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Commit 02e2a5bf authored by Kees Cook's avatar Kees Cook Committed by Jens Axboe
Browse files

mac: validate mac_partition is within sector 



If md->signature == MAC_DRIVER_MAGIC and md->block_size == 1023, a single
512 byte sector would be read (secsize / 512). However the partition
structure would be located past the end of the buffer (secsize % 512).

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 8aeea031

block/partitions/mac.c

+7 −3
Original line number Diff line number Diff line
@@ -32,7 +32,7 @@ int mac_partition(struct parsed_partitions *state) 
	Sector sect;

	unsigned char *data;

	int slot, blocks_in_map;

	unsigned secsize;

	unsigned secsize, datasize, partoffset;

#ifdef CONFIG_PPC_PMAC

	int found_root = 0;

	int found_root_goodness = 0;
@@ -50,10 +50,14 @@ int mac_partition(struct parsed_partitions *state) 
	}

	secsize = be16_to_cpu(md->block_size);

	put_dev_sector(sect);

	data = read_part_sector(state, secsize/512, &sect);

	datasize = round_down(secsize, 512);

	data = read_part_sector(state, datasize / 512, &sect);

	if (!data)

		return -1;

	part = (struct mac_partition *) (data + secsize%512);

	partoffset = secsize % 512;

	if (partoffset + sizeof(*part) > datasize)

		return -1;

	part = (struct mac_partition *) (data + partoffset);

	if (be16_to_cpu(part->signature) != MAC_PARTITION_MAGIC) {

		put_dev_sector(sect);

		return 0;		/* not a MacOS disk */