cdb21e0b9c
In grub-module-verifierXX.c, grub_target_to_host16 (e->e_shnum) is used to obtain the number of section header table entries, but it wasn't being checked if the value was there. According to the elf(5) manual page, "If the number of entries in the section header table is larger than or equal to SHN_LORESERVE (0xff00), e_shnum holds the value zero and the real number of entries in the section header table is held in the sh_size member of the intial entry in section header table. Otherwise, the sh_size member of the initial entry in the section header table holds the value zero." Since this check wasn't being made, the function get_shnum() is being added to make this check and use whichever member doesn't have a value of zero. If both are zero, then we must return an error. We also need to make sure that e_shnum doesn't have a value greater than or equal to SHN_LORESERVE and sh_size isn't less than SHN_LORESERVE. Note that it may look as though the argument *arch isn't being used, it's actually required in order to use the macros grub_target_to_host*(x) which are unwinded to grub_target_to_host*_real(arch, (x)) based on defines earlier in the file. Fixes: CID 314021 Fixes: CID 314027 Fixes: CID 314033 Signed-off-by: Alec Brown <alec.r.brown@oracle.com> Reviewed-by: Darren Kenny <darren.kenny@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'