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Add infrastructure to allow firmware to verify the integrity of GRUB by use of a Linux-kernel-module-style appended signature. We initially target powerpc-ieee1275, but the code should be extensible to other platforms. Usually these signatures are appended to a file without modifying the ELF file itself. (This is what the 'sign-file' tool does, for example.) The verifier loads the signed file from the file system and looks at the end of the file for the appended signature. However, on powerpc-ieee1275 platforms, the bootloader is often stored directly in the PReP partition as raw bytes without a file-system. This makes determining the location of an appended signature more difficult. To address this, we add a new ELF Note. The name field of shall be the string "Appended-Signature", zero-padded to 4 byte alignment. The type field shall be 0x41536967 (the ASCII values for the string "ASig"). It must be the final section in the ELF binary. The description shall contain the appended signature structure as defined by the Linux kernel. The description will also be padded to be a multiple of 4 bytes. The padding shall be added before the appended signature structure (not at the end) so that the final bytes of a signed ELF file are the appended signature magic. A subsequent patch documents how to create a GRUB core.img validly signed under this scheme. Signed-off-by: Rashmica Gupta <rashmica.g@gmail.com> Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Avnish Chouhan <avnish@linux.ibm.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This is GRUB 2, the second version of the GRand Unified Bootloader. GRUB 2 is rewritten from scratch to make GNU GRUB cleaner, safer, more robust, more powerful, and more portable. See the file NEWS for a description of recent changes to GRUB 2. See the file INSTALL for instructions on how to build and install the GRUB 2 data and program files. See the file MAINTAINERS for information about the GRUB maintainers, etc. If you found a security vulnerability in the GRUB please check the SECURITY file to get more information how to properly report this kind of bugs to the maintainers. Please visit the official web page of GRUB 2, for more information. The URL is <http://www.gnu.org/software/grub/grub.html>. More extensive documentation is available in the Info manual, accessible using 'info grub' after building and installing GRUB 2. There are a number of important user-visible differences from the first version of GRUB, now known as GRUB Legacy. For a summary, please see: info grub Introduction 'Changes from GRUB Legacy'