Re: [PATCH v7 4/6] bootm: Support boot measurement
Hi Eddie,
[...]
>
> +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;
This is nice. Basically measuring becomes the boot command responsibility.
> +
> + 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;
> +
> + elog.log_size = 0;
> + 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, 9, 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, 0, 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 +778,10 @@ 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/boo
[PATCH v7 4/6] bootm: Support boot measurement
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
Reviewed-by: Simon Glass
---
Changes since v6:
- Added comment for bootm_measure
- Fixed line length in bootm_measure
boot/Kconfig| 23
boot/bootm.c| 72 +
cmd/booti.c | 1 +
cmd/bootm.c | 2 ++
cmd/bootz.c | 1 +
include/bootm.h | 11
include/image.h | 1 +
7 files changed, 111 insertions(+)
diff --git a/boot/Kconfig b/boot/Kconfig
index 5f491625c8..d0d5e5794c 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -629,6 +629,29 @@ 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 2eec60ec7b..e3ef18166d 100644
--- a/boot/bootm.c
+++ b/boot/bootm.c
@@ -22,6 +22,7 @@
#include
#include
#include
+#include
#if defined(CONFIG_CMD_USB)
#include
#endif
@@ -659,6 +660,73 @@ 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;
+
+ elog.log_size = 0;
+ 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, 9, 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, 0, 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 +778,10 @@ int do_bootm_states(struct cmd_tbl *cmdtp, int flag, int
