From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f44.google.com (mail-ed1-f44.google.com [209.85.208.44]) (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 2CA2769DF7 for ; Tue, 21 May 2024 19:01:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.44 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716318103; cv=none; b=TIuhn75A9xuvycQqpc3kxGxgDsqfMQsc4mLbFm/TPMelMdY8fKqI1vQc7pHj2lrYCX+xQPq9RzkxiOyCts1zuA4qm5kyXrNtPMmkkw7QsvliItXje6Ex9/e2qHI8FBWlyHvkRwnLMRAWzRrhuyG+r5m+GzLvqHq2fdbq9JhRbIo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716318103; c=relaxed/simple; bh=8ix/SXPQG+wpfYFllBOv3clmJtpOeRZmoQkniDsFhak=; h=MIME-Version:References:In-Reply-To:From:Date:Message-ID:Subject: To:Cc:Content-Type; b=FuJcKrTeUyXbJNkazKuqnBJNOPuGn3i/YQSuEQQ4UyPMM7ZeDNCMMhZLPiNh+xIdedO1livBsnzLWRolcxON4JmLZQRz3M1QwzDt3MF9JO3KYb2mnl2X6dgYI+rqf7EHiGnEEs+2CFN2tCtDL/82xwsnT0cOA9GcioS2kwAoEeI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=Ht+jIFBk; arc=none smtp.client-ip=209.85.208.44 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Ht+jIFBk" Received: by mail-ed1-f44.google.com with SMTP id 4fb4d7f45d1cf-5750a8737e5so2670a12.0 for ; Tue, 21 May 2024 12:01:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1716318100; x=1716922900; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=8ix/SXPQG+wpfYFllBOv3clmJtpOeRZmoQkniDsFhak=; b=Ht+jIFBk3cNQ4LouwQ98RYvh7hB2eYM2ZbgCefBqRQRo0b01KQfg+wFBUHu50gKV5g wF41rDN07fNTqVHWvgbrAm7X3Y1gxjlW6PEbfBvkn7sytcQCC4zifIaBpcZYwXE+BfXC 03cGODrOk5d3Xp5xy9vrhkZ9JO5ZDto0cs5LjTZvX/sIjssCHFEefC5xFH4/tXLb1eS0 RnnVFHyYbrDpsoI43e2NPliiwFhSvW+LDdV6/Otk5AygJ2YOD6P7E4ZdhziJcQOV75Sa FOMD7a3jLAvoGNte0WvnFr3I95fA2vo8spEeNxI7LuZXmBlly1j0Jr//v4cYm7K5m6kb PICg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1716318100; x=1716922900; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=8ix/SXPQG+wpfYFllBOv3clmJtpOeRZmoQkniDsFhak=; b=VG/2zp+G1qGKUfRkLV3ddEcGg0nQxsImHQW4tHnz+vKrsmG9HzPl7/SZeY5S9FlnvL y4mgHenWVkTqlxlFYASNO+hnPnMvbT0GbwG7lZUB942lvqpacb7DocLS2zdrf8zygly3 pV8HR5DZDx3IyUYG24rT3mvO8/wZtORqN8bXpdd8EMsAteD2dQ7B94OEXWGYzwxvJsZH Px84e7afOwyU/znvErBCEn5OTcu786b/FUSUS0g0ypddQAr0UPaLpxMJm3l59SfyNYhQ qS2tBwNYCdC1nJpfTSM9LoQF9VF2HGaOlDQ6lpdEVd9Fs+lxIjfF0tUN2rC960+u/2E0 QBmQ== X-Forwarded-Encrypted: i=1; AJvYcCVNpZ8CqlFJiLmSqqZJFOf0yhrPdCsxfEdqdoBH1GqGoShjSNNczlt8nT3zoNGRy0xa+LNxLBwx6LE5ezcgazMMp6tpqpHc7q0U X-Gm-Message-State: AOJu0YxQectvZBXxZbHVYkHlQk8L/Oja30EYJB5kp+v34wEeakB8B2JQ i8yR23Z/mT45iERrrnSb3cRW/SutVXS2n2D3LSeDgK/2IYZ3Ux/CdohQ6BjjC3L5AkNK9ShjhKS bf0buDIqNgiPpqsQmIjuAa5gzNkHkZ9UNlnu9 X-Google-Smtp-Source: AGHT+IGsZHMYwB17/rHm2GPw8sDf3nKxTSkcIsaApOp5bux/QDPAPBCrzCKud52Dm0FNps4wM/XTSDtjC7pz3lXd3Qs= X-Received: by 2002:a05:6402:3594:b0:572:a154:7081 with SMTP id 4fb4d7f45d1cf-5782fc1d68amr18531a12.4.1716318100237; Tue, 21 May 2024 12:01:40 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20240427112451.1609471-1-stsp2@yandex.ru> In-Reply-To: <20240427112451.1609471-1-stsp2@yandex.ru> From: Jann Horn Date: Tue, 21 May 2024 21:01:02 +0200 Message-ID: Subject: Re: [PATCH v6 0/3] implement OA2_CRED_INHERIT flag for openat2() To: Stas Sergeev Cc: linux-kernel@vger.kernel.org, Stefan Metzmacher , Eric Biederman , Alexander Viro , Andy Lutomirski , Christian Brauner , Jan Kara , Jeff Layton , Chuck Lever , Alexander Aring , David Laight , linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, Paolo Bonzini , =?UTF-8?Q?Christian_G=C3=B6ttsche?= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Sat, Apr 27, 2024 at 1:24=E2=80=AFPM Stas Sergeev wrot= e: > This patch-set implements the OA2_CRED_INHERIT flag for openat2() syscall= . > It is needed to perform an open operation with the creds that were in > effect when the dir_fd was opened, if the dir was opened with O_CRED_ALLO= W > flag. This allows the process to pre-open some dirs and switch eUID > (and other UIDs/GIDs) to the less-privileged user, while still retaining > the possibility to open/create files within the pre-opened directory set. As Andy Lutomirski mentioned before, Linux already has Landlock (https://docs.kernel.org/userspace-api/landlock.html) for unprivileged filesystem sandboxing. What benefits does OA2_CRED_INHERIT have compared to Landlock?