It's just a matter of adjusting a permission check condition for S_ISGID flag. All the rest is already handled in the generic VFS code. Notice that this permission check is the analog of what we have in posix_acl_update_mode() generic helper, but fuse doesn't use this helper as on the kernel side we don't care about ensuring that POSIX ACL and CHMOD permissions are in sync as it is a responsibility of a userspace daemon to handle that. For the same reason we don't have a calls to posix_acl_chmod(), while most of other filesystem do. Cc: Christian Brauner <brauner@xxxxxxxxxx> Cc: Seth Forshee <sforshee@xxxxxxxxxx> Cc: Miklos Szeredi <miklos@xxxxxxxxxx> Cc: Amir Goldstein <amir73il@xxxxxxxxx> Cc: Bernd Schubert <bschubert@xxxxxxx> Cc: <linux-fsdevel@xxxxxxxxxxxxxxx> Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx> Reviewed-by: Christian Brauner <brauner@xxxxxxxxxx> --- fs/fuse/acl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/fuse/acl.c b/fs/fuse/acl.c index 897d813c5e92..8f484b105f13 100644 --- a/fs/fuse/acl.c +++ b/fs/fuse/acl.c @@ -144,8 +144,8 @@ int fuse_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, * be stripped. */ if (fc->posix_acl && - !in_group_or_capable(&nop_mnt_idmap, inode, - i_gid_into_vfsgid(&nop_mnt_idmap, inode))) + !in_group_or_capable(idmap, inode, + i_gid_into_vfsgid(idmap, inode))) extra_flags |= FUSE_SETXATTR_ACL_KILL_SGID; ret = fuse_setxattr(inode, name, value, size, 0, extra_flags); -- 2.34.1