Re: [PATCH] tpm-v2: allow algo name to be conigured for pcr_read and pcr_extend

On Thu, 28 Mar 2024 at 17:33, Tim Harvey tharvey@gateworks.com wrote:

On Thu, Mar 28, 2024 at 12:37 AM Ilias Apalodimas ilias.apalodimas@linaro.org wrote:

...

Hi Tim,

[...]

...

+/**

• • tpm2_algo_len() - Return an algo value and length given a algorithm name
• • @name: algorithm name
• • @rwlen: pointer to integer to populate with algorithm length if non-null
• • Return: algorithm value
• */

+int tpm2_algo_len(const char *name, int *rwlen);

+/**

• • tpm2_algo_len() - Return an algoithm name string
• • @algo: algorithm value
• • Return: algorithm string
• */

+const char *tpm2_algo_name(int algo);

#endif /* __TPM_V2_H */ diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c index 68eaaa639f89..6a090ce5810c 100644 --- a/lib/tpm-v2.c +++ b/lib/tpm-v2.c @@ -1555,3 +1555,49 @@ u32 tpm2_enable_nvcommits(struct udevice *dev, uint vendor_cmd,

    return 0;

}

+int tpm2_algo_len(const char *name, int *rwlen) +{

•   int algo = -EINVAL;
  

•   int len = 0;
  

•   if (!strcasecmp("sha1", name)) {
  

•           algo = TPM2_ALG_SHA1;
  

•           len = TPM2_SHA1_DIGEST_SIZE;
  

•   } else if (!strcasecmp("sha256", name)) {
  

•           algo = TPM2_ALG_SHA256;
  

•           len = TPM2_SHA256_DIGEST_SIZE;
  

•   } else if (!strcasecmp("sha384", name)) {
  

•           algo = TPM2_ALG_SHA384;
  

•           len = TPM2_SHA384_DIGEST_SIZE;
  

•   } else if (!strcasecmp("sha512", name)) {
  

•           algo = TPM2_ALG_SHA512;
  

•           len = TPM2_SHA512_DIGEST_SIZE;
  

•   } else if (!strcasecmp("sm3_256", name)) {
  

•           algo = TPM2_ALG_SM3_256;
  

•           len = TPM2_SM3_256_DIGEST_SIZE;
  

•   }
  

•   if (*rwlen)
  

•           *rwlen = len;
  

•   return algo;
  

+}

We already have tpm2_algorithm_to_len(). Instead of defining a new function, can we convert strings to 'enum tpm2_algorithms'? We can then reuse the existing function.

Hi Ilias,

Thanks - I didn't see tpm2_algorithm_to_len. Yes, I can use it but I still need to add a new function to turn the name into an algo.

Yep, that's fine,

I also didn't see tpm2_supported_algorithms; should I only support name-to-algorithm and algorithm-to-name for that subset?

Yea, that would be good, we can at least have a reference of what we currently support.

Cheers /Ilias

Best Regards,

Tim

...

...

+const char *tpm2_algo_name(int algo) +{

•   switch (algo) {
  

•   case TPM2_ALG_SHA1:
  

•           return "sha1";
  

•   case TPM2_ALG_SHA256:
  

•           return "sha256";
  

•   case TPM2_ALG_SHA384:
  

•           return "sha384";
  

•   case TPM2_ALG_SHA512:
  

•           return "sha512";
  

•   case TPM2_ALG_SM3_256:
  

•           return "sm3_256";
  

•   }
  

•   return "";
  

+}

2.25.1

Thanks /Ilias