Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 505 insertions, 0 deletions

diff --git a/drivers/misc/nsm.c b/drivers/misc/nsm.c
new file mode 100644
index 000000000..a3a9f9bfc
--- /dev/null
+++ b/drivers/misc/nsm.c
@@ -0,0 +1,505 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Amazon Nitro Secure Module driver.
+ *
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * The Nitro Secure Module implements commands via CBOR over virtio.
+ * This driver exposes a raw message ioctls on /dev/nsm that user
+ * space can use to issue these commands.
+ */
+
+#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 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;
+	}
+
+	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);
+
+	/* 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:
+	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");