tpm: use more algorithms than sha256 on pcr_read

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

diff --git a/cmd/tpm-v2.c b/cmd/tpm-v2.c
index daae91100a2bb41b65efb288365d5f62e7b2602f..4ea5f9f094f6002ae94745ef220b163c437899ec 100644 (file)
--- 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 ceff7d245ed2a1871779014935bbbb1b2343b136..4e9dd52cb6c577d8474ea91486cbcc4ecc5640e6 100644 (file)
--- 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 2e7b27bd6bbaa7bf72d3ba837bd157db9dccbd4c..1bf627853afbf59f561e08f1caa3f2916e13a68d 100644 (file)
--- 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)