Re: [PATCH] cifs: use helpers when parsing uid/gid mount options and validate them

[Steve French <smfrench@gmail.com>]

mildy easier to leave it in at the moment - if you want to remove it
later with a followon that is fine too

On Thu, Jul 8, 2021 at 6:25 PM ronnie sahlberg <ronniesahlberg@gmail.com> wrote:
>
> On Fri, Jul 9, 2021 at 8:12 AM Pavel Shilovsky <piastryyy@gmail.com> wrote:
> >
> > ср, 7 июл. 2021 г. в 16:25, Ronnie Sahlberg <lsahlber@redhat.com>:
> > >
> > > Use the nice helpers to initialize and the uid/gid/cred_uid when passed as mount arguments.
> > >
> > > Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
> > > ---
> > >  fs/cifs/fs_context.c | 24 +++++++++++++++++++-----
> > >  fs/cifs/fs_context.h |  1 +
> > >  2 files changed, 20 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c
> > > index 92d4ab029c91..553adfbcc22a 100644
> > > --- a/fs/cifs/fs_context.c
> > > +++ b/fs/cifs/fs_context.c
> > > @@ -322,7 +322,6 @@ smb3_fs_context_dup(struct smb3_fs_context *new_ctx, struct smb3_fs_context *ctx
> > >         new_ctx->UNC = NULL;
> > >         new_ctx->source = NULL;
> > >         new_ctx->iocharset = NULL;
> > > -
> > >         /*
> > >          * Make sure to stay in sync with smb3_cleanup_fs_context_contents()
> > >          */
> > > @@ -792,6 +791,8 @@ static int smb3_fs_context_parse_param(struct fs_context *fc,
> > >         int i, opt;
> > >         bool is_smb3 = !strcmp(fc->fs_type->name, "smb3");
> > >         bool skip_parsing = false;
> > > +       kuid_t uid;
> > > +       kgid_t gid;
> > >
> > >         cifs_dbg(FYI, "CIFS: parsing cifs mount option '%s'\n", param->key);
> > >
> > > @@ -904,18 +905,31 @@ static int smb3_fs_context_parse_param(struct fs_context *fc,
> > >                 }
> > >                 break;
> > >         case Opt_uid:
> > > -               ctx->linux_uid.val = result.uint_32;
> > > +               uid = make_kuid(current_user_ns(), result.uint_32);
> > > +               if (!uid_valid(uid))
> > > +                       goto cifs_parse_mount_err;
> > > +               ctx->linux_uid = uid;
> > >                 ctx->uid_specified = true;
> > >                 break;
> > >         case Opt_cruid:
> > > -               ctx->cred_uid.val = result.uint_32;
> > > +               uid = make_kuid(current_user_ns(), result.uint_32);
> > > +               if (!uid_valid(uid))
> > > +                       goto cifs_parse_mount_err;
> > > +               ctx->cred_uid = uid;
> > > +               ctx->cruid_specified = true;
> > >                 break;
> > >         case Opt_backupgid:
> > > -               ctx->backupgid.val = result.uint_32;
> > > +               gid = make_kgid(current_user_ns(), result.uint_32);
> > > +               if (!gid_valid(gid))
> > > +                       goto cifs_parse_mount_err;
> > > +               ctx->backupgid = gid;
> > >                 ctx->backupgid_specified = true;
> > >                 break;
> > >         case Opt_gid:
> > > -               ctx->linux_gid.val = result.uint_32;
> > > +               gid = make_kgid(current_user_ns(), result.uint_32);
> > > +               if (!gid_valid(gid))
> > > +                       goto cifs_parse_mount_err;
> > > +               ctx->linux_gid = gid;
> > >                 ctx->gid_specified = true;
> > >                 break;
> > >         case Opt_port:
> > > diff --git a/fs/cifs/fs_context.h b/fs/cifs/fs_context.h
> > > index 2a71c8e411ac..b6243972edf3 100644
> > > --- a/fs/cifs/fs_context.h
> > > +++ b/fs/cifs/fs_context.h
> > > @@ -155,6 +155,7 @@ enum cifs_param {
> > >
> > >  struct smb3_fs_context {
> > >         bool uid_specified;
> > > +       bool cruid_specified;
> >
> > Is it going to be used somewhere?
>
> I use it in other patches,  and may add a similar variable to the
> session structure as well so we can change the code where we print the
> mount argument and make it conditional on whether cruid was set on the
> original command line or not.
> We currently always print cruid as a mount argument in the mount
> output and print it as cruid=0 if it was not specified, which is fine
> but may be confusing/redundant.
>
> I am fine with either leaving it in or removing it, and I can add it
> back later once it actually starts being used.
>
> >
> > >         bool gid_specified;
> > >         bool sloppy;
> > >         bool got_ip;
> > > --
> > > 2.30.2
> > >
> >
> > Acked-by: Pavel Shilovsky <pshilovsky@samba.org>
> >
> > --
> > Best regards,
> > Pavel Shilovsky



-- 
Thanks,

Steve