Commit b8e1425b authored by Amir Goldstein's avatar Amir Goldstein Committed by Christian Brauner
Browse files

fs: move permission hook out of do_iter_read() 



We recently moved fsnotify hook, rw_verify_area() and other checks from
do_iter_write() out to its two callers.

for consistency, do the same thing for do_iter_read() - move the
rw_verify_area() checks and fsnotify hook to the callers vfs_iter_read()
and vfs_readv().

This aligns those vfs helpers with the pattern used in vfs_read() and
vfs_iocb_iter_read() and the vfs write helpers, where all the checks are
in the vfs helpers and the do_* or call_* helpers do the work.

This is needed for fanotify "pre content" events.

Suggested-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231122122715.2561213-13-amir73il@gmail.com


Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 1c8aa833

fs/read_write.c

+39 −27
Original line number Diff line number Diff line
@@ -773,12 +773,14 @@ static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter, 
	return ret;

}



static ssize_t do_iter_read(struct file *file, struct iov_iter *iter,

		loff_t *pos, rwf_t flags)

ssize_t vfs_iocb_iter_read(struct file *file, struct kiocb *iocb,

			   struct iov_iter *iter)

{

	size_t tot_len;

	ssize_t ret = 0;



	if (!file->f_op->read_iter)

		return -EINVAL;

	if (!(file->f_mode & FMODE_READ))

		return -EBADF;

	if (!(file->f_mode & FMODE_CAN_READ))
@@ -787,22 +789,20 @@ static ssize_t do_iter_read(struct file *file, struct iov_iter *iter, 
	tot_len = iov_iter_count(iter);

	if (!tot_len)

		goto out;

	ret = rw_verify_area(READ, file, pos, tot_len);

	ret = rw_verify_area(READ, file, &iocb->ki_pos, tot_len);

	if (ret < 0)

		return ret;



	if (file->f_op->read_iter)

		ret = do_iter_readv_writev(file, iter, pos, READ, flags);

	else

		ret = do_loop_readv_writev(file, iter, pos, READ, flags);

	ret = call_read_iter(file, iocb, iter);

out:

	if (ret >= 0)

		fsnotify_access(file);

	return ret;

}

EXPORT_SYMBOL(vfs_iocb_iter_read);



ssize_t vfs_iocb_iter_read(struct file *file, struct kiocb *iocb,

			   struct iov_iter *iter)

ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,

		      rwf_t flags)

{

	size_t tot_len;

	ssize_t ret = 0;
@@ -817,25 +817,16 @@ ssize_t vfs_iocb_iter_read(struct file *file, struct kiocb *iocb, 
	tot_len = iov_iter_count(iter);

	if (!tot_len)

		goto out;

	ret = rw_verify_area(READ, file, &iocb->ki_pos, tot_len);

	ret = rw_verify_area(READ, file, ppos, tot_len);

	if (ret < 0)

		return ret;



	ret = call_read_iter(file, iocb, iter);

	ret = do_iter_readv_writev(file, iter, ppos, READ, flags);

out:

	if (ret >= 0)

		fsnotify_access(file);

	return ret;

}

EXPORT_SYMBOL(vfs_iocb_iter_read);



ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,

		rwf_t flags)

{

	if (!file->f_op->read_iter)

		return -EINVAL;

	return do_iter_read(file, iter, ppos, flags);

}

EXPORT_SYMBOL(vfs_iter_read);



ssize_t vfs_iocb_iter_write(struct file *file, struct kiocb *iocb,
@@ -903,14 +894,35 @@ static ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, 
	struct iovec iovstack[UIO_FASTIOV];

	struct iovec *iov = iovstack;

	struct iov_iter iter;

	ssize_t ret;

	size_t tot_len;

	ssize_t ret = 0;



	ret = import_iovec(ITER_DEST, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);

	if (ret >= 0) {

		ret = do_iter_read(file, &iter, pos, flags);

		kfree(iov);

	}

	if (!(file->f_mode & FMODE_READ))

		return -EBADF;

	if (!(file->f_mode & FMODE_CAN_READ))

		return -EINVAL;



	ret = import_iovec(ITER_DEST, vec, vlen, ARRAY_SIZE(iovstack), &iov,

			   &iter);

	if (ret < 0)

		return ret;



	tot_len = iov_iter_count(&iter);

	if (!tot_len)

		goto out;



	ret = rw_verify_area(READ, file, pos, tot_len);

	if (ret < 0)

		goto out;



	if (file->f_op->read_iter)

		ret = do_iter_readv_writev(file, &iter, pos, READ, flags);

	else

		ret = do_loop_readv_writev(file, &iter, pos, READ, flags);

out:

	if (ret >= 0)

		fsnotify_access(file);

	kfree(iov);

	return ret;

}