On 11/6/25 06:44, Alyssa Ross wrote: > Demi Marie Obenour writes: > >> On 11/6/25 05:20, Alyssa Ross wrote: >>> Demi Marie Obenour writes: >>> >>>> This gets rid of a lot of duplicated code and allows building the verity >>>> roothash and superblock only when needed. It also removes a hack used >>>> to work around make limitations. Furthermore, >>>> 'veritysetup --root-hash-file' is used to avoid an awk script. >>>> >>>> Signed-off-by: Demi Marie Obenour >>>> --- >>>> nix-shell --pure --run 'make run' in host/initramfs fails. This is a >>>> preexisting bug and I will send a separate patch for it. >>>> --- >>>> host/initramfs/Makefile | 25 +++++-------------------- >>>> host/initramfs/shell.nix | 4 +++- >>>> host/rootfs/Makefile | 24 +++++------------------- >>>> host/rootfs/shell.nix | 3 +++ >>>> host/verity.nix | 19 +++++++++++++++++++ >>>> lib/common.mk | 1 - >>>> pkgs/default.nix | 1 + >>>> release/live/Makefile | 26 +++++--------------------- >>>> release/live/default.nix | 4 +++- >>>> 9 files changed, 44 insertions(+), 63 deletions(-) >>> >>>> diff --git a/host/rootfs/Makefile b/host/rootfs/Makefile >>>> index 00d125774bb7b98736d0928c69cb307740cee034..bb602e2745fb5873204f453b35fc529c5c96f64a 100644 >>>> --- a/host/rootfs/Makefile >>>> +++ b/host/rootfs/Makefile >>>> @@ -82,25 +82,11 @@ clean: >>>> rm -rf build >>>> .PHONY: clean >>>> >>>> -# veritysetup format produces two files, but Make only (portably) >>>> -# supports one output per rule, so we combine the two outputs then >>>> -# define two more rules to separate them again. >>>> -build/rootfs.verity: $(dest) >>>> - $(VERITYSETUP) format $(dest) build/rootfs.verity.superblock.tmp \ >>>> - | awk -F ':[[:blank:]]*' '$$1 == "Root hash" {print $$2; exit}' \ >>>> - > build/rootfs.verity.roothash.tmp >>>> - cat build/rootfs.verity.roothash.tmp build/rootfs.verity.superblock.tmp \ >>>> - > $@ >>>> - rm build/rootfs.verity.roothash.tmp build/rootfs.verity.superblock.tmp >>>> -build/rootfs.verity.roothash: build/rootfs.verity >>>> - head -n 1 build/rootfs.verity > $@ >>>> -build/rootfs.verity.superblock: build/rootfs.verity >>>> - tail -n +2 build/rootfs.verity > $@ >>>> >>>> -build/live.img: ../../scripts/format-uuid.sh ../../scripts/make-gpt.sh ../../scripts/sfdisk-field.awk build/rootfs.verity.superblock build/rootfs.verity.roothash $(dest) >>>> +build/live.img: ../../scripts/format-uuid.sh ../../scripts/make-gpt.sh ../../scripts/sfdisk-field.awk $(ROOT_FS_VERITY) $(ROOT_FS_VERITY_ROOTHASH) $(dest) >>>> ../../scripts/make-gpt.sh $@.tmp \ >>>> - build/rootfs.verity.superblock:verity:$$(../../scripts/format-uuid.sh "$$(dd if=build/rootfs.verity.roothash bs=32 skip=1 count=1 status=none)") \ >>>> - $(dest):root:$$(../../scripts/format-uuid.sh "$$(head -c 32 build/rootfs.verity.roothash)") >>>> + "$$ROOT_FS_VERITY:verity:$$(../../scripts/format-uuid.sh "$$(dd "if=$$ROOT_FS_VERITY_ROOTHASH" bs=32 skip=1 count=1 status=none)")" \ >>>> + $(dest):root:$$(../../scripts/format-uuid.sh "$$(head -c 32 "$$ROOT_FS_VERITY_ROOTHASH")") >>>> mv $@.tmp $@ >>>> >>>> debug: >>>> @@ -110,7 +96,7 @@ debug: >>>> $(VMLINUX) >>>> .PHONY: debug >>>> >>>> -run: build/live.img $(EXT_FS) build/rootfs.verity.roothash >>>> +run: build/live.img $(EXT_FS) $(ROOT_FS_VERITY_ROOTHASH) >>>> @set -x && \ >>>> ext="$$(mktemp build/spectrum-rootfs-extfs.XXXXXXXXXX.img)" && \ >>>> truncate -s 10G "$$ext" && \ >>>> @@ -131,7 +117,7 @@ run: build/live.img $(EXT_FS) build/rootfs.verity.roothash >>>> -device virtconsole,chardev=virtiocon0 \ >>>> -drive file=build/live.img,if=virtio,format=raw,readonly=on \ >>>> -drive file=/proc/self/fd/3,if=virtio,format=raw \ >>>> - -append "earlycon console=hvc0 roothash=$$(< build/rootfs.verity.roothash) intel_iommu=on nokaslr" \ >>>> + -append "earlycon console=hvc0 roothash=$$(< "$$ROOT_FS_VERITY_ROOTHASH") intel_iommu=on nokaslr" \ >>>> -device virtio-keyboard \ >>>> -device virtio-mouse \ >>>> -device virtio-gpu \ >>>> diff --git a/host/rootfs/shell.nix b/host/rootfs/shell.nix >>>> index 1bf61bebf418333624e799cc8ca231f5783206f4..f16e4905adfbc8faebde19d0a1364ad9df90219b 100644 >>>> --- a/host/rootfs/shell.nix >>>> +++ b/host/rootfs/shell.nix >>>> @@ -5,6 +5,7 @@ >>>> import ../../lib/call-package.nix ( >>>> { callSpectrumPackage, rootfs, pkgsStatic, srcOnly, stdenv >>>> , btrfs-progs, cryptsetup, jq, netcat, qemu_kvm, reuse, util-linux >>>> +, verity >>>> }: >>>> >>>> rootfs.overrideAttrs ( >>>> @@ -20,5 +21,7 @@ rootfs.overrideAttrs ( >>>> KERNEL = "${passthru.kernel}/${stdenv.hostPlatform.linux-kernel.target}"; >>>> LINUX_SRC = srcOnly passthru.kernel.configfile; >>>> VMLINUX = "${passthru.kernel.dev}/vmlinux"; >>>> + ROOT_FS_VERITY = "${verity}/rootfs.verity.superblock"; >>>> + ROOT_FS_VERITY_ROOTHASH = "${verity}/rootfs.verity.roothash"; >>>> }; >>>> })) (_: {}) >>> >>> Surely this would break interactive development of the rootfs? >>> If I'm in a Nix shell, and make a change to any part of the rootfs, the >>> verity data in the environment will be out of date. I'd have to leave >>> and re-enter the Nix shell after /any/ change, waiting for an evaluation >>> each time, as opposed to the current situation where that's only >>> necessary when modifying Nix code or other Spectrum components. >> >> It would. Are there alternatives you can recommend? I don't want the >> updater and the installer to have to use two different copies. > > Have the host/rootfs derivation install the verity files alongside the > rootfs image. Then host/rootfs/Makefile is the single place we generate > the verity images, and it will still be regenerated by make when in a > Nix shell. Is it okay to instead remove dm-verity protection for the verity images? Given that we discussed using virtiofs for live development, I don't think the verity protection is necessary. It also slows down live development. -- Sincerely, Demi Marie Obenour (she/her/hers)