From d3b1d4c188e9fcb8265ce5432ec373771068967a Mon Sep 17 00:00:00 2001 From: Mihai Moldovan Date: Thu, 6 Sep 2018 16:16:39 +0200 Subject: [PATCH] osdep/linux: Convert partition start to disk sector length When reading data off a disk, sector values are based on the disk sector length. Within grub_util_fd_open_device(), the start of the partition was taken directly from grub's partition information structure, which uses the internal sector length (currently 512b), but never transformed to the disk's sector length. Subsequent calculations were all wrong for devices that have a diverging sector length and the functions eventually skipped to the wrong stream location, reading invalid data. Signed-off-by: Mihai Moldovan Reviewed-by: Daniel Kiper --- grub-core/osdep/linux/hostdisk.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/grub-core/osdep/linux/hostdisk.c b/grub-core/osdep/linux/hostdisk.c index 06179fca7..8b92f8528 100644 --- a/grub-core/osdep/linux/hostdisk.c +++ b/grub-core/osdep/linux/hostdisk.c @@ -374,7 +374,8 @@ grub_util_fd_open_device (const grub_disk_t disk, grub_disk_addr_t sector, int f char dev[PATH_MAX]; grub_disk_addr_t part_start = 0; - part_start = grub_partition_get_start (disk->partition); + part_start = grub_partition_get_start (disk->partition) + >> (disk->log_sector_size - GRUB_DISK_SECTOR_BITS); strncpy (dev, grub_util_biosdisk_get_osdev (disk), sizeof (dev) - 1); dev[sizeof(dev) - 1] = '\0';