Support for sealing with a authorization policy.
Two new options for trusted keys:
* 'policydigest=': provide an auth policy digest for sealing.
* 'policyhandle=': provide a policy session handle for unsealing.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
---
Documentation/security/keys-trusted-encrypted.txt | 34 ++++++++++-------
drivers/char/tpm/tpm2-cmd.c | 24 ++++++++++--
include/keys/trusted-type.h | 3 ++
security/keys/trusted.c | 46 ++++++++++++++++++++++-
4 files changed, 87 insertions(+), 20 deletions(-)
diff --git a/Documentation/security/keys-trusted-encrypted.txt b/Documentation/security/keys-trusted-encrypted.txt
index fd2565b..324ddf5 100644
--- a/Documentation/security/keys-trusted-encrypted.txt
+++ b/Documentation/security/keys-trusted-encrypted.txt
@@ -27,20 +27,26 @@ Usage:
keyctl print keyid
options:
- keyhandle= ascii hex value of sealing key default 0x40000000 (SRK)
- keyauth= ascii hex auth for sealing key default 0x00...i
- (40 ascii zeros)
- blobauth= ascii hex auth for sealed data default 0x00...
- (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)
- pcrlock= pcr number to be extended to "lock" blob
- migratable= 0|1 indicating permission to reseal to new PCR values,
- default 1 (resealing allowed)
- hash= hash algorithm name as a string. For TPM 1.x the only
- allowed value is sha1. For TPM 2.x the allowed values
- are sha1, sha256, sha384, sha512 and sm3-256.
+ keyhandle= ascii hex value of sealing key default 0x40000000 (SRK)
+ keyauth= ascii hex auth for sealing key default 0x00...i
+ (40 ascii zeros)
+ blobauth= ascii hex auth for sealed data default 0x00...
+ (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)
+ pcrlock= pcr number to be extended to "lock" blob
+ migratable= 0|1 indicating permission to reseal to new PCR values,
+ default 1 (resealing allowed)
+ hash= hash algorithm name as a string. For TPM 1.x the only
+ allowed value is sha1. For TPM 2.x the allowed values
+ are sha1, sha256, sha384, sha512 and sm3-256.
+ policydigest= digest for the authorization policy. must be calculated
+ with the same hash algorithm as specified by the 'hash='
+ option.
+ policyhandle= handle to an authorization policy session that defines the
+ same policy and with the same hash algorithm as was used to
+ seal the key.
"keyctl print" returns an ascii hex copy of the sealed key, which is in standard
TPM_STORED_DATA format. The key length for new keys are always in bytes.
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index d9d0822..45a6340 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -478,12 +478,26 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
tpm_buf_append_u8(&buf, payload->migratable);
/* public */
- tpm_buf_append_u16(&buf, 14);
+ if (options->policydigest)
+ tpm_buf_append_u16(&buf, 14 + options->digest_len);
+ else
+ tpm_buf_append_u16(&buf, 14);
tpm_buf_append_u16(&buf, TPM2_ALG_KEYEDHASH);
tpm_buf_append_u16(&buf, hash);
- tpm_buf_append_u32(&buf, TPM2_ATTR_USER_WITH_AUTH);
- tpm_buf_append_u16(&buf, 0); /* policy digest size */
+
+ /* policy */
+ if (options->policydigest) {
+ tpm_buf_append_u32(&buf, 0);
+ tpm_buf_append_u16(&buf, options->digest_len);
+ tpm_buf_append(&buf, options->policydigest,
+ options->digest_len);
+ } else {
+ tpm_buf_append_u32(&buf, TPM2_ATTR_USER_WITH_AUTH);
+ tpm_buf_append_u16(&buf, 0);
+ }
+
+ /* public parameters */
tpm_buf_append_u16(&buf, TPM2_ALG_NULL);
tpm_buf_append_u16(&buf, 0);
@@ -613,7 +627,9 @@ static int tpm2_unseal(struct tpm_chip *chip,
return rc;
tpm_buf_append_u32(&buf, blob_handle);
- tpm2_buf_append_auth(&buf, TPM2_RS_PW,
+ tpm2_buf_append_auth(&buf,
+ options->policyhandle ?
+ options->policyhandle : TPM2_RS_PW,
NULL /* nonce */, 0,
0 /* session_attributes */,
options->blobauth /* hmac */,
diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h
index a6a1008..2c3f9f7 100644
--- a/include/keys/trusted-type.h
+++ b/include/keys/trusted-type.h
@@ -37,6 +37,9 @@ struct trusted_key_options {
unsigned char pcrinfo[MAX_PCRINFO_SIZE];
int pcrlock;
uint32_t hash;
+ uint32_t digest_len;
+ unsigned char *policydigest;
+ uint32_t policyhandle;
};
extern struct key_type key_type_trusted;
diff --git a/security/keys/trusted.c b/security/keys/trusted.c
index b5b0a55..b726a83 100644
--- a/security/keys/trusted.c
+++ b/security/keys/trusted.c
@@ -713,6 +713,8 @@ enum {
Opt_keyhandle, Opt_keyauth, Opt_blobauth,
Opt_pcrinfo, Opt_pcrlock, Opt_migratable,
Opt_hash,
+ Opt_policydigest,
+ Opt_policyhandle,
};
static const match_table_t key_tokens = {
@@ -726,6 +728,8 @@ static const match_table_t key_tokens = {
{Opt_pcrlock, "pcrlock=%s"},
{Opt_migratable, "migratable=%s"},
{Opt_hash, "hash=%s"},
+ {Opt_policydigest, "policydigest=%s"},
+ {Opt_policyhandle, "policyhandle=%s"},
{Opt_err, NULL}
};
@@ -739,6 +743,7 @@ static int getoptions(char *c, struct trusted_key_payload *pay,
int res;
unsigned long handle;
unsigned long lock;
+ unsigned int policydigest_len;
int i;
int tpm2;
@@ -747,6 +752,8 @@ static int getoptions(char *c, struct trusted_key_payload *pay,
return tpm2;
opt->hash = tpm2 ? HASH_ALGO_SHA256 : HASH_ALGO_SHA1;
+ opt->digest_len = hash_digest_size[opt->hash];
+ policydigest_len = opt->digest_len;
while ((p = strsep(&c, " \t"))) {
if (*p == '\0' || *p == ' ' || *p == '\t')
@@ -802,6 +809,8 @@ static int getoptions(char *c, struct trusted_key_payload *pay,
for (i = 0; i < HASH_ALGO__LAST; i++) {
if (!strcmp(args[0].from, hash_algo_name[i])) {
opt->hash = i;
+ opt->digest_len =
+ hash_digest_size[opt->hash];
break;
}
}
@@ -812,10 +821,37 @@ static int getoptions(char *c, struct trusted_key_payload *pay,
return -EINVAL;
}
break;
+ case Opt_policydigest:
+ if (!tpm2 ||
+ strlen(args[0].from) != (2 * opt->digest_len))
+ return -EINVAL;
+ kfree(opt->policydigest);
+ opt->policydigest = kzalloc(opt->digest_len,
+ GFP_KERNEL);
+ if (!opt->policydigest)
+ return -ENOMEM;
+ res = hex2bin(opt->policydigest, args[0].from,
+ opt->digest_len);
+ if (res < 0)
+ return -EINVAL;
+ policydigest_len = opt->digest_len;
+ break;
+ case Opt_policyhandle:
+ if (!tpm2)
+ return -EINVAL;
+ res = kstrtoul(args[0].from, 16, &handle);
+ if (res < 0)
+ return -EINVAL;
+ opt->policyhandle = handle;
+ break;
default:
return -EINVAL;
}
}
+
+ if (opt->policydigest && policydigest_len != opt->digest_len)
+ return -EINVAL;
+
return 0;
}
@@ -904,6 +940,12 @@ static struct trusted_key_options *trusted_options_alloc(void)
return options;
}
+static void trusted_options_free(struct trusted_key_options *options)
+{
+ kfree(options->policydigest);
+ kfree(options);
+}
+
static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
{
struct trusted_key_payload *p = NULL;
@@ -1010,7 +1052,7 @@ static int trusted_instantiate(struct key *key,
ret = pcrlock(options->pcrlock);
out:
kfree(datablob);
- kfree(options);
+ trusted_options_free(options);
if (!ret)
rcu_assign_keypointer(key, payload);
else
@@ -1098,7 +1140,7 @@ static int trusted_update(struct key *key, struct key_preparsed_payload *prep)
call_rcu(&p->rcu, trusted_rcu_free);
out:
kfree(datablob);
- kfree(new_o);
+ trusted_options_free(new_o);
return ret;
}
--
2.5.0
--
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