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.
+*/
+#define GRUB_DISK_MAX_SECTORS (1ULL << (60 - 9))
+
/* The sector size. */
#define GRUB_DISK_SECTOR_SIZE 0x200
#define GRUB_DISK_SECTOR_BITS 9
--
2.27.0
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