block/loop: fix use after free (92d77332) · Commits · 戴 / test

drivers/block/loop.c

+13 −3

Original line number	Diff line number	Diff line
		@@ -463,14 +463,21 @@ static void lo_complete_rq(struct request *rq)
		blk_mq_end_request(rq, cmd->ret < 0 ? BLK_STS_IOERR : BLK_STS_OK);
		}

		static void lo_rw_aio_do_completion(struct loop_cmd *cmd)
		{
		if (!atomic_dec_and_test(&cmd->ref))
		return;
		kfree(cmd->bvec);
		cmd->bvec = NULL;
		blk_mq_complete_request(cmd->rq);
		}

		static void lo_rw_aio_complete(struct kiocb *iocb, long ret, long ret2)
		{
		struct loop_cmd *cmd = container_of(iocb, struct loop_cmd, iocb);

		kfree(cmd->bvec);
		cmd->bvec = NULL;
		cmd->ret = ret;
		blk_mq_complete_request(cmd->rq);
		lo_rw_aio_do_completion(cmd);
		}

		static int lo_rw_aio(struct loop_device lo, struct loop_cmd cmd,
		@@ -518,6 +525,7 @@ static int lo_rw_aio(struct loop_device lo, struct loop_cmd cmd,
		bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);
		segments = bio_segments(bio);
		}
		atomic_set(&cmd->ref, 2);

		iov_iter_bvec(&iter, ITER_BVEC \| rw, bvec,
		segments, blk_rq_bytes(rq));
		@@ -533,6 +541,8 @@ static int lo_rw_aio(struct loop_device lo, struct loop_cmd cmd,
		else
		ret = call_read_iter(file, &cmd->iocb, &iter);

		lo_rw_aio_do_completion(cmd);

		if (ret != -EIOCBQUEUED)
		cmd->iocb.ki_complete(&cmd->iocb, ret, 0);
		return 0;

+4 −1

Original line number	Diff line number	Diff line
		@@ -68,7 +68,10 @@ struct loop_cmd {
		struct kthread_work work;
		struct request *rq;
		struct list_head list;
		union {
		bool use_aio; /* use AIO interface to handle I/O */
		atomic_t ref; /* only for aio */
		};
		long ret;
		struct kiocb iocb;
		struct bio_vec *bvec;