On Tue, Nov 23, 2021 at 05:23:34PM +0530, Ruchika Gupta wrote:
> The current tpm2_pcr_read is hardcoded using SHA256. Make the
> actual command to TPM configurable to use wider range of algorithms.
> The current command line is kept as is i.e limited to SHA-256 only.
>
> Signed-off-by: Ruchika Gupta <ruchika.gu...@linaro.org>
> ---
> v2:
> Change algorithm from u32 to u16
> Add parameter description in function declaration
>
> cmd/tpm-v2.c | 3 ++-
> include/tpm-v2.h | 5 ++++-
> lib/tpm-v2.c | 12 ++++++++----
> 3 files changed, 14 insertions(+), 6 deletions(-)
>
> diff --git a/cmd/tpm-v2.c b/cmd/tpm-v2.c
> index daae91100a..4ea5f9f094 100644
> --- a/cmd/tpm-v2.c
> +++ b/cmd/tpm-v2.c
> @@ -151,7 +151,8 @@ static int do_tpm_pcr_read(struct cmd_tbl *cmdtp, int
> flag, int argc,
>
> data = map_sysmem(simple_strtoul(argv[2], NULL, 0), 0);
>
> - rc = tpm2_pcr_read(dev, index, priv->pcr_select_min, data, &updates);
> + rc = tpm2_pcr_read(dev, index, priv->pcr_select_min, TPM2_ALG_SHA256,
> + data, TPM2_DIGEST_LEN, &updates);
> if (!rc) {
> printf("PCR #%u content (%u known updates):\n", index, updates);
> print_byte_string(data, TPM2_DIGEST_LEN);
> diff --git a/include/tpm-v2.h b/include/tpm-v2.h
> index ceff7d245e..4e9dd52cb6 100644
> --- a/include/tpm-v2.h
> +++ b/include/tpm-v2.h
> @@ -512,13 +512,16 @@ u32 tpm2_nv_write_value(struct udevice *dev, u32 index,
> const void *data,
> * @dev TPM device
> * @idx Index of the PCR
> * @idx_min_sz Minimum size in bytes of the pcrSelect array
> + * @algorithm Algorithm used, defined in 'enum tpm2_algorithms'
> * @data Output buffer for contents of the named PCR
> + * @digest_len len of the data
> * @updates Optional out parameter: number of updates for this PCR
> *
> * @return code of the operation
> */
> u32 tpm2_pcr_read(struct udevice *dev, u32 idx, unsigned int idx_min_sz,
> - void *data, unsigned int *updates);
> + u16 algorithm, void *data, u32 digest_len,
> + unsigned int *updates);
>
> /**
> * Issue a TPM2_GetCapability command. This implementation is limited
> diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
> index 2e7b27bd6b..1bf627853a 100644
> --- a/lib/tpm-v2.c
> +++ b/lib/tpm-v2.c
> @@ -254,7 +254,8 @@ u32 tpm2_nv_write_value(struct udevice *dev, u32 index,
> const void *data,
> }
>
> u32 tpm2_pcr_read(struct udevice *dev, u32 idx, unsigned int idx_min_sz,
> - void *data, unsigned int *updates)
> + u16 algorithm, void *data, u32 digest_len,
> + unsigned int *updates)
> {
> u8 idx_array_sz = max(idx_min_sz, DIV_ROUND_UP(idx, 8));
> u8 command_v2[COMMAND_BUFFER_SIZE] = {
> @@ -264,7 +265,7 @@ u32 tpm2_pcr_read(struct udevice *dev, u32 idx, unsigned
> int idx_min_sz,
>
> /* TPML_PCR_SELECTION */
> tpm_u32(1), /* Number of selections */
> - tpm_u16(TPM2_ALG_SHA256), /* Algorithm of the hash */
> + tpm_u16(algorithm), /* Algorithm of the hash */
> idx_array_sz, /* Array size for selection */
> /* bitmap(idx) Selected PCR bitmap */
> };
> @@ -283,10 +284,13 @@ u32 tpm2_pcr_read(struct udevice *dev, u32 idx,
> unsigned int idx_min_sz,
> if (ret)
> return ret;
>
> + if (digest_len > response_len)
> + return TPM_LIB_ERROR;
> +
> if (unpack_byte_string(response, response_len, "ds",
> 10, &counter,
> - response_len - TPM2_DIGEST_LEN, data,
> - TPM2_DIGEST_LEN))
> + response_len - digest_len, data,
> + digest_len))
> return TPM_LIB_ERROR;
>
> if (updates)
> --
> 2.25.1
>
Reviewed-by: Ilias Apalodimas <ilias.apalodi...@linaro.org>
