1 files changed, 528 insertions, 0 deletions

diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
new file mode 100644
index 000000000000..e2e059d8ffec
--- /dev/null
+++ b/drivers/char/tpm/tpm2-space.c
@@ -0,0 +1,528 @@
+/*
+ * Copyright (C) 2016 Intel Corporation
+ *
+ * Authors:
+ * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
+ *
+ * Maintained by: <tpmdd-devel@lists.sourceforge.net>
+ *
+ * This file contains TPM2 protocol implementations of the commands
+ * used by the kernel internally.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+
+#include <linux/gfp.h>
+#include <asm/unaligned.h>
+#include "tpm.h"
+
+enum tpm2_handle_types {
+	TPM2_HT_HMAC_SESSION	= 0x02000000,
+	TPM2_HT_POLICY_SESSION	= 0x03000000,
+	TPM2_HT_TRANSIENT	= 0x80000000,
+};
+
+struct tpm2_context {
+	__be64 sequence;
+	__be32 saved_handle;
+	__be32 hierarchy;
+	__be16 blob_size;
+} __packed;
+
+static void tpm2_flush_sessions(struct tpm_chip *chip, struct tpm_space *space)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(space->session_tbl); i++) {
+		if (space->session_tbl[i])
+			tpm2_flush_context_cmd(chip, space->session_tbl[i],
+					       TPM_TRANSMIT_UNLOCKED);
+	}
+}
+
+int tpm2_init_space(struct tpm_space *space)
+{
+	space->context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!space->context_buf)
+		return -ENOMEM;
+
+	space->session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (space->session_buf == NULL) {
+		kfree(space->context_buf);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space)
+{
+	mutex_lock(&chip->tpm_mutex);
+	tpm2_flush_sessions(chip, space);
+	mutex_unlock(&chip->tpm_mutex);
+	kfree(space->context_buf);
+	kfree(space->session_buf);
+}
+
+static int tpm2_load_context(struct tpm_chip *chip, u8 *buf,
+			     unsigned int *offset, u32 *handle)
+{
+	struct tpm_buf tbuf;
+	struct tpm2_context *ctx;
+	unsigned int body_size;
+	int rc;
+
+	rc = tpm_buf_init(&tbuf, TPM2_ST_NO_SESSIONS, TPM2_CC_CONTEXT_LOAD);
+	if (rc)
+		return rc;
+
+	ctx = (struct tpm2_context *)&buf[*offset];
+	body_size = sizeof(*ctx) + be16_to_cpu(ctx->blob_size);
+	tpm_buf_append(&tbuf, &buf[*offset], body_size);
+
+	rc = tpm_transmit_cmd(chip, NULL, tbuf.data, PAGE_SIZE, 4,
+			      TPM_TRANSMIT_UNLOCKED, NULL);
+	if (rc < 0) {
+		dev_warn(&chip->dev, "%s: failed with a system error %d\n",
+			 __func__, rc);
+		tpm_buf_destroy(&tbuf);
+		return -EFAULT;
+	} else if (tpm2_rc_value(rc) == TPM2_RC_HANDLE ||
+		   rc == TPM2_RC_REFERENCE_H0) {
+		/*
+		 * TPM_RC_HANDLE means that the session context can't
+		 * be loaded because of an internal counter mismatch
+		 * that makes the TPM think there might have been a
+		 * replay.  This might happen if the context was saved
+		 * and loaded outside the space.
+		 *
+		 * TPM_RC_REFERENCE_H0 means the session has been
+		 * flushed outside the space
+		 */
+		rc = -ENOENT;
+		tpm_buf_destroy(&tbuf);
+	} else if (rc > 0) {
+		dev_warn(&chip->dev, "%s: failed with a TPM error 0x%04X\n",
+			 __func__, rc);
+		tpm_buf_destroy(&tbuf);
+		return -EFAULT;
+	}
+
+	*handle = be32_to_cpup((__be32 *)&tbuf.data[TPM_HEADER_SIZE]);
+	*offset += body_size;
+
+	tpm_buf_destroy(&tbuf);
+	return 0;
+}
+
+static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf,
+			     unsigned int buf_size, unsigned int *offset)
+{
+	struct tpm_buf tbuf;
+	unsigned int body_size;
+	int rc;
+
+	rc = tpm_buf_init(&tbuf, TPM2_ST_NO_SESSIONS, TPM2_CC_CONTEXT_SAVE);
+	if (rc)
+		return rc;
+
+	tpm_buf_append_u32(&tbuf, handle);
+
+	rc = tpm_transmit_cmd(chip, NULL, tbuf.data, PAGE_SIZE, 0,
+			      TPM_TRANSMIT_UNLOCKED, NULL);
+	if (rc < 0) {
+		dev_warn(&chip->dev, "%s: failed with a system error %d\n",
+			 __func__, rc);
+		tpm_buf_destroy(&tbuf);
+		return -EFAULT;
+	} else if (tpm2_rc_value(rc) == TPM2_RC_REFERENCE_H0) {
+		tpm_buf_destroy(&tbuf);
+		return -ENOENT;
+	} else if (rc) {
+		dev_warn(&chip->dev, "%s: failed with a TPM error 0x%04X\n",
+			 __func__, rc);
+		tpm_buf_destroy(&tbuf);
+		return -EFAULT;
+	}
+
+	body_size = tpm_buf_length(&tbuf) - TPM_HEADER_SIZE;
+	if ((*offset + body_size) > buf_size) {
+		dev_warn(&chip->dev, "%s: out of backing storage\n", __func__);
+		tpm_buf_destroy(&tbuf);
+		return -ENOMEM;
+	}
+
+	memcpy(&buf[*offset], &tbuf.data[TPM_HEADER_SIZE], body_size);
+	*offset += body_size;
+	tpm_buf_destroy(&tbuf);
+	return 0;
+}
+
+static void tpm2_flush_space(struct tpm_chip *chip)
+{
+	struct tpm_space *space = &chip->work_space;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(space->context_tbl); i++)
+		if (space->context_tbl[i] && ~space->context_tbl[i])
+			tpm2_flush_context_cmd(chip, space->context_tbl[i],
+					       TPM_TRANSMIT_UNLOCKED);
+
+	tpm2_flush_sessions(chip, space);
+}
+
+static int tpm2_load_space(struct tpm_chip *chip)
+{
+	struct tpm_space *space = &chip->work_space;
+	unsigned int offset;
+	int i;
+	int rc;
+
+	for (i = 0, offset = 0; i < ARRAY_SIZE(space->context_tbl); i++) {
+		if (!space->context_tbl[i])
+			continue;
+
+		/* sanity check, should never happen */
+		if (~space->context_tbl[i]) {
+			dev_err(&chip->dev, "context table is inconsistent");
+			return -EFAULT;
+		}
+
+		rc = tpm2_load_context(chip, space->context_buf, &offset,
+				       &space->context_tbl[i]);
+		if (rc)
+			return rc;
+	}
+
+	for (i = 0, offset = 0; i < ARRAY_SIZE(space->session_tbl); i++) {
+		u32 handle;
+
+		if (!space->session_tbl[i])
+			continue;
+
+		rc = tpm2_load_context(chip, space->session_buf,
+				       &offset, &handle);
+		if (rc == -ENOENT) {
+			/* load failed, just forget session */
+			space->session_tbl[i] = 0;
+		} else if (rc) {
+			tpm2_flush_space(chip);
+			return rc;
+		}
+		if (handle != space->session_tbl[i]) {
+			dev_warn(&chip->dev, "session restored to wrong handle\n");
+			tpm2_flush_space(chip);
+			return -EFAULT;
+		}
+	}
+
+	return 0;
+}
+
+static bool tpm2_map_to_phandle(struct tpm_space *space, void *handle)
+{
+	u32 vhandle = be32_to_cpup((__be32 *)handle);
+	u32 phandle;
+	int i;
+
+	i = 0xFFFFFF - (vhandle & 0xFFFFFF);
+	if (i >= ARRAY_SIZE(space->context_tbl) || !space->context_tbl[i])
+		return false;
+
+	phandle = space->context_tbl[i];
+	*((__be32 *)handle) = cpu_to_be32(phandle);
+	return true;
+}
+
+static int tpm2_map_command(struct tpm_chip *chip, u32 cc, u8 *cmd)
+{
+	struct tpm_space *space = &chip->work_space;
+	unsigned int nr_handles;
+	u32 attrs;
+	u32 *handle;
+	int i;
+
+	i = tpm2_find_cc(chip, cc);
+	if (i < 0)
+		return -EINVAL;
+
+	attrs = chip->cc_attrs_tbl[i];
+	nr_handles = (attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0);
+
+	handle = (u32 *)&cmd[TPM_HEADER_SIZE];
+	for (i = 0; i < nr_handles; i++, handle++) {
+		if ((be32_to_cpu(*handle) & 0xFF000000) == TPM2_HT_TRANSIENT) {
+			if (!tpm2_map_to_phandle(space, handle))
+				return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
+		       u8 *cmd)
+{
+	int rc;
+
+	if (!space)
+		return 0;
+
+	memcpy(&chip->work_space.context_tbl, &space->context_tbl,
+	       sizeof(space->context_tbl));
+	memcpy(&chip->work_space.session_tbl, &space->session_tbl,
+	       sizeof(space->session_tbl));
+	memcpy(chip->work_space.context_buf, space->context_buf, PAGE_SIZE);
+	memcpy(chip->work_space.session_buf, space->session_buf, PAGE_SIZE);
+
+	rc = tpm2_load_space(chip);
+	if (rc) {
+		tpm2_flush_space(chip);
+		return rc;
+	}
+
+	rc = tpm2_map_command(chip, cc, cmd);
+	if (rc) {
+		tpm2_flush_space(chip);
+		return rc;
+	}
+
+	return 0;
+}
+
+static bool tpm2_add_session(struct tpm_chip *chip, u32 handle)
+{
+	struct tpm_space *space = &chip->work_space;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(space->session_tbl); i++)
+		if (space->session_tbl[i] == 0)
+			break;
+
+	if (i == ARRAY_SIZE(space->session_tbl))
+		return false;
+
+	space->session_tbl[i] = handle;
+	return true;
+}
+
+static u32 tpm2_map_to_vhandle(struct tpm_space *space, u32 phandle, bool alloc)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(space->context_tbl); i++) {
+		if (alloc) {
+			if (!space->context_tbl[i]) {
+				space->context_tbl[i] = phandle;
+				break;
+			}
+		} else if (space->context_tbl[i] == phandle)
+			break;
+	}
+
+	if (i == ARRAY_SIZE(space->context_tbl))
+		return 0;
+
+	return TPM2_HT_TRANSIENT | (0xFFFFFF - i);
+}
+
+static int tpm2_map_response_header(struct tpm_chip *chip, u32 cc, u8 *rsp,
+				    size_t len)
+{
+	struct tpm_space *space = &chip->work_space;
+	struct tpm_output_header *header = (void *)rsp;
+	u32 phandle;
+	u32 phandle_type;
+	u32 vhandle;
+	u32 attrs;
+	int i;
+
+	if (be32_to_cpu(header->return_code) != TPM2_RC_SUCCESS)
+		return 0;
+
+	i = tpm2_find_cc(chip, cc);
+	/* sanity check, should never happen */
+	if (i < 0)
+		return -EFAULT;
+
+	attrs = chip->cc_attrs_tbl[i];
+	if (!((attrs >> TPM2_CC_ATTR_RHANDLE) & 1))
+		return 0;
+
+	phandle = be32_to_cpup((__be32 *)&rsp[TPM_HEADER_SIZE]);
+	phandle_type = phandle & 0xFF000000;
+
+	switch (phandle_type) {
+	case TPM2_HT_TRANSIENT:
+		vhandle = tpm2_map_to_vhandle(space, phandle, true);
+		if (!vhandle)
+			goto out_no_slots;
+
+		*(__be32 *)&rsp[TPM_HEADER_SIZE] = cpu_to_be32(vhandle);
+		break;
+	case TPM2_HT_HMAC_SESSION:
+	case TPM2_HT_POLICY_SESSION:
+		if (!tpm2_add_session(chip, phandle))
+			goto out_no_slots;
+		break;
+	default:
+		dev_err(&chip->dev, "%s: unknown handle 0x%08X\n",
+			__func__, phandle);
+		break;
+	};
+
+	return 0;
+out_no_slots:
+	tpm2_flush_context_cmd(chip, phandle, TPM_TRANSMIT_UNLOCKED);
+	dev_warn(&chip->dev, "%s: out of slots for 0x%08X\n", __func__,
+		 phandle);
+	return -ENOMEM;
+}
+
+struct tpm2_cap_handles {
+	u8 more_data;
+	__be32 capability;
+	__be32 count;
+	__be32 handles[];
+} __packed;
+
+static int tpm2_map_response_body(struct tpm_chip *chip, u32 cc, u8 *rsp,
+				  size_t len)
+{
+	struct tpm_space *space = &chip->work_space;
+	struct tpm_output_header *header = (void *)rsp;
+	struct tpm2_cap_handles *data;
+	u32 phandle;
+	u32 phandle_type;
+	u32 vhandle;
+	int i;
+	int j;
+
+	if (cc != TPM2_CC_GET_CAPABILITY ||
+	    be32_to_cpu(header->return_code) != TPM2_RC_SUCCESS) {
+		return 0;
+	}
+
+	if (len < TPM_HEADER_SIZE + 9)
+		return -EFAULT;
+
+	data = (void *)&rsp[TPM_HEADER_SIZE];
+	if (be32_to_cpu(data->capability) != TPM2_CAP_HANDLES)
+		return 0;
+
+	if (len != TPM_HEADER_SIZE + 9 + 4 * be32_to_cpu(data->count))
+		return -EFAULT;
+
+	for (i = 0, j = 0; i < be32_to_cpu(data->count); i++) {
+		phandle = be32_to_cpup((__be32 *)&data->handles[i]);
+		phandle_type = phandle & 0xFF000000;
+
+		switch (phandle_type) {
+		case TPM2_HT_TRANSIENT:
+			vhandle = tpm2_map_to_vhandle(space, phandle, false);
+			if (!vhandle)
+				break;
+
+			data->handles[j] = cpu_to_be32(vhandle);
+			j++;
+			break;
+
+		default:
+			data->handles[j] = cpu_to_be32(phandle);
+			j++;
+			break;
+		}
+
+	}
+
+	header->length = cpu_to_be32(TPM_HEADER_SIZE + 9 + 4 * j);
+	data->count = cpu_to_be32(j);
+	return 0;
+}
+
+static int tpm2_save_space(struct tpm_chip *chip)
+{
+	struct tpm_space *space = &chip->work_space;
+	unsigned int offset;
+	int i;
+	int rc;
+
+	for (i = 0, offset = 0; i < ARRAY_SIZE(space->context_tbl); i++) {
+		if (!(space->context_tbl[i] && ~space->context_tbl[i]))
+			continue;
+
+		rc = tpm2_save_context(chip, space->context_tbl[i],
+				       space->context_buf, PAGE_SIZE,
+				       &offset);
+		if (rc == -ENOENT) {
+			space->context_tbl[i] = 0;
+			continue;
+		} else if (rc)
+			return rc;
+
+		tpm2_flush_context_cmd(chip, space->context_tbl[i],
+				       TPM_TRANSMIT_UNLOCKED);
+		space->context_tbl[i] = ~0;
+	}
+
+	for (i = 0, offset = 0; i < ARRAY_SIZE(space->session_tbl); i++) {
+		if (!space->session_tbl[i])
+			continue;
+
+		rc = tpm2_save_context(chip, space->session_tbl[i],
+				       space->session_buf, PAGE_SIZE,
+				       &offset);
+
+		if (rc == -ENOENT) {
+			/* handle error saving session, just forget it */
+			space->session_tbl[i] = 0;
+		} else if (rc < 0) {
+			tpm2_flush_space(chip);
+			return rc;
+		}
+	}
+
+	return 0;
+}
+
+int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
+		      u32 cc, u8 *buf, size_t *bufsiz)
+{
+	struct tpm_output_header *header = (void *)buf;
+	int rc;
+
+	if (!space)
+		return 0;
+
+	rc = tpm2_map_response_header(chip, cc, buf, *bufsiz);
+	if (rc) {
+		tpm2_flush_space(chip);
+		return rc;
+	}
+
+	rc = tpm2_map_response_body(chip, cc, buf, *bufsiz);
+	if (rc) {
+		tpm2_flush_space(chip);
+		return rc;
+	}
+
+	rc = tpm2_save_space(chip);
+	if (rc) {
+		tpm2_flush_space(chip);
+		return rc;
+	}
+
+	*bufsiz = be32_to_cpu(header->length);
+
+	memcpy(&space->context_tbl, &chip->work_space.context_tbl,
+	       sizeof(space->context_tbl));
+	memcpy(&space->session_tbl, &chip->work_space.session_tbl,
+	       sizeof(space->session_tbl));
+	memcpy(space->context_buf, chip->work_space.context_buf, PAGE_SIZE);
+	memcpy(space->session_buf, chip->work_space.session_buf, PAGE_SIZE);
+
+	return 0;
+}