From: Vivek Goyal <vgoyal@redhat.com> To: Miklos Szeredi <miklos@szeredi.hu> Cc: virtio-fs-list <virtio-fs@redhat.com>, Luis Henriques <lhenriques@suse.de>, qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>, "Dr. David Alan Gilbert" <dgilbert@redhat.com> Subject: Re: [PATCH 1/3] virtiofsd: Add an option to enable/disable posix acls Date: Wed, 17 Feb 2021 10:07:21 -0500 [thread overview] Message-ID: <20210217150721.GB31184@redhat.com> (raw) In-Reply-To: <CAJfpegspJGL_W+8zaXyHfuAhtB_Q7V0YyOZJEhpCd=KaL_W71A@mail.gmail.com> On Wed, Feb 17, 2021 at 09:53:04AM +0100, Miklos Szeredi wrote: > On Wed, Feb 17, 2021 at 12:36 AM Vivek Goyal <vgoyal@redhat.com> wrote: > > > > fuse has an option FUSE_POSIX_ACL which needs to be opted in by fuse > > server to enable posix acls. > > > > Add virtiofsd option "-o posix_acl/no_posix_acl" to let users enable/disable > > posix acl support. By default it is disabled as of now. > > If I read the code correctly, then no_posix_acl will still result in > system.posix_acl_* xattr ops being passed through to virtiofsd, which > will forward them to the underlying fs, resulting in posix acls > appearing to work, but doing so incorrectly (i.e. no change from > previous behavior). Yes, and this is confuing me a lot. fuse server has not indicated support for POSIX_ACL, still user can get and set ACLs. fuse_xattr_get() and fuse_xattr_set() must be kicking in. I do see that we have fuse_no_acl_xattr_handlers and that should be able to block setting/getting acls if acl support is not there but we register it only if we are not mounted in init_user_ns. if (sb->s_user_ns != &init_user_ns) sb->s_xattr = fuse_no_acl_xattr_handlers; So question is, should fuse client be fixed as well to block setting and getting acls if fuse server does not support ACL? Or we now need to keep it around for backward compatibility. > Possibly better would be to have three different > modes of operation: > > 1) no option: default fall back to broken acl support for backward > compat (this could be removed in the future) What about FUSE_DONT_MASK in this mode. ACLs are not enabled but user can get/set these. Should that mean we still honor default acl and not apply umask? Probably I should opt for FUSE_DONT_MASK only if posix_acl support is enabled. Given this does not work even today (atleast for virtiofs), so it is not a backward compatibility issue. And its confusing anyway. > 2) no_posix_acl: really disable acl support That is block getting and setting system.posix_acl xattr. Will do that. I think we will have to block it even if somebody has remapped xattrs in virtiofsd. > 3) posix_acl: enable proper acl support Thanks Vivek > > Thanks, > Miklos >
WARNING: multiple messages have this Message-ID (diff)
From: Vivek Goyal <vgoyal@redhat.com> To: Miklos Szeredi <miklos@szeredi.hu> Cc: virtio-fs-list <virtio-fs@redhat.com>, qemu-devel@nongnu.org Subject: Re: [Virtio-fs] [PATCH 1/3] virtiofsd: Add an option to enable/disable posix acls Date: Wed, 17 Feb 2021 10:07:21 -0500 [thread overview] Message-ID: <20210217150721.GB31184@redhat.com> (raw) In-Reply-To: <CAJfpegspJGL_W+8zaXyHfuAhtB_Q7V0YyOZJEhpCd=KaL_W71A@mail.gmail.com> On Wed, Feb 17, 2021 at 09:53:04AM +0100, Miklos Szeredi wrote: > On Wed, Feb 17, 2021 at 12:36 AM Vivek Goyal <vgoyal@redhat.com> wrote: > > > > fuse has an option FUSE_POSIX_ACL which needs to be opted in by fuse > > server to enable posix acls. > > > > Add virtiofsd option "-o posix_acl/no_posix_acl" to let users enable/disable > > posix acl support. By default it is disabled as of now. > > If I read the code correctly, then no_posix_acl will still result in > system.posix_acl_* xattr ops being passed through to virtiofsd, which > will forward them to the underlying fs, resulting in posix acls > appearing to work, but doing so incorrectly (i.e. no change from > previous behavior). Yes, and this is confuing me a lot. fuse server has not indicated support for POSIX_ACL, still user can get and set ACLs. fuse_xattr_get() and fuse_xattr_set() must be kicking in. I do see that we have fuse_no_acl_xattr_handlers and that should be able to block setting/getting acls if acl support is not there but we register it only if we are not mounted in init_user_ns. if (sb->s_user_ns != &init_user_ns) sb->s_xattr = fuse_no_acl_xattr_handlers; So question is, should fuse client be fixed as well to block setting and getting acls if fuse server does not support ACL? Or we now need to keep it around for backward compatibility. > Possibly better would be to have three different > modes of operation: > > 1) no option: default fall back to broken acl support for backward > compat (this could be removed in the future) What about FUSE_DONT_MASK in this mode. ACLs are not enabled but user can get/set these. Should that mean we still honor default acl and not apply umask? Probably I should opt for FUSE_DONT_MASK only if posix_acl support is enabled. Given this does not work even today (atleast for virtiofs), so it is not a backward compatibility issue. And its confusing anyway. > 2) no_posix_acl: really disable acl support That is block getting and setting system.posix_acl xattr. Will do that. I think we will have to block it even if somebody has remapped xattrs in virtiofsd. > 3) posix_acl: enable proper acl support Thanks Vivek > > Thanks, > Miklos >
next prev parent reply other threads:[~2021-02-17 15:09 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-02-16 23:36 [PATCH 0/3] virtiofsd: Add options to enable/disable posix acl Vivek Goyal 2021-02-16 23:36 ` [Virtio-fs] " Vivek Goyal 2021-02-16 23:36 ` [PATCH 1/3] virtiofsd: Add an option to enable/disable posix acls Vivek Goyal 2021-02-16 23:36 ` [Virtio-fs] " Vivek Goyal 2021-02-17 8:53 ` Miklos Szeredi 2021-02-17 8:53 ` [Virtio-fs] " Miklos Szeredi 2021-02-17 15:07 ` Vivek Goyal [this message] 2021-02-17 15:07 ` Vivek Goyal 2021-02-17 15:23 ` Miklos Szeredi 2021-02-17 15:23 ` [Virtio-fs] " Miklos Szeredi 2021-02-16 23:36 ` [PATCH 2/3] virtiofsd: Add umask to seccom allow list Vivek Goyal 2021-02-16 23:36 ` [Virtio-fs] " Vivek Goyal 2021-02-16 23:36 ` [PATCH 3/3] virtiofsd: Change umask if posix acls are enabled Vivek Goyal 2021-02-16 23:36 ` [Virtio-fs] " Vivek Goyal 2021-02-16 23:45 ` [PATCH 0/3] virtiofsd: Add options to enable/disable posix acl no-reply 2021-02-16 23:45 ` [Virtio-fs] " no-reply 2021-02-17 9:32 ` Luis Henriques 2021-02-17 9:32 ` [Virtio-fs] " Luis Henriques
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20210217150721.GB31184@redhat.com \ --to=vgoyal@redhat.com \ --cc=dgilbert@redhat.com \ --cc=lhenriques@suse.de \ --cc=miklos@szeredi.hu \ --cc=qemu-devel@nongnu.org \ --cc=stefanha@redhat.com \ --cc=virtio-fs@redhat.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.