b5bc456f66
A fuzzed HFS+ filesystem had log2blocksize = 22. This gave log2blocksize + GRUB_DISK_SECTOR_BITS = 31. 1 << 31 = 0x80000000, which is -1 as an int. This caused some wacky behavior later on in the function, leading to out-of-bounds writes on the destination buffer. Catch log2blocksize + GRUB_DISK_SECTOR_BITS >= 31. We could be stricter, but this is the minimum that will prevent integer size weirdness. Signed-off-by: Daniel Axtens <dja@axtens.net> 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. 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'