On Fri, Nov 27, 2020 at 02:36:23AM -0600, Glenn Washburn wrote: > There is a hardcoded maximum disk size that can be read or written from, > currently set at 1EiB in grub_disk_adjust_range. Move the literal into a > macro in disk.h, so our assumptions are more visible. This hard coded limit > does not prevent using larger disks, just grub won't read/write past the > limit. The comment accompanying this restriction didn't quite make sense to > me, so its been modified. > > Signed-off-by: Glenn Washburn <developm...@efficientek.com> > --- > grub-core/kern/disk_common.c | 13 +++++++------ > include/grub/disk.h | 6 ++++++ > 2 files changed, 13 insertions(+), 6 deletions(-) > > diff --git a/grub-core/kern/disk_common.c b/grub-core/kern/disk_common.c > index 5b92f670b..d20ed20d2 100644 > --- a/grub-core/kern/disk_common.c > +++ b/grub-core/kern/disk_common.c > @@ -32,13 +32,14 @@ grub_disk_adjust_range (grub_disk_t disk, > grub_disk_addr_t *sector, > /* Transform total_sectors to number of 512B blocks. */ > total_sectors = grub_disk_from_native_sector (disk, disk->total_sectors); > > - /* Some drivers have problems with disks above reasonable. > - Treat unknown as 1EiB disk. While on it, clamp the size to 1EiB. > - Just one condition is enough since GRUB_DISK_UNKNOWN_SIZE << ls is > always > - above 9EiB. > + /* > + Some drivers have problems with disks above reasonable sizes. > + Clamp the size to GRUB_DISK_MAX_SECTORS. Just one condition is enough > + since GRUB_DISK_UNKNOWN_SIZE is always above GRUB_DISK_MAX_SECTORS, > + assuming a maximum 4KiB sector size. > */ > - if (total_sectors > (1ULL << 51)) > - total_sectors = (1ULL << 51); > + if (total_sectors > GRUB_DISK_MAX_SECTORS) > + total_sectors = GRUB_DISK_MAX_SECTORS; > > if ((total_sectors <= *sector > || ((*offset + size + GRUB_DISK_SECTOR_SIZE - 1) > diff --git a/include/grub/disk.h b/include/grub/disk.h > index 1a9e8fcf4..0bf08091f 100644 > --- a/include/grub/disk.h > +++ b/include/grub/disk.h > @@ -157,6 +157,12 @@ struct grub_disk_memberlist > typedef struct grub_disk_memberlist *grub_disk_memberlist_t; > #endif > > +/* > + Some drivers have problems with disks above reasonable sizes. > + Set max disk size at 1EiB.
The comment is formatted incorrectly [1]. > +*/ > +#define GRUB_DISK_MAX_SECTORS (1ULL << (60 - 9)) > + > /* The sector size. */ > #define GRUB_DISK_SECTOR_SIZE 0x200 > #define GRUB_DISK_SECTOR_BITS 9 Please move the constant below these definitions and do this: #define GRUB_DISK_MAX_SECTORS (1ULL << (60 - GRUB_DISK_SECTOR_BITS)) [1] https://www.gnu.org/software/grub/manual/grub-dev/grub-dev.html#Comments _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
