On Thu 27-06-24 19:26:24, Eric Sandeen wrote: > Multiple filesystems take uid and gid as options, and the code to > create the ID from an integer and validate it is standard boilerplate > that can be moved into common helper functions, so do that for > consistency and less cut&paste. > > This also helps avoid the buggy pattern noted by Seth Jenkins at > https://lore.kernel.org/lkml/CALxfFW4BXhEwxR0Q5LSkg-8Vb4r2MONKCcUCVioehXQKr35eHg@xxxxxxxxxxxxxx/ > because uid/gid parsing will fail before any assignment in most > filesystems. > > Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxxx> I like the idea since this seems like a nobrainer but is actually surprisingly subtle... > diff --git a/fs/fs_parser.c b/fs/fs_parser.c > index a4d6ca0b8971..24727ec34e5a 100644 > --- a/fs/fs_parser.c > +++ b/fs/fs_parser.c > @@ -308,6 +308,40 @@ int fs_param_is_fd(struct p_log *log, const struct fs_parameter_spec *p, > } > EXPORT_SYMBOL(fs_param_is_fd); > > +int fs_param_is_uid(struct p_log *log, const struct fs_parameter_spec *p, > + struct fs_parameter *param, struct fs_parse_result *result) > +{ > + kuid_t uid; > + > + if (fs_param_is_u32(log, p, param, result) != 0) > + return fs_param_bad_value(log, param); > + > + uid = make_kuid(current_user_ns(), result->uint_32); But here is the problem: Filesystems mountable in user namespaces need to use fc->user_ns for resolving uids / gids (e.g. like fuse_parse_param()). Having helpers that work for some filesystems and are subtly broken for others is worse than no helpers... Or am I missing something? And the problem with fc->user_ns is that currently __fs_parse() does not get fs_context as an argument... So that will need some larger work. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
