Commit 929a3af9 authored Feb 19, 2020 by Pavel Begunkov Committed by Jens Axboe Feb 18, 2020

io_uring: fix use-after-free by io_cleanup_req()



io_cleanup_req() should be called before req->io is freed, and so
shouldn't be after __io_free_req() -> __io_req_aux_free(). Also,
it will be ignored for in io_free_req_many(), which use
__io_req_aux_free().

Place cleanup_req() into __io_req_aux_free().

Fixes: 99bc4c38 ("io_uring: fix iovec leaks")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 297a31e3

fs/io_uring.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -1260,6 +1260,9 @@ static void __io_req_aux_free(struct io_kiocb *req)
		{
		struct io_ring_ctx *ctx = req->ctx;

		if (req->flags & REQ_F_NEED_CLEANUP)
		io_cleanup_req(req);

		kfree(req->io);
		if (req->file) {
		if (req->flags & REQ_F_FIXED_FILE)
		@@ -1275,9 +1278,6 @@ static void __io_free_req(struct io_kiocb *req)
		{
		__io_req_aux_free(req);

		if (req->flags & REQ_F_NEED_CLEANUP)
		io_cleanup_req(req);

		if (req->flags & REQ_F_INFLIGHT) {
		struct io_ring_ctx *ctx = req->ctx;
		unsigned long flags;

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