From: Pavel Begunkov asml.silence@gmail.com
stable inclusion from stable-v5.10.119 commit 57d01bcae7041cfb86553091718d12bf36c082aa category: bugfix bugzilla: 186671,https://gitee.com/src-openeuler/kernel/issues/I56MH6 CVE: CVE-2022-1508
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
--------------------------------
We can't re-import or modify iterators from iocb callbacks, it's not safe as it might be reverted and/or reexpanded while unwinding stack. It's also not safe to resubmit as io-wq thread will race with stack undwinding for the iterator and other data.
Disallow resubmission from callbacks, it can fail some cases that were handled before, but the possibility of such a failure was a part of the API from the beginning and so it should be fine.
Signed-off-by: Pavel Begunkov asml.silence@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Guo Xuenan guoxuenan@huawei.com Reviewed-by: Xiu Jianfeng xiujianfeng@huawei.com Reviewed-by: Zhang Yi yi.zhang@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- fs/io_uring.c | 39 --------------------------------------- 1 file changed, 39 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c index cadd491edc6f..8a565b77dbeb 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2582,45 +2582,6 @@ static void io_complete_rw_common(struct kiocb *kiocb, long res, #ifdef CONFIG_BLOCK static bool io_resubmit_prep(struct io_kiocb *req, int error) { - struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; - ssize_t ret = -ECANCELED; - struct iov_iter iter; - int rw; - - if (error) { - ret = error; - goto end_req; - } - - switch (req->opcode) { - case IORING_OP_READV: - case IORING_OP_READ_FIXED: - case IORING_OP_READ: - rw = READ; - break; - case IORING_OP_WRITEV: - case IORING_OP_WRITE_FIXED: - case IORING_OP_WRITE: - rw = WRITE; - break; - default: - printk_once(KERN_WARNING "io_uring: bad opcode in resubmit %d\n", - req->opcode); - goto end_req; - } - - if (!req->async_data) { - ret = io_import_iovec(rw, req, &iovec, &iter, false); - if (ret < 0) - goto end_req; - ret = io_setup_async_rw(req, iovec, inline_vecs, &iter, false); - if (!ret) - return true; - kfree(iovec); - } else { - return true; - } -end_req: req_set_fail_links(req); return false; }