From f4f98f3b476f47383fd71ebc057483902752d297 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 19 Oct 2021 18:03:42 +0800 Subject: [PATCH] io_uring: ensure symmetry in handling iter types in loop_rw_iter() stable inclusion from stable-5.10.68 commit ce8f81b76d3bef7b9fe6c8f84d029ab898b19469 bugzilla: 182253 https://gitee.com/openeuler/kernel/issues/I4DDEL CVE: CVE-2021-41073 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ce8f81b76d3bef7b9fe6c8f84d029ab898b19469 -------------------------------- commit 16c8d2df7ec0eed31b7d3b61cb13206a7fb930cc upstream. When setting up the next segment, we check what type the iter is and handle it accordingly. However, when incrementing and processed amount we do not, and both iter advance and addr/len are adjusted, regardless of type. Split the increment side just like we do on the setup side. Fixes: 4017eb91a9e7 ("io_uring: make loop_rw_iter() use original user supplied pointers") Cc: stable@vger.kernel.org Reported-by: Valentina Palmiotti Reviewed-by: Pavel Begunkov Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman Signed-off-by: Chen Jun Reviewed-by: Yang Erkun Signed-off-by: Chen Jun Signed-off-by: Zheng Zengkai --- fs/io_uring.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 108b0ed31c11..4361ed15e019 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3203,12 +3203,15 @@ static ssize_t loop_rw_iter(int rw, struct io_kiocb *req, struct iov_iter *iter) ret = nr; break; } + if (!iov_iter_is_bvec(iter)) { + iov_iter_advance(iter, nr); + } else { + req->rw.len -= nr; + req->rw.addr += nr; + } ret += nr; if (nr != iovec.iov_len) break; - req->rw.len -= nr; - req->rw.addr += nr; - iov_iter_advance(iter, nr); } return ret; -- GitLab