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-rw-r--r--security/keys/trusted-keys/trusted_tpm2.c550
1 files changed, 550 insertions, 0 deletions
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
new file mode 100644
index 000000000..bc700f85f
--- /dev/null
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -0,0 +1,550 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2004 IBM Corporation
+ * Copyright (C) 2014 Intel Corporation
+ */
+
+#include <linux/asn1_encoder.h>
+#include <linux/oid_registry.h>
+#include <linux/string.h>
+#include <linux/err.h>
+#include <linux/tpm.h>
+#include <linux/tpm_command.h>
+
+#include <keys/trusted-type.h>
+#include <keys/trusted_tpm.h>
+
+#include <asm/unaligned.h>
+
+#include "tpm2key.asn1.h"
+
+static struct tpm2_hash tpm2_hash_map[] = {
+ {HASH_ALGO_SHA1, TPM_ALG_SHA1},
+ {HASH_ALGO_SHA256, TPM_ALG_SHA256},
+ {HASH_ALGO_SHA384, TPM_ALG_SHA384},
+ {HASH_ALGO_SHA512, TPM_ALG_SHA512},
+ {HASH_ALGO_SM3_256, TPM_ALG_SM3_256},
+};
+
+static u32 tpm2key_oid[] = { 2, 23, 133, 10, 1, 5 };
+
+static int tpm2_key_encode(struct trusted_key_payload *payload,
+ struct trusted_key_options *options,
+ u8 *src, u32 len)
+{
+ const int SCRATCH_SIZE = PAGE_SIZE;
+ u8 *scratch = kmalloc(SCRATCH_SIZE, GFP_KERNEL);
+ u8 *work = scratch, *work1;
+ u8 *end_work = scratch + SCRATCH_SIZE;
+ u8 *priv, *pub;
+ u16 priv_len, pub_len;
+
+ priv_len = get_unaligned_be16(src) + 2;
+ priv = src;
+
+ src += priv_len;
+
+ pub_len = get_unaligned_be16(src) + 2;
+ pub = src;
+
+ if (!scratch)
+ return -ENOMEM;
+
+ work = asn1_encode_oid(work, end_work, tpm2key_oid,
+ asn1_oid_len(tpm2key_oid));
+
+ if (options->blobauth_len == 0) {
+ unsigned char bool[3], *w = bool;
+ /* tag 0 is emptyAuth */
+ w = asn1_encode_boolean(w, w + sizeof(bool), true);
+ if (WARN(IS_ERR(w), "BUG: Boolean failed to encode"))
+ return PTR_ERR(w);
+ work = asn1_encode_tag(work, end_work, 0, bool, w - bool);
+ }
+
+ /*
+ * Assume both octet strings will encode to a 2 byte definite length
+ *
+ * Note: For a well behaved TPM, this warning should never
+ * trigger, so if it does there's something nefarious going on
+ */
+ if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE,
+ "BUG: scratch buffer is too small"))
+ return -EINVAL;
+
+ work = asn1_encode_integer(work, end_work, options->keyhandle);
+ work = asn1_encode_octet_string(work, end_work, pub, pub_len);
+ work = asn1_encode_octet_string(work, end_work, priv, priv_len);
+
+ work1 = payload->blob;
+ work1 = asn1_encode_sequence(work1, work1 + sizeof(payload->blob),
+ scratch, work - scratch);
+ if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed"))
+ return PTR_ERR(work1);
+
+ return work1 - payload->blob;
+}
+
+struct tpm2_key_context {
+ u32 parent;
+ const u8 *pub;
+ u32 pub_len;
+ const u8 *priv;
+ u32 priv_len;
+};
+
+static int tpm2_key_decode(struct trusted_key_payload *payload,
+ struct trusted_key_options *options,
+ u8 **buf)
+{
+ int ret;
+ struct tpm2_key_context ctx;
+ u8 *blob;
+
+ memset(&ctx, 0, sizeof(ctx));
+
+ ret = asn1_ber_decoder(&tpm2key_decoder, &ctx, payload->blob,
+ payload->blob_len);
+ if (ret < 0)
+ return ret;
+
+ if (ctx.priv_len + ctx.pub_len > MAX_BLOB_SIZE)
+ return -EINVAL;
+
+ blob = kmalloc(ctx.priv_len + ctx.pub_len + 4, GFP_KERNEL);
+ if (!blob)
+ return -ENOMEM;
+
+ *buf = blob;
+ options->keyhandle = ctx.parent;
+
+ memcpy(blob, ctx.priv, ctx.priv_len);
+ blob += ctx.priv_len;
+
+ memcpy(blob, ctx.pub, ctx.pub_len);
+
+ return 0;
+}
+
+int tpm2_key_parent(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct tpm2_key_context *ctx = context;
+ const u8 *v = value;
+ int i;
+
+ ctx->parent = 0;
+ for (i = 0; i < vlen; i++) {
+ ctx->parent <<= 8;
+ ctx->parent |= v[i];
+ }
+
+ return 0;
+}
+
+int tpm2_key_type(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ enum OID oid = look_up_OID(value, vlen);
+
+ if (oid != OID_TPMSealedData) {
+ char buffer[50];
+
+ sprint_oid(value, vlen, buffer, sizeof(buffer));
+ pr_debug("OID is \"%s\" which is not TPMSealedData\n",
+ buffer);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+int tpm2_key_pub(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct tpm2_key_context *ctx = context;
+
+ ctx->pub = value;
+ ctx->pub_len = vlen;
+
+ return 0;
+}
+
+int tpm2_key_priv(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct tpm2_key_context *ctx = context;
+
+ ctx->priv = value;
+ ctx->priv_len = vlen;
+
+ return 0;
+}
+
+/**
+ * tpm2_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer.
+ *
+ * @buf: an allocated tpm_buf instance
+ * @session_handle: session handle
+ * @nonce: the session nonce, may be NULL if not used
+ * @nonce_len: the session nonce length, may be 0 if not used
+ * @attributes: the session attributes
+ * @hmac: the session HMAC or password, may be NULL if not used
+ * @hmac_len: the session HMAC or password length, maybe 0 if not used
+ */
+static void tpm2_buf_append_auth(struct tpm_buf *buf, u32 session_handle,
+ const u8 *nonce, u16 nonce_len,
+ u8 attributes,
+ const u8 *hmac, u16 hmac_len)
+{
+ tpm_buf_append_u32(buf, 9 + nonce_len + hmac_len);
+ tpm_buf_append_u32(buf, session_handle);
+ tpm_buf_append_u16(buf, nonce_len);
+
+ if (nonce && nonce_len)
+ tpm_buf_append(buf, nonce, nonce_len);
+
+ tpm_buf_append_u8(buf, attributes);
+ tpm_buf_append_u16(buf, hmac_len);
+
+ if (hmac && hmac_len)
+ tpm_buf_append(buf, hmac, hmac_len);
+}
+
+/**
+ * tpm2_seal_trusted() - seal the payload of a trusted key
+ *
+ * @chip: TPM chip to use
+ * @payload: the key data in clear and encrypted form
+ * @options: authentication values and other options
+ *
+ * Return: < 0 on error and 0 on success.
+ */
+int tpm2_seal_trusted(struct tpm_chip *chip,
+ struct trusted_key_payload *payload,
+ struct trusted_key_options *options)
+{
+ int blob_len = 0;
+ struct tpm_buf buf;
+ u32 hash;
+ u32 flags;
+ int i;
+ int rc;
+
+ for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
+ if (options->hash == tpm2_hash_map[i].crypto_id) {
+ hash = tpm2_hash_map[i].tpm_id;
+ break;
+ }
+ }
+
+ if (i == ARRAY_SIZE(tpm2_hash_map))
+ return -EINVAL;
+
+ if (!options->keyhandle)
+ return -EINVAL;
+
+ rc = tpm_try_get_ops(chip);
+ if (rc)
+ return rc;
+
+ rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
+ if (rc) {
+ tpm_put_ops(chip);
+ return rc;
+ }
+
+ tpm_buf_append_u32(&buf, options->keyhandle);
+ tpm2_buf_append_auth(&buf, TPM2_RS_PW,
+ NULL /* nonce */, 0,
+ 0 /* session_attributes */,
+ options->keyauth /* hmac */,
+ TPM_DIGEST_SIZE);
+
+ /* sensitive */
+ tpm_buf_append_u16(&buf, 4 + options->blobauth_len + payload->key_len);
+
+ tpm_buf_append_u16(&buf, options->blobauth_len);
+ if (options->blobauth_len)
+ tpm_buf_append(&buf, options->blobauth, options->blobauth_len);
+
+ tpm_buf_append_u16(&buf, payload->key_len);
+ tpm_buf_append(&buf, payload->key, payload->key_len);
+
+ /* public */
+ tpm_buf_append_u16(&buf, 14 + options->policydigest_len);
+ tpm_buf_append_u16(&buf, TPM_ALG_KEYEDHASH);
+ tpm_buf_append_u16(&buf, hash);
+
+ /* key properties */
+ flags = 0;
+ flags |= options->policydigest_len ? 0 : TPM2_OA_USER_WITH_AUTH;
+ flags |= payload->migratable ? 0 : (TPM2_OA_FIXED_TPM |
+ TPM2_OA_FIXED_PARENT);
+ tpm_buf_append_u32(&buf, flags);
+
+ /* policy */
+ tpm_buf_append_u16(&buf, options->policydigest_len);
+ if (options->policydigest_len)
+ tpm_buf_append(&buf, options->policydigest,
+ options->policydigest_len);
+
+ /* public parameters */
+ tpm_buf_append_u16(&buf, TPM_ALG_NULL);
+ tpm_buf_append_u16(&buf, 0);
+
+ /* outside info */
+ tpm_buf_append_u16(&buf, 0);
+
+ /* creation PCR */
+ tpm_buf_append_u32(&buf, 0);
+
+ if (buf.flags & TPM_BUF_OVERFLOW) {
+ rc = -E2BIG;
+ goto out;
+ }
+
+ rc = tpm_transmit_cmd(chip, &buf, 4, "sealing data");
+ if (rc)
+ goto out;
+
+ blob_len = be32_to_cpup((__be32 *) &buf.data[TPM_HEADER_SIZE]);
+ if (blob_len > MAX_BLOB_SIZE) {
+ rc = -E2BIG;
+ goto out;
+ }
+ if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 4 + blob_len) {
+ rc = -EFAULT;
+ goto out;
+ }
+
+ blob_len = tpm2_key_encode(payload, options,
+ &buf.data[TPM_HEADER_SIZE + 4],
+ blob_len);
+
+out:
+ tpm_buf_destroy(&buf);
+
+ if (rc > 0) {
+ if (tpm2_rc_value(rc) == TPM2_RC_HASH)
+ rc = -EINVAL;
+ else
+ rc = -EPERM;
+ }
+ if (blob_len < 0)
+ rc = blob_len;
+ else
+ payload->blob_len = blob_len;
+
+ tpm_put_ops(chip);
+ return rc;
+}
+
+/**
+ * tpm2_load_cmd() - execute a TPM2_Load command
+ *
+ * @chip: TPM chip to use
+ * @payload: the key data in clear and encrypted form
+ * @options: authentication values and other options
+ * @blob_handle: returned blob handle
+ *
+ * Return: 0 on success.
+ * -E2BIG on wrong payload size.
+ * -EPERM on tpm error status.
+ * < 0 error from tpm_send.
+ */
+static int tpm2_load_cmd(struct tpm_chip *chip,
+ struct trusted_key_payload *payload,
+ struct trusted_key_options *options,
+ u32 *blob_handle)
+{
+ struct tpm_buf buf;
+ unsigned int private_len;
+ unsigned int public_len;
+ unsigned int blob_len;
+ u8 *blob, *pub;
+ int rc;
+ u32 attrs;
+
+ rc = tpm2_key_decode(payload, options, &blob);
+ if (rc) {
+ /* old form */
+ blob = payload->blob;
+ payload->old_format = 1;
+ }
+
+ /* new format carries keyhandle but old format doesn't */
+ if (!options->keyhandle)
+ return -EINVAL;
+
+ /* must be big enough for at least the two be16 size counts */
+ if (payload->blob_len < 4)
+ return -EINVAL;
+
+ private_len = get_unaligned_be16(blob);
+
+ /* must be big enough for following public_len */
+ if (private_len + 2 + 2 > (payload->blob_len))
+ return -E2BIG;
+
+ public_len = get_unaligned_be16(blob + 2 + private_len);
+ if (private_len + 2 + public_len + 2 > payload->blob_len)
+ return -E2BIG;
+
+ pub = blob + 2 + private_len + 2;
+ /* key attributes are always at offset 4 */
+ attrs = get_unaligned_be32(pub + 4);
+
+ if ((attrs & (TPM2_OA_FIXED_TPM | TPM2_OA_FIXED_PARENT)) ==
+ (TPM2_OA_FIXED_TPM | TPM2_OA_FIXED_PARENT))
+ payload->migratable = 0;
+ else
+ payload->migratable = 1;
+
+ blob_len = private_len + public_len + 4;
+ if (blob_len > payload->blob_len)
+ return -E2BIG;
+
+ rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD);
+ if (rc)
+ return rc;
+
+ tpm_buf_append_u32(&buf, options->keyhandle);
+ tpm2_buf_append_auth(&buf, TPM2_RS_PW,
+ NULL /* nonce */, 0,
+ 0 /* session_attributes */,
+ options->keyauth /* hmac */,
+ TPM_DIGEST_SIZE);
+
+ tpm_buf_append(&buf, blob, blob_len);
+
+ if (buf.flags & TPM_BUF_OVERFLOW) {
+ rc = -E2BIG;
+ goto out;
+ }
+
+ rc = tpm_transmit_cmd(chip, &buf, 4, "loading blob");
+ if (!rc)
+ *blob_handle = be32_to_cpup(
+ (__be32 *) &buf.data[TPM_HEADER_SIZE]);
+
+out:
+ if (blob != payload->blob)
+ kfree(blob);
+ tpm_buf_destroy(&buf);
+
+ if (rc > 0)
+ rc = -EPERM;
+
+ return rc;
+}
+
+/**
+ * tpm2_unseal_cmd() - execute a TPM2_Unload command
+ *
+ * @chip: TPM chip to use
+ * @payload: the key data in clear and encrypted form
+ * @options: authentication values and other options
+ * @blob_handle: blob handle
+ *
+ * Return: 0 on success
+ * -EPERM on tpm error status
+ * < 0 error from tpm_send
+ */
+static int tpm2_unseal_cmd(struct tpm_chip *chip,
+ struct trusted_key_payload *payload,
+ struct trusted_key_options *options,
+ u32 blob_handle)
+{
+ struct tpm_buf buf;
+ u16 data_len;
+ u8 *data;
+ int rc;
+
+ rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
+ if (rc)
+ return rc;
+
+ tpm_buf_append_u32(&buf, blob_handle);
+ tpm2_buf_append_auth(&buf,
+ options->policyhandle ?
+ options->policyhandle : TPM2_RS_PW,
+ NULL /* nonce */, 0,
+ TPM2_SA_CONTINUE_SESSION,
+ options->blobauth /* hmac */,
+ options->blobauth_len);
+
+ rc = tpm_transmit_cmd(chip, &buf, 6, "unsealing");
+ if (rc > 0)
+ rc = -EPERM;
+
+ if (!rc) {
+ data_len = be16_to_cpup(
+ (__be16 *) &buf.data[TPM_HEADER_SIZE + 4]);
+ if (data_len < MIN_KEY_SIZE || data_len > MAX_KEY_SIZE) {
+ rc = -EFAULT;
+ goto out;
+ }
+
+ if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 6 + data_len) {
+ rc = -EFAULT;
+ goto out;
+ }
+ data = &buf.data[TPM_HEADER_SIZE + 6];
+
+ if (payload->old_format) {
+ /* migratable flag is at the end of the key */
+ memcpy(payload->key, data, data_len - 1);
+ payload->key_len = data_len - 1;
+ payload->migratable = data[data_len - 1];
+ } else {
+ /*
+ * migratable flag already collected from key
+ * attributes
+ */
+ memcpy(payload->key, data, data_len);
+ payload->key_len = data_len;
+ }
+ }
+
+out:
+ tpm_buf_destroy(&buf);
+ return rc;
+}
+
+/**
+ * tpm2_unseal_trusted() - unseal the payload of a trusted key
+ *
+ * @chip: TPM chip to use
+ * @payload: the key data in clear and encrypted form
+ * @options: authentication values and other options
+ *
+ * Return: Same as with tpm_send.
+ */
+int tpm2_unseal_trusted(struct tpm_chip *chip,
+ struct trusted_key_payload *payload,
+ struct trusted_key_options *options)
+{
+ u32 blob_handle;
+ int rc;
+
+ rc = tpm_try_get_ops(chip);
+ if (rc)
+ return rc;
+
+ rc = tpm2_load_cmd(chip, payload, options, &blob_handle);
+ if (rc)
+ goto out;
+
+ rc = tpm2_unseal_cmd(chip, payload, options, blob_handle);
+ tpm2_flush_context(chip, blob_handle);
+
+out:
+ tpm_put_ops(chip);
+
+ return rc;
+}
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