From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E6A95E548; Mon, 11 Dec 2023 18:58:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="NNT76YXt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67F7DC433C8; Mon, 11 Dec 2023 18:58:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1702321091; bh=o4wuwDeDGJZ3HEXeVWHA+VNUFbX3EXIErUpmVj9MUTY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NNT76YXtot7M7eByBEf8zNMTMHSi/9DereYMUb8yvvjyG9ODKyDewoHWxif4L+7d2 QBE02uND1sVUy1++O7kOdmL13LV1YEzwKh+xWGaFUeDfpCfWsAqnFAQdHKCcOZsory oqaiTQT86IfbDhX9u3kzmEJfzTgway276QJT4Ffw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pavel Begunkov , Jens Axboe , Jann Horn Subject: [PATCH 5.15 107/141] io_uring/af_unix: disable sending io_uring over sockets Date: Mon, 11 Dec 2023 19:22:46 +0100 Message-ID: <20231211182031.183041859@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231211182026.503492284@linuxfoundation.org> References: <20231211182026.503492284@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pavel Begunkov commit 705318a99a138c29a512a72c3e0043b3cd7f55f4 upstream. File reference cycles have caused lots of problems for io_uring in the past, and it still doesn't work exactly right and races with unix_stream_read_generic(). The safest fix would be to completely disallow sending io_uring files via sockets via SCM_RIGHT, so there are no possible cycles invloving registered files and thus rendering SCM accounting on the io_uring side unnecessary. Cc: Fixes: 0091bfc81741b ("io_uring/af_unix: defer registered files gc to io_uring release") Reported-and-suggested-by: Jann Horn Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/c716c88321939156909cfa1bd8b0faaf1c804103.1701868795.git.asml.silence@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- io_uring/io_uring.c | 55 ---------------------------------------------------- net/core/scm.c | 6 +++++ 2 files changed, 6 insertions(+), 55 deletions(-) --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -8627,49 +8627,6 @@ out_free: return ret; } -static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file, - int index) -{ -#if defined(CONFIG_UNIX) - struct sock *sock = ctx->ring_sock->sk; - struct sk_buff_head *head = &sock->sk_receive_queue; - struct sk_buff *skb; - - /* - * See if we can merge this file into an existing skb SCM_RIGHTS - * file set. If there's no room, fall back to allocating a new skb - * and filling it in. - */ - spin_lock_irq(&head->lock); - skb = skb_peek(head); - if (skb) { - struct scm_fp_list *fpl = UNIXCB(skb).fp; - - if (fpl->count < SCM_MAX_FD) { - __skb_unlink(skb, head); - spin_unlock_irq(&head->lock); - fpl->fp[fpl->count] = get_file(file); - unix_inflight(fpl->user, fpl->fp[fpl->count]); - fpl->count++; - spin_lock_irq(&head->lock); - __skb_queue_head(head, skb); - } else { - skb = NULL; - } - } - spin_unlock_irq(&head->lock); - - if (skb) { - fput(file); - return 0; - } - - return __io_sqe_files_scm(ctx, 1, index); -#else - return 0; -#endif -} - static int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, struct io_rsrc_node *node, void *rsrc) { @@ -8727,12 +8684,6 @@ static int io_install_fixed_file(struct *io_get_tag_slot(ctx->file_data, slot_index) = 0; io_fixed_file_set(file_slot, file); - ret = io_sqe_file_register(ctx, file, slot_index); - if (ret) { - file_slot->file_ptr = 0; - goto err; - } - ret = 0; err: if (needs_switch) @@ -8846,12 +8797,6 @@ static int __io_sqe_files_update(struct } *io_get_tag_slot(data, i) = tag; io_fixed_file_set(file_slot, file); - err = io_sqe_file_register(ctx, file, i); - if (err) { - file_slot->file_ptr = 0; - fput(file); - break; - } } } --- a/net/core/scm.c +++ b/net/core/scm.c @@ -26,6 +26,7 @@ #include #include #include +#include #include @@ -103,6 +104,11 @@ static int scm_fp_copy(struct cmsghdr *c if (fd < 0 || !(file = fget_raw(fd))) return -EBADF; + /* don't allow io_uring files */ + if (io_uring_get_socket(file)) { + fput(file); + return -EINVAL; + } *fpp++ = file; fpl->count++; }