Messages in this thread | | | Date | Mon, 12 Jan 2015 15:47:16 -0800 | From | Dave Hansen <> | Subject | Re: [PATCH 3.19 v2 2/3] x86, mpx: Short-circuit the instruction decoder for unexpected opcodes |
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Couple of typos...
On 01/12/2015 03:04 PM, Andy Lutomirski wrote: > + /* > + * We only _really_ need to decode bndcl/bndcn/bndcu > + * Error out on anything else. Check this before decoding the > + * instruction to reduce our exposure to intentionally bad code > + * to some extent. Note that this shortcut cat incorrectly return
"...can incorrectly return"
> + * -EINVAL instead of -EFAULT under some circumstances. This > + * discrepency has no effect. > + */
^^ discrepancy
> + if (nr_copied < 2) > + goto bad_opcode; > + if (buf[0] != 0x0f) > + goto bad_opcode; > + if (buf[1] != 0x1a && buf[1] != 0x1b) > + goto bad_opcode; ... > - /* > - * We only _really_ need to decode bndcl/bndcn/bndcu > - * Error out on anything else. > - */ > - if (insn->opcode.bytes[0] != 0x0f) > - goto bad_opcode; > - if ((insn->opcode.bytes[1] != 0x1a) && > - (insn->opcode.bytes[1] != 0x1b)) > - goto bad_opcode;
Otherwise, this looks OK to me. Have you tested this at all? I know you don't have any MPX hardware, but you can still hack something in to point the instruction decoder at an MPX binary.
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