From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.216.42 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793742435; b=KDSkQTbMHqKl80fGep3jvqMJ6bqG9rcoWXuegXusK6EP9/rk+zpWqUxPQJjMR0xeLPs+ Z9hPmmp93IHik/1To/NWIS8EEZft1p7Z7sFfk+9Pt5DD+lMl39ZEj+rUIlNJqfPGDss/8 8WqxyaDPuZzH87JXYF7WuWhLaAOMRTwKdqrrjPFf05EXU0by37854eh1eBO4hguY6QQI3 PCTTtCGzD3MqFNeUHpP0BhLNIM8ZJeScDPUSwabwpHayUJZefUWArE+XYEiuTnyiboA/G WKMbV0N4bI6d3EGC5KmMZloWS+86DCeEiiJQmCIufGlcgqSKxHN4F8PNQpb1kaIGUVQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793742435; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: Date:From:To:Cc:Subject:Message-ID:Mail-Followup-To:References: MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=Gslbebf1LMvPLM8Q5E/+GJDx3HzrVAFeNFBvrSeRD3A=; b=MDdT/RB7F0VrZJ8tg0omzOoBlioZJe+WuCckFfkEqsaOx2kQAGX99fAPEtp1jAEZ8g2l YAIpY9voktvqgE5fnu+iO53tVdmDq4Uq9pDQOPWkPT3l5UiZh+pfPUNiXm4cDHkTMNAXT M/yLpODwj/QJ9tPHiBILiwyw/RSJn1G9UUC2Vp1P5khkdFAoCjM4QXg0BfZYOIajqt/6j eGmPNudytjpEz6krJNYtw3NKHGkWUU12KiIcDvo//p9J7GcAJiVYQkT5vzXZR8P6VuOSM 0SVshPRLTy4YZagZRd/Qnou4y/0UC6Q7fCuZBnKEyq3mEPYImUVmkEnMMUUHky50qQg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none header.from=dama.to; spf=none smtp.mailfrom=dama.to; dkim=pass header.d=dama-to.20260707.gappssmtp.com header.i=@dama-to.20260707.gappssmtp.com header.a=rsa-sha256 header.s=20260707 header.b=Rz9zp9i3; arc=none smtp.remote-ip=209.85.216.42 Received: from mail-pj1-f42.google.com (mail-pj1-f42.google.com [209.85.216.42]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ABF28606A32E for ; Tue, 3 Nov 2026 21:47:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org ABF28606A32E Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=dama.to Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=dama.to Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=dama-to.20260707.gappssmtp.com header.i=@dama-to.20260707.gappssmtp.com header.a=rsa-sha256 header.s=20260707 header.b=Rz9zp9i3 Received: by mail-pj1-f42.google.com with SMTP id 98e67ed59e1d1-3ac451e128cso79858a91.1 for ; Tue, 03 Nov 2026 13:47:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dama-to.20260707.gappssmtp.com; s=20260707; t=1793742434; x=1794347234; darn=vger.kernel.org; h=in-reply-to:content-disposition:content-type:mime-version :references:mail-followup-to:message-id:subject:cc:to:from:date:from :to:cc:subject:date:message-id:reply-to:content-type; bh=Gslbebf1LMvPLM8Q5E/+GJDx3HzrVAFeNFBvrSeRD3A=; b=Rz9zp9i32GrLsqYq1Wv4k+MOEXRHkge1QpJ7C6/aNofnyPzJwsED2mBJ+BO36t2Hut U/X3EX/P4yEQJBoeXN5o24QnyrjGOEkzSU+wtx5SH/xuFKBlH+Cty7/2p2y+FTtjgmls 7I7QCjDZfxEAhev/iKP3MQSpbIsLV8Ph/6Q+DPR/n0huTq4GXHNbcfILEA1X4NPlfLj2 ND391PjSxTHj0exOiD1aylibkcBR08bsztmT24DXhejY8LZmDn5tUiL/cjmU17IMgXiy Yh3kpGdUO96yk7UD5JPAXXx4ItoLfJNwcyTu4xlyq02RpXu59D1Buwn7SqITNQ1GbrHI y5pg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1793742434; x=1794347234; h=in-reply-to:content-disposition:content-type:mime-version :references:mail-followup-to:message-id:subject:cc:to:from:date :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to:content-type; bh=Gslbebf1LMvPLM8Q5E/+GJDx3HzrVAFeNFBvrSeRD3A=; b=QBHxfjZWOU+KnWov5/eSjhyW1p4RWlzP9SiOh6AfQA920zYPlKPBVbBbJ2qAJJYmdZ RQnTRhEIxzQOs0iCT0/uemYYgUokO0s9J1lrK2gk18joERfX57SafMBOpv6uJHj1VCXp k159aI/pp7YUjlsSlj/Hd5c8+mroMhwiSnsd4FxM21szdNuTtWHa2C2oYx/JA6m9X1Xr rr3wgIJj0aW23ZUygacfaJB6m2beHNlMIVsAhiDmbtKKptErQ/npfPFt8NPD3pcW7722 KOSiL5Dhh2YwR2TOfI9lWGHT67poHXy0lHHPviG19zAEUFtmhQl/gm+RIYk5rCfHsyrf MlPw== X-Forwarded-Encrypted: i=1; AKwUvBx1uc1OWCB4iR0lSFmaC7N78Wx6mFUMJbRScaX+RHWwaPlH5jgAsUT8n8Ycmr47qhD5G+zd96t0WPsp0RA=@vger.kernel.org X-Gm-Message-State: APuU4Z80zcaHzvzf8DTk3Q/2Z7dXexnnB2lFHPpBIr/PpslnqTCX3dCH iTzgm6nQy8iANrRK3j2I9MtKS5jWbKldjRk8W7ZXrCRwx6K9lmdT6p0vIbD33Ht15IQ= X-Gm-Gg: AYBFou1ZQ6HzRH64cjwzgbvY2q1VGGFDHgkzOHGsdEMnfCn0pqdC2W9ZT+Ki0+84IgJ GWg43Syax0RedTa5RzliyVt3cgyz1JkvSKvAieAFTrEL5nyfXchzpMDbOUnyONJW2E9lDFOmpfk XRaFmrdpKNQgt2c927rnTMGLkhUyJkLB2GiqLI4fj9cUQLYFLaL0BawJrRnb8Icv+nQjVF8RvYu +IVx1edAcS7WovOzlW2ZH4zoxgYUza3KNdJdmoKJkrP9alN2QmYwGV4VbbuAlm3WW9DJimQqRY5 nDV0tjU+xWlyFzFA7wiPj2jLVUbdrCdRu7wbCkufDdOv0nV9Mpm1PAsdVxXvoeYjV6HtZUx1vz+ V+fiBjm4EsRrcaxwTmKGIAoH89cSSwyspEhzSzAQcoJx2m8lQILo+aRQPOlIbh60suXhyRY5FUO IL1v7V9VJGzonr//VSwvgE2hMBMxjVlZisOGROu9OrTX30rkdV4sKXwwhmqZLVMAPQYDIBAcJhn OCAhaeuvvToR9UPohTozsef/WU8+Czowpi1sbeU58pso1C/g/larYLEAGbSEFPBjlJ8/6q8ZZAn O+8FcVQUtgjjjfL19BU7y23lNdtWbiq/CDIa+iAGVeCF3EMKwkvhUlajzIrU3t8= X-Received: by 2002:a17:90b:584c:b0:3ac:fe93:a731 with SMTP id 98e67ed59e1d1-3ae8981e640mr10608128a91.56.1793742434015; Tue, 03 Nov 2026 13:47:14 -0800 (PST) Received: from localhost ([2a03:2880:2ff:4d::]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3ae87fc548fsm12790312a91.4.2026.11.03.13.47.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Nov 2026 13:47:12 -0800 (PST) Date: Tue, 3 Nov 2026 13:47:11 -0800 From: Joe Damato To: Breno Leitao Cc: David Ahern , Ido Schimmel , "David S. Miller" , Jakub Kicinski , Paolo Abeni , Simon Horman , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Ihor Solodrai , John Fastabend , Stanislav Fomichev , Shuah Khan , Eric Dumazet , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, david.laight.linux@gmail.com, kernel-team@meta.com Subject: Re: [PATCH net-next v4 2/7] net: cap sockopt_expand_out() at MAX_RW_COUNT Message-ID: Mail-Followup-To: Joe Damato , Breno Leitao , David Ahern , Ido Schimmel , "David S. Miller" , Jakub Kicinski , Paolo Abeni , Simon Horman , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Ihor Solodrai , John Fastabend , Stanislav Fomichev , Shuah Khan , Eric Dumazet , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, david.laight.linux@gmail.com, kernel-team@meta.com References: <20261103-sockopt_expand_out_v2-v4-0-2d36da923578@debian.org> <20261103-sockopt_expand_out_v2-v4-2-2d36da923578@debian.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261103-sockopt_expand_out_v2-v4-2-2d36da923578@debian.org> On Tue, Nov 03, 2026 at 03:01:01AM -0800, Breno Leitao wrote: > sockopt_expand_out() grows the output iterator up to INT_MAX, but the > MCAST_MSFILTER getters converted by the next two patches rewind it with > iov_iter_revert() once they know the real reply size. iov_iter_revert() > refuses to unroll past MAX_RW_COUNT: > > if (WARN_ON(unroll > MAX_RW_COUNT)) > return; > > MAX_RW_COUNT is INT_MAX rounded down to a page boundary, so a caller > that expands into the (MAX_RW_COUNT, INT_MAX] range and then reverts > hits that WARN_ON, and the iterator is left where it was instead of > rewound. So does a caller whose optlen already covers such a size. > > Cap the size at MAX_RW_COUNT instead, before the early return for an > optlen that already covers it, so a size that could never be reverted > later is rejected up front. > > Sashiko found this while reviewing the conversions. > > Acked-by: Ido Schimmel > Signed-off-by: Breno Leitao > --- > include/linux/net.h | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > Reviewed-by: Joe Damato