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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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#include <linux/file.h>#include <linux/fs.h>#include <linux/interrupt.h>#include <linux/hw_random.h>#include <linux/miscdevice.h>#include <linux/module.h>#include <linux/mutex.h>#include <linux/slab.h>#include <linux/string.h>#include <linux/uaccess.h>#include <linux/uio.h>#include <linux/virtio_config.h>#include <linux/virtio_ids.h>#include <linux/virtio.h>#include <linux/wait.h>#include <uapi/linux/nsm.h>
/* Timeout for NSM virtqueue respose in milliseconds. */#define NSM_DEFAULT_TIMEOUT_MSECS (120000) /* 2 minutes */
/* Maximum length input data */struct nsm_data_req { u32 len; u8 data[NSM_REQUEST_MAX_SIZE];};
/* Maximum length output data */struct nsm_data_resp { u32 len; u8 data[NSM_RESPONSE_MAX_SIZE];};
/* Full NSM request/response message */struct nsm_msg { struct nsm_data_req req; struct nsm_data_resp resp;};
struct nsm { struct virtio_device *vdev; struct virtqueue *vq; struct mutex lock; struct completion cmd_done; struct miscdevice misc; struct hwrng hwrng; struct work_struct misc_init; struct nsm_msg msg;};
/* NSM device ID */static const struct virtio_device_id id_table[] = { { VIRTIO_ID_NITRO_SEC_MOD, VIRTIO_DEV_ANY_ID }, { }};
static struct nsm *file_to_nsm(struct file *file){ return container_of(file->private_data, struct nsm, misc);}
static struct nsm *hwrng_to_nsm(struct hwrng *rng){ return container_of(rng, struct nsm, hwrng);}
#define CBOR_TYPE_MASK 0xE0#define CBOR_TYPE_MAP 0xA0#define CBOR_TYPE_TEXT 0x60#define CBOR_TYPE_ARRAY 0x40#define CBOR_HEADER_SIZE_SHORT 1
#define CBOR_SHORT_SIZE_MAX_VALUE 23#define CBOR_LONG_SIZE_U8 24#define CBOR_LONG_SIZE_U16 25#define CBOR_LONG_SIZE_U32 26#define CBOR_LONG_SIZE_U64 27
static bool cbor_object_is_array(const u8 *cbor_object, size_t cbor_object_size){ if (cbor_object_size == 0 || cbor_object == NULL) return false;
return (cbor_object[0] & CBOR_TYPE_MASK) == CBOR_TYPE_ARRAY;}
static int cbor_object_get_array(u8 *cbor_object, size_t cbor_object_size, u8 **cbor_array){ u8 cbor_short_size; void *array_len_p; u64 array_len; u64 array_offset;
if (!cbor_object_is_array(cbor_object, cbor_object_size)) return -EFAULT;
cbor_short_size = (cbor_object[0] & 0x1F);
/* Decoding byte array length */ array_offset = CBOR_HEADER_SIZE_SHORT; if (cbor_short_size >= CBOR_LONG_SIZE_U8) array_offset += BIT(cbor_short_size - CBOR_LONG_SIZE_U8);
if (cbor_object_size < array_offset) return -EFAULT;
array_len_p = &cbor_object[1];
switch (cbor_short_size) { case 0 ... CBOR_SHORT_SIZE_MAX_VALUE: /* short encoding */ array_len = cbor_short_size; break; case CBOR_LONG_SIZE_U8: array_len = *(u8 *)array_len_p; break; case CBOR_LONG_SIZE_U16: array_len = be16_to_cpup((__be16 *)array_len_p); break; case CBOR_LONG_SIZE_U32: array_len = be32_to_cpup((__be32 *)array_len_p); break; case CBOR_LONG_SIZE_U64: array_len = be64_to_cpup((__be64 *)array_len_p); break; default: return -EFAULT; }
if (cbor_object_size < array_offset) return -EFAULT;
if (cbor_object_size - array_offset < array_len) return -EFAULT;
if (array_len > INT_MAX) return -EFAULT;
*cbor_array = cbor_object + array_offset; return array_len;}
/* Copy the request of a raw message to kernel space */static int fill_req_raw(struct nsm *nsm, struct nsm_data_req *req, struct nsm_raw *raw){ /* Verify the user input size. */ if (raw->request.len > sizeof(req->data)) return -EMSGSIZE;
/* Copy the request payload */ if (copy_from_user(req->data, u64_to_user_ptr(raw->request.addr), raw->request.len)) return -EFAULT;
req->len = raw->request.len;
return 0;}
/* Copy the response of a raw message back to user-space */static int parse_resp_raw(struct nsm *nsm, struct nsm_data_resp *resp, struct nsm_raw *raw){ /* Truncate any message that does not fit. */ raw->response.len = min_t(u64, raw->response.len, resp->len);
/* Copy the response content to user space */ if (copy_to_user(u64_to_user_ptr(raw->response.addr), resp->data, raw->response.len)) return -EFAULT;
return 0;}
/* Virtqueue interrupt handler */static void nsm_vq_callback(struct virtqueue *vq){ struct nsm *nsm = vq->vdev->priv;
complete(&nsm->cmd_done);}
/* Forward a message to the NSM device and wait for the response from it */static int nsm_sendrecv_msg_locked(struct nsm *nsm){ struct device *dev = &nsm->vdev->dev; struct scatterlist sg_in, sg_out; struct nsm_msg *msg = &nsm->msg; struct virtqueue *vq = nsm->vq; unsigned int len; void *queue_buf; bool kicked; int rc;
/* Initialize scatter-gather lists with request and response buffers. */ sg_init_one(&sg_out, msg->req.data, msg->req.len); sg_init_one(&sg_in, msg->resp.data, sizeof(msg->resp.data));
init_completion(&nsm->cmd_done); /* Add the request buffer (read by the device). */ rc = virtqueue_add_outbuf(vq, &sg_out, 1, msg->req.data, GFP_KERNEL); if (rc) return rc;
/* Add the response buffer (written by the device). */ rc = virtqueue_add_inbuf(vq, &sg_in, 1, msg->resp.data, GFP_KERNEL); if (rc) goto cleanup;
kicked = virtqueue_kick(vq); if (!kicked) { /* Cannot kick the virtqueue. */ rc = -EIO; goto cleanup; }
/* If the kick succeeded, wait for the device's response. */ if (!wait_for_completion_io_timeout(&nsm->cmd_done, msecs_to_jiffies(NSM_DEFAULT_TIMEOUT_MSECS))) { rc = -ETIMEDOUT; goto cleanup; }
queue_buf = virtqueue_get_buf(vq, &len); if (!queue_buf || (queue_buf != msg->req.data)) { dev_err(dev, "wrong request buffer."); rc = -ENODATA; goto cleanup; }
queue_buf = virtqueue_get_buf(vq, &len); if (!queue_buf || (queue_buf != msg->resp.data)) { dev_err(dev, "wrong response buffer."); rc = -ENODATA; goto cleanup; }
msg->resp.len = min_t(unsigned int, len, sizeof(msg->resp.data));
rc = 0;
cleanup: if (rc) { /* Clean the virtqueue. */ while (virtqueue_get_buf(vq, &len) != NULL) ; }
return rc;}
static int fill_req_get_random(struct nsm *nsm, struct nsm_data_req *req){ /* * 69 # text(9) * 47657452616E646F6D # "GetRandom" */ const u8 request[] = { CBOR_TYPE_TEXT + strlen("GetRandom"), 'G', 'e', 't', 'R', 'a', 'n', 'd', 'o', 'm' };
memcpy(req->data, request, sizeof(request)); req->len = sizeof(request);
return 0;}
static int parse_resp_get_random(struct nsm *nsm, struct nsm_data_resp *resp, void *out, size_t max){ /* * A1 # map(1) * 69 # text(9) - Name of field * 47657452616E646F6D # "GetRandom" * A1 # map(1) - The field itself * 66 # text(6) * 72616E646F6D # "random" * # The rest of the response is random data */ const u8 response[] = { CBOR_TYPE_MAP + 1, CBOR_TYPE_TEXT + strlen("GetRandom"), 'G', 'e', 't', 'R', 'a', 'n', 'd', 'o', 'm', CBOR_TYPE_MAP + 1, CBOR_TYPE_TEXT + strlen("random"), 'r', 'a', 'n', 'd', 'o', 'm' }; struct device *dev = &nsm->vdev->dev; u8 *rand_data = NULL; u8 *resp_ptr = resp->data; u64 resp_len = resp->len; int rc;
if ((resp->len < sizeof(response) + 1) || (memcmp(resp_ptr, response, sizeof(response)) != 0)) { dev_err(dev, "Invalid response for GetRandom"); return -EFAULT; }
resp_ptr += sizeof(response); resp_len -= sizeof(response);
rc = cbor_object_get_array(resp_ptr, resp_len, &rand_data); if (rc < 0) { dev_err(dev, "GetRandom: Invalid CBOR encoding\n"); return rc; }
rc = min_t(size_t, rc, max); memcpy(out, rand_data, rc);
return rc;}
/* * HwRNG implementation */static int nsm_rng_read(struct hwrng *rng, void *data, size_t max, bool wait){ struct nsm *nsm = hwrng_to_nsm(rng); struct device *dev = &nsm->vdev->dev; int rc = 0;
/* NSM always needs to wait for a response */ if (!wait) return 0;
mutex_lock(&nsm->lock);
rc = fill_req_get_random(nsm, &nsm->msg.req); if (rc != 0) goto out;
rc = nsm_sendrecv_msg_locked(nsm); if (rc != 0) goto out;
rc = parse_resp_get_random(nsm, &nsm->msg.resp, data, max); if (rc < 0) goto out;
dev_dbg(dev, "RNG: returning rand bytes = %d", rc);out: mutex_unlock(&nsm->lock); return rc;}
static long nsm_dev_ioctl(struct file *file, unsigned int cmd, unsigned long arg){ void __user *argp = u64_to_user_ptr((u64)arg); struct nsm *nsm = file_to_nsm(file); struct nsm_raw raw; int r = 0;
if (cmd != NSM_IOCTL_RAW) return -EINVAL;
if (_IOC_SIZE(cmd) != sizeof(raw)) return -EINVAL;
/* Copy user argument struct to kernel argument struct */ if (copy_from_user(&raw, argp, _IOC_SIZE(cmd))) return -EFAULT;
mutex_lock(&nsm->lock);
/* Convert kernel argument struct to device request */ r = fill_req_raw(nsm, &nsm->msg.req, &raw); if (r) goto out;
/* Send message to NSM and read reply */ r = nsm_sendrecv_msg_locked(nsm); if (r) goto out;
/* Parse device response into kernel argument struct */ r = parse_resp_raw(nsm, &nsm->msg.resp, &raw); if (r) goto out;
/* Copy kernel argument struct back to user argument struct */ r = -EFAULT; if (copy_to_user(argp, &raw, sizeof(raw))) goto out;
r = 0;
out: mutex_unlock(&nsm->lock); return r;}
static int nsm_device_init_vq(struct virtio_device *vdev){ struct virtqueue *vq = virtio_find_single_vq(vdev, nsm_vq_callback, "nsm.vq.0"); struct nsm *nsm = vdev->priv;
if (IS_ERR(vq)) return PTR_ERR(vq);
nsm->vq = vq;
return 0;}
static const struct file_operations nsm_dev_fops = { .owner = THIS_MODULE, .unlocked_ioctl = nsm_dev_ioctl, .compat_ioctl = compat_ptr_ioctl,};
/* Handler for probing the NSM device */static int nsm_device_probe(struct virtio_device *vdev){ struct device *dev = &vdev->dev; struct nsm *nsm; int rc;
nsm = devm_kzalloc(&vdev->dev, sizeof(*nsm), GFP_KERNEL); if (!nsm) return -ENOMEM;
vdev->priv = nsm; nsm->vdev = vdev;
rc = nsm_device_init_vq(vdev); if (rc) { dev_err(dev, "queue failed to initialize: %d.\n", rc); goto err_init_vq; }
mutex_init(&nsm->lock);
virtio_device_ready(vdev);
/* Register as hwrng provider */ nsm->hwrng = (struct hwrng) { .read = nsm_rng_read, .name = "nsm-hwrng", .quality = 1000, };
rc = hwrng_register(&nsm->hwrng); if (rc) { dev_err(dev, "RNG initialization error: %d.\n", rc); goto err_hwrng; }
/* Register /dev/nsm device node */ nsm->misc = (struct miscdevice) { .minor = MISC_DYNAMIC_MINOR, .name = "nsm", .fops = &nsm_dev_fops, .mode = 0666, };
rc = misc_register(&nsm->misc); if (rc) { dev_err(dev, "misc device registration error: %d.\n", rc); goto err_misc; }
return 0;
err_misc: hwrng_unregister(&nsm->hwrng);err_hwrng: virtio_reset_device(vdev); vdev->config->del_vqs(vdev);err_init_vq: return rc;}
/* Handler for removing the NSM device */static void nsm_device_remove(struct virtio_device *vdev){ struct nsm *nsm = vdev->priv;
hwrng_unregister(&nsm->hwrng);
vdev->config->del_vqs(vdev); misc_deregister(&nsm->misc);}
/* NSM device configuration structure */static struct virtio_driver virtio_nsm_driver = { .feature_table = 0, .feature_table_size = 0, .feature_table_legacy = 0, .feature_table_size_legacy = 0, .driver.name = KBUILD_MODNAME, .id_table = id_table, .probe = nsm_device_probe, .remove = nsm_device_remove,};
module_virtio_driver(virtio_nsm_driver);MODULE_DEVICE_TABLE(virtio, id_table);MODULE_DESCRIPTION("Virtio NSM driver");MODULE_LICENSE("GPL");