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 631412C11D6; Wed, 25 Feb 2026 06:56:09 +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=1772002569; cv=none; b=SMSLvYl7iIuqDWQtFxvKCDnjzZLSZxjis71TyjHB+FNMRXTjOQNWickXd+MPakt6zzA3+5sl+797vapUkNB3lX4GNZXof0JpgKhlxHat+cSoDjNpr02aLTbbTriYwzfGIK1yX32va78f+63/XyyiZc1Ua0NQWeKUe7FJK0VsXuU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772002569; c=relaxed/simple; bh=AZT0/WdBUPk4dvLbppaHXQmSBIfXqWHG+vSLLIE19og=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oGjMhSGm/CNjm9dV7ftqvnRywn39hxY/9DldKDOmhs03cs4DUzkgIQ7YpbTeWtqPuWjNXCQ6y9C7/saWpM4Regy4UpuD3ZyLIZne/tllT1p4bFGqixIJ/5r1QusgQd23YryuOddf6cVH6szPr4uuNAwi1LLc38tWgeJM8LEuEvE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=lYJNeMOw; 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="lYJNeMOw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3C72BC4AF0E; Wed, 25 Feb 2026 06:56:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1772002569; bh=AZT0/WdBUPk4dvLbppaHXQmSBIfXqWHG+vSLLIE19og=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lYJNeMOw0HdkrSZ3ZY4J7wTP99BYwxcru3ynHJhp9YWyy1THEaWlsMTMXWDPti42A CxJJiUYW66zKcpDDUiguyirQj3+iHMG+a6g54I9OPOPVxChHij/j0KeJKZYqxrJfGk eMiKLMBLo/obIRgjWpLSbvGapVWxhA8h3ewfgs2c= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yizhou Zhao , Eric Dumazet , David Ahern , Ido Schimmel , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 302/641] inet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMP Date: Tue, 24 Feb 2026 17:20:28 -0800 Message-ID: <20260225012356.063796219@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260225012348.915798704@linuxfoundation.org> References: <20260225012348.915798704@linuxfoundation.org> User-Agent: quilt/0.69 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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit c89477ad79446867394360b29bb801010fc3ff22 ] Yizhou Zhao reported that simply having one RAW socket on protocol IPPROTO_RAW (255) was dangerous. socket(AF_INET, SOCK_RAW, 255); A malicious incoming ICMP packet can set the protocol field to 255 and match this socket, leading to FNHE cache changes. inner = IP(src="192.168.2.1", dst="8.8.8.8", proto=255)/Raw("TEST") pkt = IP(src="192.168.1.1", dst="192.168.2.1")/ICMP(type=3, code=4, nexthopmtu=576)/inner "man 7 raw" states: A protocol of IPPROTO_RAW implies enabled IP_HDRINCL and is able to send any IP protocol that is specified in the passed header. Receiving of all IP protocols via IPPROTO_RAW is not possible using raw sockets. Make sure we drop these malicious packets. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Yizhou Zhao Link: https://lore.kernel.org/netdev/20251109134600.292125-1-zhaoyz24@mails.tsinghua.edu.cn/ Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260203192509.682208-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv4/icmp.c | 14 ++++++++++---- net/ipv6/icmp.c | 6 ++++++ 2 files changed, 16 insertions(+), 4 deletions(-) diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index 1b7fb5d935edf..8e10e9e7676c5 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -843,16 +843,22 @@ static void icmp_socket_deliver(struct sk_buff *skb, u32 info) /* Checkin full IP header plus 8 bytes of protocol to * avoid additional coding at protocol handlers. */ - if (!pskb_may_pull(skb, iph->ihl * 4 + 8)) { - __ICMP_INC_STATS(dev_net_rcu(skb->dev), ICMP_MIB_INERRORS); - return; - } + if (!pskb_may_pull(skb, iph->ihl * 4 + 8)) + goto out; + + /* IPPROTO_RAW sockets are not supposed to receive anything. */ + if (protocol == IPPROTO_RAW) + goto out; raw_icmp_error(skb, protocol, info); ipprot = rcu_dereference(inet_protos[protocol]); if (ipprot && ipprot->err_handler) ipprot->err_handler(skb, info); + return; + +out: + __ICMP_INC_STATS(dev_net_rcu(skb->dev), ICMP_MIB_INERRORS); } static bool icmp_tag_validation(int proto) diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index cf6455cbe2cc9..306eec18e82c1 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -870,6 +870,12 @@ enum skb_drop_reason icmpv6_notify(struct sk_buff *skb, u8 type, if (reason != SKB_NOT_DROPPED_YET) goto out; + if (nexthdr == IPPROTO_RAW) { + /* Add a more specific reason later ? */ + reason = SKB_DROP_REASON_NOT_SPECIFIED; + goto out; + } + /* BUGGG_FUTURE: we should try to parse exthdrs in this packet. Without this we will not able f.e. to make source routed pmtu discovery. -- 2.51.0