From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Glenn Washburn Date: Sun, 7 Aug 2022 00:18:52 -0500 Subject: [PATCH] disk/cryptodisk: Support encrypted volumes using detached headers on a partition Update the read hook to take into account encrypted volumes on a partition. GRUB disk read hooks supply an absolute sector number at which the read is started from. If the encrypted volume is in a partition, the sector number given to the read hook will be offset by the number of the sector at the start of the partition. The read hook then needs to subtract the partition start from the supplied sector to get the correct start sector for the read into the detached header file. Reported-by: brutser Signed-off-by: Glenn Washburn Tested-by: brutser Reviewed-by: Daniel Kiper --- grub-core/disk/cryptodisk.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c index 3d8472e..42370db 100644 --- a/grub-core/disk/cryptodisk.c +++ b/grub-core/disk/cryptodisk.c @@ -64,6 +64,7 @@ static const struct grub_arg_option options[] = struct cryptodisk_read_hook_ctx { grub_file_t hdr_file; + grub_disk_addr_t part_start; }; typedef struct cryptodisk_read_hook_ctx *cryptodisk_read_hook_ctx_t; @@ -1022,7 +1023,7 @@ cryptodisk_read_hook (grub_disk_addr_t sector, unsigned offset, return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("header file not found")); if (grub_file_seek (ctx->hdr_file, - (sector * GRUB_DISK_SECTOR_SIZE) + offset) + ((sector - ctx->part_start) * GRUB_DISK_SECTOR_SIZE) + offset) == (grub_off_t) -1) return grub_errno; @@ -1078,6 +1079,7 @@ grub_cryptodisk_scan_device_real (const char *name, * times by a backend. This is fine because of the assumptions mentioned * and the read hook reads from absolute offsets and is stateless. */ + read_hook_data.part_start = grub_partition_get_start (source->partition); read_hook_data.hdr_file = cargs->hdr_file; source->read_hook = cryptodisk_read_hook; source->read_hook_data = (void *) &read_hook_data;