Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 957 insertions, 0 deletions

diff --git a/crypto/asymmetric_keys/asym_tpm.c b/crypto/asymmetric_keys/asym_tpm.c
new file mode 100644
index 000000000..84a5d6af9
--- /dev/null
+++ b/crypto/asymmetric_keys/asym_tpm.c
@@ -0,0 +1,957 @@
+// SPDX-License-Identifier: GPL-2.0
+#define pr_fmt(fmt) "ASYM-TPM: "fmt
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/seq_file.h>
+#include <linux/scatterlist.h>
+#include <linux/tpm.h>
+#include <linux/tpm_command.h>
+#include <crypto/akcipher.h>
+#include <crypto/hash.h>
+#include <crypto/sha.h>
+#include <asm/unaligned.h>
+#include <keys/asymmetric-subtype.h>
+#include <keys/trusted_tpm.h>
+#include <crypto/asym_tpm_subtype.h>
+#include <crypto/public_key.h>
+
+#define TPM_ORD_FLUSHSPECIFIC	186
+#define TPM_ORD_LOADKEY2	65
+#define TPM_ORD_UNBIND		30
+#define TPM_ORD_SIGN		60
+
+#define TPM_RT_KEY                      0x00000001
+
+/*
+ * Load a TPM key from the blob provided by userspace
+ */
+static int tpm_loadkey2(struct tpm_buf *tb,
+			uint32_t keyhandle, unsigned char *keyauth,
+			const unsigned char *keyblob, int keybloblen,
+			uint32_t *newhandle)
+{
+	unsigned char nonceodd[TPM_NONCE_SIZE];
+	unsigned char enonce[TPM_NONCE_SIZE];
+	unsigned char authdata[SHA1_DIGEST_SIZE];
+	uint32_t authhandle = 0;
+	unsigned char cont = 0;
+	uint32_t ordinal;
+	int ret;
+
+	ordinal = htonl(TPM_ORD_LOADKEY2);
+
+	/* session for loading the key */
+	ret = oiap(tb, &authhandle, enonce);
+	if (ret < 0) {
+		pr_info("oiap failed (%d)\n", ret);
+		return ret;
+	}
+
+	/* generate odd nonce */
+	ret = tpm_get_random(NULL, nonceodd, TPM_NONCE_SIZE);
+	if (ret < 0) {
+		pr_info("tpm_get_random failed (%d)\n", ret);
+		return ret;
+	}
+
+	/* calculate authorization HMAC value */
+	ret = TSS_authhmac(authdata, keyauth, SHA1_DIGEST_SIZE, enonce,
+			   nonceodd, cont, sizeof(uint32_t), &ordinal,
+			   keybloblen, keyblob, 0, 0);
+	if (ret < 0)
+		return ret;
+
+	/* build the request buffer */
+	tpm_buf_reset(tb, TPM_TAG_RQU_AUTH1_COMMAND, TPM_ORD_LOADKEY2);
+	tpm_buf_append_u32(tb, keyhandle);
+	tpm_buf_append(tb, keyblob, keybloblen);
+	tpm_buf_append_u32(tb, authhandle);
+	tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE);
+	tpm_buf_append_u8(tb, cont);
+	tpm_buf_append(tb, authdata, SHA1_DIGEST_SIZE);
+
+	ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
+	if (ret < 0) {
+		pr_info("authhmac failed (%d)\n", ret);
+		return ret;
+	}
+
+	ret = TSS_checkhmac1(tb->data, ordinal, nonceodd, keyauth,
+			     SHA1_DIGEST_SIZE, 0, 0);
+	if (ret < 0) {
+		pr_info("TSS_checkhmac1 failed (%d)\n", ret);
+		return ret;
+	}
+
+	*newhandle = LOAD32(tb->data, TPM_DATA_OFFSET);
+	return 0;
+}
+
+/*
+ * Execute the FlushSpecific TPM command
+ */
+static int tpm_flushspecific(struct tpm_buf *tb, uint32_t handle)
+{
+	tpm_buf_reset(tb, TPM_TAG_RQU_COMMAND, TPM_ORD_FLUSHSPECIFIC);
+	tpm_buf_append_u32(tb, handle);
+	tpm_buf_append_u32(tb, TPM_RT_KEY);
+
+	return trusted_tpm_send(tb->data, MAX_BUF_SIZE);
+}
+
+/*
+ * Decrypt a blob provided by userspace using a specific key handle.
+ * The handle is a well known handle or previously loaded by e.g. LoadKey2
+ */
+static int tpm_unbind(struct tpm_buf *tb,
+			uint32_t keyhandle, unsigned char *keyauth,
+			const unsigned char *blob, uint32_t bloblen,
+			void *out, uint32_t outlen)
+{
+	unsigned char nonceodd[TPM_NONCE_SIZE];
+	unsigned char enonce[TPM_NONCE_SIZE];
+	unsigned char authdata[SHA1_DIGEST_SIZE];
+	uint32_t authhandle = 0;
+	unsigned char cont = 0;
+	uint32_t ordinal;
+	uint32_t datalen;
+	int ret;
+
+	ordinal = htonl(TPM_ORD_UNBIND);
+	datalen = htonl(bloblen);
+
+	/* session for loading the key */
+	ret = oiap(tb, &authhandle, enonce);
+	if (ret < 0) {
+		pr_info("oiap failed (%d)\n", ret);
+		return ret;
+	}
+
+	/* generate odd nonce */
+	ret = tpm_get_random(NULL, nonceodd, TPM_NONCE_SIZE);
+	if (ret < 0) {
+		pr_info("tpm_get_random failed (%d)\n", ret);
+		return ret;
+	}
+
+	/* calculate authorization HMAC value */
+	ret = TSS_authhmac(authdata, keyauth, SHA1_DIGEST_SIZE, enonce,
+			   nonceodd, cont, sizeof(uint32_t), &ordinal,
+			   sizeof(uint32_t), &datalen,
+			   bloblen, blob, 0, 0);
+	if (ret < 0)
+		return ret;
+
+	/* build the request buffer */
+	tpm_buf_reset(tb, TPM_TAG_RQU_AUTH1_COMMAND, TPM_ORD_UNBIND);
+	tpm_buf_append_u32(tb, keyhandle);
+	tpm_buf_append_u32(tb, bloblen);
+	tpm_buf_append(tb, blob, bloblen);
+	tpm_buf_append_u32(tb, authhandle);
+	tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE);
+	tpm_buf_append_u8(tb, cont);
+	tpm_buf_append(tb, authdata, SHA1_DIGEST_SIZE);
+
+	ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
+	if (ret < 0) {
+		pr_info("authhmac failed (%d)\n", ret);
+		return ret;
+	}
+
+	datalen = LOAD32(tb->data, TPM_DATA_OFFSET);
+
+	ret = TSS_checkhmac1(tb->data, ordinal, nonceodd,
+			     keyauth, SHA1_DIGEST_SIZE,
+			     sizeof(uint32_t), TPM_DATA_OFFSET,
+			     datalen, TPM_DATA_OFFSET + sizeof(uint32_t),
+			     0, 0);
+	if (ret < 0) {
+		pr_info("TSS_checkhmac1 failed (%d)\n", ret);
+		return ret;
+	}
+
+	memcpy(out, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t),
+	       min(outlen, datalen));
+
+	return datalen;
+}
+
+/*
+ * Sign a blob provided by userspace (that has had the hash function applied)
+ * using a specific key handle.  The handle is assumed to have been previously
+ * loaded by e.g. LoadKey2.
+ *
+ * Note that the key signature scheme of the used key should be set to
+ * TPM_SS_RSASSAPKCS1v15_DER.  This allows the hashed input to be of any size
+ * up to key_length_in_bytes - 11 and not be limited to size 20 like the
+ * TPM_SS_RSASSAPKCS1v15_SHA1 signature scheme.
+ */
+static int tpm_sign(struct tpm_buf *tb,
+		    uint32_t keyhandle, unsigned char *keyauth,
+		    const unsigned char *blob, uint32_t bloblen,
+		    void *out, uint32_t outlen)
+{
+	unsigned char nonceodd[TPM_NONCE_SIZE];
+	unsigned char enonce[TPM_NONCE_SIZE];
+	unsigned char authdata[SHA1_DIGEST_SIZE];
+	uint32_t authhandle = 0;
+	unsigned char cont = 0;
+	uint32_t ordinal;
+	uint32_t datalen;
+	int ret;
+
+	ordinal = htonl(TPM_ORD_SIGN);
+	datalen = htonl(bloblen);
+
+	/* session for loading the key */
+	ret = oiap(tb, &authhandle, enonce);
+	if (ret < 0) {
+		pr_info("oiap failed (%d)\n", ret);
+		return ret;
+	}
+
+	/* generate odd nonce */
+	ret = tpm_get_random(NULL, nonceodd, TPM_NONCE_SIZE);
+	if (ret < 0) {
+		pr_info("tpm_get_random failed (%d)\n", ret);
+		return ret;
+	}
+
+	/* calculate authorization HMAC value */
+	ret = TSS_authhmac(authdata, keyauth, SHA1_DIGEST_SIZE, enonce,
+			   nonceodd, cont, sizeof(uint32_t), &ordinal,
+			   sizeof(uint32_t), &datalen,
+			   bloblen, blob, 0, 0);
+	if (ret < 0)
+		return ret;
+
+	/* build the request buffer */
+	tpm_buf_reset(tb, TPM_TAG_RQU_AUTH1_COMMAND, TPM_ORD_SIGN);
+	tpm_buf_append_u32(tb, keyhandle);
+	tpm_buf_append_u32(tb, bloblen);
+	tpm_buf_append(tb, blob, bloblen);
+	tpm_buf_append_u32(tb, authhandle);
+	tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE);
+	tpm_buf_append_u8(tb, cont);
+	tpm_buf_append(tb, authdata, SHA1_DIGEST_SIZE);
+
+	ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
+	if (ret < 0) {
+		pr_info("authhmac failed (%d)\n", ret);
+		return ret;
+	}
+
+	datalen = LOAD32(tb->data, TPM_DATA_OFFSET);
+
+	ret = TSS_checkhmac1(tb->data, ordinal, nonceodd,
+			     keyauth, SHA1_DIGEST_SIZE,
+			     sizeof(uint32_t), TPM_DATA_OFFSET,
+			     datalen, TPM_DATA_OFFSET + sizeof(uint32_t),
+			     0, 0);
+	if (ret < 0) {
+		pr_info("TSS_checkhmac1 failed (%d)\n", ret);
+		return ret;
+	}
+
+	memcpy(out, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t),
+	       min(datalen, outlen));
+
+	return datalen;
+}
+
+/* Room to fit two u32 zeros for algo id and parameters length. */
+#define SETKEY_PARAMS_SIZE (sizeof(u32) * 2)
+
+/*
+ * Maximum buffer size for the BER/DER encoded public key.  The public key
+ * is of the form SEQUENCE { INTEGER n, INTEGER e } where n is a maximum 2048
+ * bit key and e is usually 65537
+ * The encoding overhead is:
+ * - max 4 bytes for SEQUENCE
+ *   - max 4 bytes for INTEGER n type/length
+ *     - 257 bytes of n
+ *   - max 2 bytes for INTEGER e type/length
+ *     - 3 bytes of e
+ * - 4+4 of zeros for set_pub_key parameters (SETKEY_PARAMS_SIZE)
+ */
+#define PUB_KEY_BUF_SIZE (4 + 4 + 257 + 2 + 3 + SETKEY_PARAMS_SIZE)
+
+/*
+ * Provide a part of a description of the key for /proc/keys.
+ */
+static void asym_tpm_describe(const struct key *asymmetric_key,
+			      struct seq_file *m)
+{
+	struct tpm_key *tk = asymmetric_key->payload.data[asym_crypto];
+
+	if (!tk)
+		return;
+
+	seq_printf(m, "TPM1.2/Blob");
+}
+
+static void asym_tpm_destroy(void *payload0, void *payload3)
+{
+	struct tpm_key *tk = payload0;
+
+	if (!tk)
+		return;
+
+	kfree(tk->blob);
+	tk->blob_len = 0;
+
+	kfree(tk);
+}
+
+/* How many bytes will it take to encode the length */
+static inline uint32_t definite_length(uint32_t len)
+{
+	if (len <= 127)
+		return 1;
+	if (len <= 255)
+		return 2;
+	return 3;
+}
+
+static inline uint8_t *encode_tag_length(uint8_t *buf, uint8_t tag,
+					 uint32_t len)
+{
+	*buf++ = tag;
+
+	if (len <= 127) {
+		buf[0] = len;
+		return buf + 1;
+	}
+
+	if (len <= 255) {
+		buf[0] = 0x81;
+		buf[1] = len;
+		return buf + 2;
+	}
+
+	buf[0] = 0x82;
+	put_unaligned_be16(len, buf + 1);
+	return buf + 3;
+}
+
+static uint32_t derive_pub_key(const void *pub_key, uint32_t len, uint8_t *buf)
+{
+	uint8_t *cur = buf;
+	uint32_t n_len = definite_length(len) + 1 + len + 1;
+	uint32_t e_len = definite_length(3) + 1 + 3;
+	uint8_t e[3] = { 0x01, 0x00, 0x01 };
+
+	/* SEQUENCE */
+	cur = encode_tag_length(cur, 0x30, n_len + e_len);
+	/* INTEGER n */
+	cur = encode_tag_length(cur, 0x02, len + 1);
+	cur[0] = 0x00;
+	memcpy(cur + 1, pub_key, len);
+	cur += len + 1;
+	cur = encode_tag_length(cur, 0x02, sizeof(e));
+	memcpy(cur, e, sizeof(e));
+	cur += sizeof(e);
+	/* Zero parameters to satisfy set_pub_key ABI. */
+	memzero_explicit(cur, SETKEY_PARAMS_SIZE);
+
+	return cur - buf;
+}
+
+/*
+ * Determine the crypto algorithm name.
+ */
+static int determine_akcipher(const char *encoding, const char *hash_algo,
+			      char alg_name[CRYPTO_MAX_ALG_NAME])
+{
+	if (strcmp(encoding, "pkcs1") == 0) {
+		if (!hash_algo) {
+			strcpy(alg_name, "pkcs1pad(rsa)");
+			return 0;
+		}
+
+		if (snprintf(alg_name, CRYPTO_MAX_ALG_NAME, "pkcs1pad(rsa,%s)",
+			     hash_algo) >= CRYPTO_MAX_ALG_NAME)
+			return -EINVAL;
+
+		return 0;
+	}
+
+	if (strcmp(encoding, "raw") == 0) {
+		strcpy(alg_name, "rsa");
+		return 0;
+	}
+
+	return -ENOPKG;
+}
+
+/*
+ * Query information about a key.
+ */
+static int tpm_key_query(const struct kernel_pkey_params *params,
+			 struct kernel_pkey_query *info)
+{
+	struct tpm_key *tk = params->key->payload.data[asym_crypto];
+	int ret;
+	char alg_name[CRYPTO_MAX_ALG_NAME];
+	struct crypto_akcipher *tfm;
+	uint8_t der_pub_key[PUB_KEY_BUF_SIZE];
+	uint32_t der_pub_key_len;
+	int len;
+
+	/* TPM only works on private keys, public keys still done in software */
+	ret = determine_akcipher(params->encoding, params->hash_algo, alg_name);
+	if (ret < 0)
+		return ret;
+
+	tfm = crypto_alloc_akcipher(alg_name, 0, 0);
+	if (IS_ERR(tfm))
+		return PTR_ERR(tfm);
+
+	der_pub_key_len = derive_pub_key(tk->pub_key, tk->pub_key_len,
+					 der_pub_key);
+
+	ret = crypto_akcipher_set_pub_key(tfm, der_pub_key, der_pub_key_len);
+	if (ret < 0)
+		goto error_free_tfm;
+
+	len = crypto_akcipher_maxsize(tfm);
+
+	info->key_size = tk->key_len;
+	info->max_data_size = tk->key_len / 8;
+	info->max_sig_size = len;
+	info->max_enc_size = len;
+	info->max_dec_size = tk->key_len / 8;
+
+	info->supported_ops = KEYCTL_SUPPORTS_ENCRYPT |
+			      KEYCTL_SUPPORTS_DECRYPT |
+			      KEYCTL_SUPPORTS_VERIFY |
+			      KEYCTL_SUPPORTS_SIGN;
+
+	ret = 0;
+error_free_tfm:
+	crypto_free_akcipher(tfm);
+	pr_devel("<==%s() = %d\n", __func__, ret);
+	return ret;
+}
+
+/*
+ * Encryption operation is performed with the public key.  Hence it is done
+ * in software
+ */
+static int tpm_key_encrypt(struct tpm_key *tk,
+			   struct kernel_pkey_params *params,
+			   const void *in, void *out)
+{
+	char alg_name[CRYPTO_MAX_ALG_NAME];
+	struct crypto_akcipher *tfm;
+	struct akcipher_request *req;
+	struct crypto_wait cwait;
+	struct scatterlist in_sg, out_sg;
+	uint8_t der_pub_key[PUB_KEY_BUF_SIZE];
+	uint32_t der_pub_key_len;
+	int ret;
+
+	pr_devel("==>%s()\n", __func__);
+
+	ret = determine_akcipher(params->encoding, params->hash_algo, alg_name);
+	if (ret < 0)
+		return ret;
+
+	tfm = crypto_alloc_akcipher(alg_name, 0, 0);
+	if (IS_ERR(tfm))
+		return PTR_ERR(tfm);
+
+	der_pub_key_len = derive_pub_key(tk->pub_key, tk->pub_key_len,
+					 der_pub_key);
+
+	ret = crypto_akcipher_set_pub_key(tfm, der_pub_key, der_pub_key_len);
+	if (ret < 0)
+		goto error_free_tfm;
+
+	ret = -ENOMEM;
+	req = akcipher_request_alloc(tfm, GFP_KERNEL);
+	if (!req)
+		goto error_free_tfm;
+
+	sg_init_one(&in_sg, in, params->in_len);
+	sg_init_one(&out_sg, out, params->out_len);
+	akcipher_request_set_crypt(req, &in_sg, &out_sg, params->in_len,
+				   params->out_len);
+	crypto_init_wait(&cwait);
+	akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
+				      CRYPTO_TFM_REQ_MAY_SLEEP,
+				      crypto_req_done, &cwait);
+
+	ret = crypto_akcipher_encrypt(req);
+	ret = crypto_wait_req(ret, &cwait);
+
+	if (ret == 0)
+		ret = req->dst_len;
+
+	akcipher_request_free(req);
+error_free_tfm:
+	crypto_free_akcipher(tfm);
+	pr_devel("<==%s() = %d\n", __func__, ret);
+	return ret;
+}
+
+/*
+ * Decryption operation is performed with the private key in the TPM.
+ */
+static int tpm_key_decrypt(struct tpm_key *tk,
+			   struct kernel_pkey_params *params,
+			   const void *in, void *out)
+{
+	struct tpm_buf tb;
+	uint32_t keyhandle;
+	uint8_t srkauth[SHA1_DIGEST_SIZE];
+	uint8_t keyauth[SHA1_DIGEST_SIZE];
+	int r;
+
+	pr_devel("==>%s()\n", __func__);
+
+	if (params->hash_algo)
+		return -ENOPKG;
+
+	if (strcmp(params->encoding, "pkcs1"))
+		return -ENOPKG;
+
+	r = tpm_buf_init(&tb, 0, 0);
+	if (r)
+		return r;
+
+	/* TODO: Handle a non-all zero SRK authorization */
+	memset(srkauth, 0, sizeof(srkauth));
+
+	r = tpm_loadkey2(&tb, SRKHANDLE, srkauth,
+				tk->blob, tk->blob_len, &keyhandle);
+	if (r < 0) {
+		pr_devel("loadkey2 failed (%d)\n", r);
+		goto error;
+	}
+
+	/* TODO: Handle a non-all zero key authorization */
+	memset(keyauth, 0, sizeof(keyauth));
+
+	r = tpm_unbind(&tb, keyhandle, keyauth,
+		       in, params->in_len, out, params->out_len);
+	if (r < 0)
+		pr_devel("tpm_unbind failed (%d)\n", r);
+
+	if (tpm_flushspecific(&tb, keyhandle) < 0)
+		pr_devel("flushspecific failed (%d)\n", r);
+
+error:
+	tpm_buf_destroy(&tb);
+	pr_devel("<==%s() = %d\n", __func__, r);
+	return r;
+}
+
+/*
+ * Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2].
+ */
+static const u8 digest_info_md5[] = {
+	0x30, 0x20, 0x30, 0x0c, 0x06, 0x08,
+	0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x05, /* OID */
+	0x05, 0x00, 0x04, 0x10
+};
+
+static const u8 digest_info_sha1[] = {
+	0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
+	0x2b, 0x0e, 0x03, 0x02, 0x1a,
+	0x05, 0x00, 0x04, 0x14
+};
+
+static const u8 digest_info_rmd160[] = {
+	0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
+	0x2b, 0x24, 0x03, 0x02, 0x01,
+	0x05, 0x00, 0x04, 0x14
+};
+
+static const u8 digest_info_sha224[] = {
+	0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09,
+	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04,
+	0x05, 0x00, 0x04, 0x1c
+};
+
+static const u8 digest_info_sha256[] = {
+	0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
+	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
+	0x05, 0x00, 0x04, 0x20
+};
+
+static const u8 digest_info_sha384[] = {
+	0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
+	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02,
+	0x05, 0x00, 0x04, 0x30
+};
+
+static const u8 digest_info_sha512[] = {
+	0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
+	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
+	0x05, 0x00, 0x04, 0x40
+};
+
+static const struct asn1_template {
+	const char	*name;
+	const u8	*data;
+	size_t		size;
+} asn1_templates[] = {
+#define _(X) { #X, digest_info_##X, sizeof(digest_info_##X) }
+	_(md5),
+	_(sha1),
+	_(rmd160),
+	_(sha256),
+	_(sha384),
+	_(sha512),
+	_(sha224),
+	{ NULL }
+#undef _
+};
+
+static const struct asn1_template *lookup_asn1(const char *name)
+{
+	const struct asn1_template *p;
+
+	for (p = asn1_templates; p->name; p++)
+		if (strcmp(name, p->name) == 0)
+			return p;
+	return NULL;
+}
+
+/*
+ * Sign operation is performed with the private key in the TPM.
+ */
+static int tpm_key_sign(struct tpm_key *tk,
+			struct kernel_pkey_params *params,
+			const void *in, void *out)
+{
+	struct tpm_buf tb;
+	uint32_t keyhandle;
+	uint8_t srkauth[SHA1_DIGEST_SIZE];
+	uint8_t keyauth[SHA1_DIGEST_SIZE];
+	void *asn1_wrapped = NULL;
+	uint32_t in_len = params->in_len;
+	int r;
+
+	pr_devel("==>%s()\n", __func__);
+
+	if (strcmp(params->encoding, "pkcs1"))
+		return -ENOPKG;
+
+	if (params->hash_algo) {
+		const struct asn1_template *asn1 =
+						lookup_asn1(params->hash_algo);
+
+		if (!asn1)
+			return -ENOPKG;
+
+		/* request enough space for the ASN.1 template + input hash */
+		asn1_wrapped = kzalloc(in_len + asn1->size, GFP_KERNEL);
+		if (!asn1_wrapped)
+			return -ENOMEM;
+
+		/* Copy ASN.1 template, then the input */
+		memcpy(asn1_wrapped, asn1->data, asn1->size);
+		memcpy(asn1_wrapped + asn1->size, in, in_len);
+
+		in = asn1_wrapped;
+		in_len += asn1->size;
+	}
+
+	if (in_len > tk->key_len / 8 - 11) {
+		r = -EOVERFLOW;
+		goto error_free_asn1_wrapped;
+	}
+
+	r = tpm_buf_init(&tb, 0, 0);
+	if (r)
+		goto error_free_asn1_wrapped;
+
+	/* TODO: Handle a non-all zero SRK authorization */
+	memset(srkauth, 0, sizeof(srkauth));
+
+	r = tpm_loadkey2(&tb, SRKHANDLE, srkauth,
+			 tk->blob, tk->blob_len, &keyhandle);
+	if (r < 0) {
+		pr_devel("loadkey2 failed (%d)\n", r);
+		goto error_free_tb;
+	}
+
+	/* TODO: Handle a non-all zero key authorization */
+	memset(keyauth, 0, sizeof(keyauth));
+
+	r = tpm_sign(&tb, keyhandle, keyauth, in, in_len, out, params->out_len);
+	if (r < 0)
+		pr_devel("tpm_sign failed (%d)\n", r);
+
+	if (tpm_flushspecific(&tb, keyhandle) < 0)
+		pr_devel("flushspecific failed (%d)\n", r);
+
+error_free_tb:
+	tpm_buf_destroy(&tb);
+error_free_asn1_wrapped:
+	kfree(asn1_wrapped);
+	pr_devel("<==%s() = %d\n", __func__, r);
+	return r;
+}
+
+/*
+ * Do encryption, decryption and signing ops.
+ */
+static int tpm_key_eds_op(struct kernel_pkey_params *params,
+			  const void *in, void *out)
+{
+	struct tpm_key *tk = params->key->payload.data[asym_crypto];
+	int ret = -EOPNOTSUPP;
+
+	/* Perform the encryption calculation. */
+	switch (params->op) {
+	case kernel_pkey_encrypt:
+		ret = tpm_key_encrypt(tk, params, in, out);
+		break;
+	case kernel_pkey_decrypt:
+		ret = tpm_key_decrypt(tk, params, in, out);
+		break;
+	case kernel_pkey_sign:
+		ret = tpm_key_sign(tk, params, in, out);
+		break;
+	default:
+		BUG();
+	}
+
+	return ret;
+}
+
+/*
+ * Verify a signature using a public key.
+ */
+static int tpm_key_verify_signature(const struct key *key,
+				    const struct public_key_signature *sig)
+{
+	const struct tpm_key *tk = key->payload.data[asym_crypto];
+	struct crypto_wait cwait;
+	struct crypto_akcipher *tfm;
+	struct akcipher_request *req;
+	struct scatterlist src_sg[2];
+	char alg_name[CRYPTO_MAX_ALG_NAME];
+	uint8_t der_pub_key[PUB_KEY_BUF_SIZE];
+	uint32_t der_pub_key_len;
+	int ret;
+
+	pr_devel("==>%s()\n", __func__);
+
+	BUG_ON(!tk);
+	BUG_ON(!sig);
+	BUG_ON(!sig->s);
+
+	if (!sig->digest)
+		return -ENOPKG;
+
+	ret = determine_akcipher(sig->encoding, sig->hash_algo, alg_name);
+	if (ret < 0)
+		return ret;
+
+	tfm = crypto_alloc_akcipher(alg_name, 0, 0);
+	if (IS_ERR(tfm))
+		return PTR_ERR(tfm);
+
+	der_pub_key_len = derive_pub_key(tk->pub_key, tk->pub_key_len,
+					 der_pub_key);
+
+	ret = crypto_akcipher_set_pub_key(tfm, der_pub_key, der_pub_key_len);
+	if (ret < 0)
+		goto error_free_tfm;
+
+	ret = -ENOMEM;
+	req = akcipher_request_alloc(tfm, GFP_KERNEL);
+	if (!req)
+		goto error_free_tfm;
+
+	sg_init_table(src_sg, 2);
+	sg_set_buf(&src_sg[0], sig->s, sig->s_size);
+	sg_set_buf(&src_sg[1], sig->digest, sig->digest_size);
+	akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size,
+				   sig->digest_size);
+	crypto_init_wait(&cwait);
+	akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
+				      CRYPTO_TFM_REQ_MAY_SLEEP,
+				      crypto_req_done, &cwait);
+	ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait);
+
+	akcipher_request_free(req);
+error_free_tfm:
+	crypto_free_akcipher(tfm);
+	pr_devel("<==%s() = %d\n", __func__, ret);
+	if (WARN_ON_ONCE(ret > 0))
+		ret = -EINVAL;
+	return ret;
+}
+
+/*
+ * Parse enough information out of TPM_KEY structure:
+ * TPM_STRUCT_VER -> 4 bytes
+ * TPM_KEY_USAGE -> 2 bytes
+ * TPM_KEY_FLAGS -> 4 bytes
+ * TPM_AUTH_DATA_USAGE -> 1 byte
+ * TPM_KEY_PARMS -> variable
+ * UINT32 PCRInfoSize -> 4 bytes
+ * BYTE* -> PCRInfoSize bytes
+ * TPM_STORE_PUBKEY
+ * UINT32 encDataSize;
+ * BYTE* -> encDataSize;
+ *
+ * TPM_KEY_PARMS:
+ * TPM_ALGORITHM_ID -> 4 bytes
+ * TPM_ENC_SCHEME -> 2 bytes
+ * TPM_SIG_SCHEME -> 2 bytes
+ * UINT32 parmSize -> 4 bytes
+ * BYTE* -> variable
+ */
+static int extract_key_parameters(struct tpm_key *tk)
+{
+	const void *cur = tk->blob;
+	uint32_t len = tk->blob_len;
+	const void *pub_key;
+	uint32_t sz;
+	uint32_t key_len;
+
+	if (len < 11)
+		return -EBADMSG;
+
+	/* Ensure this is a legacy key */
+	if (get_unaligned_be16(cur + 4) != 0x0015)
+		return -EBADMSG;
+
+	/* Skip to TPM_KEY_PARMS */
+	cur += 11;
+	len -= 11;
+
+	if (len < 12)
+		return -EBADMSG;
+
+	/* Make sure this is an RSA key */
+	if (get_unaligned_be32(cur) != 0x00000001)
+		return -EBADMSG;
+
+	/* Make sure this is TPM_ES_RSAESPKCSv15 encoding scheme */
+	if (get_unaligned_be16(cur + 4) != 0x0002)
+		return -EBADMSG;
+
+	/* Make sure this is TPM_SS_RSASSAPKCS1v15_DER signature scheme */
+	if (get_unaligned_be16(cur + 6) != 0x0003)
+		return -EBADMSG;
+
+	sz = get_unaligned_be32(cur + 8);
+	if (len < sz + 12)
+		return -EBADMSG;
+
+	/* Move to TPM_RSA_KEY_PARMS */
+	len -= 12;
+	cur += 12;
+
+	/* Grab the RSA key length */
+	key_len = get_unaligned_be32(cur);
+
+	switch (key_len) {
+	case 512:
+	case 1024:
+	case 1536:
+	case 2048:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* Move just past TPM_KEY_PARMS */
+	cur += sz;
+	len -= sz;
+
+	if (len < 4)
+		return -EBADMSG;
+
+	sz = get_unaligned_be32(cur);
+	if (len < 4 + sz)
+		return -EBADMSG;
+
+	/* Move to TPM_STORE_PUBKEY */
+	cur += 4 + sz;
+	len -= 4 + sz;
+
+	/* Grab the size of the public key, it should jive with the key size */
+	sz = get_unaligned_be32(cur);
+	if (sz > 256)
+		return -EINVAL;
+
+	pub_key = cur + 4;
+
+	tk->key_len = key_len;
+	tk->pub_key = pub_key;
+	tk->pub_key_len = sz;
+
+	return 0;
+}
+
+/* Given the blob, parse it and load it into the TPM */
+struct tpm_key *tpm_key_create(const void *blob, uint32_t blob_len)
+{
+	int r;
+	struct tpm_key *tk;
+
+	r = tpm_is_tpm2(NULL);
+	if (r < 0)
+		goto error;
+
+	/* We don't support TPM2 yet */
+	if (r > 0) {
+		r = -ENODEV;
+		goto error;
+	}
+
+	r = -ENOMEM;
+	tk = kzalloc(sizeof(struct tpm_key), GFP_KERNEL);
+	if (!tk)
+		goto error;
+
+	tk->blob = kmemdup(blob, blob_len, GFP_KERNEL);
+	if (!tk->blob)
+		goto error_memdup;
+
+	tk->blob_len = blob_len;
+
+	r = extract_key_parameters(tk);
+	if (r < 0)
+		goto error_extract;
+
+	return tk;
+
+error_extract:
+	kfree(tk->blob);
+	tk->blob_len = 0;
+error_memdup:
+	kfree(tk);
+error:
+	return ERR_PTR(r);
+}
+EXPORT_SYMBOL_GPL(tpm_key_create);
+
+/*
+ * TPM-based asymmetric key subtype
+ */
+struct asymmetric_key_subtype asym_tpm_subtype = {
+	.owner			= THIS_MODULE,
+	.name			= "asym_tpm",
+	.name_len		= sizeof("asym_tpm") - 1,
+	.describe		= asym_tpm_describe,
+	.destroy		= asym_tpm_destroy,
+	.query			= tpm_key_query,
+	.eds_op			= tpm_key_eds_op,
+	.verify_signature	= tpm_key_verify_signature,
+};
+EXPORT_SYMBOL_GPL(asym_tpm_subtype);
+
+MODULE_DESCRIPTION("TPM based asymmetric key subtype");
+MODULE_AUTHOR("Intel Corporation");
+MODULE_LICENSE("GPL v2");