## Overview
Introduce tpm2_key_rsa implementing asymmetric TPM RSA key. This key type
can be enabled with CONFIG_ASYMMETRIC_TPM2_KEY_RSA_SUBTYPE config option.
Carves groundwork for similar modules in future, such as tpm2_key_ecdsa.
## Testing
tpm2_createprimary --hierarchy o -G rsa2048 -c owner.txt
tpm2_evictcontrol -c owner.txt 0x81000001
tpm2_getcap handles-persistent
openssl genrsa -out private.pem 2048
tpm2_import -C 0x81000001 -G rsa -i private.pem -u key.pub -r key.priv
tpm2_encodeobject -C 0x81000001 -u key.pub -r key.priv -o key.priv.pem
openssl asn1parse -inform pem -in key.priv.pem -noout -out key.priv.der
serial=`cat key.priv.der | keyctl padd asymmetric tpm @u`
echo "abcdefg" > plaintext.txt
keyctl pkey_encrypt $serial 0 plaintext.txt enc=pkcs1 > encrypted.dat
keyctl pkey_decrypt $serial 0 encrypted.dat enc=pkcs1 > decrypted.dat
keyctl pkey_sign $serial 0 plaintext.txt enc=pkcs1 hash=sha256 > signed.dat
keyctl pkey_verify $serial 0 plaintext.txt signed.dat enc=pkcs1 hash=sha256
## References
- Derived from https://lore.kernel.org/all/[email protected]/
- Last RFC: https://lore.kernel.org/linux-integrity/[email protected]/T/#t
James Prestwood (1):
keys: asymmetric: ASYMMETRIC_TPM2_KEY_RSA_SUBTYPE
Jarkko Sakkinen (5):
crypto: rsa-pkcs1pad: export rsa1_asn_lookup()
lib: Expand asn1_encode_integer() to variable size integers
tpm: Export tpm2_load_context()
KEYS: trusted: Move tpm2_key_decode() to the TPM driver
tpm: tpm2_key: Extend parser to TPM_LoadableKey
crypto/asymmetric_keys/Kconfig | 16 +
crypto/asymmetric_keys/Makefile | 1 +
crypto/asymmetric_keys/tpm2_key_rsa.c | 726 ++++++++++++++++++
crypto/rsa-pkcs1pad.c | 16 +-
drivers/char/tpm/Kconfig | 1 +
drivers/char/tpm/Makefile | 5 +
drivers/char/tpm/tpm.h | 2 -
drivers/char/tpm/tpm2-cmd.c | 77 ++
drivers/char/tpm/tpm2-space.c | 61 --
drivers/char/tpm/tpm2_key.c | 119 +++
.../char/tpm}/tpm2key.asn1 | 0
include/crypto/rsa-pkcs1pad.h | 20 +
include/crypto/tpm2_key.h | 35 +
include/linux/asn1_encoder.h | 3 +-
include/linux/tpm.h | 4 +
lib/asn1_encoder.c | 185 ++---
security/keys/trusted-keys/Makefile | 2 -
security/keys/trusted-keys/trusted_tpm2.c | 130 +---
18 files changed, 1138 insertions(+), 265 deletions(-)
create mode 100644 crypto/asymmetric_keys/tpm2_key_rsa.c
create mode 100644 drivers/char/tpm/tpm2_key.c
rename {security/keys/trusted-keys => drivers/char/tpm}/tpm2key.asn1 (100%)
create mode 100644 include/crypto/rsa-pkcs1pad.h
create mode 100644 include/crypto/tpm2_key.h
--
2.45.1
ASN.1 template is required for TPM2 asymmetric keys, as it needs to be
piggy-packed with the input data before applying TPM2_RSA_Decrypt. This
patch prepares crypto subsystem for the addition of those keys.
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
crypto/rsa-pkcs1pad.c | 16 ++++++++++------
include/crypto/rsa-pkcs1pad.h | 20 ++++++++++++++++++++
2 files changed, 30 insertions(+), 6 deletions(-)
create mode 100644 include/crypto/rsa-pkcs1pad.h
diff --git a/crypto/rsa-pkcs1pad.c b/crypto/rsa-pkcs1pad.c
index cd501195f34a..00b6c14f861c 100644
--- a/crypto/rsa-pkcs1pad.c
+++ b/crypto/rsa-pkcs1pad.c
@@ -7,6 +7,7 @@
#include <crypto/algapi.h>
#include <crypto/akcipher.h>
+#include <crypto/rsa-pkcs1pad.h>
#include <crypto/internal/akcipher.h>
#include <crypto/internal/rsa.h>
#include <linux/err.h>
@@ -79,11 +80,7 @@ static const u8 rsa_digest_info_sha3_512[] = {
0x05, 0x00, 0x04, 0x40
};
-static const struct rsa_asn1_template {
- const char *name;
- const u8 *data;
- size_t size;
-} rsa_asn1_templates[] = {
+static const struct rsa_asn1_template rsa_asn1_templates[] = {
#define _(X) { #X, rsa_digest_info_##X, sizeof(rsa_digest_info_##X) }
_(md5),
_(sha1),
@@ -101,7 +98,13 @@ static const struct rsa_asn1_template {
{ NULL }
};
-static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
+/**
+ * rsa_lookup_asn1() - Lookup the ASN.1 digest info given the hash
+ * name: hash algorithm name
+ *
+ * Returns the ASN.1 digest info on success, and NULL on failure.
+ */
+const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
{
const struct rsa_asn1_template *p;
@@ -110,6 +113,7 @@ static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
return p;
return NULL;
}
+EXPORT_SYMBOL_GPL(rsa_lookup_asn1);
struct pkcs1pad_ctx {
struct crypto_akcipher *child;
diff --git a/include/crypto/rsa-pkcs1pad.h b/include/crypto/rsa-pkcs1pad.h
new file mode 100644
index 000000000000..32c7453ff644
--- /dev/null
+++ b/include/crypto/rsa-pkcs1pad.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * RSA padding templates.
+ */
+
+#ifndef _CRYPTO_RSA_PKCS1PAD_H
+#define _CRYPTO_RSA_PKCS1PAD_H
+
+/*
+ * Hash algorithm name to ASN.1 template mapping.
+ */
+struct rsa_asn1_template {
+ const char *name;
+ const u8 *data;
+ size_t size;
+};
+
+const struct rsa_asn1_template *rsa_lookup_asn1(const char *name);
+
+#endif /* _CRYPTO_RSA_PKCS1PAD_H */
--
2.45.1
Expand asn1_encode_integer() to variable size integers, meaning that it
will get a blob in big-endian format as integer and length of the blob as
parameters. This is required in order to encode RSA public key modulus.
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
include/linux/asn1_encoder.h | 3 +-
lib/asn1_encoder.c | 185 ++++++++++++----------
security/keys/trusted-keys/trusted_tpm2.c | 4 +-
3 files changed, 103 insertions(+), 89 deletions(-)
diff --git a/include/linux/asn1_encoder.h b/include/linux/asn1_encoder.h
index 08cd0c2ad34f..ad5fb18db9e2 100644
--- a/include/linux/asn1_encoder.h
+++ b/include/linux/asn1_encoder.h
@@ -9,9 +9,10 @@
#include <linux/bug.h>
#define asn1_oid_len(oid) (sizeof(oid)/sizeof(u32))
+
unsigned char *
asn1_encode_integer(unsigned char *data, const unsigned char *end_data,
- s64 integer);
+ const u8 *integer, int integer_len);
unsigned char *
asn1_encode_oid(unsigned char *data, const unsigned char *end_data,
u32 oid[], int oid_len);
diff --git a/lib/asn1_encoder.c b/lib/asn1_encoder.c
index 0fd3c454a468..51a2d7010a67 100644
--- a/lib/asn1_encoder.c
+++ b/lib/asn1_encoder.c
@@ -9,12 +9,78 @@
#include <linux/bug.h>
#include <linux/string.h>
#include <linux/module.h>
+#include <linux/slab.h>
+
+/**
+ * asn1_encode_length() - encode a length to follow an ASN.1 tag
+ * @data: pointer to encode at
+ * @data_len: pointer to remaining length (adjusted by routine)
+ * @len: length to encode
+ *
+ * This routine can encode lengths up to 65535 using the ASN.1 rules.
+ * It will accept a negative length and place a zero length tag
+ * instead (to keep the ASN.1 valid). This convention allows other
+ * encoder primitives to accept negative lengths as singalling the
+ * sequence will be re-encoded when the length is known.
+ */
+static int asn1_encode_length(unsigned char **data, int *data_len, int len)
+{
+ if (*data_len < 1)
+ return -EINVAL;
+
+ if (len < 0) {
+ *((*data)++) = 0;
+ (*data_len)--;
+ return 0;
+ }
+
+ if (len <= 0x7f) {
+ *((*data)++) = len;
+ (*data_len)--;
+ return 0;
+ }
+
+ if (*data_len < 2)
+ return -EINVAL;
+
+ if (len <= 0xff) {
+ *((*data)++) = 0x81;
+ *((*data)++) = len & 0xff;
+ *data_len -= 2;
+ return 0;
+ }
+
+ if (*data_len < 3)
+ return -EINVAL;
+
+ if (len <= 0xffff) {
+ *((*data)++) = 0x82;
+ *((*data)++) = (len >> 8) & 0xff;
+ *((*data)++) = len & 0xff;
+ *data_len -= 3;
+ return 0;
+ }
+
+ if (WARN(len > 0xffffff, "ASN.1 length can't be > 0xffffff"))
+ return -EINVAL;
+
+ if (*data_len < 4)
+ return -EINVAL;
+ *((*data)++) = 0x83;
+ *((*data)++) = (len >> 16) & 0xff;
+ *((*data)++) = (len >> 8) & 0xff;
+ *((*data)++) = len & 0xff;
+ *data_len -= 4;
+
+ return 0;
+}
/**
* asn1_encode_integer() - encode positive integer to ASN.1
- * @data: pointer to the pointer to the data
- * @end_data: end of data pointer, points one beyond last usable byte in @data
- * @integer: integer to be encoded
+ * @data: pointer to the pointer to the data
+ * @end_data: end of data pointer, points one beyond last usable byte in @data
+ * @integer: integer to be encoded
+ * @integer_len: length in bytes of the integer blob
*
* This is a simplified encoder: it only currently does
* positive integers, but it should be simple enough to add the
@@ -22,15 +88,17 @@
*/
unsigned char *
asn1_encode_integer(unsigned char *data, const unsigned char *end_data,
- s64 integer)
+ const u8 *integer, int integer_len)
{
int data_len = end_data - data;
- unsigned char *d = &data[2];
bool found = false;
+ unsigned char *d;
+ int encoded_len;
+ u8 *encoded;
+ int ret;
int i;
- if (WARN(integer < 0,
- "BUG: integer encode only supports positive integers"))
+ if (WARN(!integer, "BUG: integer is null"))
return ERR_PTR(-EINVAL);
if (IS_ERR(data))
@@ -40,17 +108,22 @@ asn1_encode_integer(unsigned char *data, const unsigned char *end_data,
if (data_len < 3)
return ERR_PTR(-EINVAL);
- /* remaining length where at d (the start of the integer encoding) */
- data_len -= 2;
+ (*data++) = _tag(UNIV, PRIM, INT);
+ data_len--;
- data[0] = _tag(UNIV, PRIM, INT);
- if (integer == 0) {
- *d++ = 0;
- goto out;
+ if (!memchr_inv(integer, 0, integer_len)) {
+ data[1] = 1;
+ data[2] = 0;
+ return &data[2];
}
- for (i = sizeof(integer); i > 0 ; i--) {
- int byte = integer >> (8 * (i - 1));
+ encoded = kzalloc(integer_len, GFP_KERNEL);
+ if (!encoded)
+ return ERR_PTR(-ENOMEM);
+ d = encoded;
+
+ for (i = 0; i < integer_len; i++) {
+ int byte = integer[i];
if (!found && byte == 0)
continue;
@@ -67,21 +140,23 @@ asn1_encode_integer(unsigned char *data, const unsigned char *end_data,
* have len >= 1
*/
*d++ = 0;
- data_len--;
}
found = true;
- if (data_len == 0)
- return ERR_PTR(-EINVAL);
-
*d++ = byte;
- data_len--;
}
- out:
- data[1] = d - data - 2;
+ encoded_len = d - encoded;
- return d;
+ ret = asn1_encode_length(&data, &data_len, encoded_len);
+ if (ret) {
+ kfree(encoded);
+ return ERR_PTR(ret);
+ }
+
+ memcpy(data, encoded, encoded_len);
+ kfree(encoded);
+ return data + encoded_len;
}
EXPORT_SYMBOL_GPL(asn1_encode_integer);
@@ -176,70 +251,6 @@ asn1_encode_oid(unsigned char *data, const unsigned char *end_data,
}
EXPORT_SYMBOL_GPL(asn1_encode_oid);
-/**
- * asn1_encode_length() - encode a length to follow an ASN.1 tag
- * @data: pointer to encode at
- * @data_len: pointer to remaining length (adjusted by routine)
- * @len: length to encode
- *
- * This routine can encode lengths up to 65535 using the ASN.1 rules.
- * It will accept a negative length and place a zero length tag
- * instead (to keep the ASN.1 valid). This convention allows other
- * encoder primitives to accept negative lengths as singalling the
- * sequence will be re-encoded when the length is known.
- */
-static int asn1_encode_length(unsigned char **data, int *data_len, int len)
-{
- if (*data_len < 1)
- return -EINVAL;
-
- if (len < 0) {
- *((*data)++) = 0;
- (*data_len)--;
- return 0;
- }
-
- if (len <= 0x7f) {
- *((*data)++) = len;
- (*data_len)--;
- return 0;
- }
-
- if (*data_len < 2)
- return -EINVAL;
-
- if (len <= 0xff) {
- *((*data)++) = 0x81;
- *((*data)++) = len & 0xff;
- *data_len -= 2;
- return 0;
- }
-
- if (*data_len < 3)
- return -EINVAL;
-
- if (len <= 0xffff) {
- *((*data)++) = 0x82;
- *((*data)++) = (len >> 8) & 0xff;
- *((*data)++) = len & 0xff;
- *data_len -= 3;
- return 0;
- }
-
- if (WARN(len > 0xffffff, "ASN.1 length can't be > 0xffffff"))
- return -EINVAL;
-
- if (*data_len < 4)
- return -EINVAL;
- *((*data)++) = 0x83;
- *((*data)++) = (len >> 16) & 0xff;
- *((*data)++) = (len >> 8) & 0xff;
- *((*data)++) = len & 0xff;
- *data_len -= 4;
-
- return 0;
-}
-
/**
* asn1_encode_tag() - add a tag for optional or explicit value
* @data: pointer to place tag at
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 8b7dd73d94c1..ec59f9389a2d 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -38,6 +38,7 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
u8 *end_work = scratch + SCRATCH_SIZE;
u8 *priv, *pub;
u16 priv_len, pub_len;
+ u32 key_handle;
int ret;
priv_len = get_unaligned_be16(src) + 2;
@@ -77,7 +78,8 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
goto err;
}
- work = asn1_encode_integer(work, end_work, options->keyhandle);
+ key_handle = cpu_to_be32(options->keyhandle);
+ work = asn1_encode_integer(work, end_work, (u8 *)&key_handle, 4);
work = asn1_encode_octet_string(work, end_work, pub, pub_len);
work = asn1_encode_octet_string(work, end_work, priv, priv_len);
--
2.45.1
Export tpm2_load_context() so that the null key can be loaded as the
parent of a asymmetric TPM2 key.
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
drivers/char/tpm/tpm.h | 2 -
drivers/char/tpm/tpm2-cmd.c | 77 +++++++++++++++++++++++++++++++++++
drivers/char/tpm/tpm2-space.c | 61 ---------------------------
include/linux/tpm.h | 2 +
4 files changed, 79 insertions(+), 63 deletions(-)
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 6b8b9956ba69..c9c67fe84f33 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -314,8 +314,6 @@ int tpm_devs_add(struct tpm_chip *chip);
void tpm_devs_remove(struct tpm_chip *chip);
int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf,
unsigned int buf_size, unsigned int *offset);
-int tpm2_load_context(struct tpm_chip *chip, u8 *buf,
- unsigned int *offset, u32 *handle);
void tpm_bios_log_setup(struct tpm_chip *chip);
void tpm_bios_log_teardown(struct tpm_chip *chip);
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 0cdf892ec2a7..eb07a109e2ba 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -370,6 +370,83 @@ void tpm2_flush_context(struct tpm_chip *chip, u32 handle)
}
EXPORT_SYMBOL_GPL(tpm2_flush_context);
+struct tpm2_context {
+ __be64 sequence;
+ __be32 saved_handle;
+ __be32 hierarchy;
+ __be16 blob_size;
+} __packed;
+
+/**
+ * tpm2_load_context() - Load TPM2 object to the TPM memory
+ * @chip: TPM chip to use
+ * @buf: Blob containing TPM2 object.
+ * @offset: Output variable for the offset in @buf reached.
+ * @handle: Output variable for the handle of the object in TPM memory.
+ *
+ * Load a blob encrypted with TPM from the memory to the TPM chip.
+ *
+ * Return:
+ * - 0 when the blob is successfully loaded to the TPM.
+ * - -EFAULT if the TPM chip itself fails.
+ * - -ENOENT if the TPM object is replayed.
+ * - -EINVAL if the TPM object is corrupted.
+ */
+int tpm2_load_context(struct tpm_chip *chip, const u8 *buf,
+ unsigned int *offset, u32 *handle)
+{
+ struct tpm_buf tbuf;
+ struct tpm2_context *ctx;
+ unsigned int body_size;
+ int rc;
+
+ rc = tpm_buf_init(&tbuf, TPM2_ST_NO_SESSIONS, TPM2_CC_CONTEXT_LOAD);
+ if (rc)
+ return rc;
+
+ ctx = (struct tpm2_context *)&buf[*offset];
+ body_size = sizeof(*ctx) + be16_to_cpu(ctx->blob_size);
+ tpm_buf_append(&tbuf, &buf[*offset], body_size);
+
+ rc = tpm_transmit_cmd(chip, &tbuf, 4, NULL);
+ if (rc < 0) {
+ dev_warn(&chip->dev, "%s: failed with a system error %d\n",
+ __func__, rc);
+ tpm_buf_destroy(&tbuf);
+ return -EFAULT;
+ } else if (tpm2_rc_value(rc) == TPM2_RC_HANDLE ||
+ rc == TPM2_RC_REFERENCE_H0) {
+ /*
+ * TPM_RC_HANDLE means that the session context can't
+ * be loaded because of an internal counter mismatch
+ * that makes the TPM think there might have been a
+ * replay. This might happen if the context was saved
+ * and loaded outside the space.
+ *
+ * TPM_RC_REFERENCE_H0 means the session has been
+ * flushed outside the space
+ */
+ *handle = 0;
+ tpm_buf_destroy(&tbuf);
+ return -ENOENT;
+ } else if (tpm2_rc_value(rc) == TPM2_RC_INTEGRITY) {
+ tpm_buf_destroy(&tbuf);
+ return -EINVAL;
+ } else if (rc > 0) {
+ dev_warn(&chip->dev, "%s: failed with a TPM error 0x%04X\n",
+ __func__, rc);
+ tpm_buf_destroy(&tbuf);
+ return -EFAULT;
+ }
+
+ *handle = be32_to_cpup((__be32 *)&tbuf.data[TPM_HEADER_SIZE]);
+ *offset += body_size;
+
+ tpm_buf_destroy(&tbuf);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(tpm2_load_context);
+
struct tpm2_get_cap_out {
u8 more_data;
__be32 subcap_id;
diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index 4892d491da8d..708c6e4d64cd 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -21,13 +21,6 @@ enum tpm2_handle_types {
TPM2_HT_TRANSIENT = 0x80000000,
};
-struct tpm2_context {
- __be64 sequence;
- __be32 saved_handle;
- __be32 hierarchy;
- __be16 blob_size;
-} __packed;
-
static void tpm2_flush_sessions(struct tpm_chip *chip, struct tpm_space *space)
{
int i;
@@ -68,60 +61,6 @@ void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space)
kfree(space->session_buf);
}
-int tpm2_load_context(struct tpm_chip *chip, u8 *buf,
- unsigned int *offset, u32 *handle)
-{
- struct tpm_buf tbuf;
- struct tpm2_context *ctx;
- unsigned int body_size;
- int rc;
-
- rc = tpm_buf_init(&tbuf, TPM2_ST_NO_SESSIONS, TPM2_CC_CONTEXT_LOAD);
- if (rc)
- return rc;
-
- ctx = (struct tpm2_context *)&buf[*offset];
- body_size = sizeof(*ctx) + be16_to_cpu(ctx->blob_size);
- tpm_buf_append(&tbuf, &buf[*offset], body_size);
-
- rc = tpm_transmit_cmd(chip, &tbuf, 4, NULL);
- if (rc < 0) {
- dev_warn(&chip->dev, "%s: failed with a system error %d\n",
- __func__, rc);
- tpm_buf_destroy(&tbuf);
- return -EFAULT;
- } else if (tpm2_rc_value(rc) == TPM2_RC_HANDLE ||
- rc == TPM2_RC_REFERENCE_H0) {
- /*
- * TPM_RC_HANDLE means that the session context can't
- * be loaded because of an internal counter mismatch
- * that makes the TPM think there might have been a
- * replay. This might happen if the context was saved
- * and loaded outside the space.
- *
- * TPM_RC_REFERENCE_H0 means the session has been
- * flushed outside the space
- */
- *handle = 0;
- tpm_buf_destroy(&tbuf);
- return -ENOENT;
- } else if (tpm2_rc_value(rc) == TPM2_RC_INTEGRITY) {
- tpm_buf_destroy(&tbuf);
- return -EINVAL;
- } else if (rc > 0) {
- dev_warn(&chip->dev, "%s: failed with a TPM error 0x%04X\n",
- __func__, rc);
- tpm_buf_destroy(&tbuf);
- return -EFAULT;
- }
-
- *handle = be32_to_cpup((__be32 *)&tbuf.data[TPM_HEADER_SIZE]);
- *offset += body_size;
-
- tpm_buf_destroy(&tbuf);
- return 0;
-}
-
int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf,
unsigned int buf_size, unsigned int *offset)
{
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index c17e4efbb2e5..2f25ca07127b 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -466,6 +466,8 @@ extern int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
extern int tpm_get_random(struct tpm_chip *chip, u8 *data, size_t max);
extern struct tpm_chip *tpm_default_chip(void);
void tpm2_flush_context(struct tpm_chip *chip, u32 handle);
+int tpm2_load_context(struct tpm_chip *chip, const u8 *buf,
+ unsigned int *offset, u32 *handle);
static inline void tpm_buf_append_empty_auth(struct tpm_buf *buf, u32 handle)
{
--
2.45.1
Extend parser to TPM_LoadableKey. Add field for oid to struct tpm2_key
so that callers can differentiate different key types.
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
drivers/char/tpm/tpm2_key.c | 14 +++++++++++---
include/crypto/tpm2_key.h | 2 ++
security/keys/trusted-keys/trusted_tpm2.c | 5 +++++
3 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/drivers/char/tpm/tpm2_key.c b/drivers/char/tpm/tpm2_key.c
index 0112362e432e..59797dc232f1 100644
--- a/drivers/char/tpm/tpm2_key.c
+++ b/drivers/char/tpm/tpm2_key.c
@@ -32,16 +32,24 @@ int tpm2_key_type(void *context, size_t hdrlen,
const void *value, size_t vlen)
{
enum OID oid = look_up_OID(value, vlen);
-
- if (oid != OID_TPMSealedData) {
+ struct tpm2_key *key = context;
+
+ switch (oid) {
+ case OID_TPMSealedData:
+ pr_info("TPMSealedData\n");
+ break;
+ case OID_TPMLoadableKey:
+ pr_info("TPMLodableKey\n");
+ break;
+ default:
char buffer[50];
-
sprint_oid(value, vlen, buffer, sizeof(buffer));
pr_debug("OID is \"%s\" which is not TPMSealedData\n",
buffer);
return -EINVAL;
}
+ key->oid = oid;
return 0;
}
diff --git a/include/crypto/tpm2_key.h b/include/crypto/tpm2_key.h
index acf41b2e0c92..2d2434233000 100644
--- a/include/crypto/tpm2_key.h
+++ b/include/crypto/tpm2_key.h
@@ -2,12 +2,14 @@
#ifndef __LINUX_TPM2_KEY_H__
#define __LINUX_TPM2_KEY_H__
+#include <linux/oid_registry.h>
#include <linux/slab.h>
/*
* TPM2 ASN.1 key
*/
struct tpm2_key {
+ enum OID oid;
u32 parent;
const u8 *blob;
u32 blob_len;
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 49ee2a57797a..842a8e2701e4 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -304,6 +304,11 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
blob = payload->blob;
payload->old_format = 1;
} else {
+ if (key.oid != OID_TPMSealedData) {
+ tpm2_key_destroy(&key);
+ return -EINVAL;
+ }
+
blob = kmalloc(key.priv_len + key.pub_len + 4, GFP_KERNEL);
if (blob) {
options->keyhandle = key.parent;
--
2.45.1
From: James Prestwood <[email protected]>
Based on earlier work by James Prestwood.
Add ASN.1 compatible asymmetric TPM2 RSA key subtype:
1. Signing and decryption (with the private key) is handled by
TPM2_RSA_Decrypt.
2. Encryption (with the public key) is handled by the kernel RSA
implementation.
Link: https://lore.kernel.org/all/[email protected]/
Signed-off-by: James Prestwood <[email protected]>
Co-developed-by: Jarkko Sakkinen <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
crypto/asymmetric_keys/Kconfig | 16 +
crypto/asymmetric_keys/Makefile | 1 +
crypto/asymmetric_keys/tpm2_key_rsa.c | 726 ++++++++++++++++++++++++++
include/linux/tpm.h | 2 +
4 files changed, 745 insertions(+)
create mode 100644 crypto/asymmetric_keys/tpm2_key_rsa.c
diff --git a/crypto/asymmetric_keys/Kconfig b/crypto/asymmetric_keys/Kconfig
index e1345b8f39f1..4d14bb0c346e 100644
--- a/crypto/asymmetric_keys/Kconfig
+++ b/crypto/asymmetric_keys/Kconfig
@@ -15,6 +15,7 @@ config ASYMMETRIC_PUBLIC_KEY_SUBTYPE
select MPILIB
select CRYPTO_HASH_INFO
select CRYPTO_AKCIPHER
+ select CRYPTO_RSA
select CRYPTO_SIG
select CRYPTO_HASH
help
@@ -23,6 +24,21 @@ 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_TPM2_KEY_RSA_SUBTYPE
+ tristate "Asymmetric TPM2 RSA crypto algorithm subtype"
+ depends on TCG_TPM
+ select TCG_TPM2_HMAC
+ select CRYPTO_RSA
+ select CRYPTO_SHA256
+ select CRYPTO_HASH_INFO
+ select ASN1
+ select ASN1_ENCODER
+ help
+ This option provides support for asymmetric TPM2 key type handling.
+ If signature generation and/or verification are to be used,
+ appropriate hash algorithms (such as SHA-256) must be available.
+ ENOPKG will be reported if the requisite algorithm is unavailable.
+
config X509_CERTIFICATE_PARSER
tristate "X.509 certificate parser"
depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE
diff --git a/crypto/asymmetric_keys/Makefile b/crypto/asymmetric_keys/Makefile
index bc65d3b98dcb..c6da84607824 100644
--- a/crypto/asymmetric_keys/Makefile
+++ b/crypto/asymmetric_keys/Makefile
@@ -11,6 +11,7 @@ asymmetric_keys-y := \
signature.o
obj-$(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE) += public_key.o
+obj-$(CONFIG_ASYMMETRIC_TPM2_KEY_RSA_SUBTYPE) += tpm2_key_rsa.o
#
# X.509 Certificate handling
diff --git a/crypto/asymmetric_keys/tpm2_key_rsa.c b/crypto/asymmetric_keys/tpm2_key_rsa.c
new file mode 100644
index 000000000000..f44ddb5baee6
--- /dev/null
+++ b/crypto/asymmetric_keys/tpm2_key_rsa.c
@@ -0,0 +1,726 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* TPM2 asymmetric public-key crypto subtype
+ *
+ * See Documentation/crypto/asymmetric-keys.rst
+ *
+ * Copyright (c) 2020 Intel Corporation
+ */
+
+#include <asm/unaligned.h>
+#include <crypto/akcipher.h>
+#include <crypto/public_key.h>
+#include <crypto/rsa-pkcs1pad.h>
+#include <crypto/tpm2_key.h>
+#include <keys/asymmetric-parser.h>
+#include <keys/asymmetric-subtype.h>
+#include <keys/trusted-type.h>
+#include <linux/asn1_encoder.h>
+#include <linux/keyctl.h>
+#include <linux/module.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+#include <linux/tpm.h>
+
+#undef pr_fmt
+#define pr_fmt(fmt) "tpm2_key_rsa: "fmt
+
+#define PUB_KEY_BUF_SIZE 512
+
+struct tpm2_key_rsa {
+ struct tpm2_key key;
+ const u8 *pub;
+ int pub_len;
+};
+
+/*
+ * PKCS1 padding (type 1)
+ */
+static int tpm2_pad_pkcs1(const u8 *m, unsigned int mlen,
+ u8 *em, unsigned int em_len)
+{
+ unsigned int ps_len = em_len - mlen - 3;
+
+ if (mlen > em_len - 11)
+ return -EBADMSG;
+
+ em[0] = 0;
+ em[1] = 1;
+
+ memset(em + 2, 0xff, ps_len);
+
+ em[2 + ps_len] = 0;
+ memcpy(em + 2 + ps_len + 1, m, mlen);
+
+ return 0;
+}
+
+/*
+ * RFC 3447 - Section 7.2.2
+ */
+static const u8 *tpm2_unpad_pkcs1(const u8 *data, unsigned int len,
+ unsigned int *out_len)
+{
+ unsigned int i;
+
+ /*
+ * Size of input data should be checked against public key size by
+ * caller.
+ */
+ if (data[0] != 0 || data[1] != 2)
+ return NULL;
+
+ i = 2;
+
+ while (data[i] != 0 && i < len)
+ i++;
+
+ if (i == len)
+ return NULL;
+
+ *out_len = len - i - 1;
+
+ return data + i + 1;
+}
+
+/*
+ * Outputs the cipher algorithm name on success, and retuns -ENOPKG
+ * on failure.
+ */
+static int tpm2_key_get_akcipher(const char *encoding, const char *hash_algo,
+ char *cipher)
+{
+ ssize_t ret;
+
+ if (strcmp(encoding, "pkcs1") == 0) {
+ if (!hash_algo) {
+ strcpy(cipher, "pkcs1pad(rsa)");
+ return 0;
+ }
+
+ ret = snprintf(cipher, CRYPTO_MAX_ALG_NAME,
+ "pkcs1pad(rsa,%s)",
+ hash_algo);
+ if (ret >= CRYPTO_MAX_ALG_NAME)
+ return -ENOPKG;
+
+ return 0;
+ }
+
+ if (strcmp(encoding, "raw") == 0) {
+ strcpy(cipher, "rsa");
+ return 0;
+ }
+
+ return -ENOPKG;
+}
+
+static int tpm2_key_rsa_extract_pub(struct tpm2_key_rsa *key_rsa)
+{
+ struct tpm2_key *key = &key_rsa->key;
+ struct tpm_buf buf;
+ off_t offset = 2;
+ u16 policy_len;
+ u32 attr;
+ u16 bits;
+ u16 type;
+ u16 len;
+ u16 alg;
+ u32 exp;
+
+ buf.flags = TPM_BUF_TPM2B;
+ buf.length = key->pub_len;
+ buf.data = (void *)key->pub;
+
+ if (get_unaligned_be16(key->pub) != buf.length - 2)
+ return -EINVAL;
+
+ type = tpm_buf_read_u16(&buf, &offset);
+ pr_debug("pub type: 0x%04x\n", type);
+ if (type != TPM_ALG_RSA)
+ return -EINVAL;
+
+ alg = tpm_buf_read_u16(&buf, &offset);
+ pr_debug("pub name alg: 0x%04x\n", alg);
+ attr = tpm_buf_read_u32(&buf, &offset);
+ pr_debug("pub attributes: 0x%08x\n", attr);
+ policy_len = tpm_buf_read_u16(&buf, &offset);
+ pr_debug("pub policy length: %u bytes\n", policy_len);
+ offset += policy_len;
+
+ if (buf.flags & TPM_BUF_BOUNDARY_ERROR) {
+ pr_err("pub overflow\n");
+ return -EIO;
+ }
+
+ alg = tpm_buf_read_u16(&buf, &offset);
+ pr_debug("pub symmetric: 0x%04x\n", alg);
+ if (alg != TPM_ALG_NULL)
+ return -EINVAL;
+
+ alg = tpm_buf_read_u16(&buf, &offset);
+ pr_debug("pub symmetric scheme: 0x%04x\n", alg);
+ if (alg != TPM_ALG_NULL)
+ return -EINVAL;
+
+ bits = tpm_buf_read_u16(&buf, &offset);
+ pr_debug("pub bits: %u\n", bits);
+
+ exp = tpm_buf_read_u32(&buf, &offset);
+ pr_debug("pub exponent: 0x%08x\n", exp);
+ if (exp != 0x00000000 && exp != 0x00010001)
+ return -EINVAL;
+
+ if (buf.flags & TPM_BUF_BOUNDARY_ERROR) {
+ pr_err("pub overflow\n");
+ return -EIO;
+ }
+
+ len = tpm_buf_read_u16(&buf, &offset);
+ pr_debug("pub modulus: %u bytes\n", len);
+ key_rsa->pub = key->pub + offset;
+ key_rsa->pub_len = len;
+ return 0;
+}
+
+static int tpm2_key_rsa_encode(const struct tpm2_key_rsa *key, u8 *buf)
+{
+ const int SCRATCH_SIZE = PAGE_SIZE;
+ const u8 exp[3] = {1, 0, 1};
+ u8 *scratch, *work, *work1, *end_work;
+ int pub_len = key->pub_len;
+ const u8 *pub = key->pub;
+ int ret;
+
+ scratch = kmalloc(SCRATCH_SIZE, GFP_KERNEL);
+ if (!scratch)
+ return -ENOMEM;
+
+ work = scratch;
+ end_work = &scratch[SCRATCH_SIZE];
+
+ work = asn1_encode_integer(work, end_work, pub, pub_len);
+ if (IS_ERR(work)) {
+ ret = PTR_ERR(work);
+ goto err;
+ }
+
+ work = asn1_encode_integer(work, end_work, exp, 3);
+ if (IS_ERR(work)) {
+ ret = PTR_ERR(work);
+ goto err;
+ }
+
+ work1 = buf;
+ work1 = asn1_encode_sequence(work1, &work1[PUB_KEY_BUF_SIZE],
+ scratch, work - scratch);
+ if (IS_ERR(work1)) {
+ ret = PTR_ERR(work1);
+ goto err;
+ }
+
+ memset(work1, 0, 8);
+
+ kfree(scratch);
+ return work1 - buf;
+
+err:
+ kfree(scratch);
+ return ret;
+}
+
+/*
+ * Encryption operation is performed with the public key. Hence it is done
+ * in software
+ */
+static int tpm2_key_rsa_encrypt(struct tpm2_key_rsa *key,
+ struct kernel_pkey_params *params,
+ const void *in, void *out)
+{
+ char cipher[CRYPTO_MAX_ALG_NAME];
+ struct scatterlist in_sg, out_sg;
+ u8 enc_pub_key[PUB_KEY_BUF_SIZE];
+ struct akcipher_request *req;
+ struct crypto_akcipher *tfm;
+ struct crypto_wait cwait;
+ int rc;
+
+ rc = tpm2_key_get_akcipher(params->encoding, params->hash_algo, cipher);
+ if (rc < 0)
+ return rc;
+
+ tfm = crypto_alloc_akcipher(cipher, 0, 0);
+ if (IS_ERR(tfm))
+ return PTR_ERR(tfm);
+
+ rc = tpm2_key_rsa_encode(key, enc_pub_key);
+ if (rc < 0)
+ goto err_tfm;
+
+ rc = crypto_akcipher_set_pub_key(tfm, enc_pub_key, rc);
+ if (rc < 0)
+ goto err_tfm;
+
+ req = akcipher_request_alloc(tfm, GFP_KERNEL);
+ if (!req) {
+ rc = -ENOMEM;
+ goto err_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);
+
+ rc = crypto_akcipher_encrypt(req);
+ rc = crypto_wait_req(rc, &cwait);
+
+ if (!rc)
+ rc = req->dst_len;
+
+ akcipher_request_free(req);
+
+err_tfm:
+ crypto_free_akcipher(tfm);
+
+ return rc;
+}
+
+static int __tpm2_key_rsa_decrypt(struct tpm_chip *chip,
+ struct tpm2_key_rsa *key,
+ struct kernel_pkey_params *params,
+ const void *in, int in_len, void *out)
+{
+ unsigned int offset = 0;
+ u32 key_handle = 0;
+ struct tpm_buf buf;
+ u16 decrypted_len;
+ u32 parent;
+ u8 *pos;
+ int ret;
+
+ ret = tpm_try_get_ops(chip);
+ if (ret)
+ return ret;
+
+ ret = tpm2_start_auth_session(chip);
+ if (ret)
+ goto err_ops;
+
+ if (key->key.parent == TPM2_RH_NULL) {
+ ret = tpm2_load_context(chip, chip->null_key_context, &offset,
+ &parent);
+ if (ret) {
+ ret = -EIO;
+ goto err_auth;
+ }
+ } else {
+ parent = key->key.parent;
+ }
+
+ pr_info("parent: 0x%08x\n", parent);
+
+ ret = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD);
+ if (ret < 0)
+ goto err_parent;
+
+ tpm_buf_append_name(chip, &buf, parent, NULL);
+ tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_CONTINUE_SESSION |
+ TPM2_SA_ENCRYPT, NULL, 0);
+ tpm_buf_append(&buf, key->key.blob, key->key.blob_len);
+ if (buf.flags & TPM_BUF_OVERFLOW) {
+ ret = -E2BIG;
+ goto err_buf;
+ }
+ tpm_buf_fill_hmac_session(chip, &buf);
+ ret = tpm_transmit_cmd(chip, &buf, 4, "loading blob");
+ ret = tpm_buf_check_hmac_response(chip, &buf, ret);
+ if (ret) {
+ ret = -EIO;
+ goto err_buf;
+ }
+ key_handle = be32_to_cpup((__be32 *)&buf.data[TPM_HEADER_SIZE]);
+ pr_info("key: 0x%08x\n", key_handle);
+
+ tpm_buf_reset(&buf, TPM2_ST_SESSIONS, TPM2_CC_RSA_DECRYPT);
+ tpm_buf_append_name(chip, &buf, key_handle, NULL);
+ tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_DECRYPT, NULL, 0);
+ tpm_buf_append_u16(&buf, in_len);
+ tpm_buf_append(&buf, in, in_len);
+ tpm_buf_append_u16(&buf, TPM_ALG_NULL);
+ tpm_buf_append_u16(&buf, 0);
+ tpm_buf_fill_hmac_session(chip, &buf);
+ ret = tpm_transmit_cmd(chip, &buf, 4, "RSA decryption");
+ ret = tpm_buf_check_hmac_response(chip, &buf, ret);
+ if (ret) {
+ ret = -EIO;
+ goto err_blob;
+ }
+
+ pos = buf.data + TPM_HEADER_SIZE + 4;
+ decrypted_len = be16_to_cpup((__be16 *)pos);
+ pos += 2;
+
+ if (params->out_len < decrypted_len) {
+ ret = -EMSGSIZE;
+ goto err_blob;
+ }
+
+ memcpy(out, pos, decrypted_len);
+ ret = decrypted_len;
+
+err_blob:
+ tpm2_flush_context(chip, key_handle);
+
+err_buf:
+ tpm_buf_destroy(&buf);
+
+err_parent:
+ if (key->key.parent == TPM2_RH_NULL)
+ tpm2_flush_context(chip, parent);
+
+err_auth:
+ if (ret < 0)
+ tpm2_end_auth_session(chip);
+
+err_ops:
+ tpm_put_ops(chip);
+ return ret;
+}
+
+/*
+ * Decryption operation is performed with the private key in the TPM.
+ */
+static int tpm2_key_rsa_decrypt(struct tpm_chip *chip, struct tpm2_key_rsa *key,
+ struct kernel_pkey_params *params,
+ const void *in, void *out)
+{
+ unsigned int unpadded_len;
+ const u8 *unpadded;
+ u8 *work;
+ int ret;
+
+ work = kzalloc(params->out_len, GFP_KERNEL);
+
+ ret = __tpm2_key_rsa_decrypt(chip, key, params, in, params->in_len, work);
+ if (ret < 0)
+ goto err;
+
+ unpadded = tpm2_unpad_pkcs1(work, ret, &unpadded_len);
+ if (!unpadded) {
+ ret = -EINVAL;
+ goto err;
+ }
+
+ memcpy(out, unpadded, unpadded_len);
+ kfree(work);
+ return unpadded_len;
+
+err:
+ kfree(work);
+ return ret;
+}
+
+/*
+ * Sign operation is an encryption using the TPM's private key. With RSA the
+ * only difference between encryption and decryption is where the padding goes.
+ * Since own padding can be used, TPM2_RSA_Decrypt can be repurposed to do
+ * encryption.
+ */
+static int tpm2_key_rsa_sign(struct tpm_chip *chip, struct tpm2_key_rsa *key,
+ struct kernel_pkey_params *params,
+ const void *in, void *out)
+{
+ const struct rsa_asn1_template *asn1;
+ u32 in_len = params->in_len;
+ void *asn1_wrapped = NULL;
+ int pub_len = key->pub_len;
+ u8 *padded;
+ int ret;
+
+ if (strcmp(params->encoding, "pkcs1") != 0) {
+ ret = -ENOPKG;
+ goto done;
+ }
+
+ if (params->hash_algo) {
+ asn1 = rsa_lookup_asn1(params->hash_algo);
+ if (!asn1) {
+ ret = -ENOPKG;
+ goto done;
+ }
+
+ /* Request enough space for the ASN.1 template + input hash */
+ asn1_wrapped = kzalloc(in_len + asn1->size, GFP_KERNEL);
+ if (!asn1_wrapped) {
+ ret = -ENOMEM;
+ goto done;
+ }
+
+ /* 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;
+ }
+
+ /*
+ * Using the TPM's decrypt call to sign (aka encrypt). This
+ * requires pre-padding the data with PKCS1.
+ */
+ padded = kmalloc(pub_len, GFP_KERNEL);
+ tpm2_pad_pkcs1(in, in_len, padded, pub_len);
+
+ ret = __tpm2_key_rsa_decrypt(chip, key, params, padded, pub_len, out);
+
+ kfree(padded);
+done:
+ kfree(asn1_wrapped);
+ return ret;
+}
+
+static void tpm2_key_rsa_describe(const struct key *asymmetric_key,
+ struct seq_file *m)
+{
+ struct tpm2_key_rsa *key = asymmetric_key->payload.data[asym_crypto];
+
+ if (!key) {
+ pr_err("key is empty");
+ return;
+ }
+
+ seq_puts(m, "TPM2/RSA");
+}
+
+static void tpm2_key_rsa_destroy(void *payload0, void *payload3)
+{
+ struct tpm2_key *key = payload0;
+
+ if (!key)
+ return;
+
+ tpm2_key_destroy(key);
+ kfree(key);
+}
+
+static int tpm2_key_rsa_eds_op(struct kernel_pkey_params *params,
+ const void *in, void *out)
+{
+ struct tpm2_key_rsa *key = params->key->payload.data[asym_crypto];
+ struct tpm_chip *chip = tpm_default_chip();
+
+ if (!chip)
+ return -ENODEV;
+
+ switch (params->op) {
+ case kernel_pkey_encrypt:
+ return tpm2_key_rsa_encrypt(key, params, in, out);
+ case kernel_pkey_decrypt:
+ return tpm2_key_rsa_decrypt(chip, key, params, in, out);
+ case kernel_pkey_sign:
+ return tpm2_key_rsa_sign(chip, key, params, in, out);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int tpm2_key_rsa_verify(const struct key *key,
+ const struct public_key_signature *sig)
+{
+ const struct tpm2_key_rsa *tpm2_key = key->payload.data[asym_crypto];
+ char alg_name[CRYPTO_MAX_ALG_NAME];
+ u8 enc_pub_key[PUB_KEY_BUF_SIZE];
+ struct akcipher_request *req;
+ struct scatterlist src_sg[2];
+ struct crypto_akcipher *tfm;
+ struct crypto_wait cwait;
+ int rc;
+
+ if (WARN_ON(!tpm2_key || !sig || !sig->s))
+ return -EINVAL;
+
+ if (!sig->digest)
+ return -ENOPKG;
+
+ rc = tpm2_key_get_akcipher(sig->encoding, sig->hash_algo, alg_name);
+ if (rc < 0)
+ return rc;
+
+ tfm = crypto_alloc_akcipher(alg_name, 0, 0);
+ if (IS_ERR(tfm))
+ return PTR_ERR(tfm);
+
+ rc = tpm2_key_rsa_encode(tpm2_key, enc_pub_key);
+ if (rc < 0)
+ goto err_tfm;
+
+ rc = crypto_akcipher_set_pub_key(tfm, enc_pub_key, rc);
+ if (rc < 0)
+ goto err_tfm;
+
+ rc = -ENOMEM;
+ req = akcipher_request_alloc(tfm, GFP_KERNEL);
+ if (!req)
+ goto err_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);
+ rc = crypto_wait_req(crypto_akcipher_verify(req), &cwait);
+
+ akcipher_request_free(req);
+err_tfm:
+ crypto_free_akcipher(tfm);
+ pr_devel("<=%s() = %d\n", __func__, rc);
+ if (WARN_ON_ONCE(rc > 0))
+ rc = -EINVAL;
+ return rc;
+}
+
+static int tpm2_key_rsa_query(const struct kernel_pkey_params *params,
+ struct kernel_pkey_query *info)
+{
+ struct tpm2_key_rsa *tk = params->key->payload.data[asym_crypto];
+ char alg_name[CRYPTO_MAX_ALG_NAME];
+ u8 enc_pub_key[PUB_KEY_BUF_SIZE];
+ struct crypto_akcipher *tfm;
+ unsigned int len;
+ int ret;
+
+ ret = tpm2_key_get_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);
+
+ ret = tpm2_key_rsa_encode(tk, enc_pub_key);
+ if (ret < 0)
+ goto err_tfm;
+
+ ret = crypto_akcipher_set_pub_key(tfm, enc_pub_key, ret);
+ if (ret < 0)
+ goto err_tfm;
+
+ len = crypto_akcipher_maxsize(tfm);
+
+ info->key_size = tk->pub_len * 8;
+ info->max_data_size = tk->pub_len;
+ info->max_sig_size = len;
+ info->max_enc_size = len;
+ info->max_dec_size = tk->pub_len;
+
+ info->supported_ops = KEYCTL_SUPPORTS_ENCRYPT |
+ KEYCTL_SUPPORTS_DECRYPT |
+ KEYCTL_SUPPORTS_VERIFY |
+ KEYCTL_SUPPORTS_SIGN;
+
+err_tfm:
+ crypto_free_akcipher(tfm);
+ return ret;
+}
+
+/*
+ * Asymmetric TPM2 RSA key. Signs and decrypts with TPM.
+ */
+struct asymmetric_key_subtype tpm2_key_rsa_subtype = {
+ .owner = THIS_MODULE,
+ .name = "tpm2_key_rsa",
+ .name_len = sizeof("tpm2_key_rsa") - 1,
+ .describe = tpm2_key_rsa_describe,
+ .destroy = tpm2_key_rsa_destroy,
+ .query = tpm2_key_rsa_query,
+ .eds_op = tpm2_key_rsa_eds_op,
+ .verify_signature = tpm2_key_rsa_verify,
+};
+EXPORT_SYMBOL_GPL(tpm2_key_rsa_subtype);
+
+/*
+ * Attempt to parse a data blob for a key as a TPM private key blob.
+ */
+static int tpm2_key_preparse(struct key_preparsed_payload *prep)
+{
+ struct tpm2_key_rsa *key;
+ int ret;
+
+ key = kzalloc(sizeof(*key), GFP_KERNEL);
+ if (!key)
+ return -ENOMEM;
+
+ /*
+ * TPM 2.0 RSA keys are recommended to be 2048 bits long. Assume the
+ * blob is no more than 4x that.
+ */
+ if (prep->datalen > 256 * 4) {
+ kfree(key);
+ return -EMSGSIZE;
+ }
+
+ ret = tpm2_key_decode(prep->data, prep->datalen, &key->key, PAGE_SIZE);
+ if (ret) {
+ kfree(key);
+ return ret;
+ }
+
+ if (key->key.oid != OID_TPMLoadableKey) {
+ tpm2_key_destroy(&key->key);
+ kfree(key);
+ return -EINVAL;
+ }
+
+ ret = tpm2_key_rsa_extract_pub(key);
+ if (ret < 0) {
+ tpm2_key_destroy(&key->key);
+ kfree(key);
+ return ret;
+ }
+
+ prep->payload.data[asym_subtype] = &tpm2_key_rsa_subtype;
+ prep->payload.data[asym_key_ids] = NULL;
+ prep->payload.data[asym_crypto] = key;
+ prep->payload.data[asym_auth] = NULL;
+ prep->quotalen = 100;
+
+ return 0;
+}
+
+static struct asymmetric_key_parser tpm2_key_rsa_parser = {
+ .owner = THIS_MODULE,
+ .name = "tpm2_key_rsa_parser",
+ .parse = tpm2_key_preparse,
+};
+
+static int __init tpm2_key_rsa_init(void)
+{
+ int ret;
+
+ ret = register_asymmetric_key_parser(&tpm2_key_rsa_parser);
+ if (ret)
+ return ret;
+
+ pr_info("Asymmetric TPM2 RSA key initialized\n");
+ return 0;
+}
+
+static void __exit tpm2_key_rsa_exit(void)
+{
+ unregister_asymmetric_key_parser(&tpm2_key_rsa_parser);
+}
+
+module_init(tpm2_key_rsa_init);
+module_exit(tpm2_key_rsa_exit);
+
+MODULE_DESCRIPTION("Asymmetric TPM2 RSA key");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 2f25ca07127b..8161758da19a 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -43,6 +43,7 @@ enum tpm2_session_types {
/* if you add a new hash to this, increment TPM_MAX_HASHES below */
enum tpm_algorithms {
TPM_ALG_ERROR = 0x0000,
+ TPM_ALG_RSA = 0x0001,
TPM_ALG_SHA1 = 0x0004,
TPM_ALG_AES = 0x0006,
TPM_ALG_KEYEDHASH = 0x0008,
@@ -271,6 +272,7 @@ enum tpm2_command_codes {
TPM2_CC_NV_READ = 0x014E,
TPM2_CC_CREATE = 0x0153,
TPM2_CC_LOAD = 0x0157,
+ TPM2_CC_RSA_DECRYPT = 0x0159,
TPM2_CC_SEQUENCE_UPDATE = 0x015C,
TPM2_CC_UNSEAL = 0x015E,
TPM2_CC_CONTEXT_LOAD = 0x0161,
--
2.45.1
On Mon May 20, 2024 at 9:47 PM EEST, Jarkko Sakkinen wrote:
> ## Overview
>
> Introduce tpm2_key_rsa implementing asymmetric TPM RSA key. This key type
> can be enabled with CONFIG_ASYMMETRIC_TPM2_KEY_RSA_SUBTYPE config option.
> Carves groundwork for similar modules in future, such as tpm2_key_ecdsa.
Cc to Eric (forgot).
BR, Jarkko
On Mon May 20, 2024 at 11:36 PM EEST, Jarkko Sakkinen wrote:
> On Mon May 20, 2024 at 9:47 PM EEST, Jarkko Sakkinen wrote:
> > ## Overview
> >
> > Introduce tpm2_key_rsa implementing asymmetric TPM RSA key. This key type
> > can be enabled with CONFIG_ASYMMETRIC_TPM2_KEY_RSA_SUBTYPE config option.
> > Carves groundwork for similar modules in future, such as tpm2_key_ecdsa.
>
> Cc to Eric (forgot).
Also my idea is to take the (working) model from tpm_tis. At this point
it is just tpm2_key_rsa but it would be easy to lay out tpm2_key later
on and make the different key types as submodules. That would be a kind
of model, which would support algorithmic agility side of TPM2.
So there might tpm2_key at some point with tpm2_key_rsa and tpm2_key_ecdsa
as its submodules.
BR, Jarkko