign_keypointer(key, payload); - else - kzfree(payload); return ret; }
-static void trusted_rcu_free(struct rcu_head *rcu) -{ - struct trusted_key_payload *p; - - p = container_of(rcu, struct trusted_key_payload, rcu); - kzfree(p); -} - -/* - * trusted_update - reseal an existing key with new PCR values - */ -static int trusted_update(struct key *key, struct key_preparsed_payload *prep) +static int tpm_tk_unseal(struct trusted_key_payload *p, char *datablob) { - struct trusted_key_payload *p; - struct trusted_key_payload *new_p; - struct trusted_key_options *new_o; - size_t datalen = prep->datalen; - char *datablob; + struct trusted_key_options *options = NULL; int ret = 0; + int tpm2;
- if (key_is_negative(key)) - return -ENOKEY; - p = key->payload.data[0]; - if (!p->migratable) - return -EPERM; - if (datalen <= 0 || datalen > 32767 || !prep->data) - return -EINVAL; + tpm2 = tpm_is_tpm2(chip); + if (tpm2 < 0) + return tpm2;
- datablob = kmalloc(datalen + 1, GFP_KERNEL); - if (!datablob) + options = trusted_options_alloc(); + if (!options) return -ENOMEM; - new_o = trusted_options_alloc(); - if (!new_o) { - ret = -ENOMEM; - goto out; - } - new_p = trusted_payload_alloc(key); - if (!new_p) { - ret = -ENOMEM; - goto out; - }
- memcpy(datablob, prep->data, datalen); - datablob[datalen] = '\0'; - ret = datablob_parse(datablob, new_p, new_o); - if (ret != Opt_update) { - ret = -EINVAL; - kzfree(new_p); + ret = getoptions(datablob, p, options); + if (ret < 0) goto out; - } + dump_options(options);
- if (!new_o->keyhandle) { + if (!options->keyhandle) { ret = -EINVAL; - kzfree(new_p); goto out; }
- /* copy old key values, and reseal with new pcrs */ - new_p->migratable = p->migratable; - new_p->key_len = p->key_len; - memcpy(new_p->key, p->key, p->key_len); - dump_payload(p); - dump_payload(new_p); + if (tpm2) + ret = tpm2_unseal_trusted(chip, p, options); + else + ret = key_unseal(p, options); + if (ret < 0) + pr_info("tpm_trusted_key: key_unseal failed (%d)\n", ret);
- ret = key_seal(new_p, new_o); - if (ret < 0) { - pr_info("trusted_key: key_seal failed (%d)\n", ret); - kzfree(new_p); - goto out; - } - if (new_o->pcrlock) { - ret = pcrlock(new_o->pcrlock); + if (options->pcrlock) { + ret = pcrlock(options->pcrlock); if (ret < 0) { - pr_info("trusted_key: pcrlock failed (%d)\n", ret); - kzfree(new_p); + pr_info("tpm_trusted_key: pcrlock failed (%d)\n", ret); goto out; } } - rcu_assign_keypointer(key, new_p); - call_rcu(&p->rcu, trusted_rcu_free); out: - kzfree(datablob); - kzfree(new_o); + kzfree(options); return ret; }
-/* - * trusted_read - copy the sealed blob data to userspace in hex. - * On success, return to userspace the trusted key datablob size. - */ -static long trusted_read(const struct key *key, char __user *buffer, - size_t buflen) -{ - const struct trusted_key_payload *p; - char *ascii_buf; - char *bufp; - int i; - - p = dereference_key_locked(key); - if (!p) - return -EINVAL; - - if (buffer && buflen >= 2 * p->blob_len) { - ascii_buf = kmalloc_array(2, p->blob_len, GFP_KERNEL); - if (!ascii_buf) - return -ENOMEM; - - bufp = ascii_buf; - for (i = 0; i < p->blob_len; i++) - bufp = hex_byte_pack(bufp, p->blob[i]); - if (copy_to_user(buffer, ascii_buf, 2 * p->blob_len) != 0) { - kzfree(ascii_buf); - return -EFAULT; - } - kzfree(ascii_buf); - } - return 2 * p->blob_len; -} - -/* - * trusted_destroy - clear and free the key's payload - */ -static void trusted_destroy(struct key *key) +int tpm_tk_get_random(unsigned char *key, size_t key_len) { - kzfree(key->payload.data[0]); + return tpm_get_random(chip, key, key_len); }
-struct key_type key_type_trusted = { - .name = "trusted", - .instantiate = trusted_instantiate, - .update = trusted_update, - .destroy = trusted_destroy, - .describe = user_describe, - .read = trusted_read, -}; - -EXPORT_SYMBOL_GPL(key_type_trusted); - static void trusted_shash_release(void) { if (hashalg) @@ -1192,14 +961,14 @@ static int __init trusted_shash_alloc(void)
hmacalg = crypto_alloc_shash(hmac_alg, 0, 0); if (IS_ERR(hmacalg)) { - pr_info("trusted_key: could not allocate crypto %s\n", + pr_info("tpm_trusted_key: could not allocate crypto %s\n", hmac_alg); return PTR_ERR(hmacalg); }
hashalg = crypto_alloc_shash(hash_alg, 0, 0); if (IS_ERR(hashalg)) { - pr_info("trusted_key: could not allocate crypto %s\n", + pr_info("tpm_trusted_key: could not allocate crypto %s\n", hash_alg); ret = PTR_ERR(hashalg); goto hashalg_fail; @@ -1227,16 +996,13 @@ static int __init init_digests(void) return 0; }
-static int __init init_trusted(void) +static int __init init_tpm_trusted(void) { int ret;
- /* encrypted_keys.ko depends on successful load of this module even if - * TPM is not used. - */ chip = tpm_default_chip(); if (!chip) - return 0; + return -ENODEV;
ret = init_digests(); if (ret < 0) @@ -1257,7 +1023,7 @@ static int __init init_trusted(void) return ret; }
-static void __exit cleanup_trusted(void) +static void __exit cleanup_tpm_trusted(void) { if (chip) { put_device(&chip->dev); @@ -1267,7 +1033,12 @@ static void __exit cleanup_trusted(void) } }
-late_initcall(init_trusted); -module_exit(cleanup_trusted); - -MODULE_LICENSE("GPL"); +struct trusted_key_ops tpm_trusted_key_ops = { + .migratable = 1, /* migratable by default */ + .init = init_tpm_trusted, + .seal = tpm_tk_seal, + .unseal = tpm_tk_unseal, + .get_random = tpm_tk_get_random, + .cleanup = cleanup_tpm_trusted, +}; +EXPORT_SYMBOL_GPL(tpm_trusted_key_ops);
Add support for TEE based trusted keys where TEE provides the functionality to seal and unseal trusted keys using hardware unique key.
Refer to Documentation/tee.txt for detailed information about TEE.
Signed-off-by: Sumit Garg sumit.garg@linaro.org --- include/keys/trusted-type.h | 3 + include/keys/trusted_tee.h | 66 +++++++ security/keys/Kconfig | 3 + security/keys/trusted-keys/Makefile | 1 + security/keys/trusted-keys/trusted_common.c | 3 + security/keys/trusted-keys/trusted_tee.c | 282 ++++++++++++++++++++++++++++ 6 files changed, 358 insertions(+) create mode 100644 include/keys/trusted_tee.h create mode 100644 security/keys/trusted-keys/trusted_tee.c
diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h index 5559010..e0df5df 100644 --- a/include/keys/trusted-type.h +++ b/include/keys/trusted-type.h @@ -67,6 +67,9 @@ extern struct key_type key_type_trusted; #if defined(CONFIG_TCG_TPM) extern struct trusted_key_ops tpm_trusted_key_ops; #endif +#if defined(CONFIG_TEE) +extern struct trusted_key_ops tee_trusted_key_ops; +#endif
#define TRUSTED_DEBUG 0
diff --git a/include/keys/trusted_tee.h b/include/keys/trusted_tee.h new file mode 100644 index 0000000..ab58ffd --- /dev/null +++ b/include/keys/trusted_tee.h @@ -0,0 +1,66 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2019 Linaro Ltd. + * + * Author: + * Sumit Garg sumit.garg@linaro.org + */ + +#ifndef __TEE_TRUSTED_KEY_H +#define __TEE_TRUSTED_KEY_H + +#include <linux/tee_drv.h> + +#define DRIVER_NAME "tee-trusted-key" + +/* + * Get random data for symmetric key + * + * [out] memref[0] Random data + * + * Result: + * TEE_SUCCESS - Invoke command success + * TEE_ERROR_BAD_PARAMETERS - Incorrect input param + */ +#define TA_CMD_GET_RANDOM 0x0 + +/* + * Seal trusted key using hardware unique key + * + * [in] memref[0] Plain key + * [out] memref[1] Sealed key datablob + * + * Result: + * TEE_SUCCESS - Invoke command success + * TEE_ERROR_BAD_PARAMETERS - Incorrect input param + */ +#define TA_CMD_SEAL 0x1 + +/* + * Unseal trusted key using hardware unique key + * + * [in] memref[0] Sealed key datablob + * [out] memref[1] Plain key + * + * Result: + * TEE_SUCCESS - Invoke command success + * TEE_ERROR_BAD_PARAMETERS - Incorrect input param + */ +#define TA_CMD_UNSEAL 0x2 + +/** + * struct trusted_key_private - TEE Trusted key private data + * @dev: TEE based Trusted key device. + * @ctx: TEE context handler. + * @session_id: Trusted key TA session identifier. + * @shm_pool: Memory pool shared with TEE device. + */ +struct trusted_key_private { + struct device *dev; + struct tee_context *ctx; + u32 session_id; + u32 data_rate; + struct tee_shm *shm_pool; +}; + +#endif diff --git a/security/keys/Kconfig b/security/keys/Kconfig index dd31343..0d5e37c 100644 --- a/security/keys/Kconfig +++ b/security/keys/Kconfig @@ -88,6 +88,9 @@ config TRUSTED_KEYS if the boot PCRs and other criteria match. Userspace will only ever see encrypted blobs.
+ It also provides support for alternative TEE based Trusted keys + generation and sealing in case TPM isn't present. + If you are unsure as to whether this is required, answer N.
config ENCRYPTED_KEYS diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile index 2b1085b..ea937d3 100644 --- a/security/keys/trusted-keys/Makefile +++ b/security/keys/trusted-keys/Makefile @@ -7,3 +7,4 @@ obj-$(CONFIG_TRUSTED_KEYS) += trusted.o trusted-y += trusted_common.o trusted-y += trusted_tpm1.o trusted-y += trusted_tpm2.o +trusted-y += trusted_tee.o diff --git a/security/keys/trusted-keys/trusted_common.c b/security/keys/trusted-keys/trusted_common.c index 8f00fde..a0a171f 100644 --- a/security/keys/trusted-keys/trusted_common.c +++ b/security/keys/trusted-keys/trusted_common.c @@ -27,6 +27,9 @@ static struct trusted_key_ops *available_tk_ops[] = { #if defined(CONFIG_TCG_TPM) &tpm_trusted_key_ops, #endif +#if defined(CONFIG_TEE) + &tee_trusted_key_ops, +#endif }; static struct trusted_key_ops *tk_ops;
diff --git a/security/keys/trusted-keys/trusted_tee.c b/security/keys/trusted-keys/trusted_tee.c new file mode 100644 index 0000000..724a73c --- /dev/null +++ b/security/keys/trusted-keys/trusted_tee.c @@ -0,0 +1,282 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 Linaro Ltd. + * + * Author: + * Sumit Garg sumit.garg@linaro.org + */ + +#include <linux/err.h> +#include <linux/key-type.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/uuid.h> + +#include <keys/trusted-type.h> +#include <keys/trusted_tee.h> + +static struct trusted_key_private pvt_data; + +/* + * Have the TEE seal(encrypt) the symmetric key + */ +static int tee_key_seal(struct trusted_key_payload *p, char *datablob) +{ + int ret = 0; + struct tee_ioctl_invoke_arg inv_arg; + struct tee_param param[4]; + struct tee_shm *reg_shm_in = NULL, *reg_shm_out = NULL; + + memset(&inv_arg, 0, sizeof(inv_arg)); + memset(¶m, 0, sizeof(param)); + + reg_shm_in = tee_shm_register(pvt_data.ctx, (unsigned long)p->key, + p->key_len, TEE_SHM_DMA_BUF | + TEE_SHM_KERNEL_MAPPED); + if (IS_ERR(reg_shm_in)) { + dev_err(pvt_data.dev, "key shm register failed\n"); + return PTR_ERR(reg_shm_in); + } + + reg_shm_out = tee_shm_register(pvt_data.ctx, (unsigned long)p->blob, + sizeof(p->blob), TEE_SHM_DMA_BUF | + TEE_SHM_KERNEL_MAPPED); + if (IS_ERR(reg_shm_out)) { + dev_err(pvt_data.dev, "blob shm register failed\n"); + ret = PTR_ERR(reg_shm_out); + goto out; + } + + inv_arg.func = TA_CMD_SEAL; + inv_arg.session = pvt_data.session_id; + inv_arg.num_params = 4; + + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT; + param[0].u.memref.shm = reg_shm_in; + param[0].u.memref.size = p->key_len; + param[0].u.memref.shm_offs = 0; + param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT; + param[1].u.memref.shm = reg_shm_out; + param[1].u.memref.size = sizeof(p->blob); + param[1].u.memref.shm_offs = 0; + + ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param); + if ((ret < 0) || (inv_arg.ret != 0)) { + dev_err(pvt_data.dev, "TA_CMD_SEAL invoke err: %x\n", + inv_arg.ret); + ret = -EFAULT; + } else { + p->blob_len = param[1].u.memref.size; + } + +out: + if (reg_shm_out) + tee_shm_free(reg_shm_out); + if (reg_shm_in) + tee_shm_free(reg_shm_in); + + return ret; +} + +/* + * Have the TEE unseal(decrypt) the symmetric key + */ +static int tee_key_unseal(struct trusted_key_payload *p, char *datablob) +{ + int ret = 0; + struct tee_ioctl_invoke_arg inv_arg; + struct tee_param param[4]; + struct tee_shm *reg_shm_in = NULL, *reg_shm_out = NULL; + + memset(&inv_arg, 0, sizeof(inv_arg)); + memset(¶m, 0, sizeof(param)); + + reg_shm_in = tee_shm_register(pvt_data.ctx, (unsigned long)p->blob, + p->blob_len, TEE_SHM_DMA_BUF | + TEE_SHM_KERNEL_MAPPED); + if (IS_ERR(reg_shm_in)) { + dev_err(pvt_data.dev, "blob shm register failed\n"); + return PTR_ERR(reg_shm_in); + } + + reg_shm_out = tee_shm_register(pvt_data.ctx, (unsigned long)p->key, + sizeof(p->key), TEE_SHM_DMA_BUF | + TEE_SHM_KERNEL_MAPPED); + if (IS_ERR(reg_shm_out)) { + dev_err(pvt_data.dev, "key shm register failed\n"); + ret = PTR_ERR(reg_shm_out); + goto out; + } + + inv_arg.func = TA_CMD_UNSEAL; + inv_arg.session = pvt_data.session_id; + inv_arg.num_params = 4; + + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT; + param[0].u.memref.shm = reg_shm_in; + param[0].u.memref.size = p->blob_len; + param[0].u.memref.shm_offs = 0; + param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT; + param[1].u.memref.shm = reg_shm_out; + param[1].u.memref.size = sizeof(p->key); + param[1].u.memref.shm_offs = 0; + + ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param); + if ((ret < 0) || (inv_arg.ret != 0)) { + dev_err(pvt_data.dev, "TA_CMD_UNSEAL invoke err: %x\n", + inv_arg.ret); + ret = -EFAULT; + } else { + p->key_len = param[1].u.memref.size; + } + +out: + if (reg_shm_out) + tee_shm_free(reg_shm_out); + if (reg_shm_in) + tee_shm_free(reg_shm_in); + + return ret; +} + +/* + * Have the TEE generate random symmetric key + */ +static int tee_get_random(unsigned char *key, size_t key_len) +{ + int ret = 0; + struct tee_ioctl_invoke_arg inv_arg; + struct tee_param param[4]; + struct tee_shm *reg_shm = NULL; + + memset(&inv_arg, 0, sizeof(inv_arg)); + memset(¶m, 0, sizeof(param)); + + reg_shm = tee_shm_register(pvt_data.ctx, (unsigned long)key, key_len, + TEE_SHM_DMA_BUF | TEE_SHM_KERNEL_MAPPED); + if (IS_ERR(reg_shm)) { + dev_err(pvt_data.dev, "random key shm register failed\n"); + return PTR_ERR(reg_shm); + } + + inv_arg.func = TA_CMD_GET_RANDOM; + inv_arg.session = pvt_data.session_id; + inv_arg.num_params = 4; + + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT; + param[0].u.memref.shm = reg_shm; + param[0].u.memref.size = key_len; + param[0].u.memref.shm_offs = 0; + + ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param); + if ((ret < 0) || (inv_arg.ret != 0)) { + dev_err(pvt_data.dev, "TA_CMD_GET_RANDOM invoke err: %x\n", + inv_arg.ret); + ret = -EFAULT; + } else { + ret = param[0].u.memref.size; + } + + tee_shm_free(reg_shm); + + return ret; +} + +static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data) +{ + if (ver->impl_id == TEE_IMPL_ID_OPTEE) + return 1; + else + return 0; +} + +static int trusted_key_probe(struct device *dev) +{ + struct tee_client_device *rng_device = to_tee_client_device(dev); + int ret = 0, err = -ENODEV; + struct tee_ioctl_open_session_arg sess_arg; + + memset(&sess_arg, 0, sizeof(sess_arg)); + + /* Open context with TEE driver */ + pvt_data.ctx = tee_client_open_context(NULL, optee_ctx_match, NULL, + NULL); + if (IS_ERR(pvt_data.ctx)) + return -ENODEV; + + /* Open session with hwrng Trusted App */ + memcpy(sess_arg.uuid, rng_device->id.uuid.b, TEE_IOCTL_UUID_LEN); + sess_arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL; + sess_arg.num_params = 0; + + ret = tee_client_open_session(pvt_data.ctx, &sess_arg, NULL); + if ((ret < 0) || (sess_arg.ret != 0)) { + dev_err(dev, "tee_client_open_session failed, err: %x\n", + sess_arg.ret); + err = -EINVAL; + goto out_ctx; + } + pvt_data.session_id = sess_arg.session; + + ret = register_key_type(&key_type_trusted); + if (ret < 0) + goto out_sess; + + pvt_data.dev = dev; + + return 0; + +out_sess: + tee_client_close_session(pvt_data.ctx, pvt_data.session_id); +out_ctx: + tee_client_close_context(pvt_data.ctx); + + return err; +} + +static int trusted_key_remove(struct device *dev) +{ + unregister_key_type(&key_type_trusted); + tee_client_close_session(pvt_data.ctx, pvt_data.session_id); + tee_client_close_context(pvt_data.ctx); + + return 0; +} + +static const struct tee_client_device_id trusted_key_id_table[] = { + {UUID_INIT(0xf04a0fe7, 0x1f5d, 0x4b9b, + 0xab, 0xf7, 0x61, 0x9b, 0x85, 0xb4, 0xce, 0x8c)}, + {} +}; + +MODULE_DEVICE_TABLE(tee, trusted_key_id_table); + +static struct tee_client_driver trusted_key_driver = { + .id_table = trusted_key_id_table, + .driver = { + .name = DRIVER_NAME, + .bus = &tee_bus_type, + .probe = trusted_key_probe, + .remove = trusted_key_remove, + }, +}; + +static int __init init_tee_trusted(void) +{ + return driver_register(&trusted_key_driver.driver); +} + +static void __exit cleanup_tee_trusted(void) +{ + driver_unregister(&trusted_key_driver.driver); +} + +struct trusted_key_ops tee_trusted_key_ops = { + .migratable = 0, /* non-migratable */ + .init = init_tee_trusted, + .seal = tee_key_seal, + .unseal = tee_key_unseal, + .get_random = tee_get_random, + .cleanup = cleanup_tee_trusted, +}; +EXPORT_SYMBOL_GPL(tee_trusted_key_ops);
Provide documentation for usage of TEE based Trusted Keys via existing user-space "keyctl" utility. Also, document various use-cases.
Signed-off-by: Sumit Garg sumit.garg@linaro.org --- Documentation/security/keys/index.rst | 1 + Documentation/security/keys/tee-trusted.rst | 93 +++++++++++++++++++++++++++++ 2 files changed, 94 insertions(+) create mode 100644 Documentation/security/keys/tee-trusted.rst
diff --git a/Documentation/security/keys/index.rst b/Documentation/security/keys/index.rst index 647d58f..f9ef557 100644 --- a/Documentation/security/keys/index.rst +++ b/Documentation/security/keys/index.rst @@ -9,3 +9,4 @@ Kernel Keys ecryptfs request-key trusted-encrypted + tee-trusted diff --git a/Documentation/security/keys/tee-trusted.rst b/Documentation/security/keys/tee-trusted.rst new file mode 100644 index 0000000..ef03745 --- /dev/null +++ b/Documentation/security/keys/tee-trusted.rst @@ -0,0 +1,93 @@ +====================== +TEE based Trusted Keys +====================== + +TEE based Trusted Keys provides an alternative approach for providing Trusted +Keys in case TPM chip isn't present. + +Trusted Keys use a TEE service/device both to generate and to seal the keys. +Keys are sealed under a hardware unique key in the TEE, and only unsealed by +the TEE. + +For more information about TEE, refer to ``Documentation/tee.txt``. + +Usage:: + + keyctl add trusted name "new keylen" ring + keyctl add trusted name "load hex_blob" ring + keyctl print keyid + +"keyctl print" returns an ascii hex copy of the sealed key, which is in format +specific to TEE device implementation. The key length for new keys are always +in bytes. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits). + +Examples of trusted key and its usage as 'master' key for encrypted key usage: + +More details about encrypted keys can be found here: +``Documentation/security/keys/trusted-encrypted.rst`` + +Create and save a trusted key named "kmk" of length 32 bytes:: + + $ keyctl add trusted kmk "new 32" @u + 754414669 + + $ keyctl show + Session Keyring + 827385718 --alswrv 0 65534 keyring: _uid_ses.0 + 274124851 --alswrv 0 65534 _ keyring: _uid.0 + 754414669 --als-rv 0 0 _ trusted: kmk + + $ keyctl print 754414669 + 15676790697861b422175596ae001c2f505cea2c6f3ebbc5fb08eeb1f343a07e + + $ keyctl pipe 754414669 > kmk.blob + +Load a trusted key from the saved blob:: + + $ keyctl add trusted kmk "load `cat kmk.blob`" @u + 491638700 + + $ keyctl print 491638700 + 15676790697861b422175596ae001c2f505cea2c6f3ebbc5fb08eeb1f343a07e + +The initial consumer of trusted keys is EVM, which at boot time needs a high +quality symmetric key for HMAC protection of file metadata. The use of a +TEE based trusted key provides security that the EVM key has not been +compromised by a user level problem and tied to particular hardware. + +Create and save an encrypted key "evm" using the above trusted key "kmk": + +option 1: omitting 'format':: + + $ keyctl add encrypted evm "new trusted:kmk 32" @u + 608915065 + +option 2: explicitly defining 'format' as 'default':: + + $ keyctl add encrypted evm "new default trusted:kmk 32" @u + 608915065 + + $ keyctl print 608915065 + default trusted:kmk 32 f380ac588a925f488d5be007cf23e4c900b8b652ab62241c8 + ed54906189b6659d139d619d4b51752a2645537b11fd44673f13154a65b3f595d5fb2131 + 2fe45529ea0407c644ea4026f2a1a75661f2c9b66 + + $ keyctl pipe 608915065 > evm.blob + +Load an encrypted key "evm" from saved blob:: + + $ keyctl add encrypted evm "load `cat evm.blob`" @u + 831684262 + + $ keyctl print 831684262 + default trusted:kmk 32 f380ac588a925f488d5be007cf23e4c900b8b652ab62241c8 + ed54906189b6659d139d619d4b51752a2645537b11fd44673f13154a65b3f595d5fb2131 + 2fe45529ea0407c644ea4026f2a1a75661f2c9b66 + +Other uses for trusted and encrypted keys, such as for disk and file encryption +are anticipated. In particular the 'ecryptfs' encrypted keys format can be used +to mount an eCryptfs filesystem. More details about the usage can be found in +the file ``Documentation/security/keys/ecryptfs.rst``. + +Another format 'enc32' can be used to support encrypted keys with payload size +of 32 bytes.
On Thu, Oct 31, 2019 at 07:28:42PM +0530, Sumit Garg wrote:
Provide documentation for usage of TEE based Trusted Keys via existing user-space "keyctl" utility. Also, document various use-cases.
Signed-off-by: Sumit Garg sumit.garg@linaro.org
This is the most important commit in order for someone who don't deal that much with ARM TEE to get right. Until this commit is right, I don't unfortunately have much to say about other commits.
Instead of making disjoint islands, you should edit trusted-encrypted.rst so that it describes commonalities and differences.
What the document currently describes is the usage model. It could be a section of its own. In that you should describe first the common parameters and separetely the backend specific parametrs.
From kernel internals (there could be a section with this name) the
document describe the key generation e.g. is the hardware used and how it is used, is there salting with krng and so forth.
/Jarkko
On Fri, 1 Nov 2019 at 03:17, Jarkko Sakkinen jarkko.sakkinen@linux.intel.com wrote:
On Thu, Oct 31, 2019 at 07:28:42PM +0530, Sumit Garg wrote:
Provide documentation for usage of TEE based Trusted Keys via existing user-space "keyctl" utility. Also, document various use-cases.
Signed-off-by: Sumit Garg sumit.garg@linaro.org
This is the most important commit in order for someone who don't deal that much with ARM TEE to get right.
I agree that documentation needs to be updated and your following comments seems to be somewhat similar to comments from Mimi here [1].
Until this commit is right, I don't unfortunately have much to say about other commits.
Isn't this statement contradicting with your earlier statement regarding the right order would be to complete TEE patches review first and then come up with documentation here [2]?
[1] https://lore.kernel.org/linux-integrity/1568025601.4614.253.camel@linux.ibm.... [2] https://lore.kernel.org/linux-integrity/20190909163643.qxmzpcggi567hmhv@linu...
Instead of making disjoint islands, you should edit trusted-encrypted.rst so that it describes commonalities and differences.
What the document currently describes is the usage model. It could be a section of its own. In that you should describe first the common parameters and separetely the backend specific parametrs.
From kernel internals (there could be a section with this name) the document describe the key generation e.g. is the hardware used and how it is used, is there salting with krng and so forth.
BTW, here is the info regarding RNG provided by OP-TEE (an open-source TEE implementation).
It's either direct output from hardware based RNG (if platform supports one) [3] or a software based Fortuna CSPRNG (executing in trusted environment) [4] which is seeded via multiple entropy sources as described here [5].
Overall, I think salting this with krng sounds reasonable to address single RNG source concern. So I would suggest to have a common wrapper API that would do salting of trust source (TPM or TEE) RNG output with krng.
[3] https://github.com/OP-TEE/optee_os/blob/master/core/crypto/rng_hw.c [4] https://github.com/OP-TEE/optee_os/blob/master/core/crypto/rng_fortuna.c [5] https://github.com/OP-TEE/optee_os/blob/master/core/include/crypto/crypto.h#...
-Sumit
/Jarkko
On Fri, Nov 01, 2019 at 03:04:18PM +0530, Sumit Garg wrote:
Isn't this statement contradicting with your earlier statement regarding the right order would be to complete TEE patches review first and then come up with documentation here [2]?
[1] https://lore.kernel.org/linux-integrity/1568025601.4614.253.camel@linux.ibm.... [2] https://lore.kernel.org/linux-integrity/20190909163643.qxmzpcggi567hmhv@linu...
With the intersecting issues, namely key generation and conflicting keyctl parameters, that was not a well considered statement.
/Jarkko
On Sat, 2 Nov 2019 at 01:50, Jarkko Sakkinen jarkko.sakkinen@linux.intel.com wrote:
On Fri, Nov 01, 2019 at 03:04:18PM +0530, Sumit Garg wrote:
Isn't this statement contradicting with your earlier statement regarding the right order would be to complete TEE patches review first and then come up with documentation here [2]?
[1] https://lore.kernel.org/linux-integrity/1568025601.4614.253.camel@linux.ibm.... [2] https://lore.kernel.org/linux-integrity/20190909163643.qxmzpcggi567hmhv@linu...
With the intersecting issues, namely key generation and conflicting keyctl parameters, that was not a well considered statement.
Okay, let me work on documentation first, but I think resending whole patch-set just for documentation review and rework would be an overkill. Would minor revisions of this patch only like v3.1, v3.2 etc. work for you? And later I could send next version of this patch-set once we agree on documentation.
-Sumit
/Jarkko
On Mon, Nov 04, 2019 at 12:28:47PM +0530, Sumit Garg wrote:
On Sat, 2 Nov 2019 at 01:50, Jarkko Sakkinen jarkko.sakkinen@linux.intel.com wrote:
On Fri, Nov 01, 2019 at 03:04:18PM +0530, Sumit Garg wrote:
Isn't this statement contradicting with your earlier statement regarding the right order would be to complete TEE patches review first and then come up with documentation here [2]?
[1] https://lore.kernel.org/linux-integrity/1568025601.4614.253.camel@linux.ibm.... [2] https://lore.kernel.org/linux-integrity/20190909163643.qxmzpcggi567hmhv@linu...
With the intersecting issues, namely key generation and conflicting keyctl parameters, that was not a well considered statement.
Okay, let me work on documentation first, but I think resending whole patch-set just for documentation review and rework would be an overkill. Would minor revisions of this patch only like v3.1, v3.2 etc. work for you? And later I could send next version of this patch-set once we agree on documentation.
Yeah, we could iterate through the documentation patch and once we are happy with it you can bundle it to your main patch set.
/Jarkko
Add MAINTAINERS entry for TEE based Trusted Keys framework.
Signed-off-by: Sumit Garg sumit.garg@linaro.org --- MAINTAINERS | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS index c6c34d0..08d0282 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9059,6 +9059,15 @@ F: include/keys/trusted-type.h F: security/keys/trusted.c F: include/keys/trusted.h
+KEYS-TEE-TRUSTED +M: Sumit Garg sumit.garg@linaro.org +L: linux-integrity@vger.kernel.org +L: keyrings@vger.kernel.org +S: Supported +F: Documentation/security/keys/tee-trusted.rst +F: include/keys/trusted_tee.h +F: security/keys/trusted-keys/trusted_tee.c + KEYS/KEYRINGS: M: David Howells dhowells@redhat.com M: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com
-
Jarkko Sakkinen -
Sumit Garg