Firmware Security/lang-es: Difference between revisions

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{{Ongoing Translation}}
{{Ongoing Translation}}
== Enfoque ==
== Enfoque ==
Esta pagina describe el rol de Open Firmware en la seguridad BitFrost en el XO
{{ Translated text |
{{ Translated text |
This page describes the role of Open Firmware in BitFrost security on XO.
This page describes the role of Open Firmware in BitFrost security on XO.
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== Objetivos ==
== Objetivos ==
# Correr el Firmware de recuperacion si el firmware primario esta mal.
# No acceso a el ok prompt sin clave de desarrollador
# Las imagenes de actualizacion de Firmware deben estar firmadas
# Las imagenes de booteo deben estar firmadas
# Laptops sin activar solo bootearan la imagen de activacion
# Bootear una imagen de SO aternativa si laprimaria esta dañada
{{ Translated text |
{{ Translated text |
# Run recovery firmware if primary firmware is bad
# Run recovery firmware if primary firmware is bad
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# Unactivated laptops will only boot the activation image
# Unactivated laptops will only boot the activation image
# Boot alternate OS image if primary OS image is bad
# Boot alternate OS image if primary OS image is bad
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== Archivos ==
== Archivos ==
Los archivos listados abajo estan en el NAND FLASH en JFFS2. Los archivos zip listados deben ser creados sin compression (opcion -n) y sin paths (opcion -j). Las notas de implmentacion y racionale estan en italica.
{{ Translated text |
{{ Translated text |
The files listed below are on NAND FLASH in JFFS2. The zip archives listed below must be created without compression (-n option) and without paths (-j option). Implementation notes and rationale are in italics.
The files listed below are on NAND FLASH in JFFS2. The zip archives listed below must be created without compression (-n option) and without paths (-j option). Implementation notes and rationale are in italics.

* Las imagenes primarias estan en /boot, las imagenes secundarias estan en /boot-alt


* Primary images are in /boot, secondary images are in /boot-alt
* Primary images are in /boot, secondary images are in /boot-alt
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== Notas ==
== Notas ==

{{ Translated text |
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* I am assuming that the primary use of USB/SD boot is to do OS, firmware, or activity upgrades where bandwidth is a limitation. These can easily be done with the mechanism provided by just sticking a (properly signed) "magic upgrade key" into the USB port and power-cycling.
* I am assuming that the primary use of USB/SD boot is to do OS, firmware, or activity upgrades where bandwidth is a limitation. These can easily be done with the mechanism provided by just sticking a (properly signed) "magic upgrade key" into the USB port and power-cycling.

Revision as of 05:49, 21 July 2007

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This page is a draft in active flux ...
Please leave suggestions on the talk page.

Pencil.png
This is an on-going translation

Enfoque

Esta pagina describe el rol de Open Firmware en la seguridad BitFrost en el XO

This page describes the role of Open Firmware in BitFrost security on XO.

Objetivos

  1. Correr el Firmware de recuperacion si el firmware primario esta mal.
  2. No acceso a el ok prompt sin clave de desarrollador
  3. Las imagenes de actualizacion de Firmware deben estar firmadas
  4. Las imagenes de booteo deben estar firmadas
  5. Laptops sin activar solo bootearan la imagen de activacion
  6. Bootear una imagen de SO aternativa si laprimaria esta dañada
  1. Run recovery firmware if primary firmware is bad
  2. No access to ok prompt without developer key
  3. Firmware update images must be signed
  4. Boot images must be signed
  5. Unactivated laptops will only boot the activation image
  6. Boot alternate OS image if primary OS image is bad

Archivos

Los archivos listados abajo estan en el NAND FLASH en JFFS2. Los archivos zip listados deben ser creados sin compression (opcion -n) y sin paths (opcion -j). Las notas de implmentacion y racionale estan en italica.

{{{1}}}

Proceso

  1. If OFW fails to come up correctly, a firmware recovery procedure is attempted - details TBD.
  2. In the following, the "primary" images are the files in /boot, and the "secondary" images are the files in /boot-alt, unless the "check" gamepad key is held down during boot, in which case the roles reverse: the primary files come from /boot-alt, and the secondary files come from /boot.
  3. OFW checks for a new firmware image in the /boot directory on an attached USB, then SD, device. If one exists and verifies, OFW reflashes itself and reboots.
    Upgrade USB keys may contain firmware-only upgrades.
  4. OFW checks for a new firmware image in the primary directory in the NAND flash. If one exists and verifies, OFW reflashes itself and reboots.
  5. OFW locks out further SPI FLASH writing with the hardware lock.
  6. If a valid developer key is present, OFW enters non-secure mode, where it behaves as it currently does. Otherwise ...
  7. If the activation key is present and valid (fill in details), the boot filenames will be runos.zip and (if present) runrd.zip. Otherwise, the boot filenames will be actos.zip and (if present) actrd.zip.
  8. If the activation key is present and valid, we will attempt to verify and boot from the boot files in /boot on an attached USB, then SD, device.
  9. OFW verifies and boots from the boot files in the primary directory.
  10. OFW verifies and boots from the boot files in the secondary directory.
  11. If none of the above booting steps succeed, OFW displays and error screen and halts.

Notas de Uso

  • After boot, userland can determine the source source from the OFW device tree in /ofw/<fill me in>. This can be used to determine whether activation is needed (actos.zip) or whether booting is being performed from the secondary source (boot-alt/*).
  • Although outside the scope of this spec, there are primary and secondary filesystem roots in /fsroot and /fsroot-alt corresponding to the kernels in /boot and /boot-alt. /boot/runrd.img will typically be absent to speed boot. However, /boot-alt/runrd.img will typically be required in order to switch to /fsroot-alt so that kernel and userland match. When we clone /boot into /boot-alt at the beginning of an upgrade, we link in an appropriate /boot-alt/runrd.img
  • When the alternate kernel is booted and we've switched into /fsroot-alt, we can either:
    1. add a /boot/runrd.zip link so that if we reboot into the primary we can switch the filesystem back /fsroot, or
    2. Swap /boot and /boot-alt, making future boots start this kernel. This option is preferred. We should ensure that we've done another upgrade before we try to boot into a different kernel again.
  • We will typically use hard or soft links to avoid storing multiple os and ramdisk images. The current plan is to actually have only one kernel and one ramdisk image; the ramdisk will look at how it was invoked to determine whether this is an upgrade, activation, or alternate boot.

Notas

{{{1}}}