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 6FA962566 for ; Tue, 18 Apr 2023 12:30:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E75FDC433EF; Tue, 18 Apr 2023 12:30:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1681821027; bh=YE4qJSiOLagaNThNtw2dow7VwqzkMq7btgjyphOT2ZU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JuZLmqgIPi435c+4BSSXJHXokRO9rziURMRqm0KEaJUeUC7HxZG6xHEPo0Q/opegR MvZl58s+LAom7/vaAEc5MCRqQg7ec8+vbd/kMfNoMDPxBfaDlHl+tAtE48M+VfzeV4 IHEiHEQvBroMu0aqEW+s+LxyQ4cBROzL99UJz+Ag= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, lena wang , Eric Dumazet , =?UTF-8?q?Maciej=20=C5=BBenczykowski?= , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.4 62/92] udp6: fix potential access to stale information Date: Tue, 18 Apr 2023 14:21:37 +0200 Message-Id: <20230418120307.006587024@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230418120304.658273364@linuxfoundation.org> References: <20230418120304.658273364@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Eric Dumazet [ Upstream commit 1c5950fc6fe996235f1d18539b9c6b64b597f50f ] lena wang reported an issue caused by udpv6_sendmsg() mangling msg->msg_name and msg->msg_namelen, which are later read from ____sys_sendmsg() : /* * If this is sendmmsg() and sending to current destination address was * successful, remember it. */ if (used_address && err >= 0) { used_address->name_len = msg_sys->msg_namelen; if (msg_sys->msg_name) memcpy(&used_address->name, msg_sys->msg_name, used_address->name_len); } udpv6_sendmsg() wants to pretend the remote address family is AF_INET in order to call udp_sendmsg(). A fix would be to modify the address in-place, instead of using a local variable, but this could have other side effects. Instead, restore initial values before we return from udpv6_sendmsg(). Fixes: c71d8ebe7a44 ("net: Fix security_socket_sendmsg() bypass problem.") Reported-by: lena wang Signed-off-by: Eric Dumazet Reviewed-by: Maciej Żenczykowski Link: https://lore.kernel.org/r/20230412130308.1202254-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv6/udp.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index fd1ce0405b7ea..3777ab1273f5a 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -1283,9 +1283,11 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) msg->msg_name = &sin; msg->msg_namelen = sizeof(sin); do_udp_sendmsg: - if (__ipv6_only_sock(sk)) - return -ENETUNREACH; - return udp_sendmsg(sk, msg, len); + err = __ipv6_only_sock(sk) ? + -ENETUNREACH : udp_sendmsg(sk, msg, len); + msg->msg_name = sin6; + msg->msg_namelen = addr_len; + return err; } } -- 2.39.2