Messages in this thread | | | Date | Tue, 30 Apr 2019 10:27:28 +0200 | From | Greg Kroah-Hartman <> | Subject | Re: sysfs attrs for HW ECDSA signature |
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On Mon, Apr 29, 2019 at 11:47:52PM +0200, Marek Behun wrote: > Hi Greg and Tejun, > > is it acceptable for a driver to expose sysfs attr files for ECDSA > signature generation?
What is "ECDSA signature generation"? Is it a crypto thing? If so, why not use the crypto api? If not, what exactly is it?
> The thing is that > 1. AFAIK there isn't another API for userspace to do this. > There were attempts in 2015 to expose akcipher via netlink to > userspace, but the patchseries were not accepted.
Pointers to that patchset? Why was it not accepted?
> 2. even if it was possible, that specific device for which I am > writing this driver does not provide the ability to set the > private key to sign with - the private key is just burned during > manufacturing and cannot be read, only signed with.
Why does this matter?
> The current version of my driver exposes do_sign file in > /sys/firmware/turris_mox directory. > > Userspace should write message to sign and then can read the signature > from this do_sign file.
How big are messages and signatures? Why does this have to be a sysfs api?
> According to the one attr = one file principle, it would be better to > have two files: ecdsa_msg_to_sign (write-only) and ecdsa_signature > (read-only). > Would this be acceptable in the kernel for this driver?
Why not use the crypto api, and if that doesn't work, why not just a char device to read/write?
> I have also another question, if you would not mind: > > This driver is dependant on a mailbox driver I have also written > ("mailbox: Add support for Armada 37xx rWTM mailbox"), but I have not > received any review for this driver from the mailbox subsystem > maintainer, and I have already sent three versions (on 12/17/2018, > 03/01/2019 and 03/15/2019). > What should I do in this case?
Poke the maintainer again :)
thanks,
greg k-h
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