Re: [PATCH v7 4/6] bootm: Support boot measurement

[Ilias Apalodimas <ilias.apalodimas@linaro.org>]

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/bootm.h b/include/bootm.h
> index 044a4797ed..76e8e38c82 100644
> --- a/include/bootm.h
> +++ b/include/bootm.h
> @@ -55,6 +55,17 @@ ulong bootm_disable_interrupts(void);
>  int bootm_find_images(int flag, int argc, char *const argv[], ulong start,
>  		      ulong size);
>  
> +/*
> + * Measure the boot images. Measurement is the process of hashing some binary
> + * data and storing it into secure memory, i.e. TPM PCRs. In addition, each
> + * measurement is logged into the platform event log such that the operating
> + * system can access it and perform attestation of the boot.
> + *
> + * @images:	The structure containing the various images to boot (linux,
> + *		initrd, dts, etc.)
> + */
> +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 7717a4c13d..f7414b5338 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
> 

Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>