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Thu, 23 Apr 2026 06:58:05 -0700 (PDT) X-Received: by 2002:a17:90a:16c2:b0:361:423d:203d with SMTP id 98e67ed59e1d1-361423d248bmr17653579a91.8.1776952684805; Thu, 23 Apr 2026 06:58:04 -0700 (PDT) Received: from [192.168.88.32] ([150.228.93.216]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-36143b0dc2fsm19917307a91.3.2026.04.23.06.57.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 23 Apr 2026 06:58:04 -0700 (PDT) Message-ID: <17e348e1-b551-41e4-a512-906109dded4d@redhat.com> Date: Thu, 23 Apr 2026 15:57:55 +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 net] ipv4: clamp MCAST_MSFILTER getsockopt to optlen, not gf_numsrc To: Greg Kroah-Hartman , netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org, "David S. Miller" , David Ahern , Eric Dumazet , Jakub Kicinski , Simon Horman , stable References: <2026042054-dime-spectator-820e@gregkh> Content-Language: en-US From: Paolo Abeni In-Reply-To: <2026042054-dime-spectator-820e@gregkh> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 4/20/26 9:26 PM, Greg Kroah-Hartman wrote: > @@ -1486,8 +1491,12 @@ static int compat_ip_get_mcast_msfilter(struct sock *sk, sockptr_t optval, > gf.gf_interface = gf32.gf_interface; > gf.gf_fmode = gf32.gf_fmode; > num = gf.gf_numsrc = gf32.gf_numsrc; > - gf.gf_group = gf32.gf_group; > > + if (num > (len - size0) / sizeof(struct sockaddr_storage)) > + num = (len - size0) / sizeof(struct sockaddr_storage); > + gf.gf_numsrc = num; Since this is exactly the same code added above, likely a common helper would be useful. I guess we don't care if this would break bad application passing optval area properly sized for gf_numsrc sockets and a small optval, right? I don't see how to eventually save them. /P