mac: validate mac_partition is within sector (02e2a5bf) · Commits · 戴 / test

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:

Kees Cook <keescook@chromium.org> Cc: stable@vger.kernel.org Signed-off-by:

Jens Axboe <axboe@fb.com>

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 */

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