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Commit 9f864c80 authored by Jens Axboe's avatar Jens Axboe
Browse files

block: take care not to overflow when calculating total iov length 



Reported-by: default avatarDan Rosenberg <drosenberg@vsecurity.com>
Cc: stable@kernel.org
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
parent 9284bcf4

block/scsi_ioctl.c

+24 −10
Original line number Diff line number Diff line
@@ -321,33 +321,47 @@ static int sg_io(struct request_queue *q, struct gendisk *bd_disk, 
	if (hdr->iovec_count) {

		const int size = sizeof(struct sg_iovec) * hdr->iovec_count;

		size_t iov_data_len;

		struct sg_iovec *iov;

		struct sg_iovec *sg_iov;

		struct iovec *iov;

		int i;



		iov = kmalloc(size, GFP_KERNEL);

		if (!iov) {

		sg_iov = kmalloc(size, GFP_KERNEL);

		if (!sg_iov) {

			ret = -ENOMEM;

			goto out;

		}



		if (copy_from_user(iov, hdr->dxferp, size)) {

			kfree(iov);

		if (copy_from_user(sg_iov, hdr->dxferp, size)) {

			kfree(sg_iov);

			ret = -EFAULT;

			goto out;

		}



		/*

		 * Sum up the vecs, making sure they don't overflow

		 */

		iov = (struct iovec *) sg_iov;

		iov_data_len = 0;

		for (i = 0; i < hdr->iovec_count; i++) {

			if (iov_data_len + iov[i].iov_len < iov_data_len) {

				kfree(sg_iov);

				ret = -EINVAL;

				goto out;

			}

			iov_data_len += iov[i].iov_len;

		}



		/* SG_IO howto says that the shorter of the two wins */

		iov_data_len = iov_length((struct iovec *)iov,

					  hdr->iovec_count);

		if (hdr->dxfer_len < iov_data_len) {

			hdr->iovec_count = iov_shorten((struct iovec *)iov,

			hdr->iovec_count = iov_shorten(iov,

						       hdr->iovec_count,

						       hdr->dxfer_len);

			iov_data_len = hdr->dxfer_len;

		}



		ret = blk_rq_map_user_iov(q, rq, NULL, iov, hdr->iovec_count,

		ret = blk_rq_map_user_iov(q, rq, NULL, sg_iov, hdr->iovec_count,

					  iov_data_len, GFP_KERNEL);

		kfree(iov);

		kfree(sg_iov);

	} else if (hdr->dxfer_len)

		ret = blk_rq_map_user(q, rq, NULL, hdr->dxferp, hdr->dxfer_len,

				      GFP_KERNEL);