coreboot May 2017

coreboot@coreboot.org

70 participants
202 discussions

How can improve coreboot and become developer?
by serdar tunc 08 May '17

08 May '17

Hello, I am interested in coreboot project. I compiled coreboot, made my own rom for my x200 and installed via external flasher. And i read a book named "Embedded Firmware Solutions" for understanding coreboots working logic. And im in deadend now. Because i accomplish to have fully operational x200 and i think i might know all the installing stages. But i dont want to be only user. I want to improve coreboot project and become developer. So i searched your wiki but i couldnt find for that. What should i do first? Do you have groups and mentors for that? thank all of you for your attention. Have a nice day, with my best regards. Serdar Oktay TUNÇ

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AMT bug
by ron minnich 08 May '17

08 May '17

There's a good summary about 3/4 way down the page. https://arstechnica.com/security/2017/05/the-hijacking-flaw-that-lurked-in-… Just write a simple C/Python/Perl/Go program that sends a 0 length password, done. This certainly seems to show there was no fuzzing or even simple testing of the http server in AMT. Is it possible they ONLY ever tested the login dialog by hand, with a web browser? It seems so. Yeeesh! I thought the whole reflash path of AMT was to ask it to reflash itself. Is that incorrect? If correct, and the AMT has been exploited via this path, can we really trust any reflash operation? Any thoughts on this from anyone who knows? I was involved in some USG issues around the time of Y2K and at least one agency shredded every non-Y2K-compliant system they had. Would that make sense for systems with this AMT vulnerability? Just assume the worst and destroy them? I am long past believing one can build secure platforms on any x86 chipset. This mess only strengthens that conviction. But there are some great RISC-V announcements this week! ron

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ASUS KGPE-D16 IOMMU issue
by lowsec＠airmail.cc 06 May '17

06 May '17

Hi, when starting a video I'm getting the following error with activated IOMMU under Coreboot: [ 230.800362] AMD-Vi: Event logged [ [ 230.800368] IO_PAGE_FAULT device=08:00.0 domain=0x0000 address=0x0000000073700000 flags=0x0050] [ 230.800371] AMD-Vi: Event logged [ [ 230.800373] IO_PAGE_FAULT device=08:00.0 domain=0x0000 address=0x0000000073700040 flags=0x0050] [ 230.800375] AMD-Vi: Event logged [ [ 230.800376] IO_PAGE_FAULT device=08:00.0 domain=0x0000 address=0x0000000073700000 flags=0x0050] [ 230.800377] AMD-Vi: Event logged [ [ 230.800378] IO_PAGE_FAULT device=08:00.0 domain=0x0000 address=0x0000000073700040 flags=0x0050] There are over 100 lines in dmesg and it's caused by my Xonar DX sound card. With the proprietary BIOS everthing works fine. I'm using the latest Linux-kernel and the Raptor build config for Coreboot. This is basically the same bug: https://bugzilla.kernel.org/show_bug.cgi?id=111711

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Re: [coreboot] kernel payload
by Duncan Guthrie 05 May '17

05 May '17

Hi Ron, Oooh how interesting! Maybe I'm just a little too mundane in my use case :) -Duncan On 06.05.2017 01:34, ron minnich wrote: > Duncan, I'm going to disagree with you :-) > > In the last years we've done all of these things: > - build initramfs into kernel, build kernel into flash, boot into > that, and that's all that's needed for a kiosk or other device > - use the initramfs to net boot the linux, first shown at LANL on HPC > systems in 2000. > - start the kernel and mount the root file system and run from that, > configure a network, boot from wireless or the disk (shown on the OLPC > at one point) > - put the kernel and initramfs in flash, boot that, dhcp configure the > network, wget a new kernel, gpgv that kernel, kexec that kernel, using > a Go userland to do all that (what we're doing at Google now as a > demonstration) > - kernel in flash, nfs mount root, kexec kernel on that nfs mount > point > > Once you have a kernel in flash, the possibilities are fairly endless > and much more interesting that any bootloader I can think of. > > ron

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Re: [coreboot] kernel payload
by Duncan Guthrie 05 May '17

05 May '17

Hi, In terms of the actual kernel, the same kernel can be used in theory, if you had a flash chip of a sufficient size. But there is no need to do this if you merely want to boot an OS. This is why I mentioned SeaBIOS - it can be used as a payload and it is what you will be used to. You can pretty much boot your OS as it is on-disk. It's a 16-bit BIOS, and it will likely "just work". Initrd is optional in theory, that is, the kernel will boot - it's software after all. But it will get a kernel panic as it will not find anything to boot thereafter. You'll need to build your own initrd. You might find assistance in what the build system requires by selecting "help" for the option of initrd in the coreboot menuconfig. In the case of booting a kernel as payload directly from the flash chip, initrd will have to go there on the flash chip too. -Duncan On 05.05.2017 23:48, Healer64 via coreboot wrote: > Hi Duncan, > > That really was one of the questions I was asking. Is there a > difference between the linux kernel included in my os and the linux > kernel coreboot uses as a payload? > > I wasn't aware including the initrd was optional. If it is not > included in the rom image where does the kernel get it from? Disk? > > Sent with ProtonMail [1] Secure Email. >

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Re: [coreboot] kernel payload
by Duncan Guthrie 05 May '17

05 May '17

Hi there, I'm a little confused by some of this email - at the start you seem to be asking about your "distribution" - I assume this is your operating system, and as a result I will answer that first part as far as I understand the question. I think you are confusing a Linux payload loaded by Coreboot, and the kernel that your operating system uses. Coreboot has the ability to load various payloads, including SeaBIOS, GNU Grub2, Filo, and Linux (this is a non-exhaustive list, one should note). These are almost always loaded from the flash chip directly. See the following page for more information: https://www.coreboot.org/Payloads. What you will likely want is to load SeaBIOS, which can then load your operating system as usual. As for creating a Linux payload, if you look in menuconfig, and select a Linux payload. You will see that you can specify a kernel binary, and an initrd optionally. The basic requirement is a valid bzImage. Optionally specifying an initrd environment allows us to boot this directly, which is very useful as a recovery environment. Perhaps some others can answer your question about the last part. I wish you good luck. -Duncan On 05.05.2017 19:11, Healer64 via coreboot wrote: > I've looked through all the docs I can find on this, but there doesn't > seem to be much available. Hopefully some of you can help answer my > questions. My distribution includes a vmlinuz kernel. Do I need to > compile a custom bzimage kernel or will the stock kernel suffice? > > I am using lvm on a dmcrypted disk for the root filesystem. Presumably > these binaries and helper scripts will be needed in the initrd. So far > the only help I've seen on creating the initrd for the payload is > Ron's email to this list where he says > > "Your best bet is to do the standard trivial initramfs with a simple > program: main(){printf("hin"); while (1);} Let's pretend it's called > mymain.c cc -o mymain -static mymain.c put that in your prototype root > file system with the name init. make sure you create /dev/console. > Then bundle it all up with cpio and you've got an initramfs" > > That seems to describe more of a shim than a true initrd. Also he > mentions initramfs whereas menuconfig asks for initrd. Which is > correct? I don't see any reference to filesystem drivers in Ron's > email, but surely they are required to mount the root. I'm guessing > this is a test example that is not intended to boot. > > Can anyone provide help or instructions on an actual bootable > initrd/initramfs? Can a pointer to the initramfs in /boot be used? > What kind of size will it be? My rom is limited to 8Mb and the kernel > is over 5Mb. > > Sent with ProtonMail [1] Secure Email. > > > > Links: > ------ > [1] https://protonmail.com

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Re: [coreboot] kernel payload
by Healer64 05 May '17

05 May '17

Thanks for the offer. I'll think about it once I can get a linux kernel working in my own hardware. :) There is no dedicated serial port though I guess I could do serial over usb if I needed to. It makes more sense to me to start by using the kernel I already have if possible and move to a custom kernel once I know that works. I have enough space for a kernel at this point though depending on the combined size of kernel + initrm I may run into a problem. I'm really not sure how big the initrd will end up being or if there is an option to link to the initrd on the hard drive. Sent with [ProtonMail](https://protonmail.com) Secure Email. -------- Original Message -------- Subject: Re: [coreboot] kernel payload Local Time: May 5, 2017 12:14 PM UTC Time: May 5, 2017 6:14 PM From: rminnich(a)gmail.com To: Healer64 <Healer64(a)protonmail.com> coreboot(a)coreboot.org <coreboot(a)coreboot.org> neat! Do you have serial console or just graphics? We've been doing a lot of this linux payload stuff lately. I assume you can recover from a bad image. If so, I'd recommend building a kernel with kerneltiny config (or whatever it's called -- tinykernel?), add back in console support of your choice, set the command line in menuconfig for earlypintk=tty0 or ttyS0,keep and boot it and see how far it gets. the kerneltiny configf can get you to a 400K bzImage so it's worth the effort to start small and grow it up -- that's how we've done it in my project at Google (not a chromeos project, though I'll be talking about it this fall). To give you an idea of just how far the tiny kernel stuff goes, it removes all tests for uid != 0 and also all options to set uid to !0. This makes sense in a firmware payload. There's a lot of space saving options in that config and that's how you get a tiny kernel. Once you get past this point you can then look at what initramfs to add. Or maybe you are past that point, but let's talk. I've been doing this a lot for the past year and I have probably made lots of mistakes I can help you avoid ... BTW, I'm looking for people to work with on a project embedding Linux and a Go userland in flash, so if anyone out there wants to get involved, please, we need your brains. see u-root.tk.

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Re: [coreboot] kernel payload
by ron minnich 05 May '17

05 May '17

neat! Do you have serial console or just graphics? We've been doing a lot of this linux payload stuff lately. I assume you can recover from a bad image. If so, I'd recommend building a kernel with kerneltiny config (or whatever it's called -- tinykernel?), add back in console support of your choice, set the command line in menuconfig for earlypintk=tty0 or ttyS0,keep and boot it and see how far it gets. the kerneltiny configf can get you to a 400K bzImage so it's worth the effort to start small and grow it up -- that's how we've done it in my project at Google (not a chromeos project, though I'll be talking about it this fall). To give you an idea of just how far the tiny kernel stuff goes, it removes all tests for uid != 0 and also all options to set uid to !0. This makes sense in a firmware payload. There's a lot of space saving options in that config and that's how you get a tiny kernel. Once you get past this point you can then look at what initramfs to add. Or maybe you are past that point, but let's talk. I've been doing this a lot for the past year and I have probably made lots of mistakes I can help you avoid ... BTW, I'm looking for people to work with on a project embedding Linux and a Go userland in flash, so if anyone out there wants to get involved, please, we need your brains. see u-root.tk. On Fri, May 5, 2017 at 11:02 AM Healer64 <Healer64(a)protonmail.com> wrote: > Yes, I currently have a grub payload that mostly works. > > > Sent with ProtonMail <https://protonmail.com> Secure Email. > > -------- Original Message -------- > Subject: Re: [coreboot] kernel payload > Local Time: May 5, 2017 11:25 AM > UTC Time: May 5, 2017 5:25 PM > From: rminnich(a)gmail.com > To: Healer64 <Healer64(a)protonmail.com>, coreboot(a)coreboot.org < > coreboot(a)coreboot.org> > > OK, so you told me off-list it's an auron. > > Did you try the full build/boot cycle with an unmodified coreboot first? > >

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Re: [coreboot] kernel payload
by Healer64 05 May '17

05 May '17

Yes, I currently have a grub payload that mostly works. Sent with [ProtonMail](https://protonmail.com) Secure Email. -------- Original Message -------- Subject: Re: [coreboot] kernel payload Local Time: May 5, 2017 11:25 AM UTC Time: May 5, 2017 5:25 PM From: rminnich(a)gmail.com To: Healer64 <Healer64(a)protonmail.com>, coreboot(a)coreboot.org <coreboot(a)coreboot.org> OK, so you told me off-list it's an auron. Did you try the full build/boot cycle with an unmodified coreboot first?

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Re: [coreboot] kernel payload
by ron minnich 05 May '17

05 May '17

Per my other question, did you try to burn a totally standard coreboot and see it work? On Fri, May 5, 2017 at 10:39 AM Healer64 <Healer64(a)protonmail.com> wrote: > An auron yuna chromebook. > > > Sent with ProtonMail <https://protonmail.com> Secure Email. > > -------- Original Message -------- > Subject: Re: [coreboot] kernel payload > Local Time: May 5, 2017 11:18 AM > UTC Time: May 5, 2017 5:18 PM > From: rminnich(a)gmail.com > To: Healer64 <Healer64(a)protonmail.com>, coreboot(a)coreboot.org < > coreboot(a)coreboot.org> > > First off, what board is this on? > > On Fri, May 5, 2017 at 10:12 AM Healer64 via coreboot < > coreboot(a)coreboot.org> wrote: > >> I've looked through all the docs I can find on this, but there doesn't >> seem to be much available. Hopefully some of you can help answer my >> questions. My distribution includes a vmlinuz kernel. Do I need to compile >> a custom bzimage kernel or will the stock kernel suffice? >> >> I am using lvm on a dmcrypted disk for the root filesystem. Presumably >> these binaries and helper scripts will be needed in the initrd. So far the >> only help I've seen on creating the initrd for the payload is Ron's email >> to this list where he says >> >> "Your best bet is to do the standard trivial initramfs with a simple >> program: main(){printf("hi\n"); while (1);} Let's pretend it's called >> mymain.c cc -o mymain -static mymain.c put that in your prototype root file >> system with the name init. make sure you create /dev/console. Then bundle >> it all up with cpio and you've got an initramfs" >> >> That seems to describe more of a shim than a true initrd. Also he >> mentions initramfs whereas menuconfig asks for initrd. Which is correct? I >> don't see any reference to filesystem drivers in Ron's email, but surely >> they are required to mount the root. I'm guessing this is a test example >> that is not intended to boot. >> >> Can anyone provide help or instructions on an actual bootable >> initrd/initramfs? Can a pointer to the initramfs in /boot be used? What >> kind of size will it be? My rom is limited to 8Mb and the kernel is over >> 5Mb. >> >> >> Sent with ProtonMail <https://protonmail.com> Secure Email. >> >> -- >> coreboot mailing list: coreboot(a)coreboot.org >> https://mail.coreboot.org/mailman/listinfo/coreboot >> >

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coreboot May 2017