[PATCH v4 07/15] fs/fuse: support idmapped ->permission inode op

Alexander Mikhalitsyn
2024-09-03T15:17:04Z

We only cover the case when "default_permissions" flag
is used. A reason for that is that otherwise all the permission
checks are done in the userspace and we have to deal with
VFS idmapping in the userspace (which is bad), alternatively
we have to provide the userspace with idmapped req->in.h.uid/req->in.h.gid
which is also not align with VFS idmaps philosophy.

Cc: Christian Brauner <brauner@kernel.org>
Cc: Seth Forshee <sforshee@kernel.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Bernd Schubert <bschubert@ddn.com>
Cc: <linux-fsdevel@vger.kernel.org>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
---
fs/fuse/dir.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 1c28cdf9dd41..870932543aa0 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1544,7 +1544,7 @@ static int fuse_permission(struct mnt_idmap *idmap,
}

if (fc->default_permissions) {
- err = generic_permission(&nop_mnt_idmap, inode, mask);
+ err = generic_permission(idmap, inode, mask);

/* If permission is denied, try to refresh file
attributes. This is also needed, because the root
@@ -1552,7 +1552,7 @@ static int fuse_permission(struct mnt_idmap *idmap,
if (err == -EACCES && !refreshed) {
err = fuse_perm_getattr(inode, mask);
if (!err)
- err = generic_permission(&nop_mnt_idmap,
+ err = generic_permission(idmap,
inode, mask);
}

--
2.34.1