ee0dbd86e5
In grub-module-verifierXX.c, the function grub_module_verifyXX() performs an initial check that the ELF section headers are within the module's size, but doesn't check if the sections being accessed have contents that are within the module's size. In particular, we need to check that sh_offset and sh_size are less than the module's size. However, for some section header types we don't need to make these checks. For the type SHT_NULL, the section header is marked as inactive and the rest of the members within the section header have undefined values, so we don't need to check for sh_offset or sh_size. In the case of the type SHT_NOBITS, sh_offset has a conceptual offset which may be beyond the module size. Also, this type's sh_size may have a non-zero size, but a section of this type will take up no space in the module. This can all be checked in the function get_shdr(), but in order to do so, the parameter module_size must be added to functions so that the value of the module size can be used in get_shdr() from grub_module_verifyXX(). Also, had to rework some for loops to ensure the index passed to get_shdr() is within bounds. Signed-off-by: Alec Brown <alec.r.brown@oracle.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'