tpm: add PCR authentication commands support

Add support for the TPM2_PCR_SetAuthPolicy and
TPM2_PCR_SetAuthValue commands.

Change the command file and the help accordingly.

Note: These commands could not be tested because the TPMs available
do not support them, however they could be useful for someone else.
The user is warned by the command help.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

1 files changed, 100 insertions, 0 deletions

diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
index ffe8613edc..f1bbca8e7a 100644
--- a/lib/tpm-v2.c
+++ b/lib/tpm-v2.c
@@ -317,3 +317,103 @@ int tpm2_change_auth(u32 handle, const char *newpw, const ssize_t newpw_sz,
 
 	return tpm_sendrecv_command(command_v2, NULL, NULL);
 }
+
+u32 tpm2_pcr_setauthpolicy(const char *pw, const ssize_t pw_sz, u32 index,
+			   const char *key)
+{
+	u8 command_v2[COMMAND_BUFFER_SIZE] = {
+		tpm_u16(TPM2_ST_SESSIONS),	/* TAG */
+		tpm_u32(35 + pw_sz + TPM2_DIGEST_LEN), /* Length */
+		tpm_u32(TPM2_CC_PCR_SETAUTHPOL), /* Command code */
+
+		/* HANDLE */
+		tpm_u32(TPM2_RH_PLATFORM),	/* TPM resource handle */
+
+		/* AUTH_SESSION */
+		tpm_u32(9 + pw_sz),		/* Authorization size */
+		tpm_u32(TPM2_RS_PW),		/* session handle */
+		tpm_u16(0),			/* Size of <nonce> */
+						/* <nonce> (if any) */
+		0,				/* Attributes: Cont/Excl/Rst */
+		tpm_u16(pw_sz)			/* Size of <hmac/password> */
+		/* STRING(pw)			   <hmac/password> (if any) */
+
+		/* TPM2B_AUTH (TPM2B_DIGEST) */
+		/* tpm_u16(TPM2_DIGEST_LEN)	   Digest size length */
+		/* STRING(key)			   Digest buffer (PCR key) */
+
+		/* TPMI_ALG_HASH */
+		/* tpm_u16(TPM2_ALG_SHA256)   Algorithm of the hash */
+
+		/* TPMI_DH_PCR */
+		/* tpm_u32(index),		   PCR Index */
+	};
+	unsigned int offset = 27;
+	int ret;
+
+	/*
+	 * Fill the command structure starting from the first buffer:
+	 *     - the password (if any)
+	 *     - the PCR key length
+	 *     - the PCR key
+	 *     - the hash algorithm
+	 *     - the PCR index
+	 */
+	ret = pack_byte_string(command_v2, sizeof(command_v2), "swswd",
+			       offset, pw, pw_sz,
+			       offset + pw_sz, TPM2_DIGEST_LEN,
+			       offset + pw_sz + 2, key, TPM2_DIGEST_LEN,
+			       offset + pw_sz + 2 + TPM2_DIGEST_LEN,
+			       TPM2_ALG_SHA256,
+			       offset + pw_sz + 4 + TPM2_DIGEST_LEN, index);
+	offset += pw_sz + 2 + TPM2_DIGEST_LEN + 2 + 4;
+	if (ret)
+		return TPM_LIB_ERROR;
+
+	return tpm_sendrecv_command(command_v2, NULL, NULL);
+}
+
+u32 tpm2_pcr_setauthvalue(const char *pw, const ssize_t pw_sz, u32 index,
+			  const char *key, const ssize_t key_sz)
+{
+	u8 command_v2[COMMAND_BUFFER_SIZE] = {
+		tpm_u16(TPM2_ST_SESSIONS),	/* TAG */
+		tpm_u32(33 + pw_sz + TPM2_DIGEST_LEN), /* Length */
+		tpm_u32(TPM2_CC_PCR_SETAUTHVAL), /* Command code */
+
+		/* HANDLE */
+		tpm_u32(index),			/* Handle (PCR Index) */
+
+		/* AUTH_SESSION */
+		tpm_u32(9 + pw_sz),		/* Authorization size */
+		tpm_u32(TPM2_RS_PW),		/* session handle */
+		tpm_u16(0),			/* Size of <nonce> */
+						/* <nonce> (if any) */
+		0,				/* Attributes: Cont/Excl/Rst */
+		tpm_u16(pw_sz),			/* Size of <hmac/password> */
+		/* STRING(pw)			   <hmac/password> (if any) */
+
+		/* TPM2B_DIGEST */
+		/* tpm_u16(key_sz)		   Key length */
+		/* STRING(key)			   Key */
+	};
+	unsigned int offset = 27;
+	int ret;
+
+	/*
+	 * Fill the command structure starting from the first buffer:
+	 *     - the password (if any)
+	 *     - the number of digests, 1 in our case
+	 *     - the algorithm, sha256 in our case
+	 *     - the digest (64 bytes)
+	 */
+	ret = pack_byte_string(command_v2, sizeof(command_v2), "sws",
+			       offset, pw, pw_sz,
+			       offset + pw_sz, key_sz,
+			       offset + pw_sz + 2, key, key_sz);
+	offset += pw_sz + 2 + key_sz;
+	if (ret)
+		return TPM_LIB_ERROR;
+
+	return tpm_sendrecv_command(command_v2, NULL, NULL);
+}