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 10A891D6DB4; Wed, 5 Mar 2025 18:11:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741198277; cv=none; b=mQ5AlFpGu5KaioCZ1HHWP6czJvwk2VmkDc3mLzppVt4r40EnlRREfQwAa9FW+YliBlKCP5LQhYAXXhozde+I16obrYFVIAK+RF5IrFmC3drx6sQendiYzbimMiimgdUWJ5sWIxsKDJz3JFDjLrcfjF+LCgFT47a9NpK8rfVUrb8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741198277; c=relaxed/simple; bh=b/lgOAZMTMZ5JZWl61bjCscDdYCjx6wemi4VZgjTCjU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mt19AKzoGS/gJDkfq26WPmDrOgHQOJUoNz0wD3URKlfh3zfNT62lD7Rx/OCIeZ1PgoPk7W0pn9iPwHssze/nOYeWMH9johcB9VTLJFtObAvCOv4q6I2QLUsp8+3mCq4TqapnmzX5XU5Bw6+rNtd3RBNmJkQpUox0IDj8QDW0EVY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=AZpituZs; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="AZpituZs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 72B78C4CED1; Wed, 5 Mar 2025 18:11:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741198276; bh=b/lgOAZMTMZ5JZWl61bjCscDdYCjx6wemi4VZgjTCjU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AZpituZss6g5s9u6Z/GKcBdKSq37VDrxhEh8A1oAexgz5q18kRsxg87gTuK7Rp+2X 4hPaFD2fLq6N5sF+kQl4Yjc0GHQWVQ8KjRR31Zq0gDNwVpJiqOpjIqL7aF6F/r7/qy DO8osiTSE71qTQRx+12gCjqXP9yiuZzgPsHFyg+M= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Chester A. Unal" , Paolo Abeni , "Matthieu Baerts (NGI0)" , Jakub Kicinski Subject: [PATCH 6.12 124/150] mptcp: reset when MPTCP opts are dropped after join Date: Wed, 5 Mar 2025 18:49:13 +0100 Message-ID: <20250305174508.799284551@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250305174503.801402104@linuxfoundation.org> References: <20250305174503.801402104@linuxfoundation.org> User-Agent: quilt/0.68 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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Matthieu Baerts (NGI0) commit 8668860b0ad32a13fcd6c94a0995b7aa7638c9ef upstream. Before this patch, if the checksum was not used, the subflow was only reset if map_data_len was != 0. If there were no MPTCP options or an invalid mapping, map_data_len was not set to the data len, and then the subflow was not reset as it should have been, leaving the MPTCP connection in a wrong fallback mode. This map_data_len condition has been introduced to handle the reception of the infinite mapping. Instead, a new dedicated mapping error could have been returned and treated as a special case. However, the commit 31bf11de146c ("mptcp: introduce MAPPING_BAD_CSUM") has been introduced by Paolo Abeni soon after, and backported later on to stable. It better handle the csum case, and it means the exception for valid_csum_seen in subflow_can_fallback(), plus this one for the infinite mapping in subflow_check_data_avail(), are no longer needed. In other words, the code can be simplified there: a fallback should only be done if msk->allow_infinite_fallback is set. This boolean is set to false once MPTCP-specific operations acting on the whole MPTCP connection vs the initial path have been done, e.g. a second path has been created, or an MPTCP re-injection -- yes, possible even with a single subflow. The subflow_can_fallback() helper can then be dropped, and replaced by this single condition. This also makes the code clearer: a fallback should only be done if it is possible to do so. While at it, no need to set map_data_len to 0 in get_mapping_status() for the infinite mapping case: it will be set to skb->len just after, at the end of subflow_check_data_avail(), and not read in between. Fixes: f8d4bcacff3b ("mptcp: infinite mapping receiving") Cc: stable@vger.kernel.org Reported-by: Chester A. Unal Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/544 Acked-by: Paolo Abeni Signed-off-by: Matthieu Baerts (NGI0) Tested-by: Chester A. Unal Link: https://patch.msgid.link/20250224-net-mptcp-misc-fixes-v1-2-f550f636b435@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/mptcp/subflow.c | 15 +-------------- 1 file changed, 1 insertion(+), 14 deletions(-) --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1140,7 +1140,6 @@ static enum mapping_status get_mapping_s if (data_len == 0) { pr_debug("infinite mapping received\n"); MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX); - subflow->map_data_len = 0; return MAPPING_INVALID; } @@ -1284,18 +1283,6 @@ static void subflow_sched_work_if_closed mptcp_schedule_work(sk); } -static bool subflow_can_fallback(struct mptcp_subflow_context *subflow) -{ - struct mptcp_sock *msk = mptcp_sk(subflow->conn); - - if (subflow->mp_join) - return false; - else if (READ_ONCE(msk->csum_enabled)) - return !subflow->valid_csum_seen; - else - return READ_ONCE(msk->allow_infinite_fallback); -} - static void mptcp_subflow_fail(struct mptcp_sock *msk, struct sock *ssk) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); @@ -1391,7 +1378,7 @@ fallback: return true; } - if (!subflow_can_fallback(subflow) && subflow->map_data_len) { + if (!READ_ONCE(msk->allow_infinite_fallback)) { /* fatal protocol error, close the socket. * subflow_error_report() will introduce the appropriate barriers */