diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 1c8d50a501d71a13608a0478d5567498cbf4c3dc..203a3b3cee67afa94c7b431964df1d30f6e159d2 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -49,6 +49,11 @@
* Under normal operation this function is done by
* tpm_buf_check_hmac_response(), so this is only to be used on
* error legs where the latter is not executed.
+ * tpm_buf_append_name() to add a handle to the buffer. This must be
+ * used in place of the usual tpm_buf_append_u32() for adding
+ * handles because handles have to be processed specially when
+ * calculating the HMAC. In particular, for NV, volatile and
+ * permanent objects you now need to provide the name.
*/
#include "tpm.h"
@@ -60,6 +65,9 @@
#include <crypto/hash.h>
#include <crypto/hmac.h>
+/* maximum number of names the TPM must remember for authorization */
+#define AUTH_MAX_NAMES 3
+
/*
* This is the structure that carries all the auth information (like
* session handle, nonces, session key and auth) from use to use it is
@@ -96,8 +104,31 @@ struct tpm2_auth {
u8 scratch[AES_KEY_BYTES + AES_BLOCK_SIZE];
};
u8 session_key[SHA256_DIGEST_SIZE];
+
+ /*
+ * memory for three authorization handles. We know them by
+ * handle, but they are part of the session by name, which
+ * we must compute and remember
+ */
+ u32 name_h[AUTH_MAX_NAMES];
+ u8 name[AUTH_MAX_NAMES][2 + SHA512_DIGEST_SIZE];
};
+/*
+ * Name Size based on TPM algorithm (assumes no hash bigger than 255)
+ */
+static u8 name_size(const u8 *name)
+{
+ static u8 size_map[] = {
+ [TPM_ALG_SHA1] = SHA1_DIGEST_SIZE,
+ [TPM_ALG_SHA256] = SHA256_DIGEST_SIZE,
+ [TPM_ALG_SHA384] = SHA384_DIGEST_SIZE,
+ [TPM_ALG_SHA512] = SHA512_DIGEST_SIZE,
+ };
+ u16 alg = get_unaligned_be16(name);
+ return size_map[alg] + 2;
+}
+
/*
* It turns out the crypto hmac(sha256) is hard for us to consume
* because it assumes a fixed key and the TPM seems to change the key
@@ -277,6 +308,104 @@ static void tpm_buf_append_salt(struct tpm_buf *buf, struct tpm_chip *chip)
out:
crypto_free_kpp(kpp);
}
+
+static int tpm2_parse_read_public(char *name, struct tpm_buf *buf)
+{
+ struct tpm_header *head = (struct tpm_header *)buf->data;
+ off_t offset = TPM_HEADER_SIZE;
+ u32 tot_len = be32_to_cpu(head->length);
+ u32 val;
+
+ /* we're starting after the header so adjust the length */
+ tot_len -= TPM_HEADER_SIZE;
+
+ /* skip public */
+ val = tpm_buf_read_u16(buf, &offset);
+ if (val > tot_len)
+ return -EINVAL;
+ offset += val;
+ /* name */
+ val = tpm_buf_read_u16(buf, &offset);
+ if (val != name_size(&buf->data[offset]))
+ return -EINVAL;
+ memcpy(name, &buf->data[offset], val);
+ /* forget the rest */
+ return 0;
+}
+
+static int tpm2_read_public(struct tpm_chip *chip, u32 handle, char *name)
+{
+ struct tpm_buf buf;
+ int rc;
+
+ rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_READ_PUBLIC);
+ if (rc)
+ return rc;
+
+ tpm_buf_append_u32(&buf, handle);
+ rc = tpm_transmit_cmd(chip, &buf, 0, "read public");
+ if (rc == TPM2_RC_SUCCESS)
+ rc = tpm2_parse_read_public(name, &buf);
+
+ tpm_buf_destroy(&buf);
+
+ return rc;
+}
+
+/**
+ * tpm_buf_append_name() - add a handle area to the buffer
+ * @chip: the TPM chip structure
+ * @buf: The buffer to be appended
+ * @handle: The handle to be appended
+ * @name: The name of the handle (may be NULL)
+ *
+ * In order to compute session HMACs, we need to know the names of the
+ * objects pointed to by the handles. For most objects, this is simply
+ * the actual 4 byte handle or an empty buf (in these cases @name
+ * should be NULL) but for volatile objects, permanent objects and NV
+ * areas, the name is defined as the hash (according to the name
+ * algorithm which should be set to sha256) of the public area to
+ * which the two byte algorithm id has been appended. For these
+ * objects, the @name pointer should point to this. If a name is
+ * required but @name is NULL, then TPM2_ReadPublic() will be called
+ * on the handle to obtain the name.
+ *
+ * As with most tpm_buf operations, success is assumed because failure
+ * will be caused by an incorrect programming model and indicated by a
+ * kernel message.
+ */
+void tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
+ u32 handle, u8 *name)
+{
+ enum tpm2_mso_type mso = tpm2_handle_mso(handle);
+ struct tpm2_auth *auth = chip->auth;
+ int slot;
+
+ slot = (tpm_buf_length(buf) - TPM_HEADER_SIZE)/4;
+ if (slot >= AUTH_MAX_NAMES) {
+ dev_err(&chip->dev, "TPM: too many handles\n");
+ return;
+ }
+ WARN(auth->session != tpm_buf_length(buf),
+ "name added in wrong place\n");
+ tpm_buf_append_u32(buf, handle);
+ auth->session += 4;
+
+ if (mso == TPM2_MSO_PERSISTENT ||
+ mso == TPM2_MSO_VOLATILE ||
+ mso == TPM2_MSO_NVRAM) {
+ if (!name)
+ tpm2_read_public(chip, handle, auth->name[slot]);
+ } else {
+ if (name)
+ dev_err(&chip->dev, "TPM: Handle does not require name but one is specified\n");
+ }
+
+ auth->name_h[slot] = handle;
+ if (name)
+ memcpy(auth->name[slot], name, name_size(name));
+}
+EXPORT_SYMBOL(tpm_buf_append_name);
/**
* tpm2_end_auth_session() - kill the allocated auth session
* @chip: the TPM chip structure
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 81b5a70ff80d02b0aee740ee64ad78bbcde2df3a..31c2065fcd35c912cb490faba68f5488a6300739 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -275,6 +275,7 @@ enum tpm2_command_codes {
TPM2_CC_CONTEXT_LOAD = 0x0161,
TPM2_CC_CONTEXT_SAVE = 0x0162,
TPM2_CC_FLUSH_CONTEXT = 0x0165,
+ TPM2_CC_READ_PUBLIC = 0x0173,
TPM2_CC_START_AUTH_SESS = 0x0176,
TPM2_CC_VERIFY_SIGNATURE = 0x0177,
TPM2_CC_GET_CAPABILITY = 0x017A,
@@ -292,6 +293,21 @@ enum tpm2_permanent_handles {
TPM2_RS_PW = 0x40000009,
};
+/* Most Significant Octet for key types */
+enum tpm2_mso_type {
+ TPM2_MSO_NVRAM = 0x01,
+ TPM2_MSO_SESSION = 0x02,
+ TPM2_MSO_POLICY = 0x03,
+ TPM2_MSO_PERMANENT = 0x40,
+ TPM2_MSO_VOLATILE = 0x80,
+ TPM2_MSO_PERSISTENT = 0x81,
+};
+
+static inline enum tpm2_mso_type tpm2_handle_mso(u32 handle)
+{
+ return handle >> 24;
+}
+
enum tpm2_capabilities {
TPM2_CAP_HANDLES = 1,
TPM2_CAP_COMMANDS = 2,
@@ -492,6 +508,8 @@ static inline void tpm_buf_append_empty_auth(struct tpm_buf *buf, u32 handle)
#ifdef CONFIG_TCG_TPM2_HMAC
int tpm2_start_auth_session(struct tpm_chip *chip);
+void tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
+ u32 handle, u8 *name);
void tpm2_end_auth_session(struct tpm_chip *chip);
#else
static inline int tpm2_start_auth_session(struct tpm_chip *chip)
@@ -501,6 +519,14 @@ static inline int tpm2_start_auth_session(struct tpm_chip *chip)
static inline void tpm2_end_auth_session(struct tpm_chip *chip)
{
}
+static inline void tpm_buf_append_name(struct tpm_chip *chip,
+ struct tpm_buf *buf,
+ u32 handle, u8 *name)
+{
+ tpm_buf_append_u32(buf, handle);
+ /* count the number of handles in the upper bits of flags */
+ buf->handles++;
+}
#endif /* CONFIG_TCG_TPM2_HMAC */
#endif