From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB78CC25B0E for ; Mon, 15 Aug 2022 18:58:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244701AbiHOS6e (ORCPT ); Mon, 15 Aug 2022 14:58:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34436 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244798AbiHOSzw (ORCPT ); Mon, 15 Aug 2022 14:55:52 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6942B2DF2; Mon, 15 Aug 2022 11:30:23 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id ED9E1B8106C; Mon, 15 Aug 2022 18:30:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4BDF0C433C1; Mon, 15 Aug 2022 18:30:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660588219; bh=9gl4kRdQ+WLKKQ5khPH9o29OL7Te4TCVWT384FGVGKk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YFvrVIyHedvj8BPGtTk2kG0HtAiSii/3i8n+6P0lX3t7dNoGUVqdCCNttjNMJu14X FgLTXNZkZ4x9Cdyv2oGMloxSmiljjhNp2w2c2BwmGwpdAQekpAzBLHjYhoyrtuPjBn 7cHC9q1zhqZ0ooJZQ3VPrNXz5CMpqzJJXMnVuA20= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Liu Jian , Daniel Borkmann , John Fastabend , Sasha Levin Subject: [PATCH 5.15 333/779] skmsg: Fix invalid last sg check in sk_msg_recvmsg() Date: Mon, 15 Aug 2022 19:59:37 +0200 Message-Id: <20220815180351.507977711@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180337.130757997@linuxfoundation.org> References: <20220815180337.130757997@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Liu Jian [ Upstream commit 9974d37ea75f01b47d16072b5dad305bd8d23fcc ] In sk_psock_skb_ingress_enqueue function, if the linear area + nr_frags + frag_list of the SKB has NR_MSG_FRAG_IDS blocks in total, skb_to_sgvec will return NR_MSG_FRAG_IDS, then msg->sg.end will be set to NR_MSG_FRAG_IDS, and in addition, (NR_MSG_FRAG_IDS - 1) is set to the last SG of msg. Recv the msg in sk_msg_recvmsg, when i is (NR_MSG_FRAG_IDS - 1), the sk_msg_iter_var_next(i) will change i to 0 (not NR_MSG_FRAG_IDS), the judgment condition "msg_rx->sg.start==msg_rx->sg.end" and "i != msg_rx->sg.end" can not work. As a result, the processed msg cannot be deleted from ingress_msg list. But the length of all the sge of the msg has changed to 0. Then the next recvmsg syscall will process the msg repeatedly, because the length of sge is 0, the -EFAULT error is always returned. Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Liu Jian Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20220628123616.186950-1-liujian56@huawei.com Signed-off-by: Sasha Levin --- net/core/skmsg.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/core/skmsg.c b/net/core/skmsg.c index ede0af308f40..f50f8d95b628 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -462,7 +462,7 @@ int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg, if (copied == len) break; - } while (i != msg_rx->sg.end); + } while (!sg_is_last(sge)); if (unlikely(peek)) { msg_rx = sk_psock_next_msg(psock, msg_rx); @@ -472,7 +472,7 @@ int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg, } msg_rx->sg.start = i; - if (!sge->length && msg_rx->sg.start == msg_rx->sg.end) { + if (!sge->length && sg_is_last(sge)) { msg_rx = sk_psock_dequeue_msg(psock); kfree_sk_msg(msg_rx); } -- 2.35.1