On 05/10/2017 09:45 AM, Christoph Hellwig wrote:
> Add a new ->integrity_read file operation to read data for
> integrity hash collection. This is defined to be equivalent
> to ->read_iter, except that it will be called with the i_rwsem
> held exclusively. Also the presence of ->integrity_read indicates
> that the file system can support IMA.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> fs/btrfs/file.c | 1 +
> fs/ext4/file.c | 1 +
> fs/xfs/xfs_file.c | 21 +++++++++++++++++++++
> include/linux/fs.h | 1 +
> security/integrity/iint.c | 20 ++++++++++++++------
> 5 files changed, 38 insertions(+), 6 deletions(-)
>
> diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
> index 520cb7230b2d..c5afb2264737 100644
> --- a/fs/btrfs/file.c
> +++ b/fs/btrfs/file.c
> @@ -3041,6 +3041,7 @@ const struct file_operations btrfs_file_operations = {
> #endif
> .clone_file_range = btrfs_clone_file_range,
> .dedupe_file_range = btrfs_dedupe_file_range,
> + .integrity_read = generic_file_read_iter,
> };
>
> void btrfs_auto_defrag_exit(void)
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index 8210c1f43556..b2a5025c7e0d 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -740,6 +740,7 @@ const struct file_operations ext4_file_operations = {
> .splice_read = generic_file_splice_read,
> .splice_write = iter_file_splice_write,
> .fallocate = ext4_fallocate,
> + .integrity_read = ext4_file_read_iter,
> };
>
> const struct inode_operations ext4_file_inode_operations = {
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 35703a801372..3d6ace2a79bc 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -288,6 +288,26 @@ xfs_file_read_iter(
> return ret;
> }
>
> +static ssize_t
> +xfs_integrity_read(
> + struct kiocb *iocb,
> + struct iov_iter *to)
> +{
> + struct inode *inode = file_inode(iocb->ki_filp);
> + struct xfs_mount *mp = XFS_I(inode)->i_mount;
> +
> + lockdep_assert_held(&inode->i_rwsem);
> +
> + XFS_STATS_INC(mp, xs_read_calls);
> +
> + if (XFS_FORCED_SHUTDOWN(mp))
> + return -EIO;
> +
> + if (IS_DAX(inode))
> + return dax_iomap_rw(iocb, to, &xfs_iomap_ops);
> + return generic_file_read_iter(iocb, to);
> +}
> +
> /*
> * Zero any on disk space between the current EOF and the new, larger EOF.
> *
> @@ -1534,6 +1554,7 @@ const struct file_operations xfs_file_operations = {
> .fallocate = xfs_file_fallocate,
> .clone_file_range = xfs_file_clone_range,
> .dedupe_file_range = xfs_file_dedupe_range,
> + .integrity_read = xfs_integrity_read,
> };
>
> const struct file_operations xfs_dir_file_operations = {
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 7251f7bb45e8..0c86816ca25f 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1689,6 +1689,7 @@ struct file_operations {
> u64);
> ssize_t (*dedupe_file_range)(struct file *, u64, u64, struct file *,
> u64);
> + ssize_t (*integrity_read)(struct kiocb *, struct iov_iter *);
> };
>
> struct inode_operations {
> diff --git a/security/integrity/iint.c b/security/integrity/iint.c
> index c710d22042f9..c5489672b5aa 100644
> --- a/security/integrity/iint.c
> +++ b/security/integrity/iint.c
> @@ -21,6 +21,7 @@
> #include <linux/rbtree.h>
> #include <linux/file.h>
> #include <linux/uaccess.h>
> +#include <linux/uio.h>
> #include "integrity.h"
>
> static struct rb_root integrity_iint_tree = RB_ROOT;
> @@ -184,18 +185,25 @@ security_initcall(integrity_iintcache_init);
> int integrity_kernel_read(struct file *file, loff_t offset,
> char *addr, unsigned long count)
> {
> - mm_segment_t old_fs;
> - char __user *buf = (char __user *)addr;
> + struct inode *inode = file_inode(file);
> + struct iovec iov = { .iov_base = addr, .iov_len = count };
> + struct kiocb kiocb;
> + struct iov_iter iter;
> ssize_t ret;
>
> + lockdep_assert_held(&inode->i_rwsem);
> +
> if (!(file->f_mode & FMODE_READ))
> return -EBADF;
> + if (!file->f_op->integrity_read)
> + return -EBADF;
Would you not want to call ->read_iter() in the NULL case
and have all FSs supported as today?
Thanks
Boaz
>
> - old_fs = get_fs();
> - set_fs(get_ds());
> - ret = __vfs_read(file, buf, count, &offset);
> - set_fs(old_fs);
> + init_sync_kiocb(&kiocb, file);
> + kiocb.ki_pos = offset;
> + iov_iter_init(&iter, READ | ITER_KVEC, &iov, 1, count);
>
> + ret = file->f_op->integrity_read(&kiocb, &iter);
> + BUG_ON(ret == -EIOCBQUEUED);
> return ret;
> }
>
>
