Re: [tegrarcm PATCH v1 2/4] Add option --ml_rcm <rcm_ml_blob>

[Allen Martin <amartin-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

On Fri, Mar 04, 2016 at 03:44:45PM -0800, Jimmy Zhang wrote:
> This option along with "--pkc <keyfile>" allows user to generate signed
> query version rcm, miniloader rcm and signed bootloader (flasher). With
> these signed blob, user will then be able to run tegrarcm on a fused system
> without keyfile.
> 
> Command syntax:
>  $ ./tegrarcm --ml_rcm <ml_rcm_blob> --pkc <keyfile>
> 
> Example:
> 1. connect usb cable to recovery mode usb port
> 2. put target in recovery mode
> 3. run command as below:
> $ sudo ./tegrarcm --ml_rcm t124_ml_rcm.bin --pkc rsa_priv.der
> 

Why this extra step to write the signed miniloader to a separate file?
Why not just sign the miniloader in memory when using the --signed
option?  It looks like this is also generating a file for the signed
RCM messages, which should just be done in memory as well like we do
when using CMAC signing.


> +static int initialize_rcm(uint16_t devid, usb_device_t *usb,
> +			const char *keyfile, const char *ml_rcm_file)
> +{
> +	int ret = 0;
>  	uint8_t *msg_buff;
>  	int msg_len;
>  	uint32_t status;
>  	int actual_len;
> +	#define query_rcm_ext	".qry"

Don't need this #define, just use ".qry" directly below


> +static int sign_blob(const char *blob_filename, const char *keyfile)
> +{
> +	int ret;
> +	uint8_t rsa_pss_sig[2048 / 8];
> +
> +	#define sign_ext	".sig"

Here too


> diff --git a/src/rcm.c b/src/rcm.c
> index c7f0f8dddecc..cdf81309ae96 100644
> --- a/src/rcm.c
> +++ b/src/rcm.c
> @@ -202,11 +202,12 @@ static int rcm35_sign_msg(uint8_t *buf)
>  		return -EMSGSIZE;
>  	}
>  
> +	cmac_hash(msg->reserved, crypto_len, msg->object_sig.cmac_hash);
> +
>  	if (rcm_keyfile)
>  		rsa_pss_sign(rcm_keyfile, msg->reserved, crypto_len,
>  			msg->object_sig.rsa_pss_sig, msg->modulus);
> -	else
> -		cmac_hash(msg->reserved, crypto_len, msg->object_sig.cmac_hash);

I don't understand this part, this looks like it undoes what you put
in the previous patch.


> @@ -226,11 +227,10 @@ static int rcm40_sign_msg(uint8_t *buf)
>  		return -EMSGSIZE;
>  	}
>  
> +	cmac_hash(msg->reserved, crypto_len, msg->object_sig.cmac_hash);
>  	if (rcm_keyfile)
>  		rsa_pss_sign(rcm_keyfile, msg->reserved, crypto_len,
>  			msg->object_sig.rsa_pss_sig, msg->modulus);
> -	else
> -		cmac_hash(msg->reserved, crypto_len, msg->object_sig.cmac_hash);

Same here