Commit message: sg_write()/bsg_write() is not fit to be called under KERNEL_DS

Both damn things interpret userland pointers embedded into the payload;
worse, they are actually traversing those.  Leaving aside the bad
API design, this is very much _not_ safe to call with KERNEL_DS.
Bail out early if that happens.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
CVE: CVE-2016-10088
CWE: CWE-416
Vulnerability description: The sg implementation in the Linux kernel through 4.9 does not properly restrict write operations in situations where the KERNEL_DS option is set, which allows local users to read or write to arbitrary kernel memory locations or cause a denial of service (use-after-free) by leveraging access to a /dev/sg device, related to block/bsg.c and drivers/scsi/sg.c.  NOTE: this vulnerability exists because of an incomplete fix for CVE-2016-9576.

Project: linux
File: bsg.c

static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q)
{
	struct bsg_device *bd;

	mutex_lock(&bsg_mutex);

	hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) {
		if (bd->queue == q) {
			atomic_inc(&bd->ref_count);
			goto found;
		}
	}
	bd = NULL;
found:
	mutex_unlock(&bsg_mutex);
	return bd;
}

Project: linux
File: bsg.c

__bsg_read(char __user *buf, size_t count, struct bsg_device *bd,
	   const struct iovec *iov, ssize_t *bytes_read)
{
	struct bsg_command *bc;
	int nr_commands, ret;

	if (count % sizeof(struct sg_io_v4))
		return -EINVAL;

	ret = 0;
	nr_commands = count / sizeof(struct sg_io_v4);
	while (nr_commands) {
		bc = bsg_get_done_cmd(bd);
		if (IS_ERR(bc)) {
			ret = PTR_ERR(bc);
			break;
		}

		/*
		 * this is the only case where we need to copy data back
		 * after completing the request. so do that here,
		 * bsg_complete_work() cannot do that for us
		 */
		ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
					       bc->bidi_bio);

		if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr)))
			ret = -EFAULT;

		bsg_free_command(bc);

		if (ret)
			break;

		buf += sizeof(struct sg_io_v4);
		*bytes_read += sizeof(struct sg_io_v4);
		nr_commands--;
	}

	return ret;
}

Project: linux
File: bsg.c

static int __bsg_write(struct bsg_device *bd, const char __user *buf,
		       size_t count, ssize_t *bytes_written,
		       fmode_t has_write_perm)
{
	struct bsg_command *bc;
	struct request *rq;
	int ret, nr_commands;

	if (count % sizeof(struct sg_io_v4))
		return -EINVAL;

	nr_commands = count / sizeof(struct sg_io_v4);
	rq = NULL;
	bc = NULL;
	ret = 0;
	while (nr_commands) {
		struct request_queue *q = bd->queue;

		bc = bsg_alloc_command(bd);
		if (IS_ERR(bc)) {
			ret = PTR_ERR(bc);
			bc = NULL;
			break;
		}

		if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) {
			ret = -EFAULT;
			break;
		}

		/*
		 * get a request, fill in the blanks, and add to request queue
		 */
		rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm, bc->sense);
		if (IS_ERR(rq)) {
			ret = PTR_ERR(rq);
			rq = NULL;
			break;
		}

		bsg_add_command(bd, q, bc, rq);
		bc = NULL;
		rq = NULL;
		nr_commands--;
		buf += sizeof(struct sg_io_v4);
		*bytes_written += sizeof(struct sg_io_v4);
	}

	if (bc)
		bsg_free_command(bc);

	return ret;
}

Project: linux
File: bsg.c

static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
				    struct bio *bio, struct bio *bidi_bio)
{
	int ret = 0;

	dprintk("rq %p bio %p 0x%x\n", rq, bio, rq->errors);
	/*
	 * fill in all the output members
	 */
	hdr->device_status = rq->errors & 0xff;
	hdr->transport_status = host_byte(rq->errors);
	hdr->driver_status = driver_byte(rq->errors);
	hdr->info = 0;
	if (hdr->device_status || hdr->transport_status || hdr->driver_status)
		hdr->info |= SG_INFO_CHECK;
	hdr->response_len = 0;

	if (rq->sense_len && hdr->response) {
		int len = min_t(unsigned int, hdr->max_response_len,
					rq->sense_len);

		ret = copy_to_user((void __user *)(unsigned long)hdr->response,
				   rq->sense, len);
		if (!ret)
			hdr->response_len = len;
		else
			ret = -EFAULT;
	}

	if (rq->next_rq) {
		hdr->dout_resid = rq->resid_len;
		hdr->din_resid = rq->next_rq->resid_len;
		blk_rq_unmap_user(bidi_bio);
		blk_put_request(rq->next_rq);
	} else if (rq_data_dir(rq) == READ)
		hdr->din_resid = rq->resid_len;
	else
		hdr->dout_resid = rq->resid_len;

	/*
	 * If the request generated a negative error number, return it
	 * (providing we aren't already returning an error); if it's
	 * just a protocol response (i.e. non negative), that gets
	 * processed above.
	 */
	if (!ret && rq->errors < 0)
		ret = rq->errors;

	blk_rq_unmap_user(bio);
	if (rq->cmd != rq->__cmd)
		kfree(rq->cmd);
	blk_put_request(rq);

	return ret;
}

Project: linux
File: bsg.c

static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
				struct sg_io_v4 *hdr, struct bsg_device *bd,
				fmode_t has_write_perm)
{
	if (hdr->request_len > BLK_MAX_CDB) {
		rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL);
		if (!rq->cmd)
			return -ENOMEM;
	}

	if (copy_from_user(rq->cmd, (void __user *)(unsigned long)hdr->request,
			   hdr->request_len))
		return -EFAULT;

	if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) {
		if (blk_verify_command(rq->cmd, has_write_perm))
			return -EPERM;
	} else if (!capable(CAP_SYS_RAWIO))
		return -EPERM;

	/*
	 * fill in request structure
	 */
	rq->cmd_len = hdr->request_len;

	rq->timeout = msecs_to_jiffies(hdr->timeout);
	if (!rq->timeout)
		rq->timeout = q->sg_timeout;
	if (!rq->timeout)
		rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
	if (rq->timeout < BLK_MIN_SG_TIMEOUT)
		rq->timeout = BLK_MIN_SG_TIMEOUT;

	return 0;
}

Project: linux
File: bsg.c

static void bsg_add_command(struct bsg_device *bd, struct request_queue *q,
			    struct bsg_command *bc, struct request *rq)
{
	int at_head = (0 == (bc->hdr.flags & BSG_FLAG_Q_AT_TAIL));

	/*
	 * add bc command to busy queue and submit rq for io
	 */
	bc->rq = rq;
	bc->bio = rq->bio;
	if (rq->next_rq)
		bc->bidi_bio = rq->next_rq->bio;
	bc->hdr.duration = jiffies;
	spin_lock_irq(&bd->lock);
	list_add_tail(&bc->list, &bd->busy_list);
	spin_unlock_irq(&bd->lock);

	dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc);

	rq->end_io_data = bc;
	blk_execute_rq_nowait(q, NULL, rq, at_head, bsg_rq_end_io);
}

Project: linux
File: bsg.c

static struct bsg_device *bsg_add_device(struct inode *inode,
					 struct request_queue *rq,
					 struct file *file)
{
	struct bsg_device *bd;
#ifdef BSG_DEBUG
	unsigned char buf[32];
#endif
	if (!blk_get_queue(rq))
		return ERR_PTR(-ENXIO);

	bd = bsg_alloc_device();
	if (!bd) {
		blk_put_queue(rq);
		return ERR_PTR(-ENOMEM);
	}

	bd->queue = rq;

	bsg_set_block(bd, file);

	atomic_set(&bd->ref_count, 1);
	mutex_lock(&bsg_mutex);
	hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode)));

	strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1);
	dprintk("bound to <%s>, max queue %d\n",
		format_dev_t(buf, inode->i_rdev), bd->max_queue);

	mutex_unlock(&bsg_mutex);
	return bd;
}

Project: linux
File: bsg.c

static struct bsg_command *bsg_alloc_command(struct bsg_device *bd)
{
	struct bsg_command *bc = ERR_PTR(-EINVAL);

	spin_lock_irq(&bd->lock);

	if (bd->queued_cmds >= bd->max_queue)
		goto out;

	bd->queued_cmds++;
	spin_unlock_irq(&bd->lock);

	bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL);
	if (unlikely(!bc)) {
		spin_lock_irq(&bd->lock);
		bd->queued_cmds--;
		bc = ERR_PTR(-ENOMEM);
		goto out;
	}

	bc->bd = bd;
	INIT_LIST_HEAD(&bc->list);
	dprintk("%s: returning free cmd %p\n", bd->name, bc);
	return bc;
out:
	spin_unlock_irq(&bd->lock);
	return bc;
}

Project: linux
File: bsg.c

static struct bsg_device *bsg_alloc_device(void)
{
	struct bsg_device *bd;

	bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL);
	if (unlikely(!bd))
		return NULL;

	spin_lock_init(&bd->lock);

	bd->max_queue = BSG_DEFAULT_CMDS;

	INIT_LIST_HEAD(&bd->busy_list);
	INIT_LIST_HEAD(&bd->done_list);
	INIT_HLIST_NODE(&bd->dev_list);

	init_waitqueue_head(&bd->wq_free);
	init_waitqueue_head(&bd->wq_done);
	return bd;
}

Project: linux
File: bsg.c

static bool bsg_complete(struct bsg_device *bd)
{
	bool ret = false;
	bool spin;

	do {
		spin_lock_irq(&bd->lock);

		BUG_ON(bd->done_cmds > bd->queued_cmds);

		/*
		 * All commands consumed.
		 */
		if (bd->done_cmds == bd->queued_cmds)
			ret = true;

		spin = !test_bit(BSG_F_BLOCK, &bd->flags);

		spin_unlock_irq(&bd->lock);
	} while (!ret && spin);

	return ret;
}

Project: linux
File: bsg.c

static int bsg_complete_all_commands(struct bsg_device *bd)
{
	struct bsg_command *bc;
	int ret, tret;

	dprintk("%s: entered\n", bd->name);

	/*
	 * wait for all commands to complete
	 */
	io_wait_event(bd->wq_done, bsg_complete(bd));

	/*
	 * discard done commands
	 */
	ret = 0;
	do {
		spin_lock_irq(&bd->lock);
		if (!bd->queued_cmds) {
			spin_unlock_irq(&bd->lock);
			break;
		}
		spin_unlock_irq(&bd->lock);

		bc = bsg_get_done_cmd(bd);
		if (IS_ERR(bc))
			break;

		tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
						bc->bidi_bio);
		if (!ret)
			ret = tret;

		bsg_free_command(bc);
	} while (1);

	return ret;
}

Project: linux
File: bsg.c

static inline struct hlist_head *bsg_dev_idx_hash(int index)
{
	return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)];
}

Project: linux
File: bsg.c

static char *bsg_devnode(struct device *dev, umode_t *mode)
{
	return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev));
}

Project: linux
File: bsg.c

static void bsg_free_command(struct bsg_command *bc)
{
	struct bsg_device *bd = bc->bd;
	unsigned long flags;

	kmem_cache_free(bsg_cmd_cachep, bc);

	spin_lock_irqsave(&bd->lock, flags);
	bd->queued_cmds--;
	spin_unlock_irqrestore(&bd->lock, flags);

	wake_up(&bd->wq_free);
}

Project: linux
File: bsg.c

static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd)
{
	struct bsg_command *bc;
	int ret;

	do {
		bc = bsg_next_done_cmd(bd);
		if (bc)
			break;

		if (!test_bit(BSG_F_BLOCK, &bd->flags)) {
			bc = ERR_PTR(-EAGAIN);
			break;
		}

		ret = wait_event_interruptible(bd->wq_done, bd->done_cmds);
		if (ret) {
			bc = ERR_PTR(-ERESTARTSYS);
			break;
		}
	} while (1);

	dprintk("%s: returning done %p\n", bd->name, bc);

	return bc;
}

Project: linux
File: bsg.c

static int __init bsg_init(void)
{
	int ret, i;
	dev_t devid;

	bsg_cmd_cachep = kmem_cache_create("bsg_cmd",
				sizeof(struct bsg_command), 0, 0, NULL);
	if (!bsg_cmd_cachep) {
		printk(KERN_ERR "bsg: failed creating slab cache\n");
		return -ENOMEM;
	}

	for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++)
		INIT_HLIST_HEAD(&bsg_device_list[i]);

	bsg_class = class_create(THIS_MODULE, "bsg");
	if (IS_ERR(bsg_class)) {
		ret = PTR_ERR(bsg_class);
		goto destroy_kmemcache;
	}
	bsg_class->devnode = bsg_devnode;

	ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
	if (ret)
		goto destroy_bsg_class;

	bsg_major = MAJOR(devid);

	cdev_init(&bsg_cdev, &bsg_fops);
	ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS);
	if (ret)
		goto unregister_chrdev;

	printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
	       " loaded (major %d)\n", bsg_major);
	return 0;
unregister_chrdev:
	unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS);
destroy_bsg_class:
	class_destroy(bsg_class);
destroy_kmemcache:
	kmem_cache_destroy(bsg_cmd_cachep);
	return ret;
}

Project: linux
File: bsg.c

static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	struct bsg_device *bd = file->private_data;
	int __user *uarg = (int __user *) arg;
	int ret;

	switch (cmd) {
		/*
		 * our own ioctls
		 */
	case SG_GET_COMMAND_Q:
		return put_user(bd->max_queue, uarg);
	case SG_SET_COMMAND_Q: {
		int queue;

		if (get_user(queue, uarg))
			return -EFAULT;
		if (queue < 1)
			return -EINVAL;

		spin_lock_irq(&bd->lock);
		bd->max_queue = queue;
		spin_unlock_irq(&bd->lock);
		return 0;
	}

	/*
	 * SCSI/sg ioctls
	 */
	case SG_GET_VERSION_NUM:
	case SCSI_IOCTL_GET_IDLUN:
	case SCSI_IOCTL_GET_BUS_NUMBER:
	case SG_SET_TIMEOUT:
	case SG_GET_TIMEOUT:
	case SG_GET_RESERVED_SIZE:
	case SG_SET_RESERVED_SIZE:
	case SG_EMULATED_HOST:
	case SCSI_IOCTL_SEND_COMMAND: {
		void __user *uarg = (void __user *) arg;
		return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg);
	}
	case SG_IO: {
		struct request *rq;
		struct bio *bio, *bidi_bio = NULL;
		struct sg_io_v4 hdr;
		int at_head;
		u8 sense[SCSI_SENSE_BUFFERSIZE];

		if (copy_from_user(&hdr, uarg, sizeof(hdr)))
			return -EFAULT;

		rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE, sense);
		if (IS_ERR(rq))
			return PTR_ERR(rq);

		bio = rq->bio;
		if (rq->next_rq)
			bidi_bio = rq->next_rq->bio;

		at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL));
		blk_execute_rq(bd->queue, NULL, rq, at_head);
		ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio);

		if (copy_to_user(uarg, &hdr, sizeof(hdr)))
			return -EFAULT;

		return ret;
	}
	/*
	 * block device ioctls
	 */
	default:
#if 0
		return ioctl_by_bdev(bd->bdev, cmd, arg);
#else
		return -ENOTTY;
#endif
	}
}

Project: linux
File: bsg.c

static void bsg_kref_release_function(struct kref *kref)
{
	struct bsg_class_device *bcd =
		container_of(kref, struct bsg_class_device, ref);
	struct device *parent = bcd->parent;

	if (bcd->release)
		bcd->release(bcd->parent);

	put_device(parent);
}

Project: linux
File: bsg.c

bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm,
	    u8 *sense)
{
	struct request_queue *q = bd->queue;
	struct request *rq, *next_rq = NULL;
	int ret, rw;
	unsigned int dxfer_len;
	void __user *dxferp = NULL;
	struct bsg_class_device *bcd = &q->bsg_dev;

	/* if the LLD has been removed then the bsg_unregister_queue will
	 * eventually be called and the class_dev was freed, so we can no
	 * longer use this request_queue. Return no such address.
	 */
	if (!bcd->class_dev)
		return ERR_PTR(-ENXIO);

	dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp,
		hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp,
		hdr->din_xfer_len);

	ret = bsg_validate_sgv4_hdr(hdr, &rw);
	if (ret)
		return ERR_PTR(ret);

	/*
	 * map scatter-gather elements separately and string them to request
	 */
	rq = blk_get_request(q, rw, GFP_KERNEL);
	if (IS_ERR(rq))
		return rq;
	blk_rq_set_block_pc(rq);

	ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm);
	if (ret)
		goto out;

	if (rw == WRITE && hdr->din_xfer_len) {
		if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) {
			ret = -EOPNOTSUPP;
			goto out;
		}

		next_rq = blk_get_request(q, READ, GFP_KERNEL);
		if (IS_ERR(next_rq)) {
			ret = PTR_ERR(next_rq);
			next_rq = NULL;
			goto out;
		}
		rq->next_rq = next_rq;
		next_rq->cmd_type = rq->cmd_type;

		dxferp = (void __user *)(unsigned long)hdr->din_xferp;
		ret =  blk_rq_map_user(q, next_rq, NULL, dxferp,
				       hdr->din_xfer_len, GFP_KERNEL);
		if (ret)
			goto out;
	}

	if (hdr->dout_xfer_len) {
		dxfer_len = hdr->dout_xfer_len;
		dxferp = (void __user *)(unsigned long)hdr->dout_xferp;
	} else if (hdr->din_xfer_len) {
		dxfer_len = hdr->din_xfer_len;
		dxferp = (void __user *)(unsigned long)hdr->din_xferp;
	} else
		dxfer_len = 0;

	if (dxfer_len) {
		ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len,
				      GFP_KERNEL);
		if (ret)
			goto out;
	}

	rq->sense = sense;
	rq->sense_len = 0;

	return rq;
out:
	if (rq->cmd != rq->__cmd)
		kfree(rq->cmd);
	blk_put_request(rq);
	if (next_rq) {
		blk_rq_unmap_user(next_rq->bio);
		blk_put_request(next_rq);
	}
	return ERR_PTR(ret);
}

Project: linux
File: bsg.c

static int bsg_open(struct inode *inode, struct file *file)
{
	struct bsg_device *bd;

	bd = bsg_get_device(inode, file);

	if (IS_ERR(bd))
		return PTR_ERR(bd);

	file->private_data = bd;
	return 0;
}

Project: linux
File: bsg.c

static unsigned int bsg_poll(struct file *file, poll_table *wait)
{
	struct bsg_device *bd = file->private_data;
	unsigned int mask = 0;

	poll_wait(file, &bd->wq_done, wait);
	poll_wait(file, &bd->wq_free, wait);

	spin_lock_irq(&bd->lock);
	if (!list_empty(&bd->done_list))
		mask |= POLLIN | POLLRDNORM;
	if (bd->queued_cmds < bd->max_queue)
		mask |= POLLOUT;
	spin_unlock_irq(&bd->lock);

	return mask;
}

Project: linux
File: bsg.c

static int bsg_put_device(struct bsg_device *bd)
{
	int ret = 0, do_free;
	struct request_queue *q = bd->queue;

	mutex_lock(&bsg_mutex);

	do_free = atomic_dec_and_test(&bd->ref_count);
	if (!do_free) {
		mutex_unlock(&bsg_mutex);
		goto out;
	}

	hlist_del(&bd->dev_list);
	mutex_unlock(&bsg_mutex);

	dprintk("%s: tearing down\n", bd->name);

	/*
	 * close can always block
	 */
	set_bit(BSG_F_BLOCK, &bd->flags);

	/*
	 * correct error detection baddies here again. it's the responsibility
	 * of the app to properly reap commands before close() if it wants
	 * fool-proof error detection
	 */
	ret = bsg_complete_all_commands(bd);

	kfree(bd);
out:
	kref_put(&q->bsg_dev.ref, bsg_kref_release_function);
	if (do_free)
		blk_put_queue(q);
	return ret;
}

Project: linux
File: bsg.c

bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
	struct bsg_device *bd = file->private_data;
	int ret;
	ssize_t bytes_read;

	dprintk("%s: read %Zd bytes\n", bd->name, count);

	bsg_set_block(bd, file);

	bytes_read = 0;
	ret = __bsg_read(buf, count, bd, NULL, &bytes_read);
	*ppos = bytes_read;

	if (!bytes_read || err_block_err(ret))
		bytes_read = ret;

	return bytes_read;
}

Project: linux
File: bsg.c

int bsg_register_queue(struct request_queue *q, struct device *parent,
		       const char *name, void (*release)(struct device *))
{
	struct bsg_class_device *bcd;
	dev_t dev;
	int ret;
	struct device *class_dev = NULL;
	const char *devname;

	if (name)
		devname = name;
	else
		devname = dev_name(parent);

	/*
	 * we need a proper transport to send commands, not a stacked device
	 */
	if (!queue_is_rq_based(q))
		return 0;

	bcd = &q->bsg_dev;
	memset(bcd, 0, sizeof(*bcd));

	mutex_lock(&bsg_mutex);

	ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL);
	if (ret < 0) {
		if (ret == -ENOSPC) {
			printk(KERN_ERR "bsg: too many bsg devices\n");
			ret = -EINVAL;
		}
		goto unlock;
	}

	bcd->minor = ret;
	bcd->queue = q;
	bcd->parent = get_device(parent);
	bcd->release = release;
	kref_init(&bcd->ref);
	dev = MKDEV(bsg_major, bcd->minor);
	class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname);
	if (IS_ERR(class_dev)) {
		ret = PTR_ERR(class_dev);
		goto put_dev;
	}
	bcd->class_dev = class_dev;

	if (q->kobj.sd) {
		ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
		if (ret)
			goto unregister_class_dev;
	}

	mutex_unlock(&bsg_mutex);
	return 0;

unregister_class_dev:
	device_unregister(class_dev);
put_dev:
	put_device(parent);
	idr_remove(&bsg_minor_idr, bcd->minor);
unlock:
	mutex_unlock(&bsg_mutex);
	return ret;
}

Project: linux
File: bsg.c

static int bsg_release(struct inode *inode, struct file *file)
{
	struct bsg_device *bd = file->private_data;

	file->private_data = NULL;
	return bsg_put_device(bd);
}

Project: linux
File: bsg.c

static void bsg_rq_end_io(struct request *rq, int uptodate)
{
	struct bsg_command *bc = rq->end_io_data;
	struct bsg_device *bd = bc->bd;
	unsigned long flags;

	dprintk("%s: finished rq %p bc %p, bio %p stat %d\n",
		bd->name, rq, bc, bc->bio, uptodate);

	bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration);

	spin_lock_irqsave(&bd->lock, flags);
	list_move_tail(&bc->list, &bd->done_list);
	bd->done_cmds++;
	spin_unlock_irqrestore(&bd->lock, flags);

	wake_up(&bd->wq_done);
}

Project: linux
File: bsg.c

static inline void bsg_set_block(struct bsg_device *bd, struct file *file)
{
	if (file->f_flags & O_NONBLOCK)
		clear_bit(BSG_F_BLOCK, &bd->flags);
	else
		set_bit(BSG_F_BLOCK, &bd->flags);
}

Project: linux
File: bsg.c

bsg_validate_sgv4_hdr(struct sg_io_v4 *hdr, int *rw)
{
	int ret = 0;

	if (hdr->guard != 'Q')
		return -EINVAL;

	switch (hdr->protocol) {
	case BSG_PROTOCOL_SCSI:
		switch (hdr->subprotocol) {
		case BSG_SUB_PROTOCOL_SCSI_CMD:
		case BSG_SUB_PROTOCOL_SCSI_TRANSPORT:
			break;
		default:
			ret = -EINVAL;
		}
		break;
	default:
		ret = -EINVAL;
	}

	*rw = hdr->dout_xfer_len ? WRITE : READ;
	return ret;
}

Project: linux
File: bsg.c

static inline int err_block_err(int ret)
{
	if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN)
		return 1;

	return 0;
}

Project: linux
File: sg.c

sg_common_write(Sg_fd * sfp, Sg_request * srp,
		unsigned char *cmnd, int timeout, int blocking)
{
	int k, at_head;
	Sg_device *sdp = sfp->parentdp;
	sg_io_hdr_t *hp = &srp->header;

	srp->data.cmd_opcode = cmnd[0];	/* hold opcode of command */
	hp->status = 0;
	hp->masked_status = 0;
	hp->msg_status = 0;
	hp->info = 0;
	hp->host_status = 0;
	hp->driver_status = 0;
	hp->resid = 0;
	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
			"sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
			(int) cmnd[0], (int) hp->cmd_len));

	k = sg_start_req(srp, cmnd);
	if (k) {
		SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
			"sg_common_write: start_req err=%d\n", k));
		sg_finish_rem_req(srp);
		return k;	/* probably out of space --> ENOMEM */
	}
	if (atomic_read(&sdp->detaching)) {
		if (srp->bio) {
			if (srp->rq->cmd != srp->rq->__cmd)
				kfree(srp->rq->cmd);

			blk_end_request_all(srp->rq, -EIO);
			srp->rq = NULL;
		}

		sg_finish_rem_req(srp);
		return -ENODEV;
	}

	hp->duration = jiffies_to_msecs(jiffies);
	if (hp->interface_id != '\0' &&	/* v3 (or later) interface */
	    (SG_FLAG_Q_AT_TAIL & hp->flags))
		at_head = 0;
	else
		at_head = 1;

	srp->rq->timeout = timeout;
	kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */
	blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
			      srp->rq, at_head, sg_rq_end_io);
	return 0;
}

Project: linux
File: sg.c

sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
{
	void __user *p = (void __user *)arg;
	int __user *ip = p;
	int result, val, read_only;
	Sg_device *sdp;
	Sg_fd *sfp;
	Sg_request *srp;
	unsigned long iflags;

	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
		return -ENXIO;

	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
				   "sg_ioctl: cmd=0x%x\n", (int) cmd_in));
	read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));

	switch (cmd_in) {
	case SG_IO:
		if (atomic_read(&sdp->detaching))
			return -ENODEV;
		if (!scsi_block_when_processing_errors(sdp->device))
			return -ENXIO;
		if (!access_ok(VERIFY_WRITE, p, SZ_SG_IO_HDR))
			return -EFAULT;
		result = sg_new_write(sfp, filp, p, SZ_SG_IO_HDR,
				 1, read_only, 1, &srp);
		if (result < 0)
			return result;
		result = wait_event_interruptible(sfp->read_wait,
			(srp_done(sfp, srp) || atomic_read(&sdp->detaching)));
		if (atomic_read(&sdp->detaching))
			return -ENODEV;
		write_lock_irq(&sfp->rq_list_lock);
		if (srp->done) {
			srp->done = 2;
			write_unlock_irq(&sfp->rq_list_lock);
			result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
			return (result < 0) ? result : 0;
		}
		srp->orphan = 1;
		write_unlock_irq(&sfp->rq_list_lock);
		return result;	/* -ERESTARTSYS because signal hit process */
	case SG_SET_TIMEOUT:
		result = get_user(val, ip);
		if (result)
			return result;
		if (val < 0)
			return -EIO;
		if (val >= mult_frac((s64)INT_MAX, USER_HZ, HZ))
			val = min_t(s64, mult_frac((s64)INT_MAX, USER_HZ, HZ),
				    INT_MAX);
		sfp->timeout_user = val;
		sfp->timeout = mult_frac(val, HZ, USER_HZ);

		return 0;
	case SG_GET_TIMEOUT:	/* N.B. User receives timeout as return value */
				/* strange ..., for backward compatibility */
		return sfp->timeout_user;
	case SG_SET_FORCE_LOW_DMA:
		result = get_user(val, ip);
		if (result)
			return result;
		if (val) {
			sfp->low_dma = 1;
			if ((0 == sfp->low_dma) && (0 == sg_res_in_use(sfp))) {
				val = (int) sfp->reserve.bufflen;
				sg_remove_scat(sfp, &sfp->reserve);
				sg_build_reserve(sfp, val);
			}
		} else {
			if (atomic_read(&sdp->detaching))
				return -ENODEV;
			sfp->low_dma = sdp->device->host->unchecked_isa_dma;
		}
		return 0;
	case SG_GET_LOW_DMA:
		return put_user((int) sfp->low_dma, ip);
	case SG_GET_SCSI_ID:
		if (!access_ok(VERIFY_WRITE, p, sizeof (sg_scsi_id_t)))
			return -EFAULT;
		else {
			sg_scsi_id_t __user *sg_idp = p;

			if (atomic_read(&sdp->detaching))
				return -ENODEV;
			__put_user((int) sdp->device->host->host_no,
				   &sg_idp->host_no);
			__put_user((int) sdp->device->channel,
				   &sg_idp->channel);
			__put_user((int) sdp->device->id, &sg_idp->scsi_id);
			__put_user((int) sdp->device->lun, &sg_idp->lun);
			__put_user((int) sdp->device->type, &sg_idp->scsi_type);
			__put_user((short) sdp->device->host->cmd_per_lun,
				   &sg_idp->h_cmd_per_lun);
			__put_user((short) sdp->device->queue_depth,
				   &sg_idp->d_queue_depth);
			__put_user(0, &sg_idp->unused[0]);
			__put_user(0, &sg_idp->unused[1]);
			return 0;
		}
	case SG_SET_FORCE_PACK_ID:
		result = get_user(val, ip);
		if (result)
			return result;
		sfp->force_packid = val ? 1 : 0;
		return 0;
	case SG_GET_PACK_ID:
		if (!access_ok(VERIFY_WRITE, ip, sizeof (int)))
			return -EFAULT;
		read_lock_irqsave(&sfp->rq_list_lock, iflags);
		for (srp = sfp->headrp; srp; srp = srp->nextrp) {
			if ((1 == srp->done) && (!srp->sg_io_owned)) {
				read_unlock_irqrestore(&sfp->rq_list_lock,
						       iflags);
				__put_user(srp->header.pack_id, ip);
				return 0;
			}
		}
		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
		__put_user(-1, ip);
		return 0;
	case SG_GET_NUM_WAITING:
		read_lock_irqsave(&sfp->rq_list_lock, iflags);
		for (val = 0, srp = sfp->headrp; srp; srp = srp->nextrp) {
			if ((1 == srp->done) && (!srp->sg_io_owned))
				++val;
		}
		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
		return put_user(val, ip);
	case SG_GET_SG_TABLESIZE:
		return put_user(sdp->sg_tablesize, ip);
	case SG_SET_RESERVED_SIZE:
		result = get_user(val, ip);
		if (result)
			return result;
                if (val < 0)
                        return -EINVAL;
		val = min_t(int, val,
			    max_sectors_bytes(sdp->device->request_queue));
		if (val != sfp->reserve.bufflen) {
			if (sg_res_in_use(sfp) || sfp->mmap_called)
				return -EBUSY;
			sg_remove_scat(sfp, &sfp->reserve);
			sg_build_reserve(sfp, val);
		}
		return 0;
	case SG_GET_RESERVED_SIZE:
		val = min_t(int, sfp->reserve.bufflen,
			    max_sectors_bytes(sdp->device->request_queue));
		return put_user(val, ip);
	case SG_SET_COMMAND_Q:
		result = get_user(val, ip);
		if (result)
			return result;
		sfp->cmd_q = val ? 1 : 0;
		return 0;
	case SG_GET_COMMAND_Q:
		return put_user((int) sfp->cmd_q, ip);
	case SG_SET_KEEP_ORPHAN:
		result = get_user(val, ip);
		if (result)
			return result;
		sfp->keep_orphan = val;
		return 0;
	case SG_GET_KEEP_ORPHAN:
		return put_user((int) sfp->keep_orphan, ip);
	case SG_NEXT_CMD_LEN:
		result = get_user(val, ip);
		if (result)
			return result;
		sfp->next_cmd_len = (val > 0) ? val : 0;
		return 0;
	case SG_GET_VERSION_NUM:
		return put_user(sg_version_num, ip);
	case SG_GET_ACCESS_COUNT:
		/* faked - we don't have a real access count anymore */
		val = (sdp->device ? 1 : 0);
		return put_user(val, ip);
	case SG_GET_REQUEST_TABLE:
		if (!access_ok(VERIFY_WRITE, p, SZ_SG_REQ_INFO * SG_MAX_QUEUE))
			return -EFAULT;
		else {
			sg_req_info_t *rinfo;
			unsigned int ms;

			rinfo = kmalloc(SZ_SG_REQ_INFO * SG_MAX_QUEUE,
								GFP_KERNEL);
			if (!rinfo)
				return -ENOMEM;
			read_lock_irqsave(&sfp->rq_list_lock, iflags);
			for (srp = sfp->headrp, val = 0; val < SG_MAX_QUEUE;
			     ++val, srp = srp ? srp->nextrp : srp) {
				memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
				if (srp) {
					rinfo[val].req_state = srp->done + 1;
					rinfo[val].problem =
					    srp->header.masked_status & 
					    srp->header.host_status & 
					    srp->header.driver_status;
					if (srp->done)
						rinfo[val].duration =
							srp->header.duration;
					else {
						ms = jiffies_to_msecs(jiffies);
						rinfo[val].duration =
						    (ms > srp->header.duration) ?
						    (ms - srp->header.duration) : 0;
					}
					rinfo[val].orphan = srp->orphan;
					rinfo[val].sg_io_owned =
							srp->sg_io_owned;
					rinfo[val].pack_id =
							srp->header.pack_id;
					rinfo[val].usr_ptr =
							srp->header.usr_ptr;
				}
			}
			read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
			result = __copy_to_user(p, rinfo, 
						SZ_SG_REQ_INFO * SG_MAX_QUEUE);
			result = result ? -EFAULT : 0;
			kfree(rinfo);
			return result;
		}
	case SG_EMULATED_HOST:
		if (atomic_read(&sdp->detaching))
			return -ENODEV;
		return put_user(sdp->device->host->hostt->emulated, ip);
	case SCSI_IOCTL_SEND_COMMAND:
		if (atomic_read(&sdp->detaching))
			return -ENODEV;
		if (read_only) {
			unsigned char opcode = WRITE_6;
			Scsi_Ioctl_Command __user *siocp = p;

			if (copy_from_user(&opcode, siocp->data, 1))
				return -EFAULT;
			if (sg_allow_access(filp, &opcode))
				return -EPERM;
		}
		return sg_scsi_ioctl(sdp->device->request_queue, NULL, filp->f_mode, p);
	case SG_SET_DEBUG:
		result = get_user(val, ip);
		if (result)
			return result;
		sdp->sgdebug = (char) val;
		return 0;
	case BLKSECTGET:
		return put_user(max_sectors_bytes(sdp->device->request_queue),
				ip);
	case BLKTRACESETUP:
		return blk_trace_setup(sdp->device->request_queue,
				       sdp->disk->disk_name,
				       MKDEV(SCSI_GENERIC_MAJOR, sdp->index),
				       NULL,
				       (char *)arg);
	case BLKTRACESTART:
		return blk_trace_startstop(sdp->device->request_queue, 1);
	case BLKTRACESTOP:
		return blk_trace_startstop(sdp->device->request_queue, 0);
	case BLKTRACETEARDOWN:
		return blk_trace_remove(sdp->device->request_queue);
	case SCSI_IOCTL_GET_IDLUN:
	case SCSI_IOCTL_GET_BUS_NUMBER:
	case SCSI_IOCTL_PROBE_HOST:
	case SG_GET_TRANSFORM:
	case SG_SCSI_RESET:
		if (atomic_read(&sdp->detaching))
			return -ENODEV;
		break;
	default:
		if (read_only)
			return -EPERM;	/* don't know so take safe approach */
		break;
	}

	result = scsi_ioctl_block_when_processing_errors(sdp->device,
			cmd_in, filp->f_flags & O_NDELAY);
	if (result)
		return result;
	return scsi_ioctl(sdp->device, cmd_in, p);
}

Project: linux
File: sg.c

sg_mmap(struct file *filp, struct vm_area_struct *vma)
{
	Sg_fd *sfp;
	unsigned long req_sz, len, sa;
	Sg_scatter_hold *rsv_schp;
	int k, length;

	if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
		return -ENXIO;
	req_sz = vma->vm_end - vma->vm_start;
	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
				      "sg_mmap starting, vm_start=%p, len=%d\n",
				      (void *) vma->vm_start, (int) req_sz));
	if (vma->vm_pgoff)
		return -EINVAL;	/* want no offset */
	rsv_schp = &sfp->reserve;
	if (req_sz > rsv_schp->bufflen)
		return -ENOMEM;	/* cannot map more than reserved buffer */

	sa = vma->vm_start;
	length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
	for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
		len = vma->vm_end - sa;
		len = (len < length) ? len : length;
		sa += len;
	}

	sfp->mmap_called = 1;
	vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
	vma->vm_private_data = sfp;
	vma->vm_ops = &sg_mmap_vm_ops;
	return 0;
}

Project: linux
File: sg.c

sg_start_req(Sg_request *srp, unsigned char *cmd)
{
	int res;
	struct request *rq;
	Sg_fd *sfp = srp->parentfp;
	sg_io_hdr_t *hp = &srp->header;
	int dxfer_len = (int) hp->dxfer_len;
	int dxfer_dir = hp->dxfer_direction;
	unsigned int iov_count = hp->iovec_count;
	Sg_scatter_hold *req_schp = &srp->data;
	Sg_scatter_hold *rsv_schp = &sfp->reserve;
	struct request_queue *q = sfp->parentdp->device->request_queue;
	struct rq_map_data *md, map_data;
	int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
	unsigned char *long_cmdp = NULL;

	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
				      "sg_start_req: dxfer_len=%d\n",
				      dxfer_len));

	if (hp->cmd_len > BLK_MAX_CDB) {
		long_cmdp = kzalloc(hp->cmd_len, GFP_KERNEL);
		if (!long_cmdp)
			return -ENOMEM;
	}

	/*
	 * NOTE
	 *
	 * With scsi-mq enabled, there are a fixed number of preallocated
	 * requests equal in number to shost->can_queue.  If all of the
	 * preallocated requests are already in use, then using GFP_ATOMIC with
	 * blk_get_request() will return -EWOULDBLOCK, whereas using GFP_KERNEL
	 * will cause blk_get_request() to sleep until an active command
	 * completes, freeing up a request.  Neither option is ideal, but
	 * GFP_KERNEL is the better choice to prevent userspace from getting an
	 * unexpected EWOULDBLOCK.
	 *
	 * With scsi-mq disabled, blk_get_request() with GFP_KERNEL usually
	 * does not sleep except under memory pressure.
	 */
	rq = blk_get_request(q, rw, GFP_KERNEL);
	if (IS_ERR(rq)) {
		kfree(long_cmdp);
		return PTR_ERR(rq);
	}

	blk_rq_set_block_pc(rq);

	if (hp->cmd_len > BLK_MAX_CDB)
		rq->cmd = long_cmdp;
	memcpy(rq->cmd, cmd, hp->cmd_len);
	rq->cmd_len = hp->cmd_len;

	srp->rq = rq;
	rq->end_io_data = srp;
	rq->sense = srp->sense_b;
	rq->retries = SG_DEFAULT_RETRIES;

	if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
		return 0;

	if (sg_allow_dio && hp->flags & SG_FLAG_DIRECT_IO &&
	    dxfer_dir != SG_DXFER_UNKNOWN && !iov_count &&
	    !sfp->parentdp->device->host->unchecked_isa_dma &&
	    blk_rq_aligned(q, (unsigned long)hp->dxferp, dxfer_len))
		md = NULL;
	else
		md = &map_data;

	if (md) {
		if (!sg_res_in_use(sfp) && dxfer_len <= rsv_schp->bufflen)
			sg_link_reserve(sfp, srp, dxfer_len);
		else {
			res = sg_build_indirect(req_schp, sfp, dxfer_len);
			if (res)
				return res;
		}

		md->pages = req_schp->pages;
		md->page_order = req_schp->page_order;
		md->nr_entries = req_schp->k_use_sg;
		md->offset = 0;
		md->null_mapped = hp->dxferp ? 0 : 1;
		if (dxfer_dir == SG_DXFER_TO_FROM_DEV)
			md->from_user = 1;
		else
			md->from_user = 0;
	}

	if (iov_count) {
		struct iovec *iov = NULL;
		struct iov_iter i;

		res = import_iovec(rw, hp->dxferp, iov_count, 0, &iov, &i);
		if (res < 0)
			return res;

		iov_iter_truncate(&i, hp->dxfer_len);

		res = blk_rq_map_user_iov(q, rq, md, &i, GFP_ATOMIC);
		kfree(iov);
	} else
		res = blk_rq_map_user(q, rq, md, hp->dxferp,
				      hp->dxfer_len, GFP_ATOMIC);

	if (!res) {
		srp->bio = rq->bio;

		if (!md) {
			req_schp->dio_in_use = 1;
			hp->info |= SG_INFO_DIRECT_IO;
		}
	}
	return res;
}