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There is a hardcoded maximum disk size that can be read or written from, currently set at 1 EiB 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 too. Signed-off-by: Glenn Washburn <development@efficientek.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
67 lines
2.1 KiB
C
67 lines
2.1 KiB
C
/* This function performs three tasks:
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- Make sectors disk relative from partition relative.
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- Normalize offset to be less than the sector size.
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- Verify that the range is inside the partition. */
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static grub_err_t
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grub_disk_adjust_range (grub_disk_t disk, grub_disk_addr_t *sector,
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grub_off_t *offset, grub_size_t size)
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{
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grub_partition_t part;
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grub_disk_addr_t total_sectors;
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*sector += *offset >> GRUB_DISK_SECTOR_BITS;
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*offset &= GRUB_DISK_SECTOR_SIZE - 1;
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for (part = disk->partition; part; part = part->parent)
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{
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grub_disk_addr_t start;
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grub_uint64_t len;
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start = part->start;
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len = part->len;
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if (*sector >= len
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|| len - *sector < ((*offset + size + GRUB_DISK_SECTOR_SIZE - 1)
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>> GRUB_DISK_SECTOR_BITS))
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return grub_error (GRUB_ERR_OUT_OF_RANGE,
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N_("attempt to read or write outside of partition"));
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*sector += start;
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}
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/* Transform total_sectors to number of 512B blocks. */
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total_sectors = disk->total_sectors << (disk->log_sector_size - GRUB_DISK_SECTOR_BITS);
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/*
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* Some drivers have problems with disks above reasonable sizes.
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* Clamp the size to GRUB_DISK_MAX_SECTORS. Just one condition is enough
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* since GRUB_DISK_SIZE_UNKNOWN is always above GRUB_DISK_MAX_SECTORS,
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* assuming a maximum 4 KiB sector size.
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*/
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if (total_sectors > GRUB_DISK_MAX_SECTORS)
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total_sectors = GRUB_DISK_MAX_SECTORS;
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if ((total_sectors <= *sector
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|| ((*offset + size + GRUB_DISK_SECTOR_SIZE - 1)
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>> GRUB_DISK_SECTOR_BITS) > total_sectors - *sector))
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return grub_error (GRUB_ERR_OUT_OF_RANGE,
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N_("attempt to read or write outside of disk `%s'"), disk->name);
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return GRUB_ERR_NONE;
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}
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static inline grub_disk_addr_t
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transform_sector (grub_disk_t disk, grub_disk_addr_t sector)
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{
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return sector >> (disk->log_sector_size - GRUB_DISK_SECTOR_BITS);
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}
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static unsigned
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grub_disk_cache_get_index (unsigned long dev_id, unsigned long disk_id,
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grub_disk_addr_t sector)
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{
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return ((dev_id * 524287UL + disk_id * 2606459UL
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+ ((unsigned) (sector >> GRUB_DISK_CACHE_BITS)))
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% GRUB_DISK_CACHE_NUM);
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}
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