Hi Eddie, On Wed, Jan 25, 2023 at 11:18:07AM -0600, Eddie James wrote: > Add a configuration option to measure the boot through the bootm > function. Add the measurement state to the booti and bootz paths > as well. > > Signed-off-by: Eddie James <eaja...@linux.ibm.com> > --- > boot/Kconfig | 23 ++++++++++++++++ > boot/bootm.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++ > cmd/booti.c | 1 + > cmd/bootm.c | 2 ++ > cmd/bootz.c | 1 + > include/bootm.h | 2 ++ > include/image.h | 1 + > 7 files changed, 100 insertions(+) > > diff --git a/boot/Kconfig b/boot/Kconfig > index fdcfbae7b2..831b9e954c 100644 > --- a/boot/Kconfig > +++ b/boot/Kconfig > @@ -601,6 +601,29 @@ config LEGACY_IMAGE_FORMAT > loaded. If a board needs the legacy image format support in this > case, enable it here. > > +config MEASURED_BOOT > + bool "Measure boot images and configuration to TPM and event log" > + depends on HASH && TPM_V2 > + help > + This option enables measurement of the boot process. Measurement > + involves creating cryptographic hashes of the binary images that > + are booting and storing them in the TPM. In addition, a log of > + these hashes is stored in memory for the OS to verify the booted > + images and configuration. Enable this if the OS has configured > + some memory area for the event log and you intend to use some > + attestation tools on your system. > + > +if MEASURED_BOOT > + config MEASURE_DEVICETREE > + bool "Measure the devicetree image" > + default y if MEASURED_BOOT > + help > + On some platforms, the devicetree is not static as it may contain > + random MAC addresses or other such data that changes each boot. > + Therefore, it should not be measured into the TPM. In that case, > + disable the measurement here. > +endif # MEASURED_BOOT > + > config SUPPORT_RAW_INITRD > bool "Enable raw initrd images" > help > diff --git a/boot/bootm.c b/boot/bootm.c > index 15fce8ad95..c8423f2c60 100644 > --- a/boot/bootm.c > +++ b/boot/bootm.c > @@ -22,6 +22,7 @@ > #include <asm/global_data.h> > #include <asm/io.h> > #include <linux/sizes.h> > +#include <tpm-v2.h> > #if defined(CONFIG_CMD_USB) > #include <usb.h> > #endif > @@ -659,6 +660,72 @@ int bootm_process_cmdline_env(int flags) > return 0; > } > > +int bootm_measure(struct bootm_headers *images) > +{ > + int ret = 0; > + > + /* Skip measurement if EFI is going to do it */ > + if (images->os.os == IH_OS_EFI && > + IS_ENABLED(CONFIG_EFI_TCG2_PROTOCOL) && > + IS_ENABLED(CONFIG_BOOTM_EFI)) > + return ret; > + > + if (IS_ENABLED(CONFIG_MEASURED_BOOT)) { > + struct tcg2_event_log elog; > + struct udevice *dev; > + void *initrd_buf; > + void *image_buf; > + const char *s; > + u32 rd_len; > + > + ret = tcg2_measurement_init(&dev, &elog); > + if (ret) > + return ret; > + > + image_buf = map_sysmem(images->os.image_start, > + images->os.image_len); > + ret = tcg2_measure_data(dev, &elog, 8, images->os.image_len, > + image_buf, EV_COMPACT_HASH, > + strlen("linux") + 1, (u8 *)"linux"); > + if (ret) > + goto unmap_image; > + > + rd_len = images->rd_end - images->rd_start; > + initrd_buf = map_sysmem(images->rd_start, rd_len); > + ret = tcg2_measure_data(dev, &elog, 8, rd_len, initrd_buf, > + EV_COMPACT_HASH, strlen("initrd") + 1, > + (u8 *)"initrd");
The kernel, if loaded with EFI, measures the initrd data into PCR9. Although it's not important can we please use the same PCR here? > + if (ret) > + goto unmap_initrd; > + > + if (IS_ENABLED(CONFIG_MEASURE_DEVICETREE)) { > + ret = tcg2_measure_data(dev, &elog, 9, images->ft_len, > + (u8 *)images->ft_addr, > + EV_TABLE_OF_DEVICES, > + strlen("dts") + 1, > + (u8 *)"dts"); The PC client spec describes how ACPI data should be measured. Although it has no wording on the DTB, I think it should be treated in a similar fashion. This [0] was trying to do the same thing for EFI. Any reason we can't use PCR0 here? > + if (ret) > + goto unmap_initrd; > + } > + > + s = env_get("bootargs"); > + if (!s) > + s = ""; > + ret = tcg2_measure_data(dev, &elog, 1, strlen(s) + 1, (u8 *)s, > + EV_PLATFORM_CONFIG_FLAGS, > + strlen(s) + 1, (u8 *)s); > + > +unmap_initrd: > + unmap_sysmem(initrd_buf); [0] https://lore.kernel.org/u-boot/20221207151110.529106-1-etienne.carri...@linaro.org/ Regards /Ilias