Commit 2a33e2dd authored by Amir Goldstein's avatar Amir Goldstein Committed by Christian Brauner
Browse files

splice: remove permission hook from do_splice_direct() 



All callers of do_splice_direct() have a call to rw_verify_area() for
the entire range that is being copied, e.g. by vfs_copy_file_range() or
do_sendfile() before calling do_splice_direct().

The rw_verify_area() check inside do_splice_direct() is redundant and
is called after sb_start_write(), so it is not "start-write-safe".
Remove this redundant check.

This is needed for fanotify "pre content" events.

Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231122122715.2561213-3-amir73il@gmail.com


Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent ca7ab482

fs/splice.c

+1 −4
Original line number Diff line number Diff line
@@ -1166,6 +1166,7 @@ static void direct_file_splice_eof(struct splice_desc *sd) 
 *    (splice in + splice out, as compared to just sendfile()). So this helper

 *    can splice directly through a process-private pipe.

 *

 * Callers already called rw_verify_area() on the entire range.

 */

long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,

		      loff_t *opos, size_t len, unsigned int flags)
@@ -1187,10 +1188,6 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, 
	if (unlikely(out->f_flags & O_APPEND))

		return -EINVAL;



	ret = rw_verify_area(WRITE, out, opos, len);

	if (unlikely(ret < 0))

		return ret;



	ret = splice_direct_to_actor(in, &sd, direct_splice_actor);

	if (ret > 0)

		*ppos = sd.pos;