Messages in this thread | | | Date | Tue, 07 Feb 2012 19:38:47 -0500 | From | Adam Jackson <> | Subject | Re: [PATCH 1/2] char/mem: Add /dev/io (v2) |
| |
On 2/7/12 7:17 PM, Alan Cox wrote: > On Tue, 7 Feb 2012 18:39:45 -0500 > Adam Jackson<ajax@redhat.com> wrote: > >> This is like /dev/port except not broken. /dev/port will translate all >> read/write into inb/outb streams, which is wrong since hardware can and >> does care about cycle size. /dev/io will only allow 1, 2, or 4 byte >> access, and will translate that into the appropriate bus cycle size. > > From a security perspective /dev/[k][mem is a dumb bit of ancient Unix > history we'd dearly like to kill off. /dev/port is a similar early PC > unixism that wants to go the same way. /dev/io just adds another horror > to the pile. > > Please do the decent thing, stop using /dev/mem and /dev/port for > anything. If you need to access an I/O device make it properly visible > via the kernel only for the ports and in a manner that is safe.
Yeah, I'll be sure to do that right as soon as I can stop supporting the vesa driver. Until that time I don't really have any choice but to expose the whole of I/O port space, since I have no idea what the video BIOS is going to touch.
I don't disagree with wanting to limit access to these services, but /dev/io is at least somewhat containable, whereas iopl is insane.
- ajax
| |