Messages in this thread | | | Subject | Re: [PATCH v6 02/16] chardev: introduce cdev_get_by_path() | From | Sagi Grimberg <> | Date | Thu, 25 Jul 2019 12:37:11 -0700 |
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>>>>>> Why do you have a "string" within the kernel and are not using the >>>>>> normal open() call from userspace on the character device node on the >>>>>> filesystem in your namespace/mount/whatever? >>>>> >>>>> NVMe-OF is configured using configfs. The target is specified by the >>>>> user writing a path to a configfs attribute. This is the way it works >>>>> today but with blkdev_get_by_path()[1]. For the passthru code, we need >>>>> to get a nvme_ctrl instead of a block_device, but the principal is the same. >>>> >>>> Why isn't a fd being passed in there instead of a random string? >>> >>> I wouldn't know the answer to this but I assume because once we decided >>> to use configfs, there was no way for the user to pass the kernel an fd. >> >> That's definitely not changing. But this is not different than how we >> use the block device or file configuration, this just happen to need the >> nvme controller chardev now to issue I/O. > > So, as was kind of alluded to in another part of the thread, what are > you doing about permissions? It seems that any user/group permissions > are out the window when you have the kernel itself do the opening of the > char device, right? Why is that ok? You can pass it _any_ character > device node and away it goes? What if you give it a "wrong" one? Char > devices are very different from block devices this way.
We could condition any configfs operation on capable(CAP_NET_ADMIN) to close that hole for now..
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