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ShimUtils: Rename ShimToCert as ShimUtils; add new tools:
- shim-make.tool - sbat-info.tool - unsign-efi-sig-list.tool and update shim-to-cert.tool
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,101 @@ | ||
| ## OpenCore + OpenLinuxBoot + Secure Boot | ||
|
|
||
| If you want to use OpenCore + OpenLinuxBoot + Secure Boot it is possible to self-sign | ||
| everything, including any new Linux kernels after updates. This is possible since most | ||
| standard distros leave at least the previous kernel bootable (and OpenLinuxBoot exposes | ||
| this, via the Auxiliary menu), so you can boot into the old kernel, then own-sign the | ||
| new kernel. | ||
|
|
||
| More convenient may be to trust the signing keys of the specific distros which you | ||
| want to boot, which are bundled into the `shimx64.efi` file installed with each distro. | ||
| You can extract these with `shim-to-cert.tool` distributed with OpenCore, then install | ||
| them in your system Secure Boot `db` variable. Best practice would be to install the deny | ||
| list (`vendor.dbx`) from `shimx64.efi`, if any, into your system `dbx` variable, as well. | ||
| (Otherwise you are ignoring any recovations which the vendor has made.) | ||
|
|
||
| Recently, Shim has added SBAT support, as a more efficient way to revoke unsafe | ||
| binaries. Unfortunately, the SBAT enforcement code is part of Shim, it is not | ||
| something you can extract and add to your system Secure Boot database. | ||
|
|
||
| To work round this, the new recommended way to boot OpenCore + OpenLinuxBoot + | ||
| Secure Boot is to make an own-build of Shim. The vendor certificates | ||
| and revocation lists extracted from the distro `shimx64.efi` files are combined | ||
| and signed by you, into your own build of Shim; in this approach, these vendor | ||
| certificates should NOT also be included in the system Secure Boot database, | ||
| and should be removed if you added them previously. Including them in both places | ||
| will still boot under Secure Boot, but will effectively disable SBAT revocation. (If you are | ||
| own-signing everything, including Linux kernels after updates, this will still | ||
| work as before and the below is not needed. Equally, if you are not using | ||
| Secure Boot the below is not needed.) | ||
|
|
||
| The advantages of using an own-build of Shim are: | ||
| - No need to sign every kernel after updates (same as previous method) | ||
| - Linux SBAT integration (new) | ||
| - Linux MOK integration (new) | ||
| - No need to include the Windows intermediate CA - you are trusting whichever distro | ||
| keys you choose to include in your own Shim, directly (new) | ||
|
|
||
| Disadvantages are: | ||
| - Need to update when distro keys or distro recovation lists within Shim are updated | ||
| (same as previous method) | ||
| - Need to udpate when Shim SBAT level is updated (new) | ||
|
|
||
| ### Method | ||
| `Utilities/ShimUtils` includes a script `shim-make.tool` which will download the | ||
| current Shim source and build it for you, on macOS (using Ubuntu multipass) or on | ||
| Linux (Ubuntu and Fedora supported, others may work). | ||
|
|
||
| - Extract `vendor.db` and `vendor.dbx` files from the `shimx64.efi` file of each distro | ||
| which you want to load (using `shim-to-cert.tool`) | ||
| - Concatentate these (e.g. `cat fedora/vendor.db ubuntu/vendor.db > combined/vendor.db` | ||
| and `cat fedora/vendor.dbx ubuntu/vendor.dbx > combined/vendor.dbx`) | ||
| - Do not concatenate `.der` files directly, it will not work | ||
| - If you have a single distro with a single `.der` file, you can use `VENDOR_CERT_FILE` | ||
| instead of `VENDOR_DB_FILE` in the `make` options below; otherwise, you will need to use | ||
| `cert-to-efi-sig-list` from `efitools` to convert the `.der` file to a sig list - this | ||
| is done automatically by `shim-to-cert.tool` when `efitools` are available (in | ||
| Linux; or from within Ubuntu multipass on macOS, e.g. `multipass shell oc-shim`) | ||
| - Build a version of Shim which includes these concatenated signature lists (and | ||
| launches OpenCore.efi directly): | ||
| - `./shim-make.tool setup` | ||
| - `./shim-make.tool clean` (only needed if remaking after the initial make) | ||
| - `./shim-make.tool make VENDOR_DB_FILE=combined/vendor.db VENDOR_DBX_FILE=combined/vendor.dbx` | ||
| - Copy the relevant files (`shimx64.efi` and `mmx64.efi` as well as `BOOTX64.CSV`) to your mounted ESP volume, e.g.: | ||
| - `./shim-make.tool install /Volumes/EFI` (macOS) | ||
| - `sudo ./shim-make.tool install /boot/efi` (Linux) | ||
| - Sign the newly built `shimx64.efi` and `mmx64.efi` with your own ISK (see e.g. | ||
| https://habr.com/en/articles/273497/ - Google translate is your friend) | ||
| - If you do not copy and sign `mmx64.efi` as well as `shimx64.efi`, your system will hang if any MOK operations are attempted | ||
| - `BOOTX64.CSV` is not required and is for information only | ||
|
|
||
| As before you need to sign `OpenCore.efi` and any drivers it loads with your ISK. | ||
| You now also need to add an empty SBAT section to `OpenCore.efi` before signing it. | ||
|
|
||
| > An empty SBAT section means: 'I'm not part of the system which allocates SBAT names | ||
| and signs them into boot files, and I don't want this boot file to be revoked by any | ||
| future SBAT revocations'. Of course, you can still revoke your own-signed boot files | ||
| by rotating your own signing keys. | ||
|
|
||
| As noted [here](https://github.com/fwupd/fwupd/issues/2910) and | ||
| [here](https://github.com/rhboot/shim/issues/376), | ||
| the [documented](https://github.com/rhboot/shim/blob/main/SBAT.md) method for adding an | ||
| SBAT section to an already-linked `.efi` file does not work correctly (GNU `objcopy` | ||
| corrupts the executable). This | ||
| [third party python script](https://github.com/rhboot/shim/issues/376#issuecomment-1628004034) | ||
| does work. A suitable command is: | ||
|
|
||
| `pe-add-sections.py -s .sbat <(echo -n) -z .sbat -i OpenCore.efi -o OpenCore_empty_sbat.efi` | ||
|
|
||
| This file then needs to be signed and copied back into place, e.g.: | ||
|
|
||
| `sbsign --key {path-to}/ISK.key --cert {path-to}/ISK.pem OpenCore_empty_sbat.efi --output OpenCore.efi` | ||
|
|
||
| Finally, in order for OpenCore integration with Shim to work correctly | ||
| `UEFI/Quirks/ShimRetainProtocol` must be enabled in `config.plist`, and | ||
| `LauncherPath` should be set to `\EFI\OC\shimx64.efi`. | ||
|
|
||
| > Using Ubuntu multipass, it is now possible to operate entirely within macOS for signing, | ||
| key generation, etc. Note that the `~/shim_root` directory is already shared between | ||
| macOS and the `oc-shim` multipass VM (under its macOS path, e.g. `/Users/username/shim_root`), | ||
| and other macOS folders and volumes can be mounted if you wish, e.g. | ||
| `multipass mount /Volumes/EFI oc-shim:/Volumes/EFI`. |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,130 @@ | ||
| #!/bin/bash | ||
|
|
||
| # sbat-info.tool - Dump some useful information about own-build or standard shimx64.efi. | ||
| # | ||
| # Copyright (c) 2023, Michael Beaton. All rights reserved.<BR> | ||
| # SPDX-License-Identifier: BSD-3-Clause | ||
| # | ||
|
|
||
| LIGHT_GREEN='\033[1;32m' | ||
| YELLOW='\033[1;33m' | ||
| RED='\033[0;31m' | ||
| NC='\033[0m' # No Color | ||
|
|
||
| # Note: binutils can be placed last on path in macOS, to provide objcopy but avoid overwriting native tools. | ||
| command -v objcopy >/dev/null 2>&1 || { echo >&2 "objcopy not found - please install binutils package."; exit 1; } | ||
|
|
||
| usage () { | ||
| echo "Usage: $(basename "$0") <efifile>" | ||
| echo " Display SBAT information, if present, for any .efi executable." | ||
| echo " If the file is a version of Shim, also dislay Shim version info and SBAT enforcement level." | ||
| } | ||
|
|
||
| has_section () { | ||
| objdump -h "$1" | sed -nr 's/^ *[0-9]+ ([^ ]+).*/\1/p' | grep "$2" 1>/dev/null | ||
| } | ||
|
|
||
| if [ -z "$1" ]; then | ||
| usage | ||
| exit 1 | ||
| fi | ||
|
|
||
| # https://unix.stackexchange.com/a/84980/340732 | ||
| op_dir=$(mktemp -d 2>/dev/null || mktemp -d -t 'shim_info') || exit 1 | ||
|
|
||
| # objcopy and objdump do not like writing to stdout when part of a pipe, so just write to temp files | ||
| # Note: these get created as empty files even if the section does not exist | ||
| objcopy -O binary -j ".sbat" "$1" "${op_dir}/sbat" || { rm -rf "${op_dir}"; exit 1; } | ||
| objcopy -O binary -j ".sbatlevel" "$1" "${op_dir}/sbatlevel" || { rm -rf "${op_dir}"; exit 1; } | ||
| objcopy -O binary -j ".data.ident" "$1" "${op_dir}/data.ident" || { rm -rf "${op_dir}"; exit 1; } | ||
|
|
||
| if ! has_section "$1" ".data.ident" ; then | ||
| IS_SHIM=0 | ||
| echo -e "${YELLOW}Shim version info not present (probably not Shim)${NC}" | ||
| else | ||
| # Treat this section's presence as enough for the warning colours below | ||
| IS_SHIM=1 | ||
| FILE_HEADER="$(head -n 1 "${op_dir}/data.ident")" | ||
| SHIM_HEADER="UEFI SHIM" | ||
| if [ ! "$FILE_HEADER" = "$SHIM_HEADER" ] ; then | ||
| echo -e "${RED}!!!Version header found '${FILE_HEADER}' expected '${SHIM_HEADER}'${NC}" | ||
| else | ||
| echo -e "${YELLOW}Found ${SHIM_HEADER} version header${NC}" | ||
| fi | ||
|
|
||
| # shellcheck disable=SC2016 | ||
| VERSION="$(grep -a 'Version' "${op_dir}/data.ident" | sed -n 's/^\$Version: *\([^[:space:]]*\) *\$$/\1/p')" | ||
| if [ "$VERSION" = "" ] ; then | ||
| echo -e "${RED}Expected version number not present${NC}" | ||
| else | ||
| echo -e "Version: ${LIGHT_GREEN}${VERSION}${NC} (${VERSION}+, if own build)" | ||
| fi | ||
|
|
||
| # shellcheck disable=SC2016 | ||
| COMMIT="$(grep -a 'Commit' "${op_dir}/data.ident" | sed -n 's/^\$Commit: *\([^[:space:]]*\) *\$$/\1/p')" | ||
| if [ "$COMMIT" = "" ] ; then | ||
| echo -e "${RED}Expected commit id not present${NC}" | ||
| else | ||
| echo "Commit: ${COMMIT}" | ||
| fi | ||
| fi | ||
|
|
||
| echo | ||
| echo -e "${YELLOW}SBAT (when tested by other files or by self):${NC}" | ||
|
|
||
| if ! has_section "$1" ".sbat" ; then | ||
| echo | ||
| echo -e "${RED}No .sbat section${NC}" | ||
| else | ||
| echo | ||
| echo -n -e "$LIGHT_GREEN" | ||
| cat "${op_dir}/sbat" | ||
| echo -n -e "$NC" | ||
| if ! cat "${op_dir}/sbat" | grep -E "[a-z]|[A-Z]" 1>/dev/null ; then | ||
| # Red for shim; yellow for other file | ||
| if [ "$IS_SHIM" -eq 1 ] ; then | ||
| echo -n -e "$RED" | ||
| else | ||
| echo -n -e "$LIGHT_GREEN" | ||
| fi | ||
| echo -e "Present but empty .sbat section" | ||
| fi | ||
| fi | ||
|
|
||
| echo | ||
| echo -e "${YELLOW}SBAT Level (when testing other files):${NC}" | ||
|
|
||
| if ! has_section "$1" ".sbatlevel" ; then | ||
| echo | ||
| # Yellow for shim (not present in earlier shims with .sbat, ~15.6); green for other file | ||
| if [ "$IS_SHIM" -eq 1 ] ; then | ||
| echo -n -e "$YELLOW" | ||
| else | ||
| echo -n -e "$LIGHT_GREEN" | ||
| fi | ||
| echo -n "No .sbatlevel section" | ||
| echo -e "$NC" | ||
| else | ||
| sbat_level_version=$(dd if="${op_dir}/sbatlevel" ibs=1 skip=0 count=4 2>/dev/null | od -t u4 -An | xargs) || { rm -rf "${op_dir}"; exit 1; } | ||
| sbat_level_previous=$(dd if="${op_dir}/sbatlevel" ibs=1 skip=4 count=4 2>/dev/null | od -t u4 -An | xargs) || { rm -rf "${op_dir}"; exit 1; } | ||
| sbat_level_latest=$(dd if="${op_dir}/sbatlevel" ibs=1 skip=8 count=4 2>/dev/null | od -t u4 -An | xargs) || { rm -rf "${op_dir}"; exit 1; } | ||
|
|
||
| if [ "$sbat_level_version" -ne 0 ] ; then | ||
| echo -e "${RED}!!! Unexpected .sbatlevel version $sbat_level_version != 0 !!!${NC}" | ||
| fi | ||
|
|
||
| echo | ||
| echo -e "${YELLOW}Previous (more permissive boot, default):${NC}" | ||
| echo -n -e "$LIGHT_GREEN" | ||
| dd if="${op_dir}/sbatlevel" ibs=1 skip="$(($sbat_level_previous + 4))" count="$(($sbat_level_latest - $sbat_level_previous))" 2>/dev/null | ||
| echo -e "$NC" | ||
|
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||
| echo -e "${YELLOW}Latest (stricter boot, optional):${NC}" | ||
| echo -n -e "$LIGHT_GREEN" | ||
| dd if="${op_dir}/sbatlevel" ibs=1 skip="$(($sbat_level_latest + 4))" 2>/dev/null | ||
| echo -e "$NC" | ||
| fi | ||
|
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||
| rm -rf "${op_dir}" | ||
|
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||
| exit 0 |
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