Hi Norm On Mon, Apr 25, 2022 at 2:34 AM Norman Feske <[email protected]> wrote:
> [CAUTION: Non-UBC Email] > > Hallo, > > the issue was discussed in 2014 on the se14 mailing list: > > > https://lists.sel4.systems/hyperkitty/list/[email protected]/thread/I3AYF2AMRIRAMTCBMRENP7TVTH6RDCJQ/ > > Thanks. This is such a Deja Vu. I have not read the entire post, but I feel like it will answer my questions. > We worked around it by associating a system-globally unique ID value > with each object, using this value as badge, and sharing it with the > client. Upon calling the server, the client supplies this value along > with the actual capability. At the server side, the (potentially forged) > value serves as a hint that allows the server to look up the object and > compare the value with the real badge of the addressed object. > > This approach maintains the notion of capabilities being unforgeable on > se14. However, since globally unique IDs are shared with the client, the > approach is in principle prone to covert information flow - by the means > of ID allocation influenced by two conspiring components. > > This lines up precisely with my understanding from reading the Genode code. The crux of it being - "*using this value as badge, and sharing it with the client".* I also completely agree with the security pitfalls you mentioned. Quite exciting to know that I am on the right track in terms of using and hitting the limits of the seL4 API. I will read up the exchange and follow up if needed. Thanks a ton!! Sid > As far as I know, this use case remained unaddressed by se14. But I have > admittedly not followed recent developments. > > Genode's custom base-hw kernel supports this use case. > > Norman > > -- > Dr.-Ing. Norman Feske > Genode Labs > > https://www.genode-labs.com · https://genode.org > > Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden > Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth > > _______________________________________________ > Genode users mailing list > [email protected] > https://lists.genode.org/listinfo/users >
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