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LWN.net Weekly Edition for May 16, 2013
A look at the PyPy 2.0 release
PostgreSQL 9.3 beta: Federated databases and more
LWN.net Weekly Edition for May 9, 2013
(Nearly) full tickless operation in 3.10
Except that mmaping /dev/mem with r/w permissions is exactly what every X process does... So a lot of kernels out there would be "tainted" in a way.
Tainting from user space
Posted May 25, 2006 22:58 UTC (Thu) by brouhaha (subscriber, #1698)
Back around 1999 I proposed that /proc/pci should have mmap()able files for each PCI memory region configured for a device. It looks like by 2003 this had been implemented, based on a
post by David Miller to the LKML on 24-oct-2003.
When I proposed that idea, it met a lot of resistance from people that thought it would somehow open a security hole. They didn't see that in fact it allowed BETTER control over security by using filesystem permissions to restrict an X server to only accessing the video card, and not being able to scribble over arbitrary memory. These days, with udev, it should even be possible to make the video card PCI regions owned by a specific user (e.g., "xserver"), and not give the X server root permissions at all.
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