Re: [PATCH 2/2 v4] tpm-v2: allow algoirthm name to be configured for pcr_read and pcr_extend

Hi Tim,

Minor typo on the commit message. Since there's a small change in patch #1 please fix this as well

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

On Wed, 22 May 2024 at 00:38, Tim Harvey tharvey@gateworks.com wrote:

For pcr_read and pcr_extend commands allow the digest algorithm to be specified by an additional argument. If not specified it will default to SHA256 for backwards compatibility.

Additionally update test_tpm2.py for the changes in output in pcr_read which now shows the algo and algo length in the output.

A follow-on to this could be to extend all PCR banks with the detected algo when the <digest_algo> argument is 'auto'.

Signed-off-by: Tim Harvey tharvey@gateworks.com

v4:

• update test_tpm2.py as required by changes in pcr_read output
• split out moving algos to an array of structs to its own patch and encorporate a fix for tpm2_algorithm_to_mask

v3:

• replace tpm2_supported_algorithms with struct and use this to relate hash algoirthm details

v2:

• use tpm2_algorithm_to_len
• use enum tpm2_algorithms
• make function names and parameter names more consistent with existing tpm-v2 functions
• fix various spelling errors

---

cmd/tpm-v2.c | 49 +++++++++++++++++++++++++++----------- test/py/tests/test_tpm2.py | 2 +- 2 files changed, 36 insertions(+), 15 deletions(-)

diff --git a/cmd/tpm-v2.c b/cmd/tpm-v2.c index 7e479b9dfe36..2343b4d9cb9e 100644 --- a/cmd/tpm-v2.c +++ b/cmd/tpm-v2.c @@ -99,11 +99,19 @@ static int do_tpm2_pcr_extend(struct cmd_tbl *cmdtp, int flag, int argc, struct tpm_chip_priv *priv; u32 index = simple_strtoul(argv[1], NULL, 0); void *digest = map_sysmem(simple_strtoul(argv[2], NULL, 0), 0);

•   int algo = TPM2_ALG_SHA256;
  

•   int algo_len;
    int ret;
    u32 rc;
  
  

•   if (argc != 3)
  

•   if (argc < 3 || argc > 4)
            return CMD_RET_USAGE;
  

•   if (argc == 4) {
  

•           algo = tpm2_name_to_algorithm(argv[3]);
  

•           if (algo < 0)
  

•                   return CMD_RET_FAILURE;
  

•   }
  

•   algo_len = tpm2_algorithm_to_len(algo);
  
    ret = get_tpm(&dev);
    if (ret)
  

@@ -116,8 +124,12 @@ static int do_tpm2_pcr_extend(struct cmd_tbl *cmdtp, int flag, int argc, if (index >= priv->pcr_count) return -EINVAL;

•   rc = tpm2_pcr_extend(dev, index, TPM2_ALG_SHA256, digest,
  

•                        TPM2_DIGEST_LEN);
  

•   rc = tpm2_pcr_extend(dev, index, algo, digest, algo_len);
  

•   if (!rc) {
  

•           printf("PCR #%u extended with %d byte %s digest\n", index,
  

•                  algo_len, tpm2_algorithm_name(algo));
  

•           print_byte_string(digest, algo_len);
  

•   }
  
    unmap_sysmem(digest);
  
  

@@ -127,15 +139,23 @@ static int do_tpm2_pcr_extend(struct cmd_tbl *cmdtp, int flag, int argc, static int do_tpm_pcr_read(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]) {

•   enum tpm2_algorithms algo = TPM2_ALG_SHA256;
    struct udevice *dev;
    struct tpm_chip_priv *priv;
    u32 index, rc;
  

•   int algo_len;
    unsigned int updates;
    void *data;
    int ret;
  
  

•   if (argc != 3)
  

•   if (argc < 3 || argc > 4)
            return CMD_RET_USAGE;
  

•   if (argc == 4) {
  

•           algo = tpm2_name_to_algorithm(argv[3]);
  

•           if (algo < 0)
  

•                   return CMD_RET_FAILURE;
  

•   }
  

•   algo_len = tpm2_algorithm_to_len(algo);
  
    ret = get_tpm(&dev);
    if (ret)
  

@@ -151,11 +171,12 @@ 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, TPM2_ALG_SHA256,
  

•                      data, TPM2_DIGEST_LEN, &updates);
  

•   rc = tpm2_pcr_read(dev, index, priv->pcr_select_min, algo,
  

•                      data, algo_len, &updates);
    if (!rc) {
  

•           printf("PCR #%u content (%u known updates):\n", index, updates);
  

•           print_byte_string(data, TPM2_DIGEST_LEN);
  

•           printf("PCR #%u %s %d byte content (%u known updates):\n", index,
  

•                  tpm2_algorithm_name(algo), algo_len, updates);
  

•           print_byte_string(data, algo_len);
    }
  
    unmap_sysmem(data);
  

@@ -415,14 +436,14 @@ U_BOOT_CMD(tpm2, CONFIG_SYS_MAXARGS, 1, do_tpm, "Issue a TPMv2.x command", " <hierarchy> is one of:\n" " * TPM2_RH_LOCKOUT\n" " * TPM2_RH_PLATFORM\n" -"pcr_extend <pcr> <digest_addr>\n" -" Extend PCR #<pcr> with digest at <digest_addr>.\n" +"pcr_extend <pcr> <digest_addr> [<digest_algo>]\n" +" Extend PCR #<pcr> with digest at <digest_addr> with digest_algo.\n" " <pcr>: index of the PCR\n" -" <digest_addr>: address of a 32-byte SHA256 digest\n" -"pcr_read <pcr> <digest_addr>\n" -" Read PCR #<pcr> to memory address <digest_addr>.\n" +" <digest_addr>: address of digest of digest_algo type (defaults to SHA256)\n" +"pcr_read <pcr> <digest_addr> [<digest_algo>]\n" +" Read PCR #<pcr> to memory address <digest_addr> with <digest_algo>.\n" " <pcr>: index of the PCR\n" -" <digest_addr>: address to store the a 32-byte SHA256 digest\n" +" <digest_addr>: address of digest of digest_algo type (defaults to SHA256)\n" "get_capability <capability> <property> <addr> <count>\n" " Read and display <count> entries indexed by <capability>/<property>.\n" " Values are 4 bytes long and are written at <addr>.\n" diff --git a/test/py/tests/test_tpm2.py b/test/py/tests/test_tpm2.py index 1d654cd4a23b..75f5d31fc675 100644 --- a/test/py/tests/test_tpm2.py +++ b/test/py/tests/test_tpm2.py @@ -257,7 +257,7 @@ def test_tpm2_pcr_read(u_boot_console): updates = int(re.findall(r'\d+', str)[0])

 # Check the output value

• assert 'PCR #10 content' in read_pcr

• assert 'PCR #10 sha256 32 byte content' in read_pcr assert '00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00' in read_pcr

@pytest.mark.buildconfigspec('cmd_tpm_v2')

2.25.1