Modify the TPM2 key format blob output to export and import in the
ASN.1 form for TPM2 sealed object keys. For compatibility with prior
trusted keys, the importer will also accept two TPM2B quantities
representing the public and private parts of the key. However, the
export via keyctl pipe will only output the ASN.1 format.
The benefit of the ASN.1 format is that it's a standard and thus the
exported key can be used by userspace tools (openssl_tpm2_engine,
openconnect and tpm2-tss-engine). The format includes policy
specifications, thus it gets us out of having to construct policy
handles in userspace and the format includes the parent meaning you
don't have to keep passing it in each time.
This patch only implements basic handling for the ASN.1 format, so
keys with passwords but no policy.
Signed-off-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
v2: Updated encode API, added length checks
v5: correct export format after doing interoperability checks
---
Documentation/security/keys/trusted-encrypted.rst | 19 +-
include/keys/trusted-type.h | 6 +-
include/linux/tpm.h | 7 +
security/keys/Kconfig | 2 +
security/keys/trusted-keys/Makefile | 2 +-
security/keys/trusted-keys/tpm2-policy.c | 372 ++++++++++++++++++++++
security/keys/trusted-keys/tpm2-policy.h | 30 ++
security/keys/trusted-keys/tpm2key.asn1 | 23 ++
security/keys/trusted-keys/trusted_tpm1.c | 9 +-
security/keys/trusted-keys/trusted_tpm2.c | 328 +++++++++++++++++--
10 files changed, 771 insertions(+), 27 deletions(-)
create mode 100644 security/keys/trusted-keys/tpm2-policy.c
create mode 100644 security/keys/trusted-keys/tpm2-policy.h
create mode 100644 security/keys/trusted-keys/tpm2key.asn1
diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst
index 50ac8bcd6970..053344c4df5b 100644
--- a/Documentation/security/keys/trusted-encrypted.rst
+++ b/Documentation/security/keys/trusted-encrypted.rst
@@ -60,7 +60,10 @@ Usage::
(40 ascii zeros)
blobauth= ascii hex auth for sealed data default 0x00...
(40 ascii zeros)
- pcrinfo= ascii hex of PCR_INFO or PCR_INFO_LONG (no default)
+ pcrinfo= ascii hex of PCR_INFO or PCR_INFO_LONG (no
+ default) on TPM 1.2 and a TPMS_PCR_SELECTION
+ coupled with a hash of all the selected PCRs on
+ TPM 2.0 using the selected hash.
pcrlock= pcr number to be extended to "lock" blob
migratable= 0|1 indicating permission to reseal to new PCR values,
default 1 (resealing allowed)
@@ -151,6 +154,20 @@ Load a trusted key from the saved blob::
f1f8fff03ad0acb083725535636addb08d73dedb9832da198081e5deae84bfaf0409c22b
e4a8aea2b607ec96931e6f4d4fe563ba
+Create a trusted key on TPM 2.0 using an all zero value of PCR16 and
+using the NV storage root 81000001 as the parent::
+
+ $ keyctl add trusted kmk "new 32 keyhandle=0x81000001 hash=sha1 pcrinfo=030000016768033e216468247bd031a0a2d9876d79818f8f" @u
+
+Note the TPMS_PCR_SELECT value for PCR 16 is 03000001 because all
+current TPMs have 24 PCRs, so the initial 03 says there are three
+following bytes of selection and then because the bytes are big
+endian, 16 is bit zero of byte 2. the hash is the sha1 sum of all
+zeros (the value of PCR 16)::
+
+ $ dd if=/dev/zero bs=1 count=20 2>/dev/null|sha1sum
+ 6768033e216468247bd031a0a2d9876d79818f8f
+
Reseal a trusted key under new pcr values::
$ keyctl update 268728824 "update pcrinfo=`cat pcr.blob`"
diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h
index b2ed3481c6a0..c117bf598230 100644
--- a/include/keys/trusted-type.h
+++ b/include/keys/trusted-type.h
@@ -14,16 +14,20 @@
#define MIN_KEY_SIZE 32
#define MAX_KEY_SIZE 128
#define MAX_BLOB_SIZE 512
-#define MAX_PCRINFO_SIZE 64
+#define MAX_PCRINFO_SIZE 128
#define MAX_DIGEST_SIZE 64
+#define TPM2_MAX_POLICIES 16
+
struct trusted_key_payload {
struct rcu_head rcu;
unsigned int key_len;
unsigned int blob_len;
unsigned char migratable;
+ unsigned char old_format;
unsigned char key[MAX_KEY_SIZE + 1];
unsigned char blob[MAX_BLOB_SIZE];
+ struct tpm2_policies *policies;
};
struct trusted_key_options {
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 03e9b184411b..e32e9728adce 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -222,10 +222,14 @@ enum tpm2_command_codes {
TPM2_CC_CONTEXT_LOAD = 0x0161,
TPM2_CC_CONTEXT_SAVE = 0x0162,
TPM2_CC_FLUSH_CONTEXT = 0x0165,
+ TPM2_CC_POLICY_AUTHVALUE = 0x016B,
+ TPM2_CC_POLICY_COUNTER_TIMER = 0x016D,
+ TPM2_CC_START_AUTH_SESS = 0x0176,
TPM2_CC_VERIFY_SIGNATURE = 0x0177,
TPM2_CC_GET_CAPABILITY = 0x017A,
TPM2_CC_GET_RANDOM = 0x017B,
TPM2_CC_PCR_READ = 0x017E,
+ TPM2_CC_POLICY_PCR = 0x017F,
TPM2_CC_PCR_EXTEND = 0x0182,
TPM2_CC_EVENT_SEQUENCE_COMPLETE = 0x0185,
TPM2_CC_HASH_SEQUENCE_START = 0x0186,
@@ -234,6 +238,7 @@ enum tpm2_command_codes {
};
enum tpm2_permanent_handles {
+ TPM2_RH_NULL = 0x40000007,
TPM2_RS_PW = 0x40000009,
};
@@ -297,6 +302,8 @@ struct tpm_buf {
};
enum tpm2_object_attributes {
+ TPM2_OA_FIXED_TPM = BIT(1),
+ TPM2_OA_FIXED_PARENT = BIT(4),
TPM2_OA_USER_WITH_AUTH = BIT(6),
};
diff --git a/security/keys/Kconfig b/security/keys/Kconfig
index 47c041563d41..d65f7614709a 100644
--- a/security/keys/Kconfig
+++ b/security/keys/Kconfig
@@ -76,6 +76,8 @@ config TRUSTED_KEYS
select CRYPTO
select CRYPTO_HMAC
select CRYPTO_SHA1
+ select CRYPTO_SHA256
+ select CRYPTO_SHA512
select CRYPTO_HASH_INFO
help
This option provides support for creating, sealing, and unsealing
diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile
index 7b73cebbb378..194febacf362 100644
--- a/security/keys/trusted-keys/Makefile
+++ b/security/keys/trusted-keys/Makefile
@@ -5,4 +5,4 @@
obj-$(CONFIG_TRUSTED_KEYS) += trusted.o
trusted-y += trusted_tpm1.o
-trusted-y += trusted_tpm2.o
+trusted-y += trusted_tpm2.o tpm2key.asn1.o tpm2-policy.o
diff --git a/security/keys/trusted-keys/tpm2-policy.c b/security/keys/trusted-keys/tpm2-policy.c
new file mode 100644
index 000000000000..de07e576c9f4
--- /dev/null
+++ b/security/keys/trusted-keys/tpm2-policy.c
@@ -0,0 +1,372 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2019 James.Bottomley@xxxxxxxxxxxxxxxxxxxxx
+ */
+
+#include <linux/asn1_encoder.h>
+#include <linux/err.h>
+#include <linux/types.h>
+#include <linux/printk.h>
+#include <linux/string.h>
+#include <linux/tpm.h>
+
+#include <asm/unaligned.h>
+
+#include <crypto/hash.h>
+
+#include <keys/trusted-type.h>
+#include <keys/trusted_tpm.h>
+
+#include "tpm2key.asn1.h"
+#include "tpm2-policy.h"
+
+int tpmkey_code(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct tpm2key_context *ctx = context;
+ u32 code = 0;
+ const u8 *v = value;
+ int i;
+
+ for (i = 0; i < vlen; i++) {
+ code <<= 8;
+ code |= v[i];
+ }
+
+ ctx->policy_code[ctx->policy_count] = code;
+
+ return 0;
+}
+
+int tpmkey_policy(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct tpm2key_context *ctx = context;
+
+ ctx->policies[ctx->policy_count] = value;
+ ctx->policy_len[ctx->policy_count++] = vlen;
+
+ return 0;
+}
+
+/* we only support a limited number of policy statement so
+ * make sure we don't have anything we can't support
+ */
+static int tpm2_validate_policy(struct tpm2_policies *pols)
+{
+ int i;
+
+ if (pols->count == 0)
+ return 0;
+
+ for (i = 0; i < pols->count; i++) {
+ switch (pols->code[i]) {
+ case TPM2_CC_POLICY_COUNTER_TIMER:
+ case TPM2_CC_POLICY_PCR:
+ case TPM2_CC_POLICY_AUTHVALUE:
+ break;
+ default:
+ printk(KERN_INFO "tpm2 policy 0x%x is unsupported",
+ pols->code[i]);
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * tpmkey_process_policy - collect the policty from the context
+ * @ctx: the context to collect from
+ * @payload: the payload structure to place it in
+ *
+ * THis function sizes the policy statements and allocates space
+ * within the payload to receive them before copying them over. It
+ * should be used after the ber decoder has completed successfully
+ */
+int tpmkey_policy_process(struct tpm2key_context *ctx,
+ struct trusted_key_payload *payload)
+{
+ int tot_len = 0;
+ u8 *buf;
+ int i, ret, len = 0;
+ struct tpm2_policies *pols;
+
+ if (ctx->policy_count == 0)
+ return 0;
+
+ for (i = 0; i < ctx->policy_count; i++)
+ tot_len += ctx->policy_len[i];
+ tot_len += sizeof(*pols);
+
+ pols = kmalloc(tot_len, GFP_KERNEL);
+ if (!pols)
+ return -ENOMEM;
+
+ payload->policies = pols;
+ buf = (u8 *)(pols + 1);
+
+ for (i = 0; i < ctx->policy_count; i++) {
+ pols->policies[i] = &buf[len];
+ pols->len[i] = ctx->policy_len[i];
+ pols->code[i] = ctx->policy_code[i];
+ if (pols->len[i])
+ memcpy(pols->policies[i], ctx->policies[i],
+ ctx->policy_len[i]);
+ len += ctx->policy_len[i];
+ }
+ pols->count = ctx->policy_count;
+
+ ret = tpm2_validate_policy(pols);
+ if (ret) {
+ kfree(pols);
+ payload->policies = NULL;
+ }
+
+ /* capture the hash and size */
+
+ /* the hash is the second algorithm */
+ pols->hash = get_unaligned_be16(&ctx->pub[2]);
+ /* and the digest appears after the attributes */
+ pols->hash_size = get_unaligned_be16(&ctx->pub[8]);
+
+ return ret;
+}
+
+int tpm2_generate_policy_digest(struct tpm2_policies *pols,
+ u32 hash, u8 *policydigest, u32 *plen)
+{
+ int i;
+ struct crypto_shash *tfm;
+ int rc;
+
+ if (pols->count == 0)
+ return 0;
+
+ tfm = crypto_alloc_shash(hash_algo_name[hash], 0, 0);
+ if (IS_ERR(tfm))
+ return PTR_ERR(tfm);
+
+ rc = crypto_shash_digestsize(tfm);
+ if (WARN(rc > MAX_DIGEST_SIZE,
+ "BUG: trusted key code has alg %s with digest too large (%d)",
+ hash_algo_name[hash], rc)) {
+ rc = -EINVAL;
+ goto err;
+ }
+
+ pols->hash = hash;
+ pols->hash_size = rc;
+ *plen = rc;
+
+ /* policy digests always start out all zeros */
+ memset(policydigest, 0, rc);
+
+ for (i = 0; i < pols->count; i++) {
+ u8 *policy = pols->policies[i];
+ int len = pols->len[i];
+ u32 cmd = pols->code[i];
+ u8 digest[MAX_DIGEST_SIZE];
+ u8 code[4];
+ SHASH_DESC_ON_STACK(sdesc, tfm);
+
+ sdesc->tfm = tfm;
+ rc = crypto_shash_init(sdesc);
+ if (rc)
+ goto err;
+
+ /* first hash the previous digest */
+ crypto_shash_update(sdesc, policydigest, *plen);
+
+ /* then hash the command code */
+ put_unaligned_be32(cmd, code);
+ crypto_shash_update(sdesc, code, 4);
+
+ /* commands that need special handling */
+ if (cmd == TPM2_CC_POLICY_COUNTER_TIMER) {
+ SHASH_DESC_ON_STACK(sdesc1, tfm);
+
+ sdesc1->tfm = tfm;
+
+ /* counter timer policies are double hashed */
+ crypto_shash_digest(sdesc1, policy, len,
+ digest);
+ policy = digest;
+ len = *plen;
+ }
+
+ crypto_shash_update(sdesc, policy, len);
+
+ /* now output the intermediate to the policydigest */
+ crypto_shash_final(sdesc, policydigest);
+
+ }
+ rc = 0;
+
+ err:
+ crypto_free_shash(tfm);
+ return rc;
+}
+
+int tpm2_encode_policy(struct tpm2_policies *pols, u8 **data, u32 *len)
+{
+ const int SCRATCH_SIZE = PAGE_SIZE;
+ u8 *buf = kmalloc(2 * SCRATCH_SIZE, GFP_KERNEL);
+ u8 *work = buf + SCRATCH_SIZE;
+ u8 *ptr;
+ u8 *end_work = work + SCRATCH_SIZE;
+ int i, ret;
+
+ if (!buf)
+ return -ENOMEM;
+
+ for (i = 0; i < pols->count; i++) {
+ u8 *seq, *tag;
+ u32 cmd = pols->code[i];
+
+ if (WARN(work - buf + 14 + pols->len[i] > 2 * SCRATCH_SIZE,
+ "BUG: scratch buffer is too small"))
+ return -EINVAL;
+
+ work = asn1_encode_sequence(work, end_work, NULL, -1);
+ seq = work;
+
+ work = asn1_encode_tag(work, end_work, 0, NULL, -1);
+ tag = work;
+
+ work = asn1_encode_integer(work, end_work, cmd);
+ asn1_encode_tag(tag, end_work, 0, NULL, work - tag);
+
+ work = asn1_encode_tag(work, end_work, 1, NULL, -1);
+ tag = work;
+
+ work = asn1_encode_octet_string(work, end_work,
+ pols->policies[i],
+ pols->len[i]);
+
+ asn1_encode_tag(tag, end_work, 1, NULL, work - tag);
+
+ seq = asn1_encode_sequence(seq, end_work, NULL, work - seq);
+ if (IS_ERR(seq)) {
+ ret = PTR_ERR(seq);
+ goto err;
+ }
+ }
+ ptr = asn1_encode_sequence(buf, buf + SCRATCH_SIZE, buf + PAGE_SIZE,
+ work - buf - PAGE_SIZE);
+ if (IS_ERR(ptr)) {
+ ret = PTR_ERR(ptr);
+ goto err;
+ }
+
+ *data = buf;
+ *len = ptr - buf;
+
+ return 0;
+
+ err:
+ kfree(buf);
+ return ret;
+}
+
+int tpm2_start_policy_session(struct tpm_chip *chip, u16 hash, u32 *handle)
+{
+ struct tpm_buf buf;
+ int rc;
+ int i;
+
+ rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_START_AUTH_SESS);
+ if (rc)
+ return rc;
+
+ /* NULL salt key handle */
+ tpm_buf_append_u32(&buf, TPM2_RH_NULL);
+
+ /* NULL bind key handle */
+ tpm_buf_append_u32(&buf, TPM2_RH_NULL);
+
+ /* empty nonce caller */
+ tpm_buf_append_u16(&buf, 20);
+ for (i = 0; i < 20; i++)
+ tpm_buf_append_u8(&buf, 0);
+
+ /* empty auth */
+ tpm_buf_append_u16(&buf, 0);
+
+ /* session type policy */
+ tpm_buf_append_u8(&buf, 0x01);
+
+ /* symmetric encryption parameters */
+
+ /* symmetric algorithm */
+ tpm_buf_append_u16(&buf, TPM_ALG_NULL);
+
+ /* hash algorithm for session */
+ tpm_buf_append_u16(&buf, hash);
+
+ rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
+ if (rc)
+ goto out;
+
+ *handle = get_unaligned_be32(buf.data + TPM_HEADER_SIZE);
+
+ out:
+ tpm_buf_destroy(&buf);
+
+ return rc <= 0 ? rc : -EPERM;
+}
+
+int tpm2_get_policy_session(struct tpm_chip *chip, struct tpm2_policies *pols,
+ u32 *handle)
+{
+ int i, rc;
+ const char *failure;
+
+ rc = tpm2_start_policy_session(chip, pols->hash, handle);
+ if (rc)
+ return rc;
+
+ for (i = 0; i < pols->count; i++) {
+ u32 cmd = pols->code[i];
+ struct tpm_buf buf;
+
+ rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, cmd);
+ if (rc)
+ return rc;
+
+ tpm_buf_append_u32(&buf, *handle);
+
+ switch (cmd) {
+ case TPM2_CC_POLICY_PCR:
+ failure = "PCR";
+ /*
+ * for reasons best known to the TCG we have
+ * to reverse the two arguments to send to the
+ * policy command
+ */
+ tpm_buf_append_u16(&buf, pols->hash_size);
+ tpm_buf_append(&buf, pols->policies[i] + pols->len[i] -
+ pols->hash_size, pols->hash_size);
+ tpm_buf_append(&buf, pols->policies[i],
+ pols->len[i] - pols->hash_size);
+ break;
+ default:
+ failure = "unknown policy";
+ break;
+ }
+
+ rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
+ tpm_buf_destroy(&buf);
+ if (rc) {
+ printk(KERN_NOTICE "TPM policy %s failed, rc=%d\n",
+ failure, rc);
+ tpm2_flush_context(chip, *handle);
+ *handle = 0;
+ return -EPERM;
+ }
+ }
+
+ return 0;
+}
diff --git a/security/keys/trusted-keys/tpm2-policy.h b/security/keys/trusted-keys/tpm2-policy.h
new file mode 100644
index 000000000000..152c948743f3
--- /dev/null
+++ b/security/keys/trusted-keys/tpm2-policy.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+struct tpm2key_context {
+ u32 parent;
+ const u8 *pub;
+ u32 pub_len;
+ const u8 *priv;
+ u32 priv_len;
+ const u8 *policies[TPM2_MAX_POLICIES];
+ u32 policy_code[TPM2_MAX_POLICIES];
+ u16 policy_len[TPM2_MAX_POLICIES];
+ u8 policy_count;
+};
+
+struct tpm2_policies {
+ u32 code[TPM2_MAX_POLICIES];
+ u8 *policies[TPM2_MAX_POLICIES];
+ u16 len[TPM2_MAX_POLICIES];
+ u8 count;
+ u16 hash;
+ u16 hash_size;
+};
+
+int tpmkey_policy_process(struct tpm2key_context *ctx,
+ struct trusted_key_payload *payload);
+int tpm2_generate_policy_digest(struct tpm2_policies *pols, u32 hash,
+ u8 *policydigest, u32 *plen);
+int tpm2_encode_policy(struct tpm2_policies *pols, u8 **data, u32 *len);
+int tpm2_get_policy_session(struct tpm_chip *chip, struct tpm2_policies *pols,
+ u32 *handle);
diff --git a/security/keys/trusted-keys/tpm2key.asn1 b/security/keys/trusted-keys/tpm2key.asn1
new file mode 100644
index 000000000000..f930fd812db3
--- /dev/null
+++ b/security/keys/trusted-keys/tpm2key.asn1
@@ -0,0 +1,23 @@
+---
+--- Note: This isn't quite the definition in the standard
+--- However, the Linux asn.1 parser doesn't understand
+--- [2] EXPLICIT SEQUENCE OF OPTIONAL
+--- So there's an extra intermediate TPMPolicySequence
+--- definition to work around this
+
+TPMKey ::= SEQUENCE {
+ type OBJECT IDENTIFIER ({tpmkey_type}),
+ emptyAuth [0] EXPLICIT BOOLEAN OPTIONAL,
+ policy [1] EXPLICIT TPMPolicySequence OPTIONAL,
+ secret [2] EXPLICIT OCTET STRING OPTIONAL,
+ parent INTEGER ({tpmkey_parent}),
+ pubkey OCTET STRING ({tpmkey_pub}),
+ privkey OCTET STRING ({tpmkey_priv})
+ }
+
+TPMPolicySequence ::= SEQUENCE OF TPMPolicy
+
+TPMPolicy ::= SEQUENCE {
+ commandCode [0] EXPLICIT INTEGER ({tpmkey_code}),
+ commandPolicy [1] EXPLICIT OCTET STRING ({tpmkey_policy})
+ }
diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c
index add9f071d818..08e7bb89f7bf 100644
--- a/security/keys/trusted-keys/trusted_tpm1.c
+++ b/security/keys/trusted-keys/trusted_tpm1.c
@@ -1011,7 +1011,7 @@ static int trusted_instantiate(struct key *key,
goto out;
}
- if (!options->keyhandle) {
+ if (!options->keyhandle && !tpm2) {
ret = -EINVAL;
goto out;
}
@@ -1065,6 +1065,7 @@ static void trusted_rcu_free(struct rcu_head *rcu)
struct trusted_key_payload *p;
p = container_of(rcu, struct trusted_key_payload, rcu);
+ kzfree(p->policies);
kzfree(p);
}
@@ -1184,7 +1185,11 @@ static long trusted_read(const struct key *key, char __user *buffer,
*/
static void trusted_destroy(struct key *key)
{
- kzfree(key->payload.data[0]);
+ struct trusted_key_payload *p;
+
+ p = key->payload.data[0];
+ kzfree(p->policies);
+ kzfree(p);
}
struct key_type key_type_trusted = {
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index b4a5058107c2..293db0aaada6 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -4,6 +4,8 @@
* Copyright (C) 2014 Intel Corporation
*/
+#include <linux/asn1_encoder.h>
+#include <linux/oid_registry.h>
#include <linux/string.h>
#include <linux/err.h>
#include <linux/tpm.h>
@@ -12,6 +14,11 @@
#include <keys/trusted-type.h>
#include <keys/trusted_tpm.h>
+#include <asm/unaligned.h>
+
+#include "tpm2key.asn1.h"
+#include "tpm2-policy.h"
+
static struct tpm2_hash tpm2_hash_map[] = {
{HASH_ALGO_SHA1, TPM_ALG_SHA1},
{HASH_ALGO_SHA256, TPM_ALG_SHA256},
@@ -20,6 +27,178 @@ static struct tpm2_hash tpm2_hash_map[] = {
{HASH_ALGO_SM3_256, TPM_ALG_SM3_256},
};
+static u32 tpm2key_oid[] = { 2,23,133,10,1,5 };
+
+static int tpm2_key_encode(struct trusted_key_payload *payload,
+ struct trusted_key_options *options,
+ u8 *src, u32 len)
+{
+ const int SCRATCH_SIZE = PAGE_SIZE;
+ u8 *scratch = kmalloc(SCRATCH_SIZE, GFP_KERNEL);
+ u8 *work = scratch, *work1;
+ u8 *end_work = scratch + SCRATCH_SIZE;
+ u8 *priv, *pub;
+ u16 priv_len, pub_len;
+
+ priv_len = get_unaligned_be16(src) + 2;
+ priv = src;
+
+ src += priv_len;
+
+ pub_len = get_unaligned_be16(src) + 2;
+ pub = src;
+
+ if (!scratch)
+ return -ENOMEM;
+
+ work = asn1_encode_oid(work, end_work, tpm2key_oid,
+ asn1_oid_len(tpm2key_oid));
+
+ if (options->blobauth_len == 0) {
+ unsigned char bool[3], *w = bool;
+ /* tag 0 is emptyAuth */
+ w = asn1_encode_boolean(w, w + sizeof(bool), true);
+ if (WARN(IS_ERR(w), "BUG: Boolean failed to encode"))
+ return PTR_ERR(w);
+ work = asn1_encode_tag(work, end_work, 0, bool, w - bool);
+ }
+
+ if (payload->policies) {
+ u8 *encoded_pols;
+ u32 encoded_pol_len;
+ int ret;
+
+ ret = tpm2_encode_policy(payload->policies, &encoded_pols,
+ &encoded_pol_len);
+ if (ret)
+ return ret;
+
+ work = asn1_encode_tag(work, end_work, 1, encoded_pols,
+ encoded_pol_len);
+ kfree(encoded_pols);
+ }
+
+ /*
+ * Assume both octet strings will encode to a 2 byte definite length
+ *
+ * Note: For a well behaved TPM, this warning should never
+ * trigger, so if it does there's something nefarious going on
+ */
+ if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE,
+ "BUG: scratch buffer is too small"))
+ return -EINVAL;
+
+ work = asn1_encode_integer(work, end_work, options->keyhandle);
+ work = asn1_encode_octet_string(work, end_work, pub, pub_len);
+ work = asn1_encode_octet_string(work, end_work, priv, priv_len);
+
+ work1 = payload->blob;
+ work1 = asn1_encode_sequence(work1, work1 + sizeof(payload->blob),
+ scratch, work - scratch);
+ if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed"))
+ return PTR_ERR(work1);
+
+ return work1 - payload->blob;
+}
+
+static int tpm2_key_decode(struct trusted_key_payload *payload,
+ struct trusted_key_options *options,
+ u8 **buf)
+{
+ int ret;
+ struct tpm2key_context ctx;
+ u8 *blob;
+
+ memset(&ctx, 0, sizeof(ctx));
+
+ ret = asn1_ber_decoder(&tpm2key_decoder, &ctx, payload->blob,
+ payload->blob_len);
+ if (ret < 0)
+ return ret;
+
+ if (ctx.priv_len + ctx.pub_len > MAX_BLOB_SIZE)
+ return -EINVAL;
+
+ blob = kmalloc(ctx.priv_len + ctx.pub_len + 4, GFP_KERNEL);
+ if (!blob)
+ return -ENOMEM;
+
+ ret = tpmkey_policy_process(&ctx, payload);
+ if (ret) {
+ kfree(blob);
+ return ret;
+ }
+
+ *buf = blob;
+ options->keyhandle = ctx.parent;
+
+ memcpy(blob, ctx.priv, ctx.priv_len);
+ blob += ctx.priv_len;
+
+ memcpy(blob, ctx.pub, ctx.pub_len);
+
+ return 0;
+}
+
+int tpmkey_parent(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct tpm2key_context *ctx = context;
+ const u8 *v = value;
+ int i;
+
+ ctx->parent = 0;
+ for (i = 0; i < vlen; i++) {
+ ctx->parent <<= 8;
+ ctx->parent |= v[i];
+ }
+
+ return 0;
+}
+
+int tpmkey_type(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ enum OID oid = look_up_OID(value, vlen);
+
+ if (oid != OID_TPMSealedData) {
+ char buffer[50];
+
+ sprint_oid(value, vlen, buffer, sizeof(buffer));
+ pr_debug("OID is \"%s\" which is not TPMSealedData\n",
+ buffer);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+int tpmkey_pub(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct tpm2key_context *ctx = context;
+
+ ctx->pub = value;
+ ctx->pub_len = vlen;
+
+ return 0;
+}
+
+int tpmkey_priv(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct tpm2key_context *ctx = context;
+
+ ctx->priv = value;
+ ctx->priv_len = vlen;
+
+ return 0;
+}
+
/**
* tpm_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer.
*
@@ -66,6 +245,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
unsigned int blob_len;
struct tpm_buf buf;
u32 hash;
+ u32 flags;
int i;
int rc;
@@ -79,6 +259,45 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
if (i == ARRAY_SIZE(tpm2_hash_map))
return -EINVAL;
+ if (!options->keyhandle)
+ return -EINVAL;
+
+ if (options->pcrinfo_len != 0) {
+ struct tpm2_policies *pols;
+ static u8 *scratch;
+ /* 4 array len, 2 hash alg */
+ const int len = 4 + 2 + options->pcrinfo_len;
+
+ pols = kmalloc(sizeof(*pols) + len, GFP_KERNEL);
+ if (!pols)
+ return -ENOMEM;
+
+ pols->count = 1;
+ pols->len[0] = len;
+ scratch = (u8 *)(pols + 1);
+ pols->policies[0] = scratch;
+ pols->code[0] = TPM2_CC_POLICY_PCR;
+
+ put_unaligned_be32(1, &scratch[0]);
+ put_unaligned_be16(hash, &scratch[4]);
+ memcpy(&scratch[6], options->pcrinfo, options->pcrinfo_len);
+ payload->policies = pols;
+ }
+
+ if (options->policydigest_len != 0 && payload->policies) {
+ /* can't specify both a digest and a policy */
+ return -EINVAL;
+ }
+
+ if (payload->policies) {
+ rc = tpm2_generate_policy_digest(payload->policies,
+ options->hash,
+ options->policydigest,
+ &options->policydigest_len);
+ if (rc)
+ return rc;
+ }
+
rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
if (rc)
return rc;
@@ -91,31 +310,32 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
TPM_DIGEST_SIZE);
/* sensitive */
- tpm_buf_append_u16(&buf, 4 + options->blobauth_len + payload->key_len + 1);
+ tpm_buf_append_u16(&buf, 4 + options->blobauth_len + payload->key_len);
tpm_buf_append_u16(&buf, options->blobauth_len);
if (options->blobauth_len)
tpm_buf_append(&buf, options->blobauth, options->blobauth_len);
- tpm_buf_append_u16(&buf, payload->key_len + 1);
+ tpm_buf_append_u16(&buf, payload->key_len);
tpm_buf_append(&buf, payload->key, payload->key_len);
- tpm_buf_append_u8(&buf, payload->migratable);
/* public */
tpm_buf_append_u16(&buf, 14 + options->policydigest_len);
tpm_buf_append_u16(&buf, TPM_ALG_KEYEDHASH);
tpm_buf_append_u16(&buf, hash);
+ /* key properties */
+ flags = 0;
+ flags |= options->policydigest_len ? 0 : TPM2_OA_USER_WITH_AUTH;
+ flags |= payload->migratable ? (TPM2_OA_FIXED_TPM |
+ TPM2_OA_FIXED_PARENT) : 0;
+ tpm_buf_append_u32(&buf, flags);
+
/* policy */
- if (options->policydigest_len) {
- tpm_buf_append_u32(&buf, 0);
- tpm_buf_append_u16(&buf, options->policydigest_len);
+ tpm_buf_append_u16(&buf, options->policydigest_len);
+ if (options->policydigest_len)
tpm_buf_append(&buf, options->policydigest,
options->policydigest_len);
- } else {
- tpm_buf_append_u32(&buf, TPM2_OA_USER_WITH_AUTH);
- tpm_buf_append_u16(&buf, 0);
- }
/* public parameters */
tpm_buf_append_u16(&buf, TPM_ALG_NULL);
@@ -146,8 +366,10 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
goto out;
}
- memcpy(payload->blob, &buf.data[TPM_HEADER_SIZE + 4], blob_len);
- payload->blob_len = blob_len;
+ payload->blob_len =
+ tpm2_key_encode(payload, options,
+ &buf.data[TPM_HEADER_SIZE + 4],
+ blob_len);
out:
tpm_buf_destroy(&buf);
@@ -158,6 +380,8 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
else
rc = -EPERM;
}
+ if (payload->blob_len < 0)
+ return payload->blob_len;
return rc;
}
@@ -184,13 +408,45 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
unsigned int private_len;
unsigned int public_len;
unsigned int blob_len;
+ u8 *blob, *pub;
int rc;
+ u32 attrs;
+
+ rc = tpm2_key_decode(payload, options, &blob);
+ if (rc) {
+ /* old form */
+ blob = payload->blob;
+ payload->old_format = 1;
+ }
+
+ /* new format carries keyhandle but old format doesn't */
+ if (!options->keyhandle)
+ return -EINVAL;
+
+ /* must be big enough for at least the two be16 size counts */
+ if (payload->blob_len < 4)
+ return -EINVAL;
+
+ private_len = get_unaligned_be16(blob);
- private_len = be16_to_cpup((__be16 *) &payload->blob[0]);
- if (private_len > (payload->blob_len - 2))
+ /* must be big enough for following public_len */
+ if (private_len + 2 + 2 > (payload->blob_len))
return -E2BIG;
- public_len = be16_to_cpup((__be16 *) &payload->blob[2 + private_len]);
+ public_len = get_unaligned_be16(blob + 2 + private_len);
+ if (private_len + 2 + public_len + 2 > payload->blob_len)
+ return -E2BIG;
+
+ pub = blob + 2 + private_len + 2;
+ /* key attributes are always at offset 4 */
+ attrs = get_unaligned_be32(pub + 4);
+
+ if ((attrs & (TPM2_OA_FIXED_TPM | TPM2_OA_FIXED_PARENT)) ==
+ (TPM2_OA_FIXED_TPM | TPM2_OA_FIXED_PARENT))
+ payload->migratable = 0;
+ else
+ payload->migratable = 1;
+
blob_len = private_len + public_len + 4;
if (blob_len > payload->blob_len)
return -E2BIG;
@@ -206,7 +462,7 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
options->keyauth /* hmac */,
TPM_DIGEST_SIZE);
- tpm_buf_append(&buf, payload->blob, blob_len);
+ tpm_buf_append(&buf, blob, blob_len);
if (buf.flags & TPM_BUF_OVERFLOW) {
rc = -E2BIG;
@@ -219,6 +475,8 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
(__be32 *) &buf.data[TPM_HEADER_SIZE]);
out:
+ if (blob != payload->blob)
+ kfree(blob);
tpm_buf_destroy(&buf);
if (rc > 0)
@@ -248,28 +506,44 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
u16 data_len;
u8 *data;
int rc;
+ u32 policyhandle;
+
+ if (payload->policies && options->policyhandle)
+ /* can't have both a passed in policy and a key resident one */
+ return -EINVAL;
rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
if (rc)
return rc;
+ if (payload->policies) {
+ rc = tpm2_get_policy_session(chip, payload->policies,
+ &policyhandle);
+ if (rc)
+ return rc;
+ } else {
+ policyhandle = options->policyhandle;
+ }
+
tpm_buf_append_u32(&buf, blob_handle);
tpm2_buf_append_auth(&buf,
- options->policyhandle ?
- options->policyhandle : TPM2_RS_PW,
+ policyhandle ?
+ policyhandle : TPM2_RS_PW,
NULL /* nonce */, 0,
TPM2_SA_CONTINUE_SESSION,
options->blobauth /* hmac */,
options->blobauth_len);
rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
+ if (payload->policies)
+ tpm2_flush_context(chip, policyhandle);
if (rc > 0)
rc = -EPERM;
if (!rc) {
data_len = be16_to_cpup(
(__be16 *) &buf.data[TPM_HEADER_SIZE + 4]);
- if (data_len < MIN_KEY_SIZE || data_len > MAX_KEY_SIZE + 1) {
+ if (data_len < MIN_KEY_SIZE || data_len > MAX_KEY_SIZE) {
rc = -EFAULT;
goto out;
}
@@ -280,9 +554,19 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
}
data = &buf.data[TPM_HEADER_SIZE + 6];
- memcpy(payload->key, data, data_len - 1);
- payload->key_len = data_len - 1;
- payload->migratable = data[data_len - 1];
+ if (payload->old_format) {
+ /* migratable flag is at the end of the key */
+ memcpy(payload->key, data, data_len - 1);
+ payload->key_len = data_len - 1;
+ payload->migratable = data[data_len - 1];
+ } else {
+ /*
+ * migratable flag already collected from key
+ * attributes
+ */
+ memcpy(payload->key, data, data_len);
+ payload->key_len = data_len;
+ }
}
out:
--
2.16.4
