On Wed, May 23, 2018 at 06:25:36PM -0500, Eric W. Biederman wrote: > Superblock level remounts are currently restricted to global > CAP_SYS_ADMIN, as is the path for changing the root mount to > read only on umount. Loosen both of these permission checks to > also allow CAP_SYS_ADMIN in any namespace which is privileged > towards the userns which originally mounted the filesystem.
Acked-by: Christian Brauner <christ...@brauner.io> > > Signed-off-by: Seth Forshee <seth.fors...@canonical.com> > Acked-by: "Eric W. Biederman" <ebied...@xmission.com> > Acked-by: Serge Hallyn <serge.hal...@canonical.com> Note, I just talked to Serge. This should be Acked-by: Serge Hallyn <se...@hallyn.com> > Signed-off-by: Eric W. Biederman <ebied...@xmission.com> > --- > fs/namespace.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/namespace.c b/fs/namespace.c > index 5f75969adff1..8ddd14806799 100644 > --- a/fs/namespace.c > +++ b/fs/namespace.c > @@ -1590,7 +1590,7 @@ static int do_umount(struct mount *mnt, int flags) > * Special case for "unmounting" root ... > * we just try to remount it readonly. > */ > - if (!capable(CAP_SYS_ADMIN)) > + if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) > return -EPERM; > down_write(&sb->s_umount); > if (!sb_rdonly(sb)) > @@ -2333,7 +2333,7 @@ static int do_remount(struct path *path, int ms_flags, > int sb_flags, > down_write(&sb->s_umount); > if (ms_flags & MS_BIND) > err = change_mount_flags(path->mnt, ms_flags); > - else if (!capable(CAP_SYS_ADMIN)) > + else if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) > err = -EPERM; > else > err = do_remount_sb(sb, sb_flags, data, 0); > -- > 2.14.1 > > _______________________________________________ > Containers mailing list > contain...@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/containers
