Messages in this thread | | | Date | Sun, 11 May 2014 14:05:19 -0700 | From | Josh Triplett <> | Subject | Re: [PATCH] drivers/char/mem.c: Add /dev/ioports, supporting 16-bit and 32-bit ports |
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On Sun, May 11, 2014 at 02:50:06PM +0200, Jann Horn wrote: > On Sat, May 10, 2014 at 12:32:46PM -0700, Josh Triplett wrote: > > On Sat, May 10, 2014 at 09:07:42AM +0200, Jann Horn wrote: > > > On Fri, May 09, 2014 at 12:19:16PM -0700, Josh Triplett wrote: > > > > + if (port > 65535) > > > > + return 0; > > > > + switch (count) { > > > [...] > > > > + case 4: > > > > + if (__put_user(inl(port), buf) < 0) > > > > + return -EFAULT; > > > > > > What if I attempt a four-byte read at 65535? That would access four > > > out-of-bounds bytes, right? > > > > No, it would do an ind instruction on port 65535. > > Yes, on x86. What about other architectures?
That's a good point; on architectures that map I/O to memory, this device should check port+count rather than port. Is there a reliable #define that identifies architectures with that property, other than CONFIG_X86?
- Josh Triplett
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