[PATCH v2] tpm: use more than sha256 on pcr_extend

[Ilias Apalodimas]

The current tpm2_pcr_extend is hardcoded using SHA256.
Let's make the actual command to the TPM2 configurable so we can support
a wider range of algorithms and keep the current command line as-is i.e
limited to SHA256 only

Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
Reviewed-by: Simon Glass <sjg at chromium.org>
---
changes since v1:
 - add reference to the algorithms a user can pass to the function
   in the comments

 cmd/tpm-v2.c     |  3 ++-
 include/tpm-v2.h |  5 ++++-
 lib/tpm-v2.c     | 11 ++++++-----
 3 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/cmd/tpm-v2.c b/cmd/tpm-v2.c
index 5fa4788a72de..daae91100a2b 100644
--- a/cmd/tpm-v2.c
+++ b/cmd/tpm-v2.c
@@ -116,7 +116,8 @@ 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, digest);
+	rc = tpm2_pcr_extend(dev, index, TPM2_ALG_SHA256, digest,
+			     TPM2_DIGEST_LEN);
 
 	unmap_sysmem(digest);
 
diff --git a/include/tpm-v2.h b/include/tpm-v2.h
index 74c14fe7c51d..f1826ff38589 100644
--- a/include/tpm-v2.h
+++ b/include/tpm-v2.h
@@ -309,11 +309,14 @@ u32 tpm2_clear(struct udevice *dev, u32 handle, const char *pw,
  *
  * @dev		TPM device
  * @index	Index of the PCR
+ * @algorithm	Algorithm used, defined in 'enum tpm2_algorithms'
  * @digest	Value representing the event to be recorded
+ * @digest_len  len of the hash
  *
  * @return code of the operation
  */
-u32 tpm2_pcr_extend(struct udevice *dev, u32 index, const uint8_t *digest);
+u32 tpm2_pcr_extend(struct udevice *dev, u32 index, u32 algorithm,
+		    const u8 *digest, u32 digest_len);
 
 /**
  * Issue a TPM2_PCR_Read command.
diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
index 91759068cf03..1f3deb06e487 100644
--- a/lib/tpm-v2.c
+++ b/lib/tpm-v2.c
@@ -80,11 +80,12 @@ u32 tpm2_clear(struct udevice *dev, u32 handle, const char *pw,
 	return tpm_sendrecv_command(dev, command_v2, NULL, NULL);
 }
 
-u32 tpm2_pcr_extend(struct udevice *dev, u32 index, const uint8_t *digest)
+u32 tpm2_pcr_extend(struct udevice *dev, u32 index, u32 algorithm,
+		    const u8 *digest, u32 digest_len)
 {
 	u8 command_v2[COMMAND_BUFFER_SIZE] = {
 		tpm_u16(TPM2_ST_SESSIONS),	/* TAG */
-		tpm_u32(33 + TPM2_DIGEST_LEN),	/* Length */
+		tpm_u32(33 + digest_len),	/* Length */
 		tpm_u32(TPM2_CC_PCR_EXTEND),	/* Command code */
 
 		/* HANDLE */
@@ -99,7 +100,7 @@ u32 tpm2_pcr_extend(struct udevice *dev, u32 index, const uint8_t *digest)
 		tpm_u16(0),			/* Size of <hmac/password> */
 						/* <hmac/password> (if any) */
 		tpm_u32(1),			/* Count (number of hashes) */
-		tpm_u16(TPM2_ALG_SHA256),	/* Algorithm of the hash */
+		tpm_u16(algorithm),	/* Algorithm of the hash */
 		/* STRING(digest)		   Digest */
 	};
 	unsigned int offset = 33;
@@ -110,8 +111,8 @@ u32 tpm2_pcr_extend(struct udevice *dev, u32 index, const uint8_t *digest)
 	 *     - the digest
 	 */
 	ret = pack_byte_string(command_v2, sizeof(command_v2), "s",
-			       offset, digest, TPM2_DIGEST_LEN);
-	offset += TPM2_DIGEST_LEN;
+			       offset, digest, digest_len);
+	offset += digest_len;
 	if (ret)
 		return TPM_LIB_ERROR;
 
-- 
2.29.2