tpm: Add NULL primary creation

The session handling code uses a "salted" session, meaning a session
whose salt is encrypted to the public part of another TPM key so an
observer cannot obtain it (and thus deduce the session keys).  This
patch creates and context saves in the tpm_chip area the primary key
of the NULL hierarchy for this purpose.

[jarkko@kernel.org: fixed documentation errors]
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

1 files changed, 69 insertions, 0 deletions

diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 6be263509e81..bc8c9a350e23 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -23,6 +23,7 @@
 #include <linux/fs.h>
 #include <linux/highmem.h>
 #include <crypto/hash_info.h>
+#include <crypto/aes.h>
 
 #define TPM_DIGEST_SIZE 20	/* Max TPM v1.2 PCR size */
 #define TPM_MAX_DIGEST_SIZE SHA512_DIGEST_SIZE
@@ -35,12 +36,15 @@ struct trusted_key_options;
 enum tpm_algorithms {
 	TPM_ALG_ERROR		= 0x0000,
 	TPM_ALG_SHA1		= 0x0004,
+	TPM_ALG_AES		= 0x0006,
 	TPM_ALG_KEYEDHASH	= 0x0008,
 	TPM_ALG_SHA256		= 0x000B,
 	TPM_ALG_SHA384		= 0x000C,
 	TPM_ALG_SHA512		= 0x000D,
 	TPM_ALG_NULL		= 0x0010,
 	TPM_ALG_SM3_256		= 0x0012,
+	TPM_ALG_ECC		= 0x0023,
+	TPM_ALG_CFB		= 0x0043,
 };
 
 /*
@@ -49,6 +53,11 @@ enum tpm_algorithms {
  */
 #define TPM_MAX_HASHES	5
 
+enum tpm2_curves {
+	TPM2_ECC_NONE		= 0x0000,
+	TPM2_ECC_NIST_P256	= 0x0003,
+};
+
 struct tpm_digest {
 	u16 alg_id;
 	u8 digest[TPM_MAX_DIGEST_SIZE];
@@ -116,6 +125,20 @@ struct tpm_chip_seqops {
 	const struct seq_operations *seqops;
 };
 
+/* fixed define for the curve we use which is NIST_P256 */
+#define EC_PT_SZ	32
+
+/*
+ * fixed define for the size of a name.  This is actually HASHALG size
+ * plus 2, so 32 for SHA256
+ */
+#define TPM2_NAME_SIZE	34
+
+/*
+ * The maximum size for an object context
+ */
+#define TPM2_MAX_CONTEXT_SIZE 4096
+
 struct tpm_chip {
 	struct device dev;
 	struct device devs;
@@ -170,6 +193,17 @@ struct tpm_chip {
 
 	/* active locality */
 	int locality;
+
+#ifdef CONFIG_TCG_TPM2_HMAC
+	/* details for communication security via sessions */
+
+	/* saved context for NULL seed */
+	u8 null_key_context[TPM2_MAX_CONTEXT_SIZE];
+	 /* name of NULL seed */
+	u8 null_key_name[TPM2_NAME_SIZE];
+	u8 null_ec_key_x[EC_PT_SZ];
+	u8 null_ec_key_y[EC_PT_SZ];
+#endif
 };
 
 #define TPM_HEADER_SIZE		10
@@ -194,6 +228,7 @@ enum tpm2_timeouts {
 enum tpm2_structures {
 	TPM2_ST_NO_SESSIONS	= 0x8001,
 	TPM2_ST_SESSIONS	= 0x8002,
+	TPM2_ST_CREATION	= 0x8021,
 };
 
 /* Indicates from what layer of the software stack the error comes from */
@@ -243,6 +278,7 @@ enum tpm2_command_codes {
 };
 
 enum tpm2_permanent_handles {
+	TPM2_RH_NULL		= 0x40000007,
 	TPM2_RS_PW		= 0x40000009,
 };
 
@@ -318,9 +354,28 @@ struct tpm_buf {
 enum tpm2_object_attributes {
 	TPM2_OA_FIXED_TPM		= BIT(1),
 	TPM2_OA_FIXED_PARENT		= BIT(4),
+	TPM2_OA_SENSITIVE_DATA_ORIGIN	= BIT(5),
 	TPM2_OA_USER_WITH_AUTH		= BIT(6),
+	TPM2_OA_NO_DA			= BIT(10),
+	TPM2_OA_RESTRICTED		= BIT(16),
+	TPM2_OA_DECRYPT			= BIT(17),
 };
 
+/*
+ * definitions for the canonical template.  These are mandated
+ * by the TCG key template documents
+ */
+
+#define AES_KEY_BYTES	AES_KEYSIZE_128
+#define AES_KEY_BITS	(AES_KEY_BYTES*8)
+#define TPM2_OA_TMPL	(TPM2_OA_NO_DA |			\
+			 TPM2_OA_FIXED_TPM |			\
+			 TPM2_OA_FIXED_PARENT |			\
+			 TPM2_OA_SENSITIVE_DATA_ORIGIN |	\
+			 TPM2_OA_USER_WITH_AUTH |		\
+			 TPM2_OA_DECRYPT |			\
+			 TPM2_OA_RESTRICTED)
+
 enum tpm2_session_attributes {
 	TPM2_SA_CONTINUE_SESSION	= BIT(0),
 };
@@ -373,6 +428,16 @@ extern int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
 extern int tpm_get_random(struct tpm_chip *chip, u8 *data, size_t max);
 extern struct tpm_chip *tpm_default_chip(void);
 void tpm2_flush_context(struct tpm_chip *chip, u32 handle);
+
+static inline void tpm_buf_append_empty_auth(struct tpm_buf *buf, u32 handle)
+{
+	/* simple authorization for empty auth */
+	tpm_buf_append_u32(buf, 9);		/* total length of auth */
+	tpm_buf_append_u32(buf, handle);
+	tpm_buf_append_u16(buf, 0);		/* nonce len */
+	tpm_buf_append_u8(buf, 0);		/* attributes */
+	tpm_buf_append_u16(buf, 0);		/* hmac len */
+}
 #else
 static inline int tpm_is_tpm2(struct tpm_chip *chip)
 {
@@ -399,5 +464,9 @@ static inline struct tpm_chip *tpm_default_chip(void)
 {
 	return NULL;
 }
+
+static inline void tpm_buf_append_empty_auth(struct tpm_buf *buf, u32 handle)
+{
+}
 #endif
 #endif