Date: Mon, 13 Feb 2017 22:16:29 +0100 From: Dimitry Andric <dim@FreeBSD.org> To: Eric McCorkle <eric@metricspace.net> Cc: freebsd-hackers@freebsd.org Subject: Re: GELI BIOS weirdness Message-ID: <919F6E39-476C-44B5-93EA-447D855921DE@FreeBSD.org> In-Reply-To: <d4d9f6b2-4aaf-1c61-f7d5-f8be908bcc73@metricspace.net> References: <6874308d-8892-2f03-d125-418949fd472c@metricspace.net> <F1DCB7BA-0E21-44A6-B80A-0E0429B235FE@FreeBSD.org> <d4d9f6b2-4aaf-1c61-f7d5-f8be908bcc73@metricspace.net>
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--Apple-Mail=_D83FAEC8-6DBF-4670-B99F-2DA42FE58B78 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii On 13 Feb 2017, at 21:58, Eric McCorkle <eric@metricspace.net> wrote: > > On 02/13/2017 15:36, Dimitry Andric wrote: > >> This disassembles to: >> >> 0: 66 0f 38 f6 f0 adcx %eax,%esi >> 5: 31 c6 xor %eax,%esi >> 7: 8b 4d 14 mov 0x14(%ebp),%ecx >> a: 89 cf mov %ecx,%edi >> c: c1 ff 1f sar $0x1f,%edi >> f: 8b .byte 0x8b > > Note that this was truncated, so the sar and .byte are probably a > truncated instruction. > > Also, when I had printfs in place, I could see the call instructions. > >> My first guess would be that the code simply jumped into garbage. But >> can you post the complete .o file somewhere for inspection? > > Attached. > <gptboot> Can you please post the file before it's been stripped and objcopied from ELF to binary format? That makes it a lot easier to disassemble and analyze... :) -Dimitry --Apple-Mail=_D83FAEC8-6DBF-4670-B99F-2DA42FE58B78 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP -----BEGIN PGP SIGNATURE----- iEYEARECAAYFAliiIjQACgkQsF6jCi4glqP/3ACgpoAOrSKA4dTH/Z0+y+mov+4Y LJgAoK2FL9ljxSyaQ2IJmgGRaw5xqzvS =OMJH -----END PGP SIGNATURE----- --Apple-Mail=_D83FAEC8-6DBF-4670-B99F-2DA42FE58B78--
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