[PATCH 06/13] boot_verify: make it modifiable at start time

[Michael Olbrich]

On Sun, Mar 26, 2017 at 04:44:57AM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote:
> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
> ---
>  commands/bootm.c      |  2 +-
>  common/boot_verify.c  | 39 +++++++++++++++++++++++++++++++++------
>  common/bootm.c        |  2 +-
>  include/boot_verify.h | 15 ++++++++++++---
>  4 files changed, 47 insertions(+), 11 deletions(-)
> 
> diff --git a/commands/bootm.c b/commands/bootm.c
> index b35aaa914..cb520a1ba 100644
> --- a/commands/bootm.c
> +++ b/commands/bootm.c
> @@ -64,7 +64,7 @@ static int do_bootm(int argc, char *argv[])
>  	while ((opt = getopt(argc, argv, BOOTM_OPTS)) > 0) {
>  		switch(opt) {
>  		case 'c':
> -			if (data.verify < BOOT_VERIFY_HASH)
> +			if (data.verify > BOOT_VERIFY_HASH)

This is very confusing without a comment. It took me a while to figure out
that this does not actually change anything.
I think you could change the order in the array without modifying the enum.
Or at least comment on it in the commit message.

Regards,
Michael

>  				data.verify = BOOT_VERIFY_HASH;
>  			break;
>  		case 's':
> diff --git a/common/boot_verify.c b/common/boot_verify.c
> index afe929e68..9cbeb7a65 100644
> --- a/common/boot_verify.c
> +++ b/common/boot_verify.c
> @@ -11,22 +11,49 @@ enum boot_verify boot_get_verify_mode(void)
>  	return boot_verify_mode;
>  }
>  
> +/* keep it for the most secure to the less */
>  static const char * const boot_verify_names[] = {
> -#ifndef CONFIG_BOOT_FORCE_SIGNED_IMAGES
> -	[BOOT_VERIFY_NONE] = "none",
> -	[BOOT_VERIFY_HASH] = "hash",
> -	[BOOT_VERIFY_AVAILABLE] = "available",
> -#endif
>  	[BOOT_VERIFY_SIGNATURE] = "signature",
> +	[BOOT_VERIFY_AVAILABLE] = "available",
> +	[BOOT_VERIFY_HASH] = "hash",
> +	[BOOT_VERIFY_NONE] = "none",
>  };
>  
> +/* allow architecture to overwrite it such as EFI */
> +static int default_is_secure_mode(void)
> +{
> +	if (IS_ENABLED(CONFIG_BOOT_FORCE_SIGNED_IMAGES))
> +		return 1;
> +
> +	return 0;
> +}
> +
> +static int (*__is_secure_mode)(void) = default_is_secure_mode;
> +
> +int is_secure_mode(void)
> +{
> +	return __is_secure_mode();
> +}
> +
> +void boot_set_is_secure_mode(int (*fn)(void))
> +{
> +	__is_secure_mode = fn;
> +}
> +
>  static int init_boot_verify(void)
>  {
> +	int size;
> +
>  	if (IS_ENABLED(CONFIG_BOOT_FORCE_SIGNED_IMAGES))
>  		boot_verify_mode = BOOT_VERIFY_SIGNATURE;
>  
> +	if (is_secure_mode())
> +		size = 1;
> +	else
> +		size = ARRAY_SIZE(boot_verify_names);
> +
>  	globalvar_add_simple_enum("boot.verify", (unsigned int *)&boot_verify_mode,
> -				  boot_verify_names, ARRAY_SIZE(boot_verify_names));
> +				  boot_verify_names, size);
>  
>  	return 0;
>  }
> diff --git a/common/bootm.c b/common/bootm.c
> index 74202a829..1558f3c5d 100644
> --- a/common/bootm.c
> +++ b/common/bootm.c
> @@ -159,7 +159,7 @@ static int bootm_open_initrd_uimage(struct image_data *data)
>  		if (!data->initrd)
>  			return -EINVAL;
>  
> -		if (boot_get_verify_mode() > BOOT_VERIFY_NONE) {
> +		if (boot_get_verify_mode() != BOOT_VERIFY_NONE) {
>  			ret = uimage_verify(data->initrd);
>  			if (ret) {
>  				printf("Checking data crc failed with %s\n",
> diff --git a/include/boot_verify.h b/include/boot_verify.h
> index 3a4436584..ee830bf5c 100644
> --- a/include/boot_verify.h
> +++ b/include/boot_verify.h
> @@ -2,10 +2,10 @@
>  #define __BOOT_VERIFY_H__
>  
>  enum boot_verify {
> -	BOOT_VERIFY_NONE,
> -	BOOT_VERIFY_HASH,
> -	BOOT_VERIFY_AVAILABLE,
>  	BOOT_VERIFY_SIGNATURE,
> +	BOOT_VERIFY_AVAILABLE,
> +	BOOT_VERIFY_HASH,
> +	BOOT_VERIFY_NONE,
>  };
>  
>  #ifndef CONFIG_BOOT_VERIFY
> @@ -13,8 +13,17 @@ static inline enum boot_verify boot_get_verify_mode(void)
>  {
>  	return BOOT_VERIFY_NONE;
>  }
> +
> +static int inline is_secure_mode(void)
> +{
> +	return 0;
> +}
> +
> +static void inline boot_set_is_secure_mode(int (*fn)(void)) {}
>  #else
>  enum boot_verify boot_get_verify_mode(void);
> +int is_secure_mode(void);
> +void boot_set_is_secure_mode(int (*fn)(void));
>  #endif
>  
>  #endif /* __BOOT_VERIFY_H__ */
> -- 
> 2.11.0
> 
> 
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