From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f45.google.com (mail-pj1-f45.google.com [209.85.216.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 916DB2BE059 for ; Tue, 16 Sep 2025 22:59:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758063580; cv=none; b=BZCuUHlpfhbcxWobaW1pXHjBFNbaNtJkxXsRrlZA7rs1k0EgF529fNNrsOkvxlRNIXs2a3MeX0nd4O6V6YV8gTnrG4jh/m7fEO5MBQ40iBDWFmjmlCH5+DUwYJdPoyCoQ38gavcL+2wh0lQHjVyZ7rVYogedhrKsuHJLuT+TOc0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758063580; c=relaxed/simple; bh=tPGnB6W8V2+1oCmv0j3Zz2bP5yCdnMpsIDDYeTAvBOI=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=GUMnzhwochp3UACBlePxbicmajFEPfVPDCN4HjfttEUG4dcj1g4bisJWmdyDGv5C1skFeIHFgiWokCvi+I1dIOdUKuZBAZp7JjSdnwhHrlboWhUJwwdonDdp59LfrSk2rDWeYb3oeWf1Y1tpZvIBB7iFOYS+xPhBxLw31566Lec= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=NTqDqXmf; arc=none smtp.client-ip=209.85.216.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="NTqDqXmf" Received: by mail-pj1-f45.google.com with SMTP id 98e67ed59e1d1-32e372c413aso2286979a91.0 for ; Tue, 16 Sep 2025 15:59:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1758063578; x=1758668378; darn=vger.kernel.org; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:from:to:cc:subject :date:message-id:reply-to; bh=S0FlaDdmidhcR8Sy73qdHacija4PnJkqCsQzapdYglc=; b=NTqDqXmfP4BLdXVJ30zhU8W1Y+DW1uda+UuNhd46J8HIIMMORxjVwkNmjVbIzzQTgP KjKx/R7wOzALjwHaxVszSPzuhRYNzLdqYQQz760uCuPZlTsxDSkhdOi55520Vbuw9Hgc M70j94pV5NtG5tN4ISCFs1mkhbKT+TQAOC47O6LxTSQ++dYCxjHwHK7iwU542XlghWVH FxM4LhbrGZIklnAWGA7rMkgvC5D3XmgHl+XGdFIiV36/hhZw9C7/2EeI0MSsqx4i6ZUv GQwk7BjsZG/ulPTm+DydS4SfVsuRKd1mpQlhGq3jp8CXZL5Qmsk8DkaKXovXo3xVXwkB KvUg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1758063578; x=1758668378; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=S0FlaDdmidhcR8Sy73qdHacija4PnJkqCsQzapdYglc=; b=fys4rLtiVJVGTlETaab46HQs5fhwA5CwLLKHfvCnkBX+bQewQIYC4wJybrmoTE7YHQ WSRoLC1X2SkWibRwNbcMQW5h3MQtyXAbdY1DdNJ2S16XjFzX3umi9dYBDPagt7hMZczc GBPmaI391SmJuxVQ7+8LgCwuyFGtkKKaHqQ887drV1mtgpIjXgRf80o6fkcVQA5ynoll GEmkcZnw6bJLU0Qm2WRDmyCrhLvwmqjp2y9TpSrmBMoumA5JgFRjjUhanPsF0A/HYqxC wlPnd6bk9HIXzzC8u6sglWFLxtykDxMTn9DSe5Staq/Eqv/0lhXhR5MOh7HDktcyPIoU nJFA== X-Forwarded-Encrypted: i=1; AJvYcCUt+NGsm257yJjkSdaUjfANjnQFtOS39i96ymhfh5VWvoP1O2dYkAYbt1a+gW/JEMgWW/4=@vger.kernel.org X-Gm-Message-State: AOJu0YxAhKx98syDUlLZpK1d/5lH7FZxFicD11cpKAIzV65Lk5UHWcWx BFeZLDIqj6ub+6P9EOQz46E3j29Gx3euhA/aC3+PpXYhWUgLb9q3TOAS X-Gm-Gg: ASbGnctxCcvF8adOsilKaFqqsx2H4gRkASli5T5slNrTqYJ1VriesT+ktotSCL71SV5 3/SSk4Bpzqw7eyYe7rz/U9YN1ZDM11ZW4XysuKnpS6CKHrA5b0/yluOXhKqIhs/zgOwIahiKwSM EU+a4WSgdTThUl53QdRilXgUtLHcVW5dKC30soQDQ2+Y5tE9uH2FqE7pOEA5+UJ/S8/2NNTQzIn FXPoDyPzvqGkAVTB7Y0BK47iD/ycCNF0VwHFkQ32029BIiw0PSNKWBfwk6TUY/YGK/gI7pfMWDL fJOhfNahKU6vN1ap8bfLaaXjRSzBRoS78+k67CGIlBsY+uMtUxYHEyKW2qR4lngIukNxvXvpNB0 NgWA028OVPmH8K71/tnZLWcOxaFQj37KvP+p5obqJBie/KQ== X-Google-Smtp-Source: AGHT+IF8JAjakJb69I4VWOObACBGqRZ5zZirDwAYS3ayqawrxgl18bSCO2wW1GRJ0yVxT3RHWhnyRg== X-Received: by 2002:a17:90b:51ca:b0:32e:345c:54fe with SMTP id 98e67ed59e1d1-32ee3f759aamr60937a91.20.1758063577889; Tue, 16 Sep 2025 15:59:37 -0700 (PDT) Received: from ?IPv6:2a03:83e0:115c:1:2a1:9747:e67f:953a? ([2620:10d:c090:500::4:432]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-32ed257bbf8sm652413a91.0.2025.09.16.15.59.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Sep 2025 15:59:37 -0700 (PDT) Message-ID: <5546d7d1074c1441a2fa0924eef0cf6eed5b98fc.camel@gmail.com> Subject: Re: [PATCH bpf 3/3] selftest/bpf: Test accesses to ctx padding From: Eduard Zingerman To: Paul Chaignon , bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau Date: Tue, 16 Sep 2025 15:59:36 -0700 In-Reply-To: <6efe1666f4747c2c0da87467cf1c61910f64a687.1758032885.git.paul.chaignon@gmail.com> References: <6efe1666f4747c2c0da87467cf1c61910f64a687.1758032885.git.paul.chaignon@gmail.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-1.fc42) Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2025-09-16 at 17:19 +0200, Paul Chaignon wrote: > This patch adds tests covering the various paddings in ctx structures. > In case of sk_lookup BPF programs, the behavior is a bit different > because accesses to the padding are explicitly allowed. Other cases > result in a clear reject from the verifier. >=20 > Signed-off-by: Paul Chaignon > --- Acked-by: Eduard Zingerman [...] > +#define padding_access(type, ctx, prev_field, sz) \ > + SEC(type) \ > + __description("access on " #ctx " padding after " #prev_field) \ > + __naked void padding_ctx_access_##ctx(void) \ > + { \ > + asm volatile (" \ > + r1 =3D *(u%[size] *)(r1 + %[off]); \ > + r0 =3D 0; \ > + exit;" \ > + : \ > + : __imm_const(size, sz * 8), \ ^^^^^^ Surprised this works, but nice. > + __imm_const(off, offsetofend(struct ctx, prev_field)) \ > + : __clobber_all); \ > + } [...]