Messages in this thread | | | From | (H. Peter Anvin) | Subject | Re: 2.2.0p7: fix to ioperm() ranges also needed | Date | 12 Jan 1999 19:53:22 GMT |
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Followup to: <Pine.LNX.3.96.990111221729.13448A-100000@ferret.lmh.ox.ac.uk> By author: Chris Evans <chris@ferret.lmh.ox.ac.uk> In newsgroup: linux.dev.kernel > > Hi, > > The pre-patch for 2.2.0p7 includes a fix I suggest so that an iopl(3) > process can drop privs to iopl(0) without needing to be root to do so! > > As a complementary fix, processes should probably always be allowed to use > ioperm() if they specify 0 as the "set" argument. > > Cheers > Chris > > P.S. Offtopic. Can someome clarify for me the differences between iopl(1), > iopl(2) and iopl(3)? Thank you! >
On Linux/i386, only iopl(3) matters. A process is I/O privileged if IOPL >= CPL. A Linux user-space process has CPL 3.
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