From: Jens Axboe axboe@kernel.dk

stable inclusion from stable-v5.10.118 commit 3c48558be571e01f67e65edcf03193484eeb2b79 category: bugfix bugzilla: 187134, https://gitee.com/openeuler/kernel/issues/I5HEXY CVE: NA

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Lee reports that there's a use-after-free of the process file table. There's an assumption that we don't need the file table for some variants of statx invocation, but that turns out to be false and we end up with not grabbing a reference for the request even if the deferred execution uses it.

Get rid of the REQ_F_NO_FILE_TABLE optimization for statx, and always grab that reference.

This issues doesn't exist upstream since the native workers got introduced with 5.12.

Link: https://lore.kernel.org/io-uring/YoOJ%2FT4QRKC+fAZE@google.com/ Reported-by: Lee Jones lee.jones@linaro.org Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Li Lingfeng lilingfeng3@huawei.com Reviewed-by: Zhang Yi yi.zhang@huawei.com Signed-off-by: Yongqiang Liu liuyongqiang13@huawei.com --- fs/io_uring.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c index 7ae8ba98e73b..8a96b7df4112 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3836,12 +3836,8 @@ static int io_statx(struct io_kiocb *req, bool force_nonblock) struct io_statx *ctx = &req->statx; int ret;

- if (force_nonblock) { - /* only need file table for an actual valid fd */ - if (ctx->dfd == -1 || ctx->dfd == AT_FDCWD) - req->flags |= REQ_F_NO_FILE_TABLE; + if (force_nonblock) return -EAGAIN; - }

ret = do_statx(ctx->dfd, ctx->filename, ctx->flags, ctx->mask, ctx->buffer);