man: Use ukify instead of objcopy in examples

These hardcoded VMA section offsets are a terrible thing and should
vanish from earth.
This commit is contained in:
Jan Janssen 2023-01-10 16:00:49 +01:00 committed by Zbigniew Jędrzejewski-Szmek
parent 2aba77057e
commit e069c57f06
2 changed files with 30 additions and 80 deletions

View file

@ -208,22 +208,13 @@
<example>
<title>Generate a unified kernel image, and calculate the expected TPM PCR 11 value</title>
<programlisting># objcopy \
--add-section .linux=vmlinux --change-section-vma .linux=0x2000000 \
--add-section .osrel=os-release.txt --change-section-vma .osrel=0x20000 \
--add-section .cmdline=cmdline.txt --change-section-vma .cmdline=0x30000 \
--add-section .initrd=initrd.cpio --change-section-vma .initrd=0x3000000 \
--add-section .splash=splash.bmp --change-section-vma .splash=0x100000 \
--add-section .dtb=devicetree.dtb --change-section-vma .dtb=0x40000 \
/usr/lib/systemd/boot/efi/linuxx64.efi.stub \
foo.efi
# systemd-measure calculate \
--linux=vmlinux \
--osrel=os-release.txt \
--cmdline=cmdline.txt \
--initrd=initrd.cpio \
--splash=splash.bmp \
--dtb=devicetree.dtb
<programlisting># ukify --output foo.efi \
--os-release @os-release.txt \
--cmdline @cmdline.txt \
--splash splash.bmp \
--devicetree devicetree.dtb \
--measure \
vmlinux initrd.cpio
11:sha1=d775a7b4482450ac77e03ee19bda90bd792d6ec7
11:sha256=bc6170f9ce28eb051ab465cd62be8cf63985276766cf9faf527ffefb66f45651
11:sha384=1cf67dff4757e61e5a73d2a21a6694d668629bbc3761747d493f7f49ad720be02fd07263e1f93061243aec599d1ee4b4
@ -249,17 +240,15 @@
--bank=sha256 \
--private-key=tpm2-pcr-private.pem \
--public-key=tpm2-pcr-public.pem > tpm2-pcr-signature.json
# objcopy \
--add-section .linux=vmlinux --change-section-vma .linux=0x2000000 \
--add-section .osrel=os-release.txt --change-section-vma .osrel=0x20000 \
--add-section .cmdline=cmdline.txt --change-section-vma .cmdline=0x30000 \
--add-section .initrd=initrd.cpio --change-section-vma .initrd=0x3000000 \
--add-section .splash=splash.bmp --change-section-vma .splash=0x100000 \
--add-section .dtb=devicetree.dtb --change-section-vma .dtb=0x40000 \
--add-section .pcrsig=tpm2-pcr-signature.json --change-section-vma .pcrsig=0x80000 \
--add-section .pcrpkey=tpm2-pcr-public.pem --change-section-vma .pcrpkey=0x90000 \
/usr/lib/systemd/boot/efi/linuxx64.efi.stub \
foo.efi</programlisting>
# ukify --output foo.efi \
--os-release @os-release.txt \
--cmdline @cmdline.txt \
--splash splash.bmp \
--devicetree devicetree.dtb \
--pcr-private-key tpm2-pcr-private.pem \
--pcr-public-key tpm2-pcr-public.pem \
--pcr-banks sha1,sha256 \
vmlinux initrd.cpio</programlisting>
<para>Later on, enroll the signed PCR policy on a LUKS volume:</para>
@ -314,17 +303,16 @@
--public-key=tpm2-pcr-initrd-public.pem \
--phase=enter-initrd \
--append=tpm2-pcr-signature.json.tmp >tpm2-pcr-signature.json
# objcopy \
--add-section .linux=vmlinux --change-section-vma .linux=0x2000000 \
--add-section .osrel=os-release.txt --change-section-vma .osrel=0x20000 \
--add-section .cmdline=cmdline.txt --change-section-vma .cmdline=0x30000 \
--add-section .initrd=initrd.cpio --change-section-vma .initrd=0x3000000 \
--add-section .splash=splash.bmp --change-section-vma .splash=0x100000 \
--add-section .dtb=devicetree.dtb --change-section-vma .dtb=0x40000 \
--add-section .pcrsig=tpm2-pcr-signature.json --change-section-vma .pcrsig=0x80000 \
--add-section .pcrpkey=tpm2-pcr-public.pem --change-section-vma .pcrpkey=0x90000 \
/usr/lib/systemd/boot/efi/linuxx64.efi.stub \
foo.efi</programlisting>
# ukify --output foo.efi \
--os-release @os-release.txt \
--cmdline @cmdline.txt \
--splash splash.bmp \
--devicetree devicetree.dtb \
--pcr-private-key tpm2-pcr-initrd-private.pem \
--pcr-public-key tpm2-pcr-initrd-public.pem \
--section .pcrsig=@tpm2-pcr-signature.json \
--section .pcrpkey=@tpm2-pcr-public.pem \
vmlinux initrd.cpio</programlisting>
</example>
<para>Note that in this example the <literal>.pcrpkey</literal> PE section contains the key covering all
@ -345,7 +333,7 @@
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-stub</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>objcopy</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>ukify</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-creds</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-pcrphase.service</refentrytitle><manvolnum>1</manvolnum></citerefentry>

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@ -382,45 +382,8 @@
<refsect1>
<title>Assembling Kernel Images</title>
<para>In order to assemble an UEFI PE kernel image from various components as described above, use an
<citerefentry project='man-pages'><refentrytitle>objcopy</refentrytitle><manvolnum>1</manvolnum></citerefentry> command line
like this:</para>
<programlisting>objcopy \
--add-section .osrel=os-release --change-section-vma .osrel=0x20000 \
--add-section .cmdline=cmdline.txt --change-section-vma .cmdline=0x30000 \
--add-section .dtb=devicetree.dtb --change-section-vma .dtb=0x40000 \
--add-section .splash=splash.bmp --change-section-vma .splash=0x100000 \
--add-section .linux=vmlinux --change-section-vma .linux=0x2000000 \
--add-section .initrd=initrd.cpio --change-section-vma .initrd=0x3000000 \
/usr/lib/systemd/boot/efi/linuxx64.efi.stub \
foo-unsigned.efi</programlisting>
<para>Note that these PE section offsets are example values and a properly assembled image must not
contain any overlapping sections (this includes already existing sections inside the stub before
assembly) or boot may fail.</para>
<para>This generates one PE executable file <filename>foo-unsigned.efi</filename> from the six individual
files for OS release information, kernel command line, boot splash image, kernel image, main initrd and
UEFI boot stub.</para>
<para>To then sign the resulting image for UEFI SecureBoot use an
<citerefentry project='archlinux'><refentrytitle>sbsign</refentrytitle><manvolnum>1</manvolnum></citerefentry> command like
the following:</para>
<programlisting>sbsign \
--key mykey.pem \
--cert mykey.crt \
--output foo.efi \
foo-unsigned.efi</programlisting>
<para>This expects a pair of X.509 private key and certificate as parameters and then signs the UEFI PE
executable we generated above for UEFI SecureBoot and generates a signed UEFI PE executable as
result.</para>
<para>See
<citerefentry><refentrytitle>systemd-measure</refentrytitle><manvolnum>1</manvolnum></citerefentry> for
an example involving the <literal>.pcrsig</literal> and <literal>.pcrpkey</literal> sections.</para>
<para>In order to assemble a bootable Unified Kernel Image from various components as described above, use
<citerefentry><refentrytitle>ukify</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
</refsect1>
<refsect1>
@ -432,8 +395,7 @@
<citerefentry><refentrytitle>systemd-sysext</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<ulink url="https://uapi-group.org/specifications/specs/boot_loader_specification">Boot Loader Specification</ulink>,
<ulink url="https://systemd.io/BOOT_LOADER_INTERFACE">Boot Loader Interface</ulink>,
<citerefentry project='man-pages'><refentrytitle>objcopy</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry project='archlinux'><refentrytitle>sbsign</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>ukify</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-measure</refentrytitle><manvolnum>1</manvolnum></citerefentry>
</para>
</refsect1>