On Monday 26 February 2018 14:40:31 Jan Kara wrote: > On Sat 24-02-18 12:56:07, Pali Rohár wrote: > > On Thursday 22 February 2018 11:45:14 Jan Kara wrote: > > > Hello, > > > > > > this patch series improves uid and gid handling for UDF filesystems. In > > > particular when uid/gid mount options are used, we make sure even newly created > > > and chowned files still belong to the target user/group (UDF now behaves the > > > same way as FAT in this mode to be easy to use for removable media). Also when > > > the filesystem does not store uid/gid for files, we now present these files as > > > belonging to overflow[ug]id instead of invalid ids if uid/gid mount option are > > > not used so that at least sysadmin can modify the filesystem. > > > > > > Honza > > > > Looks good, this should improve handling of uid/gid on removable UDF > > filesystems. Add my Reviewed-by: Pali Rohár <pali.rohar@xxxxxxxxx> > > Thanks for review! > > > Anyway, I would propose backporting patch "[PATCH 4/5] udf: Provide > > saner default for invalid uid / gid" into stable kernels to allow root > > user to modify files without uid/gid. > > Also patch 3/5 would be needed to make this change safe in presence of user > namespaces. But as much as the problem is annoying when it happens, I > didn't get many reports of it over the years (just Steve and you when you > tried to modify UDF tools) and it can be worked around by using > uid=<something> mount option so I don't think stable backport is really > warranted. Ok, then let it as is. Anyway, should not be this uid= and gid= handling implemented in genetic VFS layer instead in filesystem drivers? Because e.g. missing options uid= and gid= in ext4 filesystem driver make usage of ext4 on removable media really problematic. Basically any filesystem which implement permissions is due to this reason problematic for removable media which is supposed to be read/write by anybody. -- Pali Rohár pali.rohar@xxxxxxxxx
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