From: Jens Axboe axboe@kernel.dk
stable inclusion from stable-v5.10.118 commit 3c48558be571e01f67e65edcf03193484eeb2b79 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5L686
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
--------------------------------
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: Zheng Zengkai zhengzengkai@huawei.com Acked-by: Xie XiuQi xiexiuqi@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 040d1aafc968..5a88260a8dd8 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4263,12 +4263,8 @@ 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);