[PATCH v3 07/11] tpm: Reduce duplication in a few functions

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

On Sat, Jan 23, 2021 at 10:26:03AM -0700, Simon Glass wrote:
> Update tpm2_clear() and tpm2_pcr_extend() so that the command size
> is not repeated twice. Add a small comment to the latter.
> 
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---
> 
> (no changes since v2)
> 
> Changes in v2:
> - Add comments for the offset value
> 
>  lib/tpm-v2.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
> index 1f3deb06e48..c4e869ec5b5 100644
> --- a/lib/tpm-v2.c
> +++ b/lib/tpm-v2.c
> @@ -47,9 +47,11 @@ u32 tpm2_self_test(struct udevice *dev, enum tpm2_yes_no full_test)
>  u32 tpm2_clear(struct udevice *dev, u32 handle, const char *pw,
>  	       const ssize_t pw_sz)
>  {
> +	/* Length of the message header, up to start of password */
> +	uint offset = 27;
>  	u8 command_v2[COMMAND_BUFFER_SIZE] = {
>  		tpm_u16(TPM2_ST_SESSIONS),	/* TAG */
> -		tpm_u32(27 + pw_sz),		/* Length */
> +		tpm_u32(offset + pw_sz),	/* Length */
>  		tpm_u32(TPM2_CC_CLEAR),		/* Command code */
>  
>  		/* HANDLE */
> @@ -64,7 +66,6 @@ u32 tpm2_clear(struct udevice *dev, u32 handle, const char *pw,
>  		tpm_u16(pw_sz),			/* Size of <hmac/password> */
>  		/* STRING(pw)			   <hmac/password> (if any) */
>  	};
> -	unsigned int offset = 27;
>  	int ret;
>  
>  	/*
> @@ -83,9 +84,11 @@ u32 tpm2_clear(struct udevice *dev, u32 handle, const char *pw,
>  u32 tpm2_pcr_extend(struct udevice *dev, u32 index, u32 algorithm,
>  		    const u8 *digest, u32 digest_len)
>  {
> +	/* Length of the message header, up to start of digest */
> +	uint offset = 33;
>  	u8 command_v2[COMMAND_BUFFER_SIZE] = {
>  		tpm_u16(TPM2_ST_SESSIONS),	/* TAG */
> -		tpm_u32(33 + digest_len),	/* Length */
> +		tpm_u32(offset + digest_len),	/* Length */
>  		tpm_u32(TPM2_CC_PCR_EXTEND),	/* Command code */
>  
>  		/* HANDLE */
> @@ -99,11 +102,12 @@ u32 tpm2_pcr_extend(struct udevice *dev, u32 index, u32 algorithm,
>  		0,				/* Attributes: Cont/Excl/Rst */
>  		tpm_u16(0),			/* Size of <hmac/password> */
>  						/* <hmac/password> (if any) */
> +
> +		/* hashes */
>  		tpm_u32(1),			/* Count (number of hashes) */
>  		tpm_u16(algorithm),	/* Algorithm of the hash */
>  		/* STRING(digest)		   Digest */
>  	};
> -	unsigned int offset = 33;
>  	int ret;
>  
>  	/*
> @@ -112,7 +116,6 @@ u32 tpm2_pcr_extend(struct udevice *dev, u32 index, u32 algorithm,
>  	 */
>  	ret = pack_byte_string(command_v2, sizeof(command_v2), "s",
>  			       offset, digest, digest_len);
> -	offset += digest_len;
>  	if (ret)
>  		return TPM_LIB_ERROR;
>  
> -- 
> 2.30.0.280.ga3ce27912f-goog
> 

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