a8d6b06331
When the format string, fmt0, includes a positional argument grub_strtoul() or grub_strtoull() is called to extract the argument position. However, the returned argument position isn't fully validated. If the format is something like "%0$x" then these functions return 0 which leads to an underflow in the calculation of the args index, curn. The fix is to add a check to ensure the extracted argument position is greater than 0 before computing curn. Additionally, replace one grub_strtoull() with grub_strtoul() and change curn type to make code more correct. Fixes: CID 473841 Signed-off-by: Lidong Chen <lidong.chen@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'