[PATCH] KEYS: remove support for asym_tpm keys

Ard Biesheuvel ardb at kernel.org
Sat Jan 29 08:29:56 UTC 2022


On Fri, 28 Jan 2022 at 20:57, Eric Biggers <ebiggers at kernel.org> wrote:
>
> From: Eric Biggers <ebiggers at google.com>
>
> asym_tpm keys are tied to TPM v1.2, which uses outdated crypto and has
> been deprecated in favor of TPM v2.0 for over 7 years.  A very quick
> look at this code also immediately found some memory safety bugs
> (https://lore.kernel.org/r/20220113235440.90439-2-ebiggers@kernel.org).
> Note that this code is reachable by unprivileged users.
>
> According to Jarkko (one of the keyrings subsystem maintainers), this
> code has no practical use cases, and he isn't willing to maintain it
> (https://lore.kernel.org/r/YfFZPbKkgYJGWu1Q@iki.fi).
>
> Therefore, let's remove it.
>
> Note that this feature didn't have any documentation or tests, so we
> don't need to worry about removing those.
>
> Cc: David Howells <dhowells at redhat.com>
> Cc: Denis Kenzior <denkenz at gmail.com>
> Cc: James Morris <jmorris at namei.org>
> Cc: Jarkko Sakkinen <jarkko at kernel.org>
> Cc: Marcel Holtmann <marcel at holtmann.org>
> Signed-off-by: Eric Biggers <ebiggers at google.com>

Acked-by: Ard Biesheuvel <ardb at kernel.org>

> ---
>  crypto/asymmetric_keys/Kconfig      |  21 -
>  crypto/asymmetric_keys/Makefile     |  12 -
>  crypto/asymmetric_keys/asym_tpm.c   | 957 ----------------------------
>  crypto/asymmetric_keys/tpm.asn1     |   5 -
>  crypto/asymmetric_keys/tpm_parser.c | 102 ---
>  include/crypto/asym_tpm_subtype.h   |  19 -
>  6 files changed, 1116 deletions(-)
>  delete mode 100644 crypto/asymmetric_keys/asym_tpm.c
>  delete mode 100644 crypto/asymmetric_keys/tpm.asn1
>  delete mode 100644 crypto/asymmetric_keys/tpm_parser.c
>  delete mode 100644 include/crypto/asym_tpm_subtype.h
>
> diff --git a/crypto/asymmetric_keys/Kconfig b/crypto/asymmetric_keys/Kconfig
> index 1f1f004dc7577..460bc5d0a828c 100644
> --- a/crypto/asymmetric_keys/Kconfig
> +++ b/crypto/asymmetric_keys/Kconfig
> @@ -22,18 +22,6 @@ config ASYMMETRIC_PUBLIC_KEY_SUBTYPE
>           appropriate hash algorithms (such as SHA-1) must be available.
>           ENOPKG will be reported if the requisite algorithm is unavailable.
>
> -config ASYMMETRIC_TPM_KEY_SUBTYPE
> -       tristate "Asymmetric TPM backed private key subtype"
> -       depends on TCG_TPM
> -       depends on TRUSTED_KEYS
> -       select CRYPTO_HMAC
> -       select CRYPTO_SHA1
> -       select CRYPTO_HASH_INFO
> -       help
> -         This option provides support for TPM backed private key type handling.
> -         Operations such as sign, verify, encrypt, decrypt are performed by
> -         the TPM after the private key is loaded.
> -
>  config X509_CERTIFICATE_PARSER
>         tristate "X.509 certificate parser"
>         depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE
> @@ -54,15 +42,6 @@ config PKCS8_PRIVATE_KEY_PARSER
>           private key data and provides the ability to instantiate a crypto key
>           from that data.
>
> -config TPM_KEY_PARSER
> -       tristate "TPM private key parser"
> -       depends on ASYMMETRIC_TPM_KEY_SUBTYPE
> -       select ASN1
> -       help
> -         This option provides support for parsing TPM format blobs for
> -         private key data and provides the ability to instantiate a crypto key
> -         from that data.
> -
>  config PKCS7_MESSAGE_PARSER
>         tristate "PKCS#7 message parser"
>         depends on X509_CERTIFICATE_PARSER
> diff --git a/crypto/asymmetric_keys/Makefile b/crypto/asymmetric_keys/Makefile
> index 28b91adba2aed..c38424f55b08d 100644
> --- a/crypto/asymmetric_keys/Makefile
> +++ b/crypto/asymmetric_keys/Makefile
> @@ -11,7 +11,6 @@ asymmetric_keys-y := \
>         signature.o
>
>  obj-$(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE) += public_key.o
> -obj-$(CONFIG_ASYMMETRIC_TPM_KEY_SUBTYPE) += asym_tpm.o
>
>  #
>  # X.509 Certificate handling
> @@ -75,14 +74,3 @@ verify_signed_pefile-y := \
>
>  $(obj)/mscode_parser.o: $(obj)/mscode.asn1.h $(obj)/mscode.asn1.h
>  $(obj)/mscode.asn1.o: $(obj)/mscode.asn1.c $(obj)/mscode.asn1.h
> -
> -#
> -# TPM private key parsing
> -#
> -obj-$(CONFIG_TPM_KEY_PARSER) += tpm_key_parser.o
> -tpm_key_parser-y := \
> -       tpm.asn1.o \
> -       tpm_parser.o
> -
> -$(obj)/tpm_parser.o: $(obj)/tpm.asn1.h
> -$(obj)/tpm.asn1.o: $(obj)/tpm.asn1.c $(obj)/tpm.asn1.h
> diff --git a/crypto/asymmetric_keys/asym_tpm.c b/crypto/asymmetric_keys/asym_tpm.c
> deleted file mode 100644
> index 0959613560b9e..0000000000000
> --- a/crypto/asymmetric_keys/asym_tpm.c
> +++ /dev/null
> @@ -1,957 +0,0 @@
> -// 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/sha1.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");
> diff --git a/crypto/asymmetric_keys/tpm.asn1 b/crypto/asymmetric_keys/tpm.asn1
> deleted file mode 100644
> index d7f194232f30a..0000000000000
> --- a/crypto/asymmetric_keys/tpm.asn1
> +++ /dev/null
> @@ -1,5 +0,0 @@
> ---
> --- Unencryted TPM Blob.  For details of the format, see:
> --- http://david.woodhou.se/draft-woodhouse-cert-best-practice.html#I-D.mavrogiannopoulos-tpmuri
> ---
> -PrivateKeyInfo ::= OCTET STRING ({ tpm_note_key })
> diff --git a/crypto/asymmetric_keys/tpm_parser.c b/crypto/asymmetric_keys/tpm_parser.c
> deleted file mode 100644
> index 96405d8dcd98d..0000000000000
> --- a/crypto/asymmetric_keys/tpm_parser.c
> +++ /dev/null
> @@ -1,102 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -#define pr_fmt(fmt) "TPM-PARSER: "fmt
> -#include <linux/module.h>
> -#include <linux/kernel.h>
> -#include <linux/export.h>
> -#include <linux/slab.h>
> -#include <linux/err.h>
> -#include <keys/asymmetric-subtype.h>
> -#include <keys/asymmetric-parser.h>
> -#include <crypto/asym_tpm_subtype.h>
> -#include "tpm.asn1.h"
> -
> -struct tpm_parse_context {
> -       const void      *blob;
> -       u32             blob_len;
> -};
> -
> -/*
> - * Note the key data of the ASN.1 blob.
> - */
> -int tpm_note_key(void *context, size_t hdrlen,
> -                  unsigned char tag,
> -                  const void *value, size_t vlen)
> -{
> -       struct tpm_parse_context *ctx = context;
> -
> -       ctx->blob = value;
> -       ctx->blob_len = vlen;
> -
> -       return 0;
> -}
> -
> -/*
> - * Parse a TPM-encrypted private key blob.
> - */
> -static struct tpm_key *tpm_parse(const void *data, size_t datalen)
> -{
> -       struct tpm_parse_context ctx;
> -       long ret;
> -
> -       memset(&ctx, 0, sizeof(ctx));
> -
> -       /* Attempt to decode the private key */
> -       ret = asn1_ber_decoder(&tpm_decoder, &ctx, data, datalen);
> -       if (ret < 0)
> -               goto error;
> -
> -       return tpm_key_create(ctx.blob, ctx.blob_len);
> -
> -error:
> -       return ERR_PTR(ret);
> -}
> -/*
> - * Attempt to parse a data blob for a key as a TPM private key blob.
> - */
> -static int tpm_key_preparse(struct key_preparsed_payload *prep)
> -{
> -       struct tpm_key *tk;
> -
> -       /*
> -        * TPM 1.2 keys are max 2048 bits long, so assume the blob is no
> -        * more than 4x that
> -        */
> -       if (prep->datalen > 256 * 4)
> -               return -EMSGSIZE;
> -
> -       tk = tpm_parse(prep->data, prep->datalen);
> -
> -       if (IS_ERR(tk))
> -               return PTR_ERR(tk);
> -
> -       /* We're pinning the module by being linked against it */
> -       __module_get(asym_tpm_subtype.owner);
> -       prep->payload.data[asym_subtype] = &asym_tpm_subtype;
> -       prep->payload.data[asym_key_ids] = NULL;
> -       prep->payload.data[asym_crypto] = tk;
> -       prep->payload.data[asym_auth] = NULL;
> -       prep->quotalen = 100;
> -       return 0;
> -}
> -
> -static struct asymmetric_key_parser tpm_key_parser = {
> -       .owner  = THIS_MODULE,
> -       .name   = "tpm_parser",
> -       .parse  = tpm_key_preparse,
> -};
> -
> -static int __init tpm_key_init(void)
> -{
> -       return register_asymmetric_key_parser(&tpm_key_parser);
> -}
> -
> -static void __exit tpm_key_exit(void)
> -{
> -       unregister_asymmetric_key_parser(&tpm_key_parser);
> -}
> -
> -module_init(tpm_key_init);
> -module_exit(tpm_key_exit);
> -
> -MODULE_DESCRIPTION("TPM private key-blob parser");
> -MODULE_LICENSE("GPL v2");
> diff --git a/include/crypto/asym_tpm_subtype.h b/include/crypto/asym_tpm_subtype.h
> deleted file mode 100644
> index 48198c36d6b9b..0000000000000
> --- a/include/crypto/asym_tpm_subtype.h
> +++ /dev/null
> @@ -1,19 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -#ifndef _LINUX_ASYM_TPM_SUBTYPE_H
> -#define _LINUX_ASYM_TPM_SUBTYPE_H
> -
> -#include <linux/keyctl.h>
> -
> -struct tpm_key {
> -       void *blob;
> -       u32 blob_len;
> -       uint16_t key_len; /* Size in bits of the key */
> -       const void *pub_key; /* pointer inside blob to the public key bytes */
> -       uint16_t pub_key_len; /* length of the public key */
> -};
> -
> -struct tpm_key *tpm_key_create(const void *blob, uint32_t blob_len);
> -
> -extern struct asymmetric_key_subtype asym_tpm_subtype;
> -
> -#endif /* _LINUX_ASYM_TPM_SUBTYPE_H */
> --
> 2.35.0
>



More information about the Linux-security-module-archive mailing list