From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from atuin.qyliss.net (localhost [IPv6:::1]) by atuin.qyliss.net (Postfix) with ESMTP id 08F5A746A; Tue, 02 Dec 2025 03:47:53 +0000 (UTC) Received: by atuin.qyliss.net (Postfix, from userid 993) id 3FE95743B; Tue, 02 Dec 2025 03:47:49 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on atuin.qyliss.net X-Spam-Level: X-Spam-Status: No, score=-0.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,DMARC_PASS,FREEMAIL_FROM,SPF_HELO_NONE autolearn=unavailable autolearn_force=no version=4.0.1 Received: from mail-yx1-xb130.google.com (mail-yx1-xb130.google.com [IPv6:2607:f8b0:4864:20::b130]) by atuin.qyliss.net (Postfix) with ESMTPS id 8700573D3 for ; Tue, 02 Dec 2025 03:47:47 +0000 (UTC) Received: by mail-yx1-xb130.google.com with SMTP id 956f58d0204a3-6420dc2e5feso3916289d50.3 for ; Mon, 01 Dec 2025 19:47:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1764647265; x=1765252065; darn=spectrum-os.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=HeE7ZwUiSy3qiZZ+nseWxGw0onov3xOji5Fa50jpESU=; b=fCV75P6TNq1sIyioYFwQTxYeb0tkst8OrsGNbL+NeFntaDizkQ3+bieTRo6ErVeMxj fedcYAeIaHOHcyWBMIM3ywL8J7LNtWIVq6tRbTLOiIAM5aXOGQfj+3H2ERXgkRIiIdpb R75LdmqRxjUkNhberL4vt9GTB6VBdn8dAU3HlMmxDtxXF5kGZ80AT3Lxmyz3MvmP5uHg s66Xo3NGv6oQxGzxqwAWjRo7NnHUhY6ku2kN8uPbw4N8lo+w+WmD3kh8qa658bXjHY2p keBgtP5ip/IPI12fYTWJbcXjeFgrGXJ7gW/EgU7JTsDJAbZEaF346F6KePOy7LoYsqua QdSw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1764647265; x=1765252065; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-gg:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=HeE7ZwUiSy3qiZZ+nseWxGw0onov3xOji5Fa50jpESU=; b=DtjM49TEojyOg7wuR8U3oBWRJgA/aok9USvcTTVvGaV7Qa/NqBDtKHznVuQ7X2yh/e ZSMSa4b3EwuDzxrLW95T5P+Vdbq1iXAskXwbSaA5VIXwkzIVgRqqGmxmZi+J2quUuOGv 30uZLnBGm7W/uOeV9gfocl3FRoeZvjmHRclxCNhO7VGQfLfmv1AhQyiBloAXncHPxmpH mRYJIX+do2THAI7D4POTZvDJaGgBjDlz8bDMIZHmDkQ3i7VhZLXjU6REsLBiLi6OA7gi sVEYznFQ3rldl9Atd8NrloLE8fEzUvt2AkIg8xCj1vULVLMM2oPEw8Ln7FVu4ftBivpL T3iw== X-Gm-Message-State: AOJu0YycbOzu6Ym/9t4uBExSQCfC6k9BX5Y+pfKiFpR4nNdOxIOlAJIv uA4/uufl03EQCNIObhZYHsezjkNQh8hpMO1HZoI0WqiY+nEE+9tqx2Pr2iQaiA== X-Gm-Gg: ASbGncumqbYzLzbd6azYCERlTcj+8O/kb63puf7PGHCKvuBKcTPjvs9B32JI1euLAwx ZIGt5QmVgTD8HpK/mXqC1XDLlG78p8JsUqHiPcr+s/wOw4nodmI3xnxB6HonKzQs0yKJGXxwH8+ 4oG6yVX+wBNi+cRda+gs25QSlBh9hyyG/9k+0hwk//1PpgVXDwDdylfP5v73bJKMYHnsupPDbt3 V/Oo1yI538yJ3lhvWOEb2MWqCN6Z7iAPFh/H6MeqGmqVDkWbvqgiUbSS0TkebVjO3gUaGdbk9Ny Shn53dE7CVAL7Jpl5wCuBjIDiPMi/1ic979Wky4Dx0FbQGaOHpLRzwIThCNEm+eKwOjtCSWtMqs BVntNb+lvN59+fVnGirEQd/NwMwmebdvv/XTiWsgJ544XuhMZqoW2+SHt+MXvOO/LD7aTORQspZ Ubw4Zt/QsoHFWQWa0PNB4XSTgjO08Df7RchWB0GWoHEuJofdwD3NJQk1zBbc5yGQt1ZKKdNbCMY Ow6PVLhF2IoeNvH0cNMlLN+xYTVBq4xreg= X-Google-Smtp-Source: AGHT+IGf3MpJbmOEzROyeHwyuQRIN3PTCZselcgwheiEw5P0cRR76Lnq1GTqCXm/wZdQL6V6PN64Kg== X-Received: by 2002:a05:690e:1596:20b0:63f:9f6d:5b1e with SMTP id 956f58d0204a3-64302ae42e0mr25267906d50.67.1764647264781; Mon, 01 Dec 2025 19:47:44 -0800 (PST) Received: from localhost.localdomain (h96-60-249-169.cncrtn.broadband.dynamic.tds.net. [96.60.249.169]) by smtp.gmail.com with UTF8SMTPSA id 00721157ae682-78ad1045914sm58649467b3.53.2025.12.01.19.47.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Dec 2025 19:47:44 -0800 (PST) From: Demi Marie Obenour Date: Mon, 01 Dec 2025 22:46:38 -0500 Subject: [PATCH v2 1/4] host/rootfs: Sandbox crosvm MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20251201-sandbox-v2-1-9f4e58252c2b@gmail.com> References: <20251201-sandbox-v2-0-9f4e58252c2b@gmail.com> In-Reply-To: <20251201-sandbox-v2-0-9f4e58252c2b@gmail.com> To: Spectrum OS Development X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1764647197; l=3495; i=demiobenour@gmail.com; s=20250729; h=from:subject:message-id; bh=FoOhqhM2ihXwhUo/J/m83CKDq9sB+QWGpQIeuL6xf/c=; b=frAD/NiAPS30ka2Ip/K15nBWPg2omGyfhEB85QBp6x1DIymBDNZkRObqNplZiT9YYFLrpI4Yp IOAD7T6sNyNBPcgY29QlgQ79mfcSuz9xTLhkZeyJ+sxCm2Ts8wGctcc X-Developer-Key: i=demiobenour@gmail.com; a=ed25519; pk=X57Q4/YQDj9t4SBeKaDwvXYKB6quZJVx/DE2Ly2out0= Message-ID-Hash: 4ZYIGRJR6JKUC4NPNO7S4O5KVB6L2RJK X-Message-ID-Hash: 4ZYIGRJR6JKUC4NPNO7S4O5KVB6L2RJK X-MailFrom: demiobenour@gmail.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-devel.spectrum-os.org-0; header-match-devel.spectrum-os.org-1; header-match-devel.spectrum-os.org-2; header-match-devel.spectrum-os.org-3; header-match-devel.spectrum-os.org-4; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: Demi Marie Obenour , Alyssa Ross X-Mailman-Version: 3.3.9 Precedence: list List-Id: Patches and low-level development discussion Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: This means that a breach of crosvm is not guaranteed to be fatal. The Wayland socket is still only accessible by root, so crosvm must run as root. The known container escape via /proc/self/exe is blocked by bwrap being on a read-only filesystem. Container escapes via /proc are blocked by remounting /proc read-only. Crosvm does not have CAP_SYS_ADMIN so it cannot change mounts. The two remaining steps are: - Run crosvm as an unprivileged user. - Enable seccomp to block most system calls. The latter should be done from within crosvm itself. Signed-off-by: Demi Marie Obenour --- host/rootfs/default.nix | 4 ++-- .../template/data/service/vhost-user-gpu/run | 24 +++++++++++++++++++++- 2 files changed, 25 insertions(+), 3 deletions(-) diff --git a/host/rootfs/default.nix b/host/rootfs/default.nix index ca2084f26d58be5e0e1695634e125032c50f82b2..4716bb7298515b2940cad09bb55e42c196ce7ebc 100644 --- a/host/rootfs/default.nix +++ b/host/rootfs/default.nix @@ -10,7 +10,7 @@ pkgsMusl.callPackage ( { spectrum-host-tools, spectrum-router , lib, stdenvNoCC, nixos, runCommand, writeClosure, erofs-utils, s6-rc -, btrfs-progs, busybox, cloud-hypervisor, cosmic-files, crosvm +, btrfs-progs, bubblewrap, busybox, cloud-hypervisor, cosmic-files, crosvm , cryptsetup, dejavu_fonts, dbus, execline, foot, fuse3, iproute2 , inotify-tools, jq, kmod, mdevd, mesa, mount-flatpak, s6 , s6-linux-init, socat, systemd, util-linuxMinimal, virtiofsd @@ -25,7 +25,7 @@ let trivial; packages = [ - btrfs-progs cloud-hypervisor cosmic-files crosvm cryptsetup dbus + btrfs-progs bubblewrap cloud-hypervisor cosmic-files crosvm cryptsetup dbus execline fuse3 inotify-tools iproute2 jq kmod mdevd mount-flatpak s6 s6-linux-init s6-rc socat spectrum-host-tools spectrum-router util-linuxMinimal virtiofsd xdg-desktop-portal-spectrum-host diff --git a/host/rootfs/image/etc/s6-linux-init/run-image/service/vm-services/template/data/service/vhost-user-gpu/run b/host/rootfs/image/etc/s6-linux-init/run-image/service/vm-services/template/data/service/vhost-user-gpu/run index 0b4f6a00bc7aed0e721454d584d3bcd47fb18e2a..9b5dfad91944bd2c6c8994f387ab91394c68c1df 100755 --- a/host/rootfs/image/etc/s6-linux-init/run-image/service/vm-services/template/data/service/vhost-user-gpu/run +++ b/host/rootfs/image/etc/s6-linux-init/run-image/service/vm-services/template/data/service/vhost-user-gpu/run @@ -1,10 +1,32 @@ #!/bin/execlineb -P # SPDX-License-Identifier: EUPL-1.2+ # SPDX-FileCopyrightText: 2025 Alyssa Ross +# SPDX-FileCopyrightText: 2025 Demi Marie Obenour s6-ipcserver -1a 0700 -C 1 -b 1 env/crosvm.sock -crosvm --no-syslog device gpu +bwrap + --unshare-all + --unshare-user + --bind /run/user/0/wayland-1 /run/user/0/wayland-1 + --ro-bind /usr /usr + --ro-bind /lib /lib + --tmpfs /tmp + --dev /dev + --tmpfs /dev/shm + --ro-bind /nix /nix + --disable-userns + --proc /proc + --remount-ro /proc + --ro-bind /dev/null /proc/timer_list + --tmpfs /proc/scsi + --remount-ro /proc/scsi + --ro-bind /dev/null /proc/kcore + --ro-bind /dev/null /proc/sysrq-trigger + --tmpfs /proc/acpi + --remount-ro /proc/acpi + -- + crosvm --no-syslog device gpu --fd 0 --wayland-sock /run/user/0/wayland-1 --params "{\"context-types\":\"cross-domain\"}" -- 2.52.0