1 files changed, 383 insertions, 93 deletions

diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 08ec7f48f01d..a7ea4a1c3bed 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -4,6 +4,8 @@
  * 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>
@@ -12,16 +14,184 @@
 #include <keys/trusted-type.h>
 #include <keys/trusted_tpm.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},
+#include <linux/unaligned.h>
+
+#include "tpm2key.asn1.h"
+
+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;
+	int ret;
+
+	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")) {
+			ret = PTR_ERR(w);
+			goto err;
+		}
+		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")) {
+		ret = -EINVAL;
+		goto err;
+	}
+
+	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 (IS_ERR(work1)) {
+		ret = PTR_ERR(work1);
+		pr_err("BUG: ASN.1 encoder failed with %d\n", ret);
+		goto err;
+	}
+
+	kfree(scratch);
+	return work1 - payload->blob;
+
+err:
+	kfree(scratch);
+	return ret;
+}
+
+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;
+}
+
 /**
- * tpm_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer.
+ * tpm2_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer.
  *
  * @buf: an allocated tpm_buf instance
  * @session_handle: session handle
@@ -63,61 +233,79 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 		      struct trusted_key_payload *payload,
 		      struct trusted_key_options *options)
 {
-	unsigned int blob_len;
-	struct tpm_buf buf;
-	u32 hash;
-	int i;
+	off_t offset = TPM_HEADER_SIZE;
+	struct tpm_buf buf, sized;
+	int blob_len = 0;
+	int hash;
+	u32 flags;
 	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;
-		}
-	}
+	hash = tpm2_find_hash_alg(options->hash);
+	if (hash < 0)
+		return hash;
 
-	if (i == ARRAY_SIZE(tpm2_hash_map))
+	if (!options->keyhandle)
 		return -EINVAL;
 
-	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
+	rc = tpm_try_get_ops(chip);
 	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);
+	rc = tpm2_start_auth_session(chip);
+	if (rc)
+		goto out_put;
+
+	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
+	if (rc) {
+		tpm2_end_auth_session(chip);
+		goto out_put;
+	}
+
+	rc = tpm_buf_init_sized(&sized);
+	if (rc) {
+		tpm_buf_destroy(&buf);
+		tpm2_end_auth_session(chip);
+		goto out_put;
+	}
+
+	rc = tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
+	if (rc)
+		goto out;
+
+	tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_DECRYPT,
+				    options->keyauth, TPM_DIGEST_SIZE);
 
 	/* sensitive */
-	tpm_buf_append_u16(&buf, 4 + TPM_DIGEST_SIZE + payload->key_len + 1);
+	tpm_buf_append_u16(&sized, options->blobauth_len);
 
-	tpm_buf_append_u16(&buf, TPM_DIGEST_SIZE);
-	tpm_buf_append(&buf, options->blobauth, TPM_DIGEST_SIZE);
-	tpm_buf_append_u16(&buf, payload->key_len + 1);
-	tpm_buf_append(&buf, payload->key, payload->key_len);
-	tpm_buf_append_u8(&buf, payload->migratable);
+	if (options->blobauth_len)
+		tpm_buf_append(&sized, options->blobauth, options->blobauth_len);
+
+	tpm_buf_append_u16(&sized, payload->key_len);
+	tpm_buf_append(&sized, payload->key, payload->key_len);
+	tpm_buf_append(&buf, sized.data, sized.length);
 
 	/* public */
-	tpm_buf_append_u16(&buf, 14 + options->policydigest_len);
-	tpm_buf_append_u16(&buf, TPM_ALG_KEYEDHASH);
-	tpm_buf_append_u16(&buf, hash);
+	tpm_buf_reset_sized(&sized);
+	tpm_buf_append_u16(&sized, TPM_ALG_KEYEDHASH);
+	tpm_buf_append_u16(&sized, 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(&sized, flags);
 
 	/* policy */
-	if (options->policydigest_len) {
-		tpm_buf_append_u32(&buf, 0);
-		tpm_buf_append_u16(&buf, options->policydigest_len);
-		tpm_buf_append(&buf, options->policydigest,
-			       options->policydigest_len);
-	} else {
-		tpm_buf_append_u32(&buf, TPM2_OA_USER_WITH_AUTH);
-		tpm_buf_append_u16(&buf, 0);
-	}
+	tpm_buf_append_u16(&sized, options->policydigest_len);
+	if (options->policydigest_len)
+		tpm_buf_append(&sized, options->policydigest, options->policydigest_len);
 
 	/* public parameters */
-	tpm_buf_append_u16(&buf, TPM_ALG_NULL);
-	tpm_buf_append_u16(&buf, 0);
+	tpm_buf_append_u16(&sized, TPM_ALG_NULL);
+	tpm_buf_append_u16(&sized, 0);
+
+	tpm_buf_append(&buf, sized.data, sized.length);
 
 	/* outside info */
 	tpm_buf_append_u16(&buf, 0);
@@ -127,37 +315,43 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 
 	if (buf.flags & TPM_BUF_OVERFLOW) {
 		rc = -E2BIG;
+		tpm2_end_auth_session(chip);
 		goto out;
 	}
 
-	rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
+	rc = tpm_buf_fill_hmac_session(chip, &buf);
 	if (rc)
 		goto out;
 
-	blob_len = be32_to_cpup((__be32 *) &buf.data[TPM_HEADER_SIZE]);
-	if (blob_len > MAX_BLOB_SIZE) {
+	rc = tpm_transmit_cmd(chip, &buf, 4, "sealing data");
+	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
+	if (rc)
+		goto out;
+
+	blob_len = tpm_buf_read_u32(&buf, &offset);
+	if (blob_len > MAX_BLOB_SIZE || buf.flags & TPM_BUF_BOUNDARY_ERROR) {
 		rc = -E2BIG;
 		goto out;
 	}
-	if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 4 + blob_len) {
+	if (buf.length - offset < blob_len) {
 		rc = -EFAULT;
 		goto out;
 	}
 
-	memcpy(payload->blob, &buf.data[TPM_HEADER_SIZE + 4], blob_len);
-	payload->blob_len = blob_len;
+	blob_len = tpm2_key_encode(payload, options, &buf.data[offset], blob_len);
+	if (blob_len < 0)
+		rc = blob_len;
 
 out:
+	tpm_buf_destroy(&sized);
 	tpm_buf_destroy(&buf);
 
-	if (rc > 0) {
-		if (tpm2_rc_value(rc) == TPM2_RC_HASH)
-			rc = -EINVAL;
-		else
-			rc = -EPERM;
-	}
+	if (!rc)
+		payload->blob_len = blob_len;
 
-	return rc;
+out_put:
+	tpm_put_ops(chip);
+	return tpm_ret_to_err(rc);
 }
 
 /**
@@ -178,40 +372,88 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 			 struct trusted_key_options *options,
 			 u32 *blob_handle)
 {
+	u8 *blob_ref __free(kfree) = NULL;
 	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;
+	} else {
+		/* Bind for cleanup: */
+		blob_ref = blob;
+	}
+
+	/* 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 = be16_to_cpup((__be16 *) &payload->blob[0]);
-	if (private_len > (payload->blob_len - 2))
+	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;
 
-	public_len = be16_to_cpup((__be16 *) &payload->blob[2 + private_len]);
+	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);
+	rc = tpm2_start_auth_session(chip);
 	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);
+	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD);
+	if (rc) {
+		tpm2_end_auth_session(chip);
+		return rc;
+	}
+
+	rc = tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
+	if (rc)
+		goto out;
+
+	tpm_buf_append_hmac_session(chip, &buf, 0, options->keyauth,
+				    TPM_DIGEST_SIZE);
 
-	tpm_buf_append(&buf, payload->blob, blob_len);
+	tpm_buf_append(&buf, blob, blob_len);
 
 	if (buf.flags & TPM_BUF_OVERFLOW) {
 		rc = -E2BIG;
+		tpm2_end_auth_session(chip);
 		goto out;
 	}
 
-	rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
+	rc = tpm_buf_fill_hmac_session(chip, &buf);
+	if (rc)
+		goto out;
+
+	rc = tpm_transmit_cmd(chip, &buf, 4, "loading blob");
+	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
 	if (!rc)
 		*blob_handle = be32_to_cpup(
 			(__be32 *) &buf.data[TPM_HEADER_SIZE]);
@@ -219,10 +461,7 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 out:
 	tpm_buf_destroy(&buf);
 
-	if (rc > 0)
-		rc = -EPERM;
-
-	return rc;
+	return tpm_ret_to_err(rc);
 }
 
 /**
@@ -242,32 +481,67 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 			   struct trusted_key_options *options,
 			   u32 blob_handle)
 {
+	struct tpm_header *head;
 	struct tpm_buf buf;
 	u16 data_len;
+	int offset;
 	u8 *data;
 	int rc;
 
-	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
+	rc = tpm2_start_auth_session(chip);
 	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 */,
-			     TPM_DIGEST_SIZE);
+	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
+	if (rc) {
+		tpm2_end_auth_session(chip);
+		return rc;
+	}
 
-	rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
-	if (rc > 0)
-		rc = -EPERM;
+	rc = tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
+	if (rc)
+		goto out;
+
+	if (!options->policyhandle) {
+		tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_ENCRYPT,
+					    options->blobauth,
+					    options->blobauth_len);
+	} else {
+		/*
+		 * FIXME: The policy session was generated outside the
+		 * kernel so we don't known the nonce and thus can't
+		 * calculate a HMAC on it.  Therefore, the user can
+		 * only really use TPM2_PolicyPassword and we must
+		 * send down the plain text password, which could be
+		 * intercepted.  We can still encrypt the returned
+		 * key, but that's small comfort since the interposer
+		 * could repeat our actions with the exfiltrated
+		 * password.
+		 */
+		tpm2_buf_append_auth(&buf, options->policyhandle,
+				     NULL /* nonce */, 0, 0,
+				     options->blobauth, options->blobauth_len);
+		if (tpm2_chip_auth(chip)) {
+			tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_ENCRYPT, NULL, 0);
+		} else  {
+			offset = buf.handles * 4 + TPM_HEADER_SIZE;
+			head = (struct tpm_header *)buf.data;
+			if (tpm_buf_length(&buf) == offset)
+				head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
+		}
+	}
+
+	rc = tpm_buf_fill_hmac_session(chip, &buf);
+	if (rc)
+		goto out;
+
+	rc = tpm_transmit_cmd(chip, &buf, 6, "unsealing");
+	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
 
 	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 + 1) {
+		if (data_len < MIN_KEY_SIZE ||  data_len > MAX_KEY_SIZE) {
 			rc = -EFAULT;
 			goto out;
 		}
@@ -278,14 +552,24 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 		}
 		data = &buf.data[TPM_HEADER_SIZE + 6];
 
-		memcpy(payload->key, data, data_len - 1);
-		payload->key_len = data_len - 1;
-		payload->migratable = data[data_len - 1];
+		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;
+	return tpm_ret_to_err(rc);
 }
 
 /**
@@ -304,12 +588,18 @@ int tpm2_unseal_trusted(struct tpm_chip *chip,
 	u32 blob_handle;
 	int rc;
 
-	rc = tpm2_load_cmd(chip, payload, options, &blob_handle);
+	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);
 
-	return rc;
+out:
+	tpm_put_ops(chip);
+	return tpm_ret_to_err(rc);
 }