Messages in this thread | | | Date | Tue, 14 Nov 2023 17:16:45 +0100 | Subject | Re: [PATCH v4 2/5] x86/alternative: add indirect call patching | From | Juergen Gross <> |
| |
On 14.11.23 16:06, Borislav Petkov wrote: > On Mon, Oct 30, 2023 at 03:25:05PM +0100, Juergen Gross wrote: >> +#ifdef CONFIG_X86_64 >> + /* ff 15 00 00 00 00 call *0x0(%rip) */ >> + target = *(void **)(instr + a->instrlen + *(s32 *)(instr + 2)); >> +#else >> + /* ff 15 00 00 00 00 call *0x0 */ >> + target = *(void **)(*(s32 *)(instr + 2)); > > Yeah, let's document those a bit better. Either with comments above or > as Peter suggests: > > /* Add 2 to skip opcode and ModRM byte: */ > disp32 = *(s32 *)(instr + 2); > > rip_rela_ptr = (void **)(instr + a->instrlen + disp32); > target = *rip_rela_ptr; > > so that it is crystal clear what we're doing here.
Okay.
Juergen
[unhandled content-type:application/pgp-keys][unhandled content-type:application/pgp-signature] | |