> On Tue, 8 Jun 1999, Martin [iso-8859-1] S�fke wrote:
> > Alistair MacDonald schrieb:
> > > That said, *I* didn't understand *exactly* what you were asking because
> > > *you* didn't provide any details of the source and target of the transfer.
> > Ok... the DMA is supposed to transfer 625kb/s on 16 bit DMA #5 from a
> > satellite receiver card to memory.
> > If it is emuated, I see that it won't transfer data from that receiver
> > hardware.
> > Would there be any way to get that DMA work ?
>
> Only in the same way that you could get *any* DMA to work. You have to get
> the kernel to give a user space program (eg DOSEMU) rights to manipulate
> the DMA registers (and to prevent problems, the kernel tables that go with
> it).
>
> I *DID* receive a patch that provided a series of *devices* which enabled
> *ANY* application to pick & manipulate the IRQs & DMA channels. *However*
> the only security hole *bigger* than this would be having just a single
> user on a machine (root) and having all processess run/owned by this user
> (and, of course, logging in as this user all the time). Oh - and for good
> measure you would probably want the root password to be an empty string
> ....
>
>
> In case that last paragraph *didn't* frighten you enough, I'll put it a
> different way. Allowing arbitrary software access to control & manipulate
> your IRQs & DMA channels allows *any* process to trash your OS, Disks and
> (virtually) anything else you care to mention.
>
> This will *never* become part of DOSEMU *unless* this issue can be
> resolved.
I don't know much about DMA but if the DMA is emulated, I would suspect
it would not be too
difficult to get the code that emulates it to ensure that transfers
only occur between:
1. memory that belongs to DOS
2. devices in a list of allowed devices
