diff options
Diffstat (limited to 'drivers/staging/greybus/authentication.c')
| -rw-r--r-- | drivers/staging/greybus/authentication.c | 429 |
1 files changed, 429 insertions, 0 deletions
diff --git a/drivers/staging/greybus/authentication.c b/drivers/staging/greybus/authentication.c new file mode 100644 index 000000000000..168626ba0c03 --- /dev/null +++ b/drivers/staging/greybus/authentication.c @@ -0,0 +1,429 @@ +/* + * Greybus Component Authentication Protocol (CAP) Driver. + * + * Copyright 2016 Google Inc. + * Copyright 2016 Linaro Ltd. + * + * Released under the GPLv2 only. + */ + +#include "greybus.h" + +#include <linux/cdev.h> +#include <linux/fs.h> +#include <linux/ioctl.h> +#include <linux/uaccess.h> + +#include "greybus_authentication.h" +#include "firmware.h" +#include "greybus.h" + +#define CAP_TIMEOUT_MS 1000 + +/* + * Number of minor devices this driver supports. + * There will be exactly one required per Interface. + */ +#define NUM_MINORS U8_MAX + +struct gb_cap { + struct device *parent; + struct gb_connection *connection; + struct kref kref; + struct list_head node; + bool disabled; /* connection getting disabled */ + + struct mutex mutex; + struct cdev cdev; + struct device *class_device; + dev_t dev_num; +}; + +static struct class *cap_class; +static dev_t cap_dev_num; +static DEFINE_IDA(cap_minors_map); +static LIST_HEAD(cap_list); +static DEFINE_MUTEX(list_mutex); + +static void cap_kref_release(struct kref *kref) +{ + struct gb_cap *cap = container_of(kref, struct gb_cap, kref); + + kfree(cap); +} + +/* + * All users of cap take a reference (from within list_mutex lock), before + * they get a pointer to play with. And the structure will be freed only after + * the last user has put the reference to it. + */ +static void put_cap(struct gb_cap *cap) +{ + kref_put(&cap->kref, cap_kref_release); +} + +/* Caller must call put_cap() after using struct gb_cap */ +static struct gb_cap *get_cap(struct cdev *cdev) +{ + struct gb_cap *cap; + + mutex_lock(&list_mutex); + + list_for_each_entry(cap, &cap_list, node) { + if (&cap->cdev == cdev) { + kref_get(&cap->kref); + goto unlock; + } + } + + cap = NULL; + +unlock: + mutex_unlock(&list_mutex); + + return cap; +} + +static int cap_get_endpoint_uid(struct gb_cap *cap, u8 *euid) +{ + struct gb_connection *connection = cap->connection; + struct gb_cap_get_endpoint_uid_response response; + int ret; + + ret = gb_operation_sync(connection, GB_CAP_TYPE_GET_ENDPOINT_UID, NULL, + 0, &response, sizeof(response)); + if (ret) { + dev_err(cap->parent, "failed to get endpoint uid (%d)\n", ret); + return ret; + } + + memcpy(euid, response.uid, sizeof(response.uid)); + + return 0; +} + +static int cap_get_ims_certificate(struct gb_cap *cap, u32 class, u32 id, + u8 *certificate, u32 *size, u8 *result) +{ + struct gb_connection *connection = cap->connection; + struct gb_cap_get_ims_certificate_request *request; + struct gb_cap_get_ims_certificate_response *response; + size_t max_size = gb_operation_get_payload_size_max(connection); + struct gb_operation *op; + int ret; + + op = gb_operation_create_flags(connection, + GB_CAP_TYPE_GET_IMS_CERTIFICATE, + sizeof(*request), max_size, + GB_OPERATION_FLAG_SHORT_RESPONSE, + GFP_KERNEL); + if (!op) + return -ENOMEM; + + request = op->request->payload; + request->certificate_class = cpu_to_le32(class); + request->certificate_id = cpu_to_le32(id); + + ret = gb_operation_request_send_sync(op); + if (ret) { + dev_err(cap->parent, "failed to get certificate (%d)\n", ret); + goto done; + } + + response = op->response->payload; + *result = response->result_code; + *size = op->response->payload_size - sizeof(*response); + memcpy(certificate, response->certificate, *size); + +done: + gb_operation_put(op); + return ret; +} + +static int cap_authenticate(struct gb_cap *cap, u32 auth_type, u8 *uid, + u8 *challenge, u8 *result, u8 *auth_response, + u32 *signature_size, u8 *signature) +{ + struct gb_connection *connection = cap->connection; + struct gb_cap_authenticate_request *request; + struct gb_cap_authenticate_response *response; + size_t max_size = gb_operation_get_payload_size_max(connection); + struct gb_operation *op; + int ret; + + op = gb_operation_create_flags(connection, GB_CAP_TYPE_AUTHENTICATE, + sizeof(*request), max_size, + GB_OPERATION_FLAG_SHORT_RESPONSE, + GFP_KERNEL); + if (!op) + return -ENOMEM; + + request = op->request->payload; + request->auth_type = cpu_to_le32(auth_type); + memcpy(request->uid, uid, sizeof(request->uid)); + memcpy(request->challenge, challenge, sizeof(request->challenge)); + + ret = gb_operation_request_send_sync(op); + if (ret) { + dev_err(cap->parent, "failed to authenticate (%d)\n", ret); + goto done; + } + + response = op->response->payload; + *result = response->result_code; + *signature_size = op->response->payload_size - sizeof(*response); + memcpy(auth_response, response->response, sizeof(response->response)); + memcpy(signature, response->signature, *signature_size); + +done: + gb_operation_put(op); + return ret; +} + +/* Char device fops */ + +static int cap_open(struct inode *inode, struct file *file) +{ + struct gb_cap *cap = get_cap(inode->i_cdev); + + /* cap structure can't get freed until file descriptor is closed */ + if (cap) { + file->private_data = cap; + return 0; + } + + return -ENODEV; +} + +static int cap_release(struct inode *inode, struct file *file) +{ + struct gb_cap *cap = file->private_data; + + put_cap(cap); + return 0; +} + +static int cap_ioctl(struct gb_cap *cap, unsigned int cmd, + void __user *buf) +{ + struct cap_ioc_get_endpoint_uid endpoint_uid; + struct cap_ioc_get_ims_certificate *ims_cert; + struct cap_ioc_authenticate *authenticate; + size_t size; + int ret; + + switch (cmd) { + case CAP_IOC_GET_ENDPOINT_UID: + ret = cap_get_endpoint_uid(cap, endpoint_uid.uid); + if (ret) + return ret; + + if (copy_to_user(buf, &endpoint_uid, sizeof(endpoint_uid))) + return -EFAULT; + + return 0; + case CAP_IOC_GET_IMS_CERTIFICATE: + size = sizeof(*ims_cert); + ims_cert = memdup_user(buf, size); + if (IS_ERR(ims_cert)) + return PTR_ERR(ims_cert); + + ret = cap_get_ims_certificate(cap, ims_cert->certificate_class, + ims_cert->certificate_id, + ims_cert->certificate, + &ims_cert->cert_size, + &ims_cert->result_code); + if (!ret && copy_to_user(buf, ims_cert, size)) + ret = -EFAULT; + kfree(ims_cert); + + return ret; + case CAP_IOC_AUTHENTICATE: + size = sizeof(*authenticate); + authenticate = memdup_user(buf, size); + if (IS_ERR(authenticate)) + return PTR_ERR(authenticate); + + ret = cap_authenticate(cap, authenticate->auth_type, + authenticate->uid, + authenticate->challenge, + &authenticate->result_code, + authenticate->response, + &authenticate->signature_size, + authenticate->signature); + if (!ret && copy_to_user(buf, authenticate, size)) + ret = -EFAULT; + kfree(authenticate); + + return ret; + default: + return -ENOTTY; + } +} + +static long cap_ioctl_unlocked(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct gb_cap *cap = file->private_data; + struct gb_bundle *bundle = cap->connection->bundle; + int ret = -ENODEV; + + /* + * Serialize ioctls. + * + * We don't want the user to do multiple authentication operations in + * parallel. + * + * This is also used to protect ->disabled, which is used to check if + * the connection is getting disconnected, so that we don't start any + * new operations. + */ + mutex_lock(&cap->mutex); + if (!cap->disabled) { + ret = gb_pm_runtime_get_sync(bundle); + if (!ret) { + ret = cap_ioctl(cap, cmd, (void __user *)arg); + gb_pm_runtime_put_autosuspend(bundle); + } + } + mutex_unlock(&cap->mutex); + + return ret; +} + +static const struct file_operations cap_fops = { + .owner = THIS_MODULE, + .open = cap_open, + .release = cap_release, + .unlocked_ioctl = cap_ioctl_unlocked, +}; + +int gb_cap_connection_init(struct gb_connection *connection) +{ + struct gb_cap *cap; + int ret, minor; + + if (!connection) + return 0; + + cap = kzalloc(sizeof(*cap), GFP_KERNEL); + if (!cap) + return -ENOMEM; + + cap->parent = &connection->bundle->dev; + cap->connection = connection; + mutex_init(&cap->mutex); + gb_connection_set_data(connection, cap); + kref_init(&cap->kref); + + mutex_lock(&list_mutex); + list_add(&cap->node, &cap_list); + mutex_unlock(&list_mutex); + + ret = gb_connection_enable(connection); + if (ret) + goto err_list_del; + + minor = ida_simple_get(&cap_minors_map, 0, NUM_MINORS, GFP_KERNEL); + if (minor < 0) { + ret = minor; + goto err_connection_disable; + } + + /* Add a char device to allow userspace to interact with cap */ + cap->dev_num = MKDEV(MAJOR(cap_dev_num), minor); + cdev_init(&cap->cdev, &cap_fops); + + ret = cdev_add(&cap->cdev, cap->dev_num, 1); + if (ret) + goto err_remove_ida; + + /* Add a soft link to the previously added char-dev within the bundle */ + cap->class_device = device_create(cap_class, cap->parent, cap->dev_num, + NULL, "gb-authenticate-%d", minor); + if (IS_ERR(cap->class_device)) { + ret = PTR_ERR(cap->class_device); + goto err_del_cdev; + } + + return 0; + +err_del_cdev: + cdev_del(&cap->cdev); +err_remove_ida: + ida_simple_remove(&cap_minors_map, minor); +err_connection_disable: + gb_connection_disable(connection); +err_list_del: + mutex_lock(&list_mutex); + list_del(&cap->node); + mutex_unlock(&list_mutex); + + put_cap(cap); + + return ret; +} + +void gb_cap_connection_exit(struct gb_connection *connection) +{ + struct gb_cap *cap; + + if (!connection) + return; + + cap = gb_connection_get_data(connection); + + device_destroy(cap_class, cap->dev_num); + cdev_del(&cap->cdev); + ida_simple_remove(&cap_minors_map, MINOR(cap->dev_num)); + + /* + * Disallow any new ioctl operations on the char device and wait for + * existing ones to finish. + */ + mutex_lock(&cap->mutex); + cap->disabled = true; + mutex_unlock(&cap->mutex); + + /* All pending greybus operations should have finished by now */ + gb_connection_disable(cap->connection); + + /* Disallow new users to get access to the cap structure */ + mutex_lock(&list_mutex); + list_del(&cap->node); + mutex_unlock(&list_mutex); + + /* + * All current users of cap would have taken a reference to it by + * now, we can drop our reference and wait the last user will get + * cap freed. + */ + put_cap(cap); +} + +int cap_init(void) +{ + int ret; + + cap_class = class_create(THIS_MODULE, "gb_authenticate"); + if (IS_ERR(cap_class)) + return PTR_ERR(cap_class); + + ret = alloc_chrdev_region(&cap_dev_num, 0, NUM_MINORS, + "gb_authenticate"); + if (ret) + goto err_remove_class; + + return 0; + +err_remove_class: + class_destroy(cap_class); + return ret; +} + +void cap_exit(void) +{ + unregister_chrdev_region(cap_dev_num, NUM_MINORS); + class_destroy(cap_class); + ida_destroy(&cap_minors_map); +} |