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([2a0d:3344:2712:7e10:4d59:d956:544f:d65c]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-70ba9382300sm100386566d6.64.2025.08.21.02.23.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 21 Aug 2025 02:23:26 -0700 (PDT) Message-ID: <062219ff-6abf-4289-84da-67a5c731564e@redhat.com> Date: Thu, 21 Aug 2025 11:23:23 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] ipv6: mcast: extend RCU protection in igmp6_send() To: Chanho Min , "David S . Miller" , Alexey Kuznetsov , Hideaki YOSHIFUJI Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, gunho.lee@lge.com, stable@vger.kernel.org, Sasha Levin , Greg Kroah-Hartman , Eric Dumazet , Jakub Kicinski References: <20250818092453.38281-1-chanho.min@lge.com> Content-Language: en-US From: Paolo Abeni In-Reply-To: <20250818092453.38281-1-chanho.min@lge.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/18/25 11:24 AM, Chanho Min wrote: > From: Eric Dumazet > > [ Upstream commit 087c1faa594fa07a66933d750c0b2610aa1a2946 ] > > igmp6_send() can be called without RTNL or RCU being held. > > Extend RCU protection so that we can safely fetch the net pointer > and avoid a potential UAF. > > Note that we no longer can use sock_alloc_send_skb() because > ipv6.igmp_sk uses GFP_KERNEL allocations which can sleep. > > Instead use alloc_skb() and charge the net->ipv6.igmp_sk > socket under RCU protection. > > Cc: stable@vger.kernel.org # 5.4 > Fixes: b8ad0cbc58f7 ("[NETNS][IPV6] mcast - handle several network namespace") > Signed-off-by: Eric Dumazet > Reviewed-by: David Ahern > Reviewed-by: Kuniyuki Iwashima > Link: https://patch.msgid.link/20250207135841.1948589-9-edumazet@google.com > [ chanho: Backports to v5.4.y. v5.4.y does not include > commit b4a11b2033b7(net: fix IPSTATS_MIB_OUTPKGS increment in OutForwDatagrams), > so IPSTATS_MIB_OUTREQUESTS was changed to IPSTATS_MIB_OUTPKGS defined as > 'OutRequests'. ] > Signed-off-by: Chanho Min > Signed-off-by: Jakub Kicinski > Signed-off-by: Sasha Levin FWIW, the SoB chain above looks incorrect, as I think that neither Jakub nor Sasha have touched yet this patch. /P