On Tue, 13 Oct 2020 at 07:22, Jarkko Sakkinen
[off-list ref] wrote:

On Wed, Oct 07, 2020 at 03:37:46PM +0530, Sumit Garg wrote:

quoted

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 <redacted>
---
 include/keys/trusted_tee.h                |  55 ++++++
 security/keys/trusted-keys/Makefile       |   1 +
 security/keys/trusted-keys/trusted_core.c |   4 +
 security/keys/trusted-keys/trusted_tee.c  | 278 ++++++++++++++++++++++++++++++
 4 files changed, 338 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_tee.h b/include/keys/trusted_tee.h
new file mode 100644
index 0000000..2e2bb15
--- /dev/null
+++ b/include/keys/trusted_tee.h

@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019-2020 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
+ */
+#define TA_CMD_GET_RANDOM    0x0
+
+/*
+ * Seal trusted key using hardware unique key
+ *
+ * [in]      memref[0]        Plain key
+ * [out]     memref[1]        Sealed key datablob
+ */
+#define TA_CMD_SEAL          0x1
+
+/*
+ * Unseal trusted key using hardware unique key
+ *
+ * [in]      memref[0]        Sealed key datablob
+ * [out]     memref[1]        Plain key
+ */
+#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;
+     struct tee_shm *shm_pool;
+};
+
+extern struct trusted_key_ops tee_trusted_key_ops;
+
+#endif

diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile
index 49e3bcf..012dd78 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_core.o
 trusted-y += trusted_tpm1.o
 trusted-y += trusted_tpm2.o
+trusted-y += trusted_tee.o

diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
index 71a5e27..74a3d80 100644
--- a/security/keys/trusted-keys/trusted_core.c
+++ b/security/keys/trusted-keys/trusted_core.c

@@ -8,6 +8,7 @@

 #include <keys/user-type.h>
 #include <keys/trusted-type.h>
+#include <keys/trusted_tee.h>
 #include <keys/trusted_tpm.h>
 #include <linux/capability.h>
 #include <linux/err.h>

@@ -28,6 +29,9 @@ static struct trusted_key_source trusted_key_sources[] = {
 #if defined(CONFIG_TCG_TPM)
      { "tpm", &tpm_trusted_key_ops },
 #endif
+#if defined(CONFIG_TEE)
+     { "tee", &tee_trusted_key_ops },
+#endif
 };
 static struct trusted_key_ops *trusted_key_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..b414d52
--- /dev/null
+++ b/security/keys/trusted-keys/trusted_tee.c

@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019-2020 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_trusted_seal(struct trusted_key_payload *p, char *datablob)

Use trusted_tee_* prefix.

Okay, so will also switch to trusted_tpm_* prefix in patch #1 too.

quoted

+{
+     int ret = 0;

"int ret;"

It is never used uninitialized.

Ack.

quoted

+     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(&param, 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_trusted_unseal(struct trusted_key_payload *p, char *datablob)
+{
+     int ret = 0;

Ditto.

Ack.

quoted

+     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(&param, 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_trusted_get_random(unsigned char *key, size_t key_len)
+{
+     int ret = 0;

Ditto.

Ack.

quoted

+     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(&param, 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, "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;

Ditto. I'm not sure why you need both 'ret' and 'err'.

Okay, will use 'ret' only.

quoted

+
+     memset(&sess_arg, 0, sizeof(sess_arg));
+
+     pvt_data.ctx = tee_client_open_context(NULL, optee_ctx_match, NULL,
+                                            NULL);
+     if (IS_ERR(pvt_data.ctx))
+             return -ENODEV;
+
+     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;

Couldn't you just overwrite 'ret'?

Ack.

-Sumit

quoted

+             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 exit_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_trusted_seal,
+     .unseal = tee_trusted_unseal,
+     .get_random = tee_trusted_get_random,
+     .exit = exit_tee_trusted,
+};
--
2.7.4

/Jarkko