Hi Eddie, On Thu, 12 Jan 2023 at 09:16, Eddie James <eaja...@linux.ibm.com> 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 30bc182fcd..e90d61412e 100644 > --- a/boot/Kconfig > +++ b/boot/Kconfig > @@ -587,6 +587,29 @@ 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)) {
Isn't this an EFI feature? I would expect MEASURED_BOOT to be a generic U-Boot feature that can be used by non-EFI code. So I believe what we need here is some sort of API for measuring things, enabled by MEASURED_BOOT, with EFI providing its implementation (in lib/efi_loader/). Driver model would be a good approach I think, or perhaps a linker list as is done with the environment / partitions? In any case, adding EFI code into bootm is a non-starter. The first thing is to define what the API is, e.g. with a header file called measured_boot.h or similar. > + 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"); > + 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"); > + 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); > + > +unmap_image: > + unmap_sysmem(image_buf); > + tcg2_measurement_term(dev, &elog, ret != 0); > + } > + > + return ret; > +} > + > /** > * Execute selected states of the bootm command. > * > @@ -710,6 +777,9 @@ int do_bootm_states(struct cmd_tbl *cmdtp, int flag, int > argc, > if (!ret && (states & BOOTM_STATE_FINDOTHER)) > ret = bootm_find_other(cmdtp, flag, argc, argv); > > + if (IS_ENABLED(CONFIG_MEASURED_BOOT) && !ret && (states & > BOOTM_STATE_MEASURE)) > + bootm_measure(images); > + > /* Load the OS */ > if (!ret && (states & BOOTM_STATE_LOADOS)) { > iflag = bootm_disable_interrupts(); > diff --git a/cmd/booti.c b/cmd/booti.c > index 6ac39193db..659bb10549 100644 > --- a/cmd/booti.c > +++ b/cmd/booti.c > @@ -127,6 +127,7 @@ int do_booti(struct cmd_tbl *cmdtp, int flag, int argc, > char *const argv[]) > #ifdef CONFIG_SYS_BOOT_RAMDISK_HIGH > BOOTM_STATE_RAMDISK | > #endif > + BOOTM_STATE_MEASURE | > BOOTM_STATE_OS_PREP | BOOTM_STATE_OS_FAKE_GO | > BOOTM_STATE_OS_GO, > &images, 1); > diff --git a/cmd/bootm.c b/cmd/bootm.c > index 37c2af96e0..0c4a713e02 100644 > --- a/cmd/bootm.c > +++ b/cmd/bootm.c > @@ -161,6 +161,8 @@ int do_bootm(struct cmd_tbl *cmdtp, int flag, int argc, > char *const argv[]) > BOOTM_STATE_OS_GO; > if (IS_ENABLED(CONFIG_SYS_BOOT_RAMDISK_HIGH)) > states |= BOOTM_STATE_RAMDISK; > + if (IS_ENABLED(CONFIG_MEASURED_BOOT)) > + states |= BOOTM_STATE_MEASURE; > if (IS_ENABLED(CONFIG_PPC) || IS_ENABLED(CONFIG_MIPS)) > states |= BOOTM_STATE_OS_CMDLINE; > ret = do_bootm_states(cmdtp, flag, argc, argv, states, &images, 1); > diff --git a/cmd/bootz.c b/cmd/bootz.c > index f1423573d2..87922bfc3c 100644 > --- a/cmd/bootz.c > +++ b/cmd/bootz.c > @@ -81,6 +81,7 @@ int do_bootz(struct cmd_tbl *cmdtp, int flag, int argc, > char *const argv[]) > #ifdef CONFIG_SYS_BOOT_RAMDISK_HIGH > BOOTM_STATE_RAMDISK | > #endif > + BOOTM_STATE_MEASURE | > BOOTM_STATE_OS_PREP | BOOTM_STATE_OS_FAKE_GO | > BOOTM_STATE_OS_GO, > &images, 1); > diff --git a/include/bootm.h b/include/bootm.h > index 044a4797ed..06d8b1acd8 100644 > --- a/include/bootm.h > +++ b/include/bootm.h > @@ -55,6 +55,8 @@ ulong bootm_disable_interrupts(void); > int bootm_find_images(int flag, int argc, char *const argv[], ulong start, > ulong size); > > +int bootm_measure(struct bootm_headers *images); > + > int do_bootm_states(struct cmd_tbl *cmdtp, int flag, int argc, > char *const argv[], int states, struct bootm_headers > *images, > int boot_progress); > diff --git a/include/image.h b/include/image.h > index bed75ce1b3..bd74e74a75 100644 > --- a/include/image.h > +++ b/include/image.h > @@ -407,6 +407,7 @@ struct bootm_headers { > #define BOOTM_STATE_OS_FAKE_GO 0x00000200 /* 'Almost' run the OS */ > #define BOOTM_STATE_OS_GO 0x00000400 > #define BOOTM_STATE_PRE_LOAD 0x00000800 > +#define BOOTM_STATE_MEASURE 0x00001000 > int state; > > #if defined(CONFIG_LMB) && !defined(USE_HOSTCC) > -- > 2.31.1 > Regards, Simon