Commit 073f21ae authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse 

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: verify ioctl retries
  fuse: fix ioctl when server is 32bit
parents 497b5b13 7572777e

fs/fuse/file.c

+66 −6
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/module.h>

#include <linux/compat.h>



static const struct file_operations fuse_direct_io_file_operations;
@@ -1627,6 +1628,58 @@ static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov, 
	return 0;

}



/*

 * CUSE servers compiled on 32bit broke on 64bit kernels because the

 * ABI was defined to be 'struct iovec' which is different on 32bit

 * and 64bit.  Fortunately we can determine which structure the server

 * used from the size of the reply.

 */

static int fuse_copy_ioctl_iovec(struct iovec *dst, void *src,

				 size_t transferred, unsigned count,

				 bool is_compat)

{

#ifdef CONFIG_COMPAT

	if (count * sizeof(struct compat_iovec) == transferred) {

		struct compat_iovec *ciov = src;

		unsigned i;



		/*

		 * With this interface a 32bit server cannot support

		 * non-compat (i.e. ones coming from 64bit apps) ioctl

		 * requests

		 */

		if (!is_compat)

			return -EINVAL;



		for (i = 0; i < count; i++) {

			dst[i].iov_base = compat_ptr(ciov[i].iov_base);

			dst[i].iov_len = ciov[i].iov_len;

		}

		return 0;

	}

#endif



	if (count * sizeof(struct iovec) != transferred)

		return -EIO;



	memcpy(dst, src, transferred);

	return 0;

}



/* Make sure iov_length() won't overflow */

static int fuse_verify_ioctl_iov(struct iovec *iov, size_t count)

{

	size_t n;

	u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT;



	for (n = 0; n < count; n++) {

		if (iov->iov_len > (size_t) max)

			return -ENOMEM;

		max -= iov->iov_len;

	}

	return 0;

}



/*

 * For ioctls, there is no generic way to determine how much memory

 * needs to be read and/or written.  Furthermore, ioctls are allowed
@@ -1808,18 +1861,25 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg, 
		    in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)

			goto out;



		err = -EIO;

		if ((in_iovs + out_iovs) * sizeof(struct iovec) != transferred)

			goto out;



		/* okay, copy in iovs and retry */

		vaddr = kmap_atomic(pages[0], KM_USER0);

		memcpy(page_address(iov_page), vaddr, transferred);

		err = fuse_copy_ioctl_iovec(page_address(iov_page), vaddr,

					    transferred, in_iovs + out_iovs,

					    (flags & FUSE_IOCTL_COMPAT) != 0);

		kunmap_atomic(vaddr, KM_USER0);

		if (err)

			goto out;



		in_iov = page_address(iov_page);

		out_iov = in_iov + in_iovs;



		err = fuse_verify_ioctl_iov(in_iov, in_iovs);

		if (err)

			goto out;



		err = fuse_verify_ioctl_iov(out_iov, out_iovs);

		if (err)

			goto out;



		goto retry;

	}