2010-11-18 22:42:59

by Mimi Zohar

[permalink] [raw]
Subject: [PATCH v1.4 0/5] keys: trusted and encrypted keys

Changes were made in this patchset based on David Howell's comments. The
major technical change was converting from the crypto hash to shash API.
The remaining changes are listed in the individual patch changelogs.

Trusted and Encrypted Keys are two new key types added to the existing
kernel key ring service. Both of these new types are variable length
symmetic keys, and in both cases all keys are created in the kernel, and
user space sees, stores, and loads only encrypted blobs. Trusted Keys
require the availability of a Trusted Platform Module (TPM) chip for
greater security, while Encrypted Keys can be used on any system. All
user level blobs, are displayed and loaded in hex ascii for convenience,
and are integrity verified.

Trusted Keys use a TPM both to generate and to seal the keys. Keys are
sealed under a 2048 bit RSA key in the TPM, and optionally sealed to
specified PCR (integrity measurement) values, and only unsealed by the
TPM, if PCRs and blob integrity verifications match. A loaded Trusted
Key can be updated with new (future) PCR values, so keys are easily
migrated to new pcr values, such as when the kernel and initramfs are
updated. The same key can have many saved blobs under different PCR
values, so multiple boots are easily supported.

By default, trusted keys are sealed under the SRK, which has the default
authorization value (20 zeros). This can be set at takeownership time
with the trouser's utility: "tpm_takeownership -u -z".

Usage:
keyctl add trusted name "new keylen [options]" ring
keyctl add trusted name "load hex_blob [pcrlock=pcrnum]" ring
keyctl update key "update [options]"
keyctl print keyid

options:
keyhandle= ascii hex value of sealing key default 0x40000000 (SRK)
keyauth= ascii hex auth for sealing key 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)

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. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits), the
upper limit is to fit within the 2048 bit SRK (RSA) keylength, with all
necessary structure/padding.

Encrypted keys do not depend on a TPM, and are faster, as they use AES
for encryption/decryption. New keys are created from kernel generated
random numbers, and are encrypted/decrypted using a specified 'master'
key. The 'master' key can either be a trusted-key or user-key type. The
main disadvantage of encrypted keys is that if they are not rooted in a
trusted key, they are only as secure as the user key encrypting them.
The master user key should therefore be loaded in as secure a way as
possible, preferably early in boot.

Usage:
keyctl add encrypted name "new master-key-name keylen" ring
keyctl add encrypted name "load key-type:master-key-name keylen hex_blob" ring
keyctl update keyid "update master-key-name"

where 'key-type' is either 'trusted' or 'user'.

The initial consumer of trusted keys is EVM, which at boot time needs a
high quality symmetric key for HMAC protection of file metadata. The use
of a trusted key provides strong guarantees that the EVM key has not
been compromised by a user level problem, and when sealed to specific
boot PCR values, protects against boot and offline attacks. Other uses
for trusted and encrypted keys, such as for disk and file encryption are
anticipated.

Mimi Zohar
David Safford

Mimi Zohar (5):
lib: hex2bin converts ascii hexadecimal string to binary
tpm: add module_put wrapper
key: add tpm_send command
keys: add new trusted key-type
keys: add new key-type encrypted

Documentation/keys-trusted-encrypted.txt | 68 ++
drivers/char/tpm/tpm.c | 20 +-
drivers/char/tpm/tpm.h | 5 +
include/keys/encrypted-type.h | 29 +
include/keys/trusted-type.h | 31 +
include/linux/kernel.h | 1 +
include/linux/tpm.h | 4 +
lib/hexdump.c | 16 +
security/Kconfig | 31 +
security/keys/Makefile | 2 +
security/keys/encrypted_defined.c | 876 +++++++++++++++++++++++
security/keys/encrypted_defined.h | 56 ++
security/keys/trusted_defined.c | 1136 ++++++++++++++++++++++++++++++
security/keys/trusted_defined.h | 147 ++++
14 files changed, 2420 insertions(+), 2 deletions(-)
create mode 100644 Documentation/keys-trusted-encrypted.txt
create mode 100644 include/keys/encrypted-type.h
create mode 100644 include/keys/trusted-type.h
create mode 100644 security/keys/encrypted_defined.c
create mode 100644 security/keys/encrypted_defined.h
create mode 100644 security/keys/trusted_defined.c
create mode 100644 security/keys/trusted_defined.h

--
1.7.2.2


2010-11-18 22:42:43

by Mimi Zohar

[permalink] [raw]
Subject: [PATCH v1.4 2/5] tpm: add module_put wrapper

For readability, define a tpm_chip_put() wrapper to call module_put().
Replace existing module_put() calls with the wrapper.

(Change based on trusted/encrypted patchset review by David Howells.)

Signed-off-by: Mimi Zohar <[email protected]>
Signed-off-by: David Safford <[email protected]>
---
drivers/char/tpm/tpm.c | 4 ++--
drivers/char/tpm/tpm.h | 5 +++++
2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 7c41335..26c09f3 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -736,7 +736,7 @@ int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf)
if (chip == NULL)
return -ENODEV;
rc = __tpm_pcr_read(chip, pcr_idx, res_buf);
- module_put(chip->dev->driver->owner);
+ tpm_chip_put(chip);
return rc;
}
EXPORT_SYMBOL_GPL(tpm_pcr_read);
@@ -775,7 +775,7 @@ int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash)
rc = transmit_cmd(chip, &cmd, EXTEND_PCR_RESULT_SIZE,
"attempting extend a PCR value");

- module_put(chip->dev->driver->owner);
+ tpm_chip_put(chip);
return rc;
}
EXPORT_SYMBOL_GPL(tpm_pcr_extend);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 792868d..72ddb03 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -113,6 +113,11 @@ struct tpm_chip {

#define to_tpm_chip(n) container_of(n, struct tpm_chip, vendor)

+static inline void tpm_chip_put(struct tpm_chip *chip)
+{
+ module_put(chip->dev->driver->owner);
+}
+
static inline int tpm_read_index(int base, int index)
{
outb(index, base);
--
1.7.2.2


2010-11-18 22:42:42

by Mimi Zohar

[permalink] [raw]
Subject: [PATCH v1.4 1/5] lib: hex2bin converts ascii hexadecimal string to binary

Similar to the kgdb_hex2mem() code, hex2bin converts a string
to binary using the hex_to_bin() library call.

Changelog:
- Replace parameter names with src/dst (based on David Howell's comment)
- Add 'const' where needed (based on David Howell's comment)
- Replace int with size_t (based on David Howell's comment)

Signed-off-by: Mimi Zohar <[email protected]>
Acked-by: Serge E. Hallyn <[email protected]>
---
include/linux/kernel.h | 1 +
lib/hexdump.c | 16 ++++++++++++++++
2 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 3f648d2..fbca217 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -419,6 +419,7 @@ static inline char *pack_hex_byte(char *buf, u8 byte)
}

extern int hex_to_bin(char ch);
+extern void hex2bin(u8 *dst, const char *src, size_t count);

#ifndef pr_fmt
#define pr_fmt(fmt) fmt
diff --git a/lib/hexdump.c b/lib/hexdump.c
index 5d7a480..0eea94d 100644
--- a/lib/hexdump.c
+++ b/lib/hexdump.c
@@ -34,6 +34,22 @@ int hex_to_bin(char ch)
EXPORT_SYMBOL(hex_to_bin);

/**
+ * hex2bin - convert an ascii hexadecimal string to its binary representation
+ * @dst: binary result
+ * @src: ascii hexadecimal string
+ * @count: result length
+ */
+void hex2bin(u8 *dst, const char *src, size_t count)
+{
+ while (count--) {
+ *dst = hex_to_bin(*src++) << 4;
+ *dst += hex_to_bin(*src++);
+ dst++;
+ }
+}
+EXPORT_SYMBOL(hex2bin);
+
+/**
* hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
* @buf: data blob to dump
* @len: number of bytes in the @buf
--
1.7.2.2

2010-11-18 22:42:44

by Mimi Zohar

[permalink] [raw]
Subject: [PATCH v1.4 3/5] key: add tpm_send command

Add internal kernel tpm_send() command used to seal/unseal keys.

Changelog:
- replaced module_put in tpm_send() with new tpm_chip_put() wrapper
(suggested by David Howells)
- Make tpm_send() cmd argument a 'void *' (suggested by David Howells)

Signed-off-by: David Safford <[email protected]>
Signed-off-by: Mimi Zohar <[email protected]>
---
drivers/char/tpm/tpm.c | 16 ++++++++++++++++
include/linux/tpm.h | 4 ++++
2 files changed, 20 insertions(+), 0 deletions(-)

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 26c09f3..b737cf3 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -780,6 +780,22 @@ int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash)
}
EXPORT_SYMBOL_GPL(tpm_pcr_extend);

+int tpm_send(u32 chip_num, void *cmd, int buflen)
+{
+ struct tpm_chip *chip;
+ int rc;
+
+ chip = tpm_chip_find_get(chip_num);
+ if (chip == NULL)
+ return -ENODEV;
+
+ rc = transmit_cmd(chip, cmd, buflen, "attempting tpm_cmd");
+
+ tpm_chip_put(chip);
+ return rc;
+}
+EXPORT_SYMBOL_GPL(tpm_send);
+
ssize_t tpm_show_pcrs(struct device *dev, struct device_attribute *attr,
char *buf)
{
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index ac5d1c1..a25ab8f 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -31,6 +31,7 @@

extern int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf);
extern int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash);
+extern int tpm_send(u32 chip_num, void *cmd, int buflen);
#else
static inline int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf) {
return -ENODEV;
@@ -38,5 +39,8 @@ static inline int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf) {
static inline int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash) {
return -ENODEV;
}
+static inline int tpm_send(u32 chip_num, void *cmd, int buflen) {
+ return -ENODEV;
+}
#endif
#endif
--
1.7.2.2

2010-11-18 22:42:46

by Mimi Zohar

[permalink] [raw]
Subject: [PATCH v1.4 5/5] keys: add new key-type encrypted

Define a new kernel key-type called 'encrypted'. Encrypted keys are kernel
generated random numbers, which are encrypted/decrypted with a 'trusted'
symmetric key. Encrypted keys are created/encrypted/decrypted in the kernel.
Userspace only ever sees/stores encrypted blobs.

Changelog:
- Moved documentation to Documentation/keys-trusted-encrypted.txt
- Replace hash with shash (based on comments by David Howells)
- Make lengths/counts size_t where possible (based on comments by David Howells)
Could not convert most lengths, as crypto expects 'unsigned int'
(size_t: on 32 bit is defined as unsigned int, but on 64 bit is unsigned long)
- Add 'const' where possible (based on comments by David Howells)
- allocate derived_buf dynamically to support arbitrary length master key
(fixed by Roberto Sassu)
- wait until late_initcall for crypto libraries to be registered
- cleanup security/Kconfig
- Add missing 'update' keyword (reported/fixed by Roberto Sassu)
- Free epayload on failure to create key (reported/fixed by Roberto Sassu)
- Increase the data size limit (requested by Roberto Sassu)
- Crypto return codes are always 0 on success and negative on failure,
remove unnecessary tests.
- Replaced kzalloc() with kmalloc()

Signed-off-by: Mimi Zohar <[email protected]>
Signed-off-by: David Safford <[email protected]>
Reviewed-by: Roberto Sassu <[email protected]>
---
include/keys/encrypted-type.h | 29 ++
security/Kconfig | 16 +
security/keys/Makefile | 1 +
security/keys/encrypted_defined.c | 876 +++++++++++++++++++++++++++++++++++++
security/keys/encrypted_defined.h | 56 +++
5 files changed, 978 insertions(+), 0 deletions(-)
create mode 100644 include/keys/encrypted-type.h
create mode 100644 security/keys/encrypted_defined.c
create mode 100644 security/keys/encrypted_defined.h

diff --git a/include/keys/encrypted-type.h b/include/keys/encrypted-type.h
new file mode 100644
index 0000000..9585501
--- /dev/null
+++ b/include/keys/encrypted-type.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2010 IBM Corporation
+ * Author: Mimi Zohar <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ */
+
+#ifndef _KEYS_ENCRYPTED_TYPE_H
+#define _KEYS_ENCRYPTED_TYPE_H
+
+#include <linux/key.h>
+#include <linux/rcupdate.h>
+
+struct encrypted_key_payload {
+ struct rcu_head rcu;
+ char *master_desc; /* datablob: master key name */
+ char *datalen; /* datablob: decrypted key length */
+ u8 *iv; /* datablob: iv */
+ u8 *encrypted_data; /* datablob: encrypted data */
+ unsigned short datablob_len; /* length of datablob */
+ unsigned short decrypted_datalen; /* decrypted data length */
+ u8 decrypted_data[0]; /* decrypted data + datablob + hmac */
+};
+
+extern struct key_type key_type_encrypted;
+
+#endif /* _KEYS_ENCRYPTED_TYPE_H */
diff --git a/security/Kconfig b/security/Kconfig
index be2d1c6..de2a170 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -36,6 +36,22 @@ config TRUSTED_KEYS

If you are unsure as to whether this is required, answer N.

+config ENCRYPTED_KEYS
+ tristate "ENCRYPTED KEYS"
+ depends on KEYS && TRUSTED_KEYS
+ select CRYPTO_AES
+ select CRYPTO_CBC
+ select CRYPTO_SHA256
+ select CRYPTO_RNG
+ help
+ This option provides support for create/encrypting/decrypting keys
+ in the kernel. Encrypted keys are kernel generated random numbers,
+ which are encrypted/decrypted with a 'master' symmetric key. The
+ 'master' key can be either a trusted-key or user-key type.
+ Userspace only ever sees/stores encrypted blobs.
+
+ If you are unsure as to whether this is required, answer N.
+
config KEYS_DEBUG_PROC_KEYS
bool "Enable the /proc/keys file by which keys may be viewed"
depends on KEYS
diff --git a/security/keys/Makefile b/security/keys/Makefile
index fcb1070..6c94105 100644
--- a/security/keys/Makefile
+++ b/security/keys/Makefile
@@ -14,6 +14,7 @@ obj-y := \
user_defined.o

obj-$(CONFIG_TRUSTED_KEYS) += trusted_defined.o
+obj-$(CONFIG_ENCRYPTED_KEYS) += encrypted_defined.o
obj-$(CONFIG_KEYS_COMPAT) += compat.o
obj-$(CONFIG_PROC_FS) += proc.o
obj-$(CONFIG_SYSCTL) += sysctl.o
diff --git a/security/keys/encrypted_defined.c b/security/keys/encrypted_defined.c
new file mode 100644
index 0000000..f2105a7
--- /dev/null
+++ b/security/keys/encrypted_defined.c
@@ -0,0 +1,876 @@
+/*
+ * Copyright (C) 2010 IBM Corporation
+ *
+ * Author:
+ * Mimi Zohar <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ *
+ * See Documentation/keys-trusted-encrypted.txt
+ */
+
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/parser.h>
+#include <linux/string.h>
+#include <keys/user-type.h>
+#include <keys/trusted-type.h>
+#include <keys/encrypted-type.h>
+#include <linux/key-type.h>
+#include <linux/random.h>
+#include <linux/rcupdate.h>
+#include <linux/scatterlist.h>
+#include <linux/crypto.h>
+#include <crypto/hash.h>
+#include <crypto/sha.h>
+#include <crypto/aes.h>
+
+#include "encrypted_defined.h"
+
+#define HASH_SIZE SHA256_DIGEST_SIZE
+#define MAX_DATA_SIZE 4096
+#define MIN_DATA_SIZE 20
+
+static const char hash_alg[] = "sha256";
+static const char hmac_alg[] = "hmac(sha256)";
+static const char blkcipher_alg[] = "cbc(aes)";
+static unsigned int ivsize;
+static int blksize;
+
+struct sdesc {
+ struct shash_desc shash;
+ char ctx[];
+};
+
+static struct crypto_shash *hashalg;
+static struct crypto_shash *hmacalg;
+
+static int aes_get_sizes(void)
+{
+ struct crypto_blkcipher *tfm;
+
+ tfm = crypto_alloc_blkcipher(blkcipher_alg, 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(tfm)) {
+ pr_err("encrypted_key: failed to alloc_cipher (%ld)\n",
+ PTR_ERR(tfm));
+ return PTR_ERR(tfm);
+ }
+ ivsize = crypto_blkcipher_ivsize(tfm);
+ blksize = crypto_blkcipher_blocksize(tfm);
+ crypto_free_blkcipher(tfm);
+ return 0;
+}
+
+enum {
+ Opt_err = -1, Opt_new, Opt_load, Opt_update
+};
+
+static const match_table_t key_tokens = {
+ {Opt_new, "new"},
+ {Opt_load, "load"},
+ {Opt_update, "update"},
+ {Opt_err, NULL}
+};
+
+/*
+ * datablob_parse - parse the keyctl data
+ *
+ * datablob format:
+ * new <master-key name> <decrypted data length>
+ * load <master-key name> <decrypted data length> <encrypted iv + data>
+ * update <new-master-key name>
+ *
+ * Tokenizes a copy of the keyctl data, returning a pointer to each token,
+ * which is null terminated.
+ *
+ * On success returns 0, otherwise -EINVAL.
+ */
+static int datablob_parse(char *datablob, char **master_desc,
+ char **decrypted_datalen, char **hex_encoded_iv,
+ char **hex_encoded_data)
+{
+ substring_t args[MAX_OPT_ARGS];
+ int ret = -EINVAL;
+ int key_cmd;
+ size_t index;
+ char *p;
+
+ p = strsep(&datablob, " \t");
+ if (!p)
+ return ret;
+ key_cmd = match_token(p, key_tokens, args);
+
+ *master_desc = strsep(&datablob, " \t");
+ if (!*master_desc)
+ goto out;
+
+ /* desc must be prefixed with key-type ('trusted:' or 'user:') */
+ index = strcspn(*master_desc, ":");
+ if (index == strlen(*master_desc))
+ goto out;
+
+ if (decrypted_datalen) {
+ *decrypted_datalen = strsep(&datablob, " \t");
+ if (!*decrypted_datalen)
+ goto out;
+ }
+
+ switch (key_cmd) {
+ case Opt_new:
+ if (!decrypted_datalen)
+ break;
+ ret = 0;
+ break;
+ case Opt_load:
+ if (!decrypted_datalen)
+ break;
+ *hex_encoded_iv = strsep(&datablob, " \t");
+ if (!*hex_encoded_iv)
+ break;
+ *hex_encoded_data = *hex_encoded_iv + (2 * ivsize) + 2;
+ ret = 0;
+ break;
+ case Opt_update:
+ if (decrypted_datalen)
+ break;
+ ret = 0;
+ break;
+ case Opt_err:
+ break;
+ }
+out:
+ return ret;
+}
+
+/*
+ * datablob_format - format as an ascii string, before copying to userspace
+ */
+static int datablob_format(char __user *buffer,
+ struct encrypted_key_payload *epayload,
+ int asciiblob_len)
+{
+ char *ascii_buf, *bufp;
+ u8 *iv = epayload->iv;
+ int ret = 0;
+ int len;
+ int i;
+
+ ascii_buf = kmalloc(asciiblob_len + 1, GFP_KERNEL);
+ if (!ascii_buf)
+ return -ENOMEM;
+
+ ascii_buf[asciiblob_len] = '\0';
+
+ /* copy datablob master_desc and datalen strings */
+ len = sprintf(ascii_buf, "%s %s ", epayload->master_desc,
+ epayload->datalen);
+
+ /* convert the hex encoded iv, encrypted-data and HMAC to ascii */
+ bufp = &ascii_buf[len];
+ for (i = 0; i < (asciiblob_len - len) / 2; i++)
+ bufp = pack_hex_byte(bufp, iv[i]);
+
+ if (copy_to_user(buffer, ascii_buf, asciiblob_len) != 0)
+ ret = -EFAULT;
+ kfree(ascii_buf);
+ return ret;
+}
+
+/*
+ * request_trusted_key - request the trusted key
+ *
+ * Trusted keys are sealed to PCRs and other metadata. Although userspace
+ * manages both trusted/encrypted key-types, like the encrypted key type
+ * data, trusted key type data is not visible decrypted from userspace.
+ */
+static struct key *request_trusted_key(const char *trusted_desc,
+ u8 **master_key,
+ unsigned int *master_keylen)
+{
+ struct trusted_key_payload *tpayload;
+ struct key *tkey;
+
+ tkey = request_key(&key_type_trusted, trusted_desc, NULL);
+ if (IS_ERR(tkey))
+ goto error;
+
+ rcu_read_lock();
+ tpayload = rcu_dereference(tkey->payload.data);
+ *master_key = tpayload->key;
+ *master_keylen = tpayload->key_len;
+error:
+ return tkey;
+}
+
+/*
+ * request_user_key - request the user key
+ *
+ * Use a user provided key to encrypt/decrypt an encrypted-key.
+ */
+static struct key *request_user_key(const char *master_desc, u8 **master_key,
+ unsigned int *master_keylen)
+{
+ struct user_key_payload *upayload;
+ struct key *ukey;
+
+ ukey = request_key(&key_type_user, master_desc, NULL);
+ if (IS_ERR(ukey))
+ goto error;
+
+ rcu_read_lock();
+ upayload = rcu_dereference(ukey->payload.data);
+ *master_key = upayload->data;
+ *master_keylen = (unsigned int)upayload->datalen;
+error:
+ return ukey;
+}
+
+static struct sdesc *init_sdesc(struct crypto_shash *alg)
+{
+ struct sdesc *sdesc;
+ int size;
+
+ size = sizeof(struct shash_desc) + crypto_shash_descsize(alg);
+ sdesc = kmalloc(size, GFP_KERNEL);
+ if (!sdesc)
+ return ERR_PTR(-ENOMEM);
+ sdesc->shash.tfm = alg;
+ sdesc->shash.flags = 0x0;
+ return sdesc;
+}
+
+static int calc_hmac(u8 *digest, const u8 *key, unsigned int keylen,
+ const u8 *buf, unsigned int buflen)
+{
+ struct sdesc *sdesc;
+ int ret;
+
+ sdesc = init_sdesc(hmacalg);
+ if (IS_ERR(sdesc)) {
+ pr_info("encrypted_key: can't alloc %s\n", hmac_alg);
+ return PTR_ERR(sdesc);
+ }
+
+ ret = crypto_shash_setkey(hmacalg, key, keylen);
+ if (!ret)
+ ret = crypto_shash_digest(&sdesc->shash, buf, buflen, digest);
+ kfree(sdesc);
+ return ret;
+}
+
+static int calc_hash(u8 *digest, const u8 *buf, unsigned int buflen)
+{
+ struct sdesc *sdesc;
+ int ret;
+
+ sdesc = init_sdesc(hashalg);
+ if (IS_ERR(sdesc)) {
+ pr_info("encrypted_key: can't alloc %s\n", hash_alg);
+ return PTR_ERR(sdesc);
+ }
+
+ ret = crypto_shash_digest(&sdesc->shash, buf, buflen, digest);
+ kfree(sdesc);
+ return ret;
+}
+
+enum derived_key_type { ENC_KEY, AUTH_KEY };
+
+/* Derive authentication/encryption key from trusted key */
+static int get_derived_key(u8 *derived_key, enum derived_key_type key_type,
+ const u8 *master_key, unsigned int master_keylen)
+{
+ u8 *derived_buf;
+ unsigned int derived_buf_len;
+ int ret;
+
+ derived_buf_len = strlen("AUTH_KEY") + 1 + master_keylen;
+ if (derived_buf_len < HASH_SIZE)
+ derived_buf_len = HASH_SIZE;
+
+ derived_buf = kzalloc(derived_buf_len, GFP_KERNEL);
+ if (!derived_buf) {
+ pr_err("encrypted_key: out of memory\n");
+ return -ENOMEM;
+ }
+ if (key_type)
+ strcpy(derived_buf, "AUTH_KEY");
+ else
+ strcpy(derived_buf, "ENC_KEY");
+
+ memcpy(derived_buf + strlen(derived_buf) + 1, master_key,
+ master_keylen);
+ ret = calc_hash(derived_key, derived_buf, derived_buf_len);
+ kfree(derived_buf);
+ return ret;
+}
+
+static int init_blkcipher_desc(struct blkcipher_desc *desc, const u8 *key,
+ unsigned int key_len, const u8 *iv,
+ unsigned int ivsize)
+{
+ int ret;
+
+ desc->tfm = crypto_alloc_blkcipher(blkcipher_alg, 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(desc->tfm)) {
+ pr_err("encrypted_key: failed to load %s transform (%ld)\n",
+ blkcipher_alg, PTR_ERR(desc->tfm));
+ return PTR_ERR(desc->tfm);
+ }
+ desc->flags = 0;
+
+ ret = crypto_blkcipher_setkey(desc->tfm, key, key_len);
+ if (ret < 0) {
+ pr_err("encrypted_key: failed to setkey (%d)\n", ret);
+ crypto_free_blkcipher(desc->tfm);
+ return ret;
+ }
+ crypto_blkcipher_set_iv(desc->tfm, iv, ivsize);
+ return 0;
+}
+
+static struct key *request_master_key(struct encrypted_key_payload *epayload,
+ u8 **master_key,
+ unsigned int *master_keylen)
+{
+ struct key *mkey = NULL;
+ size_t index;
+
+ /* desc must be prefixed with key-type ('trusted:' or 'user:') */
+ index = strcspn(epayload->master_desc, ":");
+ if (index == strlen(epayload->master_desc))
+ goto out;
+
+ if (strncmp(epayload->master_desc, "trusted", index) == 0)
+ mkey = request_trusted_key(epayload->master_desc + index + 1,
+ master_key, master_keylen);
+ else if (strncmp(epayload->master_desc, "user", index) == 0)
+ mkey = request_user_key(epayload->master_desc + index + 1,
+ master_key, master_keylen);
+ if (IS_ERR(mkey))
+ pr_info("encrypted_key: key %s not found",
+ epayload->master_desc);
+ if (mkey)
+ dump_master_key(*master_key, *master_keylen);
+out:
+ return mkey;
+}
+
+/* Before returning data to userspace, encrypt decrypted data. */
+static int derived_key_encrypt(struct encrypted_key_payload *epayload,
+ u8 *derived_key, unsigned int derived_keylen)
+{
+ struct scatterlist sg_in[2];
+ struct scatterlist sg_out[1];
+ struct blkcipher_desc desc;
+ unsigned int encrypted_datalen;
+ unsigned int padlen;
+ char pad[16];
+ int ret;
+
+ encrypted_datalen = roundup(epayload->decrypted_datalen, blksize);
+ padlen = encrypted_datalen - epayload->decrypted_datalen;
+
+ ret = init_blkcipher_desc(&desc, derived_key, derived_keylen,
+ epayload->iv, ivsize);
+ if (ret < 0)
+ goto out;
+ dump_decrypted_data(epayload);
+
+ memset(pad, 0, sizeof pad);
+ sg_init_table(sg_in, 2);
+ sg_set_buf(&sg_in[0], epayload->decrypted_data,
+ epayload->decrypted_datalen);
+ sg_set_buf(&sg_in[1], pad, padlen);
+
+ sg_init_table(sg_out, 1);
+ sg_set_buf(sg_out, epayload->encrypted_data, encrypted_datalen);
+
+ ret = crypto_blkcipher_encrypt(&desc, sg_out, sg_in, encrypted_datalen);
+ crypto_free_blkcipher(desc.tfm);
+ if (ret < 0)
+ pr_err("encrypted_key: failed to encrypt (%d)\n", ret);
+ else
+ dump_encrypted_data(epayload, encrypted_datalen);
+out:
+ return ret;
+}
+
+static int datablob_hmac_append(struct encrypted_key_payload *epayload,
+ const u8 *master_key,
+ unsigned int master_keylen)
+{
+ u8 derived_key[HASH_SIZE];
+ u8 *digest;
+ int ret;
+
+ memset(derived_key, 0, sizeof derived_key);
+ ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen);
+ if (ret < 0)
+ goto out;
+
+ digest = epayload->master_desc + epayload->datablob_len;
+ ret = calc_hmac(digest, derived_key, sizeof derived_key,
+ epayload->master_desc, epayload->datablob_len);
+ if (!ret)
+ dump_hmac(NULL, digest, HASH_SIZE);
+out:
+ return ret;
+}
+
+/* verify HMAC before decrypting encrypted key */
+static int datablob_hmac_verify(struct encrypted_key_payload *epayload,
+ const u8 *master_key,
+ unsigned int master_keylen)
+{
+ u8 derived_key[HASH_SIZE];
+ u8 digest[HASH_SIZE];
+ int ret;
+
+ memset(derived_key, 0, sizeof derived_key);
+ ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen);
+ if (ret < 0)
+ goto out;
+
+ memset(digest, 0, sizeof digest);
+ ret = calc_hmac(digest, derived_key, sizeof derived_key,
+ epayload->master_desc, epayload->datablob_len);
+ if (ret < 0)
+ goto out;
+ ret = memcmp(digest, epayload->master_desc + epayload->datablob_len,
+ sizeof digest);
+ if (ret) {
+ ret = -EINVAL;
+ dump_hmac("datablob",
+ epayload->master_desc + epayload->datablob_len,
+ HASH_SIZE);
+ dump_hmac("calc", digest, HASH_SIZE);
+ }
+out:
+ return ret;
+}
+
+static int derived_key_decrypt(struct encrypted_key_payload *epayload,
+ const u8 *derived_key,
+ unsigned int derived_keylen)
+{
+ struct scatterlist sg_in[1];
+ struct scatterlist sg_out[2];
+ struct blkcipher_desc desc;
+ unsigned int encrypted_datalen;
+ char pad[16];
+ int ret;
+
+ encrypted_datalen = roundup(epayload->decrypted_datalen, blksize);
+ ret = init_blkcipher_desc(&desc, derived_key, derived_keylen,
+ epayload->iv, ivsize);
+ if (ret < 0)
+ goto out;
+ dump_encrypted_data(epayload, encrypted_datalen);
+
+ memset(pad, 0, sizeof pad);
+ sg_init_table(sg_in, 1);
+ sg_init_table(sg_out, 2);
+ sg_set_buf(sg_in, epayload->encrypted_data, encrypted_datalen);
+ sg_set_buf(&sg_out[0], epayload->decrypted_data,
+ (unsigned int)epayload->decrypted_datalen);
+ sg_set_buf(&sg_out[1], pad, sizeof pad);
+
+ ret = crypto_blkcipher_decrypt(&desc, sg_out, sg_in, encrypted_datalen);
+ crypto_free_blkcipher(desc.tfm);
+ if (ret < 0)
+ goto out;
+ dump_decrypted_data(epayload);
+out:
+ return ret;
+}
+
+/* Allocate memory for decrypted key and datablob. */
+static struct encrypted_key_payload *encrypted_key_alloc(struct key *key,
+ const char *master_desc,
+ char *datalen)
+{
+ struct encrypted_key_payload *epayload = NULL;
+ unsigned short datablob_len;
+ unsigned short decrypted_datalen;
+ unsigned int encrypted_datalen;
+ long dlen;
+ int ret;
+
+ ret = strict_strtol(datalen, 10, &dlen);
+ if (ret < 0 || dlen < MIN_DATA_SIZE || dlen > MAX_DATA_SIZE)
+ return ERR_PTR(-EINVAL);
+
+ decrypted_datalen = (unsigned short)dlen;
+ encrypted_datalen = roundup(decrypted_datalen, blksize);
+
+ datablob_len = strlen(master_desc) + 1 + strlen(datalen) + 1
+ + ivsize + 1 + encrypted_datalen;
+
+ ret = key_payload_reserve(key, decrypted_datalen + datablob_len
+ + HASH_SIZE + 1);
+ if (ret < 0)
+ return ERR_PTR(ret);
+
+ epayload = kzalloc(sizeof(*epayload) + decrypted_datalen +
+ datablob_len + HASH_SIZE + 1, GFP_KERNEL);
+ if (!epayload)
+ return ERR_PTR(-ENOMEM);
+
+ epayload->decrypted_datalen = decrypted_datalen;
+ epayload->datablob_len = datablob_len;
+ return epayload;
+}
+
+static int encrypted_key_decrypt(struct encrypted_key_payload *epayload,
+ const char *hex_encoded_iv,
+ const char *hex_encoded_data)
+{
+ struct key *mkey;
+ u8 derived_key[HASH_SIZE];
+ u8 *master_key;
+ u8 *hmac;
+ unsigned int master_keylen;
+ unsigned int encrypted_datalen;
+ int ret;
+
+ encrypted_datalen = roundup(epayload->decrypted_datalen, blksize);
+ hex2bin(epayload->iv, hex_encoded_iv, ivsize);
+ hex2bin(epayload->encrypted_data, hex_encoded_data, encrypted_datalen);
+
+ hmac = epayload->master_desc + epayload->datablob_len;
+ hex2bin(hmac, hex_encoded_data + (encrypted_datalen * 2), HASH_SIZE);
+
+ mkey = request_master_key(epayload, &master_key, &master_keylen);
+ if (IS_ERR(mkey))
+ return PTR_ERR(mkey);
+
+ ret = datablob_hmac_verify(epayload, master_key, master_keylen);
+ if (ret < 0) {
+ pr_err("encrypted_key: bad hmac (%d)\n", ret);
+ goto out;
+ }
+
+ memset(derived_key, 0, sizeof derived_key);
+ ret = get_derived_key(derived_key, ENC_KEY, master_key, master_keylen);
+ if (ret < 0)
+ goto out;
+
+ ret = derived_key_decrypt(epayload, derived_key, sizeof derived_key);
+ if (ret < 0)
+ pr_err("encrypted_key: failed to decrypt key (%d)\n", ret);
+out:
+ rcu_read_unlock();
+ key_put(mkey);
+ return ret;
+}
+
+static void __ekey_init(struct encrypted_key_payload *epayload,
+ const char *master_desc, const char *datalen)
+{
+ epayload->master_desc = epayload->decrypted_data
+ + epayload->decrypted_datalen;
+ epayload->datalen = epayload->master_desc + strlen(master_desc) + 1;
+ epayload->iv = epayload->datalen + strlen(datalen) + 1;
+ epayload->encrypted_data = epayload->iv + ivsize + 1;
+
+ memcpy(epayload->master_desc, master_desc, strlen(master_desc));
+ memcpy(epayload->datalen, datalen, strlen(datalen));
+}
+
+/*
+ * encrypted_init - initialize an encrypted key
+ *
+ * For a new key, use a random number for both the iv and data
+ * itself. For an old key, decrypt the hex encoded data.
+ */
+static int encrypted_init(struct encrypted_key_payload *epayload,
+ const char *master_desc, const char *datalen,
+ const char *hex_encoded_iv,
+ const char *hex_encoded_data)
+{
+ int ret = 0;
+
+ __ekey_init(epayload, master_desc, datalen);
+ if (!hex_encoded_data) {
+ get_random_bytes(epayload->iv, ivsize);
+
+ get_random_bytes(epayload->decrypted_data,
+ epayload->decrypted_datalen);
+ } else
+ ret = encrypted_key_decrypt(epayload, hex_encoded_iv,
+ hex_encoded_data);
+ return ret;
+}
+
+/*
+ * encrypted_instantiate - instantiate an encrypted key
+ *
+ * Decrypt an existing encrypted datablob or create a new encrypted key
+ * based on a kernel random number.
+ *
+ * On success, return 0. Otherwise return errno.
+ */
+static int encrypted_instantiate(struct key *key, const void *data,
+ size_t datalen)
+{
+ struct encrypted_key_payload *epayload = NULL;
+ char *datablob = NULL;
+ char *master_desc = NULL;
+ char *decrypted_datalen = NULL;
+ char *hex_encoded_iv = NULL;
+ char *hex_encoded_data = NULL;
+ int ret;
+
+ if (datalen <= 0 || datalen > 32767 || !data)
+ return -EINVAL;
+
+ datablob = kmalloc(datalen + 1, GFP_KERNEL);
+ if (!datablob)
+ return -ENOMEM;
+ *(datablob + datalen) = 0;
+ memcpy(datablob, data, datalen);
+ ret = datablob_parse(datablob, &master_desc, &decrypted_datalen,
+ &hex_encoded_iv, &hex_encoded_data);
+ if (ret < 0)
+ goto out;
+
+ epayload = encrypted_key_alloc(key, master_desc, decrypted_datalen);
+ if (IS_ERR(epayload)) {
+ ret = PTR_ERR(epayload);
+ goto out;
+ }
+ ret = encrypted_init(epayload, master_desc, decrypted_datalen,
+ hex_encoded_iv, hex_encoded_data);
+ if (ret < 0) {
+ kfree(epayload);
+ goto out;
+ }
+
+ rcu_assign_pointer(key->payload.data, epayload);
+out:
+ kfree(datablob);
+ return ret;
+}
+
+static void encrypted_rcu_free(struct rcu_head *rcu)
+{
+ struct encrypted_key_payload *epayload;
+
+ epayload = container_of(rcu, struct encrypted_key_payload, rcu);
+ memset(epayload->decrypted_data, 0, epayload->decrypted_datalen);
+ kfree(epayload);
+}
+
+/*
+ * encrypted_update - update the master key description
+ *
+ * Change the master key description for an existing encrypted key.
+ * The next read will return an encrypted datablob using the new
+ * master key description.
+ *
+ * On success, return 0. Otherwise return errno.
+ */
+static int encrypted_update(struct key *key, const void *data, size_t datalen)
+{
+ struct encrypted_key_payload *epayload = key->payload.data;
+ struct encrypted_key_payload *new_epayload;
+ char *buf;
+ char *new_master_desc = NULL;
+ size_t index;
+ int ret = 0;
+
+ if (datalen <= 0 || datalen > 32767 || !data)
+ return -EINVAL;
+
+ buf = kmalloc(datalen + 1, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ *(buf + datalen) = 0;
+ memcpy(buf, data, datalen);
+ ret = datablob_parse(buf, &new_master_desc, NULL, NULL, NULL);
+ if (ret < 0)
+ goto out;
+
+ index = strcspn(epayload->master_desc, ":");
+ if (index == strlen(new_master_desc)
+ || (strncmp(new_master_desc, epayload->master_desc, index) != 0)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ new_epayload = encrypted_key_alloc(key, new_master_desc,
+ epayload->datalen);
+ if (IS_ERR(new_epayload)) {
+ ret = PTR_ERR(new_epayload);
+ goto out;
+ }
+
+ __ekey_init(new_epayload, new_master_desc, epayload->datalen);
+
+ memcpy(new_epayload->iv, epayload->iv, ivsize);
+ memcpy(new_epayload->decrypted_data, epayload->decrypted_data,
+ epayload->decrypted_datalen);
+
+ rcu_assign_pointer(key->payload.data, new_epayload);
+ call_rcu(&epayload->rcu, encrypted_rcu_free);
+out:
+ kfree(buf);
+ return ret;
+}
+
+/*
+ * encrypted_read - format and copy the encrypted data to userspace
+ *
+ * The resulting datablob format is:
+ * <master-key name> <decrypted data length> <encrypted iv> <encrypted data>
+ *
+ * On success, return to userspace the encrypted key datablob size.
+ */
+static long encrypted_read(const struct key *key, char __user *buffer,
+ size_t buflen)
+{
+ struct encrypted_key_payload *epayload;
+ struct key *mkey;
+ u8 *master_key;
+ unsigned int master_keylen;
+ char derived_key[HASH_SIZE];
+ int asciiblob_len;
+ int ret;
+
+ epayload = rcu_dereference_protected(key->payload.data,
+ rwsem_is_locked(&((struct key *)key)->sem));
+
+ /* returns the hex encoded iv, encrypted-data, and hmac as ascii */
+ asciiblob_len = epayload->datablob_len + ivsize + 1
+ + roundup(epayload->decrypted_datalen, blksize)
+ + (HASH_SIZE * 2);
+
+ if (!buffer || buflen <= 0)
+ return asciiblob_len;
+
+ mkey = request_master_key(epayload, &master_key, &master_keylen);
+ if (IS_ERR(mkey))
+ return PTR_ERR(mkey);
+
+ memset(derived_key, 0, sizeof derived_key);
+ ret = get_derived_key(derived_key, ENC_KEY, master_key, master_keylen);
+ if (ret < 0)
+ goto out;
+
+ ret = derived_key_encrypt(epayload, derived_key, sizeof derived_key);
+ if (ret < 0)
+ goto out;
+
+ ret = datablob_hmac_append(epayload, master_key, master_keylen);
+ if (ret < 0)
+ goto out;
+
+ ret = datablob_format(buffer, epayload, asciiblob_len);
+ if (ret < 0)
+ goto out;
+
+ rcu_read_unlock();
+ key_put(mkey);
+ return asciiblob_len;
+out:
+ rcu_read_unlock();
+ key_put(mkey);
+ return ret;
+}
+
+/*
+ * encrypted_destroy - before freeing the key, clear the decrypted data
+ *
+ * Before freeing the key, clear the memory containing the descrypted
+ * key data.
+ */
+static void encrypted_destroy(struct key *key)
+{
+ struct encrypted_key_payload *epayload = key->payload.data;
+
+ if (!epayload)
+ return;
+
+ memset(epayload->decrypted_data, 0, epayload->decrypted_datalen);
+ kfree(key->payload.data);
+}
+
+struct key_type key_type_encrypted = {
+ .name = "encrypted",
+ .instantiate = encrypted_instantiate,
+ .update = encrypted_update,
+ .match = user_match,
+ .destroy = encrypted_destroy,
+ .describe = user_describe,
+ .read = encrypted_read,
+};
+EXPORT_SYMBOL_GPL(key_type_encrypted);
+
+static void encrypted_shash_release(void)
+{
+ if (hashalg)
+ crypto_free_shash(hashalg);
+ if (hmacalg)
+ crypto_free_shash(hmacalg);
+}
+
+static int __init encrypted_shash_alloc(void)
+{
+ int ret;
+
+ hmacalg = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(hmacalg)) {
+ pr_info("encrypted_key: could not allocate crypto %s\n",
+ hmac_alg);
+ return PTR_ERR(hmacalg);
+ }
+
+ hashalg = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(hashalg)) {
+ pr_info("encrypted_key: could not allocate crypto %s\n",
+ hash_alg);
+ ret = PTR_ERR(hashalg);
+ goto hashalg_fail;
+ }
+
+ return 0;
+
+hashalg_fail:
+ crypto_free_shash(hmacalg);
+ return ret;
+}
+
+static int __init init_encrypted(void)
+{
+ int ret;
+
+ ret = encrypted_shash_alloc();
+ if (ret < 0)
+ return ret;
+ ret = register_key_type(&key_type_encrypted);
+ if (ret < 0)
+ goto out;
+ ret = aes_get_sizes();
+ return ret;
+out:
+ encrypted_shash_release();
+ return ret;
+
+}
+
+static void __exit cleanup_encrypted(void)
+{
+ encrypted_shash_release();
+ unregister_key_type(&key_type_encrypted);
+}
+
+late_initcall(init_encrypted);
+module_exit(cleanup_encrypted);
+
+MODULE_LICENSE("GPL");
diff --git a/security/keys/encrypted_defined.h b/security/keys/encrypted_defined.h
new file mode 100644
index 0000000..c298a3f
--- /dev/null
+++ b/security/keys/encrypted_defined.h
@@ -0,0 +1,56 @@
+#ifndef __ENCRYPTED_KEY_H
+#define __ENCRYPTED_KEY_H
+
+#define ENCRYPTED_DEBUG 0
+
+#if ENCRYPTED_DEBUG
+static inline void dump_master_key(const u8 *master_key,
+ unsigned int master_keylen)
+{
+ print_hex_dump(KERN_ERR, "master key: ", DUMP_PREFIX_NONE, 32, 1,
+ master_key, master_keylen, 0);
+}
+
+static inline void dump_decrypted_data(struct encrypted_key_payload *epayload)
+{
+ print_hex_dump(KERN_ERR, "decrypted data: ", DUMP_PREFIX_NONE, 32, 1,
+ epayload->decrypted_data,
+ epayload->decrypted_datalen, 0);
+}
+
+static inline void dump_encrypted_data(struct encrypted_key_payload *epayload,
+ unsigned int encrypted_datalen)
+{
+ print_hex_dump(KERN_ERR, "encrypted data: ", DUMP_PREFIX_NONE, 32, 1,
+ epayload->encrypted_data, encrypted_datalen, 0);
+}
+
+static inline void dump_hmac(const char *str, const u8 *digest,
+ unsigned int hmac_size)
+{
+ if (str)
+ pr_info("encrypted_key: %s", str);
+ print_hex_dump(KERN_ERR, "hmac: ", DUMP_PREFIX_NONE, 32, 1, digest,
+ hmac_size, 0);
+}
+#else
+static inline void dump_master_key(const u8 *master_key,
+ unsigned int master_keylen)
+{
+}
+
+static inline void dump_decrypted_data(struct encrypted_key_payload *epayload)
+{
+}
+
+static inline void dump_encrypted_data(struct encrypted_key_payload *epayload,
+ unsigned int encrypted_datalen)
+{
+}
+
+static inline void dump_hmac(const char *str, const u8 *digest,
+ unsigned int hmac_size)
+{
+}
+#endif
+#endif
--
1.7.2.2

2010-11-18 22:43:20

by Mimi Zohar

[permalink] [raw]
Subject: [PATCH v1.4 4/5] keys: add new trusted key-type

Define a new kernel key-type called 'trusted'. Trusted keys are random
number symmetric keys, generated and RSA-sealed by the TPM. The TPM
only unseals the keys, if the boot PCRs and other criteria match.
Userspace can only ever see encrypted blobs.

Based on suggestions by Jason Gunthorpe, several new options have been
added to support additional usages.

The new options are:
migratable= designates that the key may/may not ever be updated
(resealed under a new key, new pcrinfo or new auth.)

pcrlock=n extends the designated PCR 'n' with a random value,
so that a key sealed to that PCR may not be unsealed
again until after a reboot.

keyhandle= specifies the sealing/unsealing key handle.

keyauth= specifies the sealing/unsealing key auth.

blobauth= specifies the sealed data auth.

Implementation of a kernel reserved locality for trusted keys will be
investigated for a possible future extension.

Changelog:
- moved to late_initcall
- updated from hash to shash (suggestion by David Howells)
- reduced worst stack usage (tpm_seal) from 530 to 312 bytes
- moved documentation to Documentation directory (suggestion by David Howells)
- all the other code cleanups suggested by David Howells
- Add pcrlock CAP_SYS_ADMIN dependency (based on comment by Jason Gunthorpe)
- New options: migratable, pcrlock, keyhandle, keyauth, blobauth (based on
discussions with Jason Gunthorpe)
- Free payload on failure to create key(reported/fixed by Roberto Sassu)
- Updated Kconfig and other descriptions (based on Serge Hallyn's suggestion)
- Replaced kzalloc() with kmalloc() (reported by Serge Hallyn)

Signed-off-by: David Safford <[email protected]>
Signed-off-by: Mimi Zohar <[email protected]>
---
Documentation/keys-trusted-encrypted.txt | 68 ++
include/keys/trusted-type.h | 31 +
security/Kconfig | 15 +
security/keys/Makefile | 1 +
security/keys/trusted_defined.c | 1136 ++++++++++++++++++++++++++++++
security/keys/trusted_defined.h | 147 ++++
6 files changed, 1398 insertions(+), 0 deletions(-)
create mode 100644 Documentation/keys-trusted-encrypted.txt
create mode 100644 include/keys/trusted-type.h
create mode 100644 security/keys/trusted_defined.c
create mode 100644 security/keys/trusted_defined.h

diff --git a/Documentation/keys-trusted-encrypted.txt b/Documentation/keys-trusted-encrypted.txt
new file mode 100644
index 0000000..6e6db62
--- /dev/null
+++ b/Documentation/keys-trusted-encrypted.txt
@@ -0,0 +1,68 @@
+ Trusted and Encrypted Keys
+
+Trusted and Encrypted Keys are two new key types added to the existing kernel
+key ring service. Both of these new types are variable length symmetic keys,
+and in both cases all keys are created in the kernel, and user space sees,
+stores, and loads only encrypted blobs. Trusted Keys require the availability
+of a Trusted Platform Module (TPM) chip for greater security, while Encrypted
+Keys can be used on any system. All user level blobs, are displayed and loaded
+in hex ascii for convenience, and are integrity verified.
+
+Trusted Keys use a TPM both to generate and to seal the keys. Keys are sealed
+under a 2048 bit RSA key in the TPM, and optionally sealed to specified PCR
+(integrity measurement) values, and only unsealed by the TPM, if PCRs and blob
+integrity verifications match. A loaded Trusted Key can be updated with new
+(future) PCR values, so keys are easily migrated to new pcr values, such as
+when the kernel and initramfs are updated. The same key can have many saved
+blobs under different PCR values, so multiple boots are easily supported.
+
+By default, trusted keys are sealed under the SRK, which has the default
+authorization value (20 zeros). This can be set at takeownership time with the
+trouser's utility: "tpm_takeownership -u -z".
+
+Usage:
+ keyctl add trusted name "new keylen [options]" ring
+ keyctl add trusted name "load hex_blob [pcrlock=pcrnum]" ring
+ keyctl update key "update [options]"
+ 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)
+
+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.
+Trusted Keys can be 32 - 128 bytes (256 - 1024 bits), the upper limit is to fit
+within the 2048 bit SRK (RSA) keylength, with all necessary structure/padding.
+
+Encrypted keys do not depend on a TPM, and are faster, as they use AES for
+encryption/decryption. New keys are created from kernel generated random
+numbers, and are encrypted/decrypted using a specified 'master' key. The
+'master' key can either be a trusted-key or user-key type. The main
+disadvantage of encrypted keys is that if they are not rooted in a trusted key,
+they are only as secure as the user key encrypting them. The master user key
+should therefore be loaded in as secure a way as possible, preferably early in
+boot.
+
+Usage:
+ keyctl add encrypted name "new key-type:master-key-name keylen" ring
+ keyctl add encrypted name "load key-type:master-key-name keylen hex_blob" ring
+ keyctl update keyid "update key-type:master-key-name"
+
+where 'key-type' is either 'trusted' or 'user'.
+
+The initial consumer of trusted keys is EVM, which at boot time needs a high
+quality symmetric key for HMAC protection of file metadata. The use of a
+trusted key provides strong guarantees that the EVM key has not been
+compromised by a user level problem, and when sealed to specific boot PCR
+values, protects against boot and offline attacks. Other uses for trusted and
+encrypted keys, such as for disk and file encryption are anticipated.
diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h
new file mode 100644
index 0000000..56f82e5
--- /dev/null
+++ b/include/keys/trusted-type.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2010 IBM Corporation
+ * Author: David Safford <[email protected]us.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ */
+
+#ifndef _KEYS_TRUSTED_TYPE_H
+#define _KEYS_TRUSTED_TYPE_H
+
+#include <linux/key.h>
+#include <linux/rcupdate.h>
+
+#define MIN_KEY_SIZE 32
+#define MAX_KEY_SIZE 128
+#define MAX_BLOB_SIZE 320
+
+struct trusted_key_payload {
+ struct rcu_head rcu;
+ unsigned int key_len;
+ unsigned int blob_len;
+ unsigned char migratable;
+ unsigned char key[MAX_KEY_SIZE + 1];
+ unsigned char blob[MAX_BLOB_SIZE];
+};
+
+extern struct key_type key_type_trusted;
+
+#endif /* _KEYS_TRUSTED_TYPE_H */
diff --git a/security/Kconfig b/security/Kconfig
index bd72ae6..be2d1c6 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -21,6 +21,21 @@ config KEYS

If you are unsure as to whether this is required, answer N.

+config TRUSTED_KEYS
+ tristate "TRUSTED KEYS"
+ depends on KEYS && TCG_TPM
+ select CRYPTO
+ select CRYPTO_HMAC
+ select CRYPTO_SHA1
+ help
+ This option provides support for creating, sealing, and unsealing
+ keys in the kernel. Trusted keys are random number symmetric keys,
+ generated and RSA-sealed by the TPM. The TPM only unseals the keys,
+ if the boot PCRs and other criteria match. Userspace will only ever
+ see encrypted blobs.
+
+ If you are unsure as to whether this is required, answer N.
+
config KEYS_DEBUG_PROC_KEYS
bool "Enable the /proc/keys file by which keys may be viewed"
depends on KEYS
diff --git a/security/keys/Makefile b/security/keys/Makefile
index 74d5447..fcb1070 100644
--- a/security/keys/Makefile
+++ b/security/keys/Makefile
@@ -13,6 +13,7 @@ obj-y := \
request_key_auth.o \
user_defined.o

+obj-$(CONFIG_TRUSTED_KEYS) += trusted_defined.o
obj-$(CONFIG_KEYS_COMPAT) += compat.o
obj-$(CONFIG_PROC_FS) += proc.o
obj-$(CONFIG_SYSCTL) += sysctl.o
diff --git a/security/keys/trusted_defined.c b/security/keys/trusted_defined.c
new file mode 100644
index 0000000..6f35826
--- /dev/null
+++ b/security/keys/trusted_defined.c
@@ -0,0 +1,1136 @@
+/*
+ * Copyright (C) 2010 IBM Corporation
+ *
+ * Author:
+ * David Safford <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ *
+ * See Documentation/keys-trusted-encrypted.txt
+ */
+
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/parser.h>
+#include <linux/string.h>
+#include <keys/user-type.h>
+#include <keys/trusted-type.h>
+#include <linux/key-type.h>
+#include <linux/rcupdate.h>
+#include <linux/crypto.h>
+#include <crypto/hash.h>
+#include <crypto/sha.h>
+#include <linux/capability.h>
+#include <linux/tpm.h>
+
+#include "trusted_defined.h"
+
+static const char hmac_alg[] = "hmac(sha1)";
+static const char hash_alg[] = "sha1";
+
+struct sdesc {
+ struct shash_desc shash;
+ char ctx[];
+};
+
+static struct crypto_shash *hashalg;
+static struct crypto_shash *hmacalg;
+
+static struct sdesc *init_sdesc(struct crypto_shash *alg)
+{
+ struct sdesc *sdesc;
+ int size;
+
+ size = sizeof(struct shash_desc) + crypto_shash_descsize(alg);
+ sdesc = kmalloc(size, GFP_KERNEL);
+ if (!sdesc)
+ return ERR_PTR(-ENOMEM);
+ sdesc->shash.tfm = alg;
+ sdesc->shash.flags = 0x0;
+ return sdesc;
+}
+
+static int TSS_sha1(unsigned char *data, int datalen, unsigned char *digest)
+{
+ struct sdesc *sdesc;
+ int ret;
+
+ sdesc = init_sdesc(hashalg);
+ if (IS_ERR(sdesc)) {
+ pr_info("trusted_key: can't alloc %s\n", hash_alg);
+ return PTR_ERR(sdesc);
+ }
+
+ ret = crypto_shash_digest(&sdesc->shash, data, datalen, digest);
+ kfree(sdesc);
+ return ret;
+}
+
+static int TSS_rawhmac(unsigned char *digest, unsigned char *key,
+ unsigned int keylen, ...)
+{
+ struct sdesc *sdesc;
+ va_list argp;
+ unsigned int dlen;
+ unsigned char *data;
+ int ret;
+
+ sdesc = init_sdesc(hmacalg);
+ if (IS_ERR(sdesc)) {
+ pr_info("trusted_key: can't alloc %s\n", hmac_alg);
+ return PTR_ERR(sdesc);
+ }
+
+ ret = crypto_shash_setkey(hmacalg, key, keylen);
+ if (ret < 0)
+ goto out;
+ ret = crypto_shash_init(&sdesc->shash);
+ if (ret < 0)
+ goto out;
+
+ va_start(argp, keylen);
+ for (;;) {
+ dlen = va_arg(argp, unsigned int);
+ if (dlen == 0)
+ break;
+ data = va_arg(argp, unsigned char *);
+ if (data == NULL)
+ return -EINVAL;
+ ret = crypto_shash_update(&sdesc->shash, data, dlen);
+ if (ret < 0)
+ goto out;
+ }
+ va_end(argp);
+ ret = crypto_shash_final(&sdesc->shash, digest);
+out:
+ kfree(sdesc);
+ return ret;
+}
+
+/*
+ * calculate authorization info fields to send to TPM
+ */
+static uint32_t TSS_authhmac(unsigned char *digest, unsigned char *key,
+ unsigned int keylen, unsigned char *h1,
+ unsigned char *h2, unsigned char h3, ...)
+{
+ unsigned char paramdigest[SHA1_DIGEST_SIZE];
+ struct sdesc *sdesc;
+ unsigned int dlen;
+ unsigned char *data;
+ unsigned char c;
+ int ret;
+ va_list argp;
+
+ sdesc = init_sdesc(hashalg);
+ if (IS_ERR(sdesc)) {
+ pr_info("trusted_key: can't alloc %s\n", hash_alg);
+ return PTR_ERR(sdesc);
+ }
+
+ c = h3;
+ ret = crypto_shash_init(&sdesc->shash);
+ if (ret < 0)
+ goto out;
+ va_start(argp, h3);
+ for (;;) {
+ dlen = va_arg(argp, unsigned int);
+ if (dlen == 0)
+ break;
+ data = va_arg(argp, unsigned char *);
+ ret = crypto_shash_update(&sdesc->shash, data, dlen);
+ if (ret < 0)
+ goto out;
+ }
+ va_end(argp);
+ ret = crypto_shash_final(&sdesc->shash, paramdigest);
+ if (!ret)
+ TSS_rawhmac(digest, key, keylen, SHA1_DIGEST_SIZE,
+ paramdigest, TPM_NONCE_SIZE, h1,
+ TPM_NONCE_SIZE, h2, 1, &c, 0, 0);
+out:
+ kfree(sdesc);
+ return ret;
+}
+
+/*
+ * verify the AUTH1_COMMAND (Seal) result from TPM
+ */
+static uint32_t TSS_checkhmac1(unsigned char *buffer, uint32_t command,
+ unsigned char *ononce, unsigned char *key,
+ unsigned int keylen, ...)
+{
+ uint32_t bufsize;
+ uint16_t tag;
+ uint32_t ordinal;
+ uint32_t result;
+ unsigned char *enonce;
+ unsigned char *continueflag;
+ unsigned char *authdata;
+ unsigned char testhmac[SHA1_DIGEST_SIZE];
+ unsigned char paramdigest[SHA1_DIGEST_SIZE];
+ struct sdesc *sdesc;
+ unsigned int dlen;
+ unsigned int dpos;
+ va_list argp;
+ int ret;
+
+ bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
+ tag = LOAD16(buffer, 0);
+ ordinal = command;
+ result = LOAD32N(buffer, TPM_RETURN_OFFSET);
+ if (tag == TPM_TAG_RSP_COMMAND)
+ return 0;
+ if (tag != TPM_TAG_RSP_AUTH1_COMMAND)
+ return -EINVAL;
+ authdata = buffer + bufsize - SHA1_DIGEST_SIZE;
+ continueflag = authdata - 1;
+ enonce = continueflag - TPM_NONCE_SIZE;
+
+ sdesc = init_sdesc(hashalg);
+ if (IS_ERR(sdesc)) {
+ pr_info("trusted_key: can't alloc %s\n", hash_alg);
+ return PTR_ERR(sdesc);
+ }
+ ret = crypto_shash_init(&sdesc->shash);
+ if (ret < 0)
+ goto out;
+ ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result,
+ sizeof result);
+ if (ret < 0)
+ goto out;
+ ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal,
+ sizeof ordinal);
+ if (ret < 0)
+ goto out;
+ va_start(argp, keylen);
+ for (;;) {
+ dlen = va_arg(argp, unsigned int);
+ if (dlen == 0)
+ break;
+ dpos = va_arg(argp, unsigned int);
+ ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen);
+ if (ret < 0)
+ goto out;
+ }
+ va_end(argp);
+ ret = crypto_shash_final(&sdesc->shash, paramdigest);
+ if (ret < 0)
+ goto out;
+ ret = TSS_rawhmac(testhmac, key, keylen, SHA1_DIGEST_SIZE, paramdigest,
+ TPM_NONCE_SIZE, enonce, TPM_NONCE_SIZE, ononce,
+ 1, continueflag, 0, 0);
+ if (ret < 0)
+ goto out;
+ if (memcmp(testhmac, authdata, SHA1_DIGEST_SIZE))
+ ret = -EINVAL;
+out:
+ kfree(sdesc);
+ return ret;
+}
+
+/*
+ * verify the AUTH2_COMMAND (unseal) result from TPM
+ */
+static uint32_t TSS_checkhmac2(unsigned char *buffer, uint32_t command,
+ unsigned char *ononce, unsigned char *key1,
+ unsigned int keylen1, unsigned char *key2,
+ unsigned int keylen2, ...)
+{
+ uint32_t bufsize;
+ uint16_t tag;
+ uint32_t ordinal;
+ uint32_t result;
+ unsigned char *enonce1;
+ unsigned char *continueflag1;
+ unsigned char *authdata1;
+ unsigned char *enonce2;
+ unsigned char *continueflag2;
+ unsigned char *authdata2;
+ unsigned char testhmac1[SHA1_DIGEST_SIZE];
+ unsigned char testhmac2[SHA1_DIGEST_SIZE];
+ unsigned char paramdigest[SHA1_DIGEST_SIZE];
+ struct sdesc *sdesc;
+ unsigned int dlen;
+ unsigned int dpos;
+ va_list argp;
+ int ret;
+
+ bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
+ tag = LOAD16(buffer, 0);
+ ordinal = command;
+ result = LOAD32N(buffer, TPM_RETURN_OFFSET);
+
+ if (tag == TPM_TAG_RSP_COMMAND)
+ return 0;
+ if (tag != TPM_TAG_RSP_AUTH2_COMMAND)
+ return -EINVAL;
+ authdata1 = buffer + bufsize - (SHA1_DIGEST_SIZE + 1
+ + SHA1_DIGEST_SIZE + SHA1_DIGEST_SIZE);
+ authdata2 = buffer + bufsize - (SHA1_DIGEST_SIZE);
+ continueflag1 = authdata1 - 1;
+ continueflag2 = authdata2 - 1;
+ enonce1 = continueflag1 - TPM_NONCE_SIZE;
+ enonce2 = continueflag2 - TPM_NONCE_SIZE;
+
+ sdesc = init_sdesc(hashalg);
+ if (IS_ERR(sdesc)) {
+ pr_info("trusted_key: can't alloc %s\n", hash_alg);
+ return PTR_ERR(sdesc);
+ }
+ ret = crypto_shash_init(&sdesc->shash);
+ if (ret < 0)
+ goto out;
+ ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result,
+ sizeof result);
+ if (ret < 0)
+ goto out;
+ ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal,
+ sizeof ordinal);
+ if (ret < 0)
+ goto out;
+
+ va_start(argp, keylen2);
+ for (;;) {
+ dlen = va_arg(argp, unsigned int);
+ if (dlen == 0)
+ break;
+ dpos = va_arg(argp, unsigned int);
+ ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen);
+ if (ret < 0)
+ goto out;
+ }
+ ret = crypto_shash_final(&sdesc->shash, paramdigest);
+ if (ret < 0)
+ goto out;
+
+ ret = TSS_rawhmac(testhmac1, key1, keylen1, SHA1_DIGEST_SIZE,
+ paramdigest, TPM_NONCE_SIZE, enonce1,
+ TPM_NONCE_SIZE, ononce, 1, continueflag1, 0, 0);
+ if (memcmp(testhmac1, authdata1, SHA1_DIGEST_SIZE)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ ret = TSS_rawhmac(testhmac2, key2, keylen2, SHA1_DIGEST_SIZE,
+ paramdigest, TPM_NONCE_SIZE, enonce2,
+ TPM_NONCE_SIZE, ononce, 1, continueflag2, 0, 0);
+ if (memcmp(testhmac2, authdata2, SHA1_DIGEST_SIZE))
+ ret = -EINVAL;
+out:
+ kfree(sdesc);
+ return ret;
+}
+
+/*
+ * For key specific tpm requests, we will generate and send our
+ * own TPM command packets using the drivers send function.
+ */
+static int trusted_tpm_send(u32 chip_num, unsigned char *cmd, int buflen)
+{
+ int rc;
+
+ dump_tpm_buf(cmd);
+ rc = tpm_send(chip_num, cmd, buflen);
+ dump_tpm_buf(cmd);
+ if (rc > 0)
+ /* Can't return positive return codes values to keyctl */
+ rc = -EPERM;
+ return rc;
+}
+
+/*
+ * get a random value from TPM
+ */
+static int tpm_get_random(struct tpm_buf *tb, unsigned char *buf, uint32_t len)
+{
+ int ret;
+
+ INIT_BUF(tb);
+ store16(tb, TPM_TAG_RQU_COMMAND);
+ store32(tb, TPM_GETRANDOM_SIZE);
+ store32(tb, TPM_ORD_GETRANDOM);
+ store32(tb, len);
+ ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, sizeof tb->data);
+ memcpy(buf, tb->data + TPM_GETRANDOM_RETURN, len);
+
+ return ret;
+}
+
+static int my_get_random(unsigned char *buf, int len)
+{
+ struct tpm_buf *tb;
+ int ret;
+
+ tb = kzalloc(sizeof *tb, GFP_KERNEL);
+ if (!tb)
+ return -ENOMEM;
+ ret = tpm_get_random(tb, buf, len);
+
+ kfree(tb);
+ return ret;
+}
+
+/*
+ * Lock a trusted key, by extending a selected PCR.
+ *
+ * Prevents a trusted key that is sealed to PCRs from being accessed.
+ * This uses the tpm driver's extend function.
+ */
+static int pcrlock(int pcrnum)
+{
+ unsigned char hash[SHA1_DIGEST_SIZE];
+ int ret;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ my_get_random(hash, SHA1_DIGEST_SIZE);
+ ret = tpm_pcr_extend(TPM_ANY_NUM, pcrnum, hash);
+ return ret;
+}
+
+/*
+ * Create an object specific authorisation protocol (OSAP) session
+ */
+static int osap(struct tpm_buf *tb, struct osapsess *s,
+ unsigned char *key, uint16_t type, uint32_t handle)
+{
+ unsigned char enonce[TPM_NONCE_SIZE];
+ unsigned char ononce[TPM_NONCE_SIZE];
+ int ret;
+
+ ret = tpm_get_random(tb, ononce, TPM_NONCE_SIZE);
+ if (ret < 0)
+ return ret;
+
+ INIT_BUF(tb);
+ store16(tb, TPM_TAG_RQU_COMMAND);
+ store32(tb, TPM_OSAP_SIZE);
+ store32(tb, TPM_ORD_OSAP);
+ store16(tb, type);
+ store32(tb, handle);
+ storebytes(tb, ononce, TPM_NONCE_SIZE);
+
+ ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
+ if (ret < 0)
+ return ret;
+
+ s->handle = LOAD32(tb->data, TPM_DATA_OFFSET);
+ memcpy(s->enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)]),
+ TPM_NONCE_SIZE);
+ memcpy(enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t) +
+ TPM_NONCE_SIZE]), TPM_NONCE_SIZE);
+ ret = TSS_rawhmac(s->secret, key, SHA1_DIGEST_SIZE, TPM_NONCE_SIZE,
+ enonce, TPM_NONCE_SIZE, ononce, 0, 0);
+ return ret;
+}
+
+/*
+ * Create an object independent authorisation protocol (oiap) session
+ */
+static int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce)
+{
+ int ret;
+
+ INIT_BUF(tb);
+ store16(tb, TPM_TAG_RQU_COMMAND);
+ store32(tb, TPM_OIAP_SIZE);
+ store32(tb, TPM_ORD_OIAP);
+ ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
+ if (ret < 0)
+ return ret;
+
+ *handle = LOAD32(tb->data, TPM_DATA_OFFSET);
+ memcpy(nonce, &tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)],
+ TPM_NONCE_SIZE);
+ return ret;
+}
+
+struct tpm_digests {
+ unsigned char encauth[SHA1_DIGEST_SIZE];
+ unsigned char pubauth[SHA1_DIGEST_SIZE];
+ unsigned char xorwork[SHA1_DIGEST_SIZE * 2];
+ unsigned char xorhash[SHA1_DIGEST_SIZE];
+ unsigned char nonceodd[TPM_NONCE_SIZE];
+};
+
+/*
+ * Have the TPM seal(encrypt) the trusted key, possibly based on
+ * Platform Configuration Registers (PCRs). AUTH1 for sealing key.
+ */
+static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
+ uint32_t keyhandle, unsigned char *keyauth,
+ unsigned char *data, uint32_t datalen,
+ unsigned char *blob, uint32_t *bloblen,
+ unsigned char *blobauth,
+ unsigned char *pcrinfo, uint32_t pcrinfosize)
+{
+ struct osapsess sess;
+ struct tpm_digests *td;
+ unsigned char cont;
+ uint32_t ordinal;
+ uint32_t pcrsize;
+ uint32_t datsize;
+ int sealinfosize;
+ int encdatasize;
+ int storedsize;
+ int ret;
+ int i;
+
+ /* alloc some work space for all the hashes */
+ td = kzalloc(sizeof *td, GFP_KERNEL);
+ if (!td)
+ return -ENOMEM;
+
+ /* get session for sealing key */
+ ret = osap(tb, &sess, keyauth, keytype, keyhandle);
+ if (ret < 0)
+ return ret;
+ dump_sess(&sess);
+
+ /* calculate encrypted authorization value */
+ memcpy(td->xorwork, sess.secret, SHA1_DIGEST_SIZE);
+ memcpy(td->xorwork + SHA1_DIGEST_SIZE, sess.enonce, SHA1_DIGEST_SIZE);
+ ret = TSS_sha1(td->xorwork, SHA1_DIGEST_SIZE * 2, td->xorhash);
+ if (ret < 0)
+ return ret;
+
+ ret = tpm_get_random(tb, td->nonceodd, TPM_NONCE_SIZE);
+ if (ret < 0)
+ return ret;
+ ordinal = htonl(TPM_ORD_SEAL);
+ datsize = htonl(datalen);
+ pcrsize = htonl(pcrinfosize);
+ cont = 0;
+
+ /* encrypt data authorization key */
+ for (i = 0; i < SHA1_DIGEST_SIZE; ++i)
+ td->encauth[i] = td->xorhash[i] ^ blobauth[i];
+
+ /* calculate authorization HMAC value */
+ if (pcrinfosize == 0) {
+ /* no pcr info specified */
+ TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
+ sess.enonce, td->nonceodd, cont, sizeof(uint32_t),
+ &ordinal, SHA1_DIGEST_SIZE, td->encauth,
+ sizeof(uint32_t), &pcrsize, sizeof(uint32_t),
+ &datsize, datalen, data, 0, 0);
+ } else {
+ /* pcr info specified */
+ TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
+ sess.enonce, td->nonceodd, cont, sizeof(uint32_t),
+ &ordinal, SHA1_DIGEST_SIZE, td->encauth,
+ sizeof(uint32_t), &pcrsize, pcrinfosize,
+ pcrinfo, sizeof(uint32_t), &datsize, datalen,
+ data, 0, 0);
+ }
+
+ /* build and send the TPM request packet */
+ INIT_BUF(tb);
+ store16(tb, TPM_TAG_RQU_AUTH1_COMMAND);
+ store32(tb, TPM_SEAL_SIZE + pcrinfosize + datalen);
+ store32(tb, TPM_ORD_SEAL);
+ store32(tb, keyhandle);
+ storebytes(tb, td->encauth, SHA1_DIGEST_SIZE);
+ store32(tb, pcrinfosize);
+ storebytes(tb, pcrinfo, pcrinfosize);
+ store32(tb, datalen);
+ storebytes(tb, data, datalen);
+ store32(tb, sess.handle);
+ storebytes(tb, td->nonceodd, TPM_NONCE_SIZE);
+ store8(tb, cont);
+ storebytes(tb, td->pubauth, SHA1_DIGEST_SIZE);
+
+ ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
+ if (ret < 0)
+ return ret;
+
+ /* calculate the size of the returned Blob */
+ sealinfosize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t));
+ encdatasize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t) +
+ sizeof(uint32_t) + sealinfosize);
+ storedsize = sizeof(uint32_t) + sizeof(uint32_t) + sealinfosize +
+ sizeof(uint32_t) + encdatasize;
+
+ /* check the HMAC in the response */
+ ret = TSS_checkhmac1(tb->data, ordinal, td->nonceodd, sess.secret,
+ SHA1_DIGEST_SIZE, storedsize, TPM_DATA_OFFSET, 0,
+ 0);
+
+ /* copy the returned blob to caller */
+ memcpy(blob, tb->data + TPM_DATA_OFFSET, storedsize);
+ *bloblen = storedsize;
+ return ret;
+}
+
+/*
+ * use the AUTH2_COMMAND form of unseal, to authorize both key and blob
+ */
+static int tpm_unseal(struct tpm_buf *tb,
+ uint32_t keyhandle, unsigned char *keyauth,
+ unsigned char *blob, int bloblen,
+ unsigned char *blobauth,
+ unsigned char *data, unsigned int *datalen)
+{
+ unsigned char nonceodd[TPM_NONCE_SIZE];
+ unsigned char enonce1[TPM_NONCE_SIZE];
+ unsigned char enonce2[TPM_NONCE_SIZE];
+ unsigned char authdata1[SHA1_DIGEST_SIZE];
+ unsigned char authdata2[SHA1_DIGEST_SIZE];
+ uint32_t authhandle1 = 0;
+ uint32_t authhandle2 = 0;
+ unsigned char cont = 0;
+ uint32_t ordinal;
+ uint32_t keyhndl;
+ int ret;
+
+ /* sessions for unsealing key and data */
+ ret = oiap(tb, &authhandle1, enonce1);
+ if (ret < 0) {
+ pr_info("trusted_key: oiap failed (%d)\n", ret);
+ return ret;
+ }
+ ret = oiap(tb, &authhandle2, enonce2);
+ if (ret < 0) {
+ pr_info("trusted_key: oiap failed (%d)\n", ret);
+ return ret;
+ }
+
+ ordinal = htonl(TPM_ORD_UNSEAL);
+ keyhndl = htonl(SRKHANDLE);
+ ret = tpm_get_random(tb, nonceodd, TPM_NONCE_SIZE);
+ if (ret < 0) {
+ pr_info("trusted_key: tpm_get_random failed (%d)\n", ret);
+ return ret;
+ }
+ TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE,
+ enonce1, nonceodd, cont, sizeof(uint32_t),
+ &ordinal, bloblen, blob, 0, 0);
+ TSS_authhmac(authdata2, blobauth, TPM_NONCE_SIZE,
+ enonce2, nonceodd, cont, sizeof(uint32_t),
+ &ordinal, bloblen, blob, 0, 0);
+
+ /* build and send TPM request packet */
+ INIT_BUF(tb);
+ store16(tb, TPM_TAG_RQU_AUTH2_COMMAND);
+ store32(tb, TPM_UNSEAL_SIZE + bloblen);
+ store32(tb, TPM_ORD_UNSEAL);
+ store32(tb, keyhandle);
+ storebytes(tb, blob, bloblen);
+ store32(tb, authhandle1);
+ storebytes(tb, nonceodd, TPM_NONCE_SIZE);
+ store8(tb, cont);
+ storebytes(tb, authdata1, SHA1_DIGEST_SIZE);
+ store32(tb, authhandle2);
+ storebytes(tb, nonceodd, TPM_NONCE_SIZE);
+ store8(tb, cont);
+ storebytes(tb, authdata2, SHA1_DIGEST_SIZE);
+
+ ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
+ if (ret < 0) {
+ pr_info("trusted_key: authhmac failed (%d)\n", ret);
+ return ret;
+ }
+
+ *datalen = LOAD32(tb->data, TPM_DATA_OFFSET);
+ ret = TSS_checkhmac2(tb->data, ordinal, nonceodd,
+ keyauth, SHA1_DIGEST_SIZE,
+ blobauth, SHA1_DIGEST_SIZE,
+ sizeof(uint32_t), TPM_DATA_OFFSET,
+ *datalen, TPM_DATA_OFFSET + sizeof(uint32_t), 0,
+ 0);
+ if (ret < 0)
+ pr_info("trusted_key: TSS_checkhmac2 failed (%d)\n", ret);
+ memcpy(data, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t), *datalen);
+ return ret;
+}
+
+/*
+ * Have the TPM seal(encrypt) the symmetric key
+ */
+static int key_seal(struct trusted_key_payload *p,
+ struct trusted_key_options *o)
+{
+ struct tpm_buf *tb;
+ int ret;
+
+ tb = kzalloc(sizeof *tb, GFP_KERNEL);
+ if (!tb)
+ return -ENOMEM;
+
+ /* include migratable flag at end of sealed key */
+ p->key[p->key_len] = p->migratable;
+
+ ret = tpm_seal(tb, o->keytype, o->keyhandle, o->keyauth,
+ p->key, p->key_len + 1, p->blob, &p->blob_len,
+ o->blobauth, o->pcrinfo, o->pcrinfo_len);
+ if (ret < 0)
+ pr_info("trusted_key: srkseal failed (%d)\n", ret);
+
+ kfree(tb);
+ return ret;
+}
+
+/*
+ * Have the TPM unseal(decrypt) the symmetric key
+ */
+static int key_unseal(struct trusted_key_payload *p,
+ struct trusted_key_options *o)
+{
+ struct tpm_buf *tb;
+ int ret;
+
+ tb = kzalloc(sizeof *tb, GFP_KERNEL);
+ if (!tb)
+ return -ENOMEM;
+
+ ret = tpm_unseal(tb, o->keyhandle, o->keyauth, p->blob, p->blob_len,
+ o->blobauth, p->key, &p->key_len);
+ /* pull migratable flag out of sealed key */
+ p->migratable = p->key[--p->key_len];
+
+ if (ret < 0)
+ pr_info("trusted_key: srkunseal failed (%d)\n", ret);
+
+ kfree(tb);
+ return ret;
+}
+
+enum {
+ Opt_err = -1,
+ Opt_new, Opt_load, Opt_update,
+ Opt_keyhandle, Opt_keyauth, Opt_blobauth,
+ Opt_pcrinfo, Opt_pcrlock, Opt_migratable
+};
+
+static const match_table_t key_tokens = {
+ {Opt_new, "new"},
+ {Opt_load, "load"},
+ {Opt_update, "update"},
+ {Opt_keyhandle, "keyhandle=%s"},
+ {Opt_keyauth, "keyauth=%s"},
+ {Opt_blobauth, "blobauth=%s"},
+ {Opt_pcrinfo, "pcrinfo=%s"},
+ {Opt_pcrlock, "pcrlock=%s"},
+ {Opt_migratable, "migratable=%s"},
+ {Opt_err, NULL}
+};
+
+/* can have zero or more token= options */
+static int getoptions(char *c, struct trusted_key_payload *pay,
+ struct trusted_key_options *opt)
+{
+ substring_t args[MAX_OPT_ARGS];
+ char *p = c;
+ int token;
+ int res;
+ unsigned long handle;
+ unsigned long lock;
+
+ while ((p = strsep(&c, " \t"))) {
+ if (*p == '\0' || *p == ' ' || *p == '\t')
+ continue;
+ token = match_token(p, key_tokens, args);
+
+ switch (token) {
+ case Opt_pcrinfo:
+ opt->pcrinfo_len = strlen(args[0].from) / 2;
+ if (opt->pcrinfo_len > MAX_PCRINFO_SIZE)
+ return -EINVAL;
+ hex2bin(opt->pcrinfo, args[0].from, opt->pcrinfo_len);
+ break;
+ case Opt_keyhandle:
+ res = strict_strtoul(args[0].from, 16, &handle);
+ if (res < 0)
+ return -EINVAL;
+ opt->keytype = SEAL_keytype;
+ opt->keyhandle = handle;
+ break;
+ case Opt_keyauth:
+ if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
+ return -EINVAL;
+ hex2bin(opt->keyauth, args[0].from, SHA1_DIGEST_SIZE);
+ break;
+ case Opt_blobauth:
+ if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
+ return -EINVAL;
+ hex2bin(opt->blobauth, args[0].from, SHA1_DIGEST_SIZE);
+ break;
+ case Opt_migratable:
+ if (*args[0].from == '0')
+ pay->migratable = 0;
+ else
+ return -EINVAL;
+ break;
+ case Opt_pcrlock:
+ res = strict_strtoul(args[0].from, 10, &lock);
+ if (res < 0)
+ return -EINVAL;
+ opt->pcrlock = lock;
+ break;
+ default:
+ return -EINVAL;
+ }
+ }
+ return 0;
+}
+
+/*
+ * datablob_parse - parse the keyctl data and fill in the
+ * payload and options structures
+ *
+ * On success returns 0, otherwise -EINVAL.
+ */
+static int datablob_parse(char *datablob, struct trusted_key_payload *p,
+ struct trusted_key_options *o)
+{
+ substring_t args[MAX_OPT_ARGS];
+ long keylen;
+ int ret = -EINVAL;
+ int key_cmd;
+ char *c;
+
+ /* main command */
+ c = strsep(&datablob, " \t");
+ if (!c)
+ return -EINVAL;
+ key_cmd = match_token(c, key_tokens, args);
+ switch (key_cmd) {
+ case Opt_new:
+ /* first argument is key size */
+ c = strsep(&datablob, " \t");
+ if (!c)
+ return -EINVAL;
+ ret = strict_strtol(c, 10, &keylen);
+ if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE)
+ return -EINVAL;
+ p->key_len = keylen;
+ ret = getoptions(datablob, p, o);
+ if (ret < 0)
+ return ret;
+ ret = Opt_new;
+ break;
+ case Opt_load:
+ /* first argument is sealed blob */
+ c = strsep(&datablob, " \t");
+ if (!c)
+ return -EINVAL;
+ p->blob_len = strlen(c) / 2;
+ if (p->blob_len > MAX_BLOB_SIZE)
+ return -EINVAL;
+ hex2bin(p->blob, c, p->blob_len);
+ ret = getoptions(datablob, p, o);
+ if (ret < 0)
+ return ret;
+ ret = Opt_load;
+ break;
+ case Opt_update:
+ /* all arguments are options */
+ ret = getoptions(datablob, p, o);
+ if (ret < 0)
+ return ret;
+ ret = Opt_update;
+ break;
+ case Opt_err:
+ return -EINVAL;
+ break;
+ }
+ return ret;
+}
+
+static struct trusted_key_options *trusted_options_alloc(void)
+{
+ struct trusted_key_options *options;
+
+ options = kzalloc(sizeof *options, GFP_KERNEL);
+ if (!options)
+ return options;
+
+ /* set any non-zero defaults */
+ options->keytype = SRK_keytype;
+ options->keyhandle = SRKHANDLE;
+ return options;
+}
+
+static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
+{
+ struct trusted_key_payload *p = NULL;
+ int ret;
+
+ ret = key_payload_reserve(key, sizeof *p);
+ if (ret < 0)
+ return p;
+ p = kzalloc(sizeof *p, GFP_KERNEL);
+
+ /* migratable by default */
+ p->migratable = 1;
+ return p;
+}
+
+/*
+ * trusted_instantiate - create a new trusted key
+ *
+ * Unseal an existing trusted blob or, for a new key, get a
+ * random key, then seal and create a trusted key-type key,
+ * adding it to the specified keyring.
+ *
+ * On success, return 0. Otherwise return errno.
+ */
+static int trusted_instantiate(struct key *key, const void *data,
+ size_t datalen)
+{
+ struct trusted_key_payload *payload = NULL;
+ struct trusted_key_options *options = NULL;
+ char *datablob;
+ int ret = 0;
+ int key_cmd;
+
+ if (datalen <= 0 || datalen > 32767 || !data)
+ return -EINVAL;
+
+ datablob = kmalloc(datalen + 1, GFP_KERNEL);
+ if (!datablob)
+ return -ENOMEM;
+ memcpy(datablob, data, datalen);
+ *(datablob + datalen) = '\0';
+
+ options = trusted_options_alloc();
+ if (!options) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ payload = trusted_payload_alloc(key);
+ if (!payload) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ key_cmd = datablob_parse(datablob, payload, options);
+ if (key_cmd < 0) {
+ ret = key_cmd;
+ goto out;
+ }
+
+ dump_payload(payload);
+ dump_options(options);
+
+ switch (key_cmd) {
+ case Opt_load:
+ ret = key_unseal(payload, options);
+ if (ret < 0)
+ pr_info("trusted_key: key_unseal failed (%d)\n", ret);
+ break;
+ case Opt_new:
+ ret = my_get_random(payload->key, payload->key_len);
+ if (ret < 0) {
+ pr_info("trusted_key: key_create failed (%d)\n", ret);
+ goto out;
+ }
+ ret = key_seal(payload, options);
+ if (ret < 0)
+ pr_info("trusted_key: key_seal failed (%d)\n", ret);
+ break;
+ default:
+ ret = -EINVAL;
+ goto out;
+ }
+ if (!ret && options->pcrlock)
+ ret = pcrlock(options->pcrlock);
+out:
+ kfree(datablob);
+ kfree(options);
+ if (!ret)
+ rcu_assign_pointer(key->payload.data, payload);
+ else
+ kfree(payload);
+ return ret;
+}
+
+static void trusted_rcu_free(struct rcu_head *rcu)
+{
+ struct trusted_key_payload *p;
+
+ p = container_of(rcu, struct trusted_key_payload, rcu);
+ memset(p->key, 0, p->key_len);
+ kfree(p);
+}
+
+/*
+ * trusted_update - reseal an existing key with new PCR values
+ */
+static int trusted_update(struct key *key, const void *data, size_t datalen)
+{
+ struct trusted_key_payload *p = key->payload.data;
+ struct trusted_key_payload *new_p;
+ struct trusted_key_options *new_o;
+ char *datablob;
+ int ret = 0;
+
+ if (!p->migratable)
+ return -EPERM;
+ if (datalen <= 0 || datalen > 32767 || !data)
+ return -EINVAL;
+
+ datablob = kmalloc(datalen + 1, GFP_KERNEL);
+ if (!datablob)
+ return -ENOMEM;
+ new_o = trusted_options_alloc();
+ if (!new_o) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ new_p = trusted_payload_alloc(key);
+ if (!new_p) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ memcpy(datablob, data, datalen);
+ *(datablob + datalen) = '\0';
+ ret = datablob_parse(datablob, new_p, new_o);
+ if (ret != Opt_update) {
+ ret = -EINVAL;
+ goto out;
+ }
+ /* copy old key values, and reseal with new pcrs */
+ new_p->migratable = p->migratable;
+ new_p->key_len = p->key_len;
+ memcpy(new_p->key, p->key, p->key_len);
+ dump_payload(p);
+ dump_payload(new_p);
+
+ ret = key_seal(new_p, new_o);
+ if (ret < 0) {
+ pr_info("trusted_key: key_seal failed (%d)\n", ret);
+ kfree(new_p);
+ goto out;
+ }
+ if (new_o->pcrlock)
+ ret = pcrlock(new_o->pcrlock);
+ rcu_assign_pointer(key->payload.data, new_p);
+ call_rcu(&p->rcu, trusted_rcu_free);
+out:
+ kfree(datablob);
+ if (new_o)
+ kfree(new_o);
+ return ret;
+}
+
+/*
+ * trusted_read - copy the sealed blob data to userspace in hex.
+ * On success, return to userspace the trusted key datablob size.
+ */
+static long trusted_read(const struct key *key, char __user *buffer,
+ size_t buflen)
+{
+ struct trusted_key_payload *p;
+ char *ascii_buf;
+ char *bufp;
+ int i;
+
+ p = rcu_dereference_protected(key->payload.data,
+ rwsem_is_locked(&((struct key *)key)->sem));
+ if (!p)
+ return -EINVAL;
+ if (!buffer || buflen <= 0)
+ return 2 * p->blob_len;
+ ascii_buf = kmalloc(2 * p->blob_len, GFP_KERNEL);
+ if (!ascii_buf)
+ return -ENOMEM;
+
+ bufp = ascii_buf;
+ for (i = 0; i < p->blob_len; i++)
+ bufp = pack_hex_byte(bufp, p->blob[i]);
+ if ((copy_to_user(buffer, ascii_buf, 2 * p->blob_len)) != 0) {
+ kfree(ascii_buf);
+ return -EFAULT;
+ }
+ kfree(ascii_buf);
+ return 2 * p->blob_len;
+}
+
+/*
+ * trusted_destroy - before freeing the key, clear the decrypted data
+ */
+static void trusted_destroy(struct key *key)
+{
+ struct trusted_key_payload *p = key->payload.data;
+
+ if (!p)
+ return;
+ memset(p->key, 0, p->key_len);
+ kfree(key->payload.data);
+}
+
+struct key_type key_type_trusted = {
+ .name = "trusted",
+ .instantiate = trusted_instantiate,
+ .update = trusted_update,
+ .match = user_match,
+ .destroy = trusted_destroy,
+ .describe = user_describe,
+ .read = trusted_read,
+};
+
+EXPORT_SYMBOL_GPL(key_type_trusted);
+
+static void trusted_shash_release(void)
+{
+ if (hashalg)
+ crypto_free_shash(hashalg);
+ if (hmacalg)
+ crypto_free_shash(hmacalg);
+}
+
+static int __init trusted_shash_alloc(void)
+{
+ int ret;
+
+ hmacalg = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(hmacalg)) {
+ pr_info("trusted_key: could not allocate crypto %s\n",
+ hmac_alg);
+ return PTR_ERR(hmacalg);
+ }
+
+ hashalg = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(hashalg)) {
+ pr_info("trusted_key: could not allocate crypto %s\n",
+ hash_alg);
+ ret = PTR_ERR(hashalg);
+ goto hashalg_fail;
+ }
+
+ return 0;
+
+hashalg_fail:
+ crypto_free_shash(hmacalg);
+ return ret;
+}
+
+static int __init init_trusted(void)
+{
+ int ret;
+
+ ret = trusted_shash_alloc();
+ if (ret < 0)
+ return ret;
+ ret = register_key_type(&key_type_trusted);
+ if (ret < 0)
+ trusted_shash_release();
+ return ret;
+}
+
+static void __exit cleanup_trusted(void)
+{
+ trusted_shash_release();
+ unregister_key_type(&key_type_trusted);
+}
+
+late_initcall(init_trusted);
+module_exit(cleanup_trusted);
+
+MODULE_LICENSE("GPL");
diff --git a/security/keys/trusted_defined.h b/security/keys/trusted_defined.h
new file mode 100644
index 0000000..e0afbf2
--- /dev/null
+++ b/security/keys/trusted_defined.h
@@ -0,0 +1,147 @@
+#ifndef __TRUSTED_KEY_H
+#define __TRUSTED_KEY_H
+
+/* not already defined in tpm.h - specific to this use */
+#define TPM_TAG_RQU_COMMAND 193
+#define TPM_TAG_RQU_AUTH1_COMMAND 194
+#define TPM_TAG_RQU_AUTH2_COMMAND 195
+#define TPM_TAG_RSP_COMMAND 196
+#define TPM_TAG_RSP_AUTH1_COMMAND 197
+#define TPM_TAG_RSP_AUTH2_COMMAND 198
+#define TPM_NONCE_SIZE 20
+#define TPM_GETRANDOM_SIZE 14
+#define TPM_GETRANDOM_RETURN 14
+#define TPM_ORD_GETRANDOM 70
+#define TPM_OSAP_SIZE 36
+#define TPM_ORD_OSAP 11
+#define TPM_OIAP_SIZE 10
+#define TPM_ORD_OIAP 10
+#define TPM_SEAL_SIZE 87
+#define TPM_ORD_SEAL 23
+#define TPM_ORD_UNSEAL 24
+#define TPM_UNSEAL_SIZE 104
+#define MAX_PCRINFO_SIZE 64
+#define MAX_BUF_SIZE 512
+#define TPM_SIZE_OFFSET 2
+#define TPM_RETURN_OFFSET 6
+#define TPM_DATA_OFFSET 10
+#define SRKHANDLE 0x40000000
+
+#define LOAD32(buffer, offset) (ntohl(*(uint32_t *)&buffer[offset]))
+#define LOAD32N(buffer, offset) (*(uint32_t *)&buffer[offset])
+#define LOAD16(buffer, offset) (ntohs(*(uint16_t *)&buffer[offset]))
+
+struct tpm_buf {
+ int len;
+ unsigned char data[MAX_BUF_SIZE];
+};
+
+#define INIT_BUF(tb) (tb->len = 0)
+
+struct osapsess {
+ uint32_t handle;
+ unsigned char secret[SHA1_DIGEST_SIZE];
+ unsigned char enonce[TPM_NONCE_SIZE];
+};
+
+/* discrete values, but have to store in uint16_t for TPM use */
+enum {
+ SEAL_keytype = 1,
+ SRK_keytype = 4
+};
+
+struct trusted_key_options {
+ uint16_t keytype;
+ uint32_t keyhandle;
+ unsigned char keyauth[SHA1_DIGEST_SIZE];
+ unsigned char blobauth[SHA1_DIGEST_SIZE];
+ uint32_t pcrinfo_len;
+ unsigned char pcrinfo[MAX_PCRINFO_SIZE];
+ int pcrlock;
+};
+
+#define TPM_DEBUG 0
+
+#if TPM_DEBUG
+static inline void dump_options(struct trusted_key_options *o)
+{
+ pr_info("trusted_key: sealing key type %d\n", o->keytype);
+ pr_info("trusted_key: sealing key handle %0X\n", o->keyhandle);
+ pr_info("trusted_key: pcrlock %d\n", o->pcrlock);
+ pr_info("trusted_key: pcrinfo %d\n", o->pcrinfo_len);
+ print_hex_dump(KERN_INFO, "pcrinfo ", DUMP_PREFIX_NONE,
+ 16, 1, o->pcrinfo, o->pcrinfo_len, 0);
+}
+
+static inline void dump_payload(struct trusted_key_payload *p)
+{
+ pr_info("trusted_key: key_len %d\n", p->key_len);
+ print_hex_dump(KERN_INFO, "key ", DUMP_PREFIX_NONE,
+ 16, 1, p->key, p->key_len, 0);
+ pr_info("trusted_key: bloblen %d\n", p->blob_len);
+ print_hex_dump(KERN_INFO, "blob ", DUMP_PREFIX_NONE,
+ 16, 1, p->blob, p->blob_len, 0);
+ pr_info("trusted_key: migratable %d\n", p->migratable);
+}
+
+static inline void dump_sess(struct osapsess *s)
+{
+ print_hex_dump(KERN_INFO, "trusted-key: handle ", DUMP_PREFIX_NONE,
+ 16, 1, &s->handle, 4, 0);
+ pr_info("trusted-key: secret:\n");
+ print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE,
+ 16, 1, &s->secret, SHA1_DIGEST_SIZE, 0);
+ pr_info("trusted-key: enonce:\n");
+ print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE,
+ 16, 1, &s->enonce, SHA1_DIGEST_SIZE, 0);
+}
+
+static inline void dump_tpm_buf(unsigned char *buf)
+{
+ int len;
+
+ pr_info("\ntrusted-key: tpm buffer\n");
+ len = LOAD32(buf, TPM_SIZE_OFFSET);
+ print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1, buf, len, 0);
+}
+#else
+static inline void dump_options(struct trusted_key_options *o)
+{
+}
+
+static inline void dump_payload(struct trusted_key_payload *p)
+{
+}
+
+static inline void dump_sess(struct osapsess *s)
+{
+}
+
+static inline void dump_tpm_buf(unsigned char *buf)
+{
+}
+#endif
+
+static inline void store8(struct tpm_buf *buf, unsigned char value)
+{
+ buf->data[buf->len++] = value;
+}
+
+static inline void store16(struct tpm_buf *buf, uint16_t value)
+{
+ *(uint16_t *) & buf->data[buf->len] = htons(value);
+ buf->len += sizeof value;
+}
+
+static inline void store32(struct tpm_buf *buf, uint32_t value)
+{
+ *(uint32_t *) & buf->data[buf->len] = htonl(value);
+ buf->len += sizeof value;
+}
+
+static inline void storebytes(struct tpm_buf *buf, unsigned char *in, int len)
+{
+ memcpy(buf->data + buf->len, in, len);
+ buf->len += len;
+}
+#endif
--
1.7.2.2

2010-11-19 15:43:03

by David Howells

[permalink] [raw]
Subject: Re: [PATCH v1.4 1/5] lib: hex2bin converts ascii hexadecimal string to binary

Mimi Zohar <[email protected]> wrote:

> Similar to the kgdb_hex2mem() code, hex2bin converts a string
> to binary using the hex_to_bin() library call.
>
> Changelog:
> - Replace parameter names with src/dst (based on David Howell's comment)
> - Add 'const' where needed (based on David Howell's comment)
> - Replace int with size_t (based on David Howell's comment)
>
> Signed-off-by: Mimi Zohar <[email protected]>
> Acked-by: Serge E. Hallyn <[email protected]>

Acked-by: David Howells <[email protected]>

2010-11-19 15:43:46

by David Howells

[permalink] [raw]
Subject: Re: [PATCH v1.4 2/5] tpm: add module_put wrapper

Mimi Zohar <[email protected]> wrote:

> For readability, define a tpm_chip_put() wrapper to call module_put().
> Replace existing module_put() calls with the wrapper.
>
> (Change based on trusted/encrypted patchset review by David Howells.)
>
> Signed-off-by: Mimi Zohar <[email protected]>
> Signed-off-by: David Safford <[email protected]>

Acked-by: David Howells <[email protected]>

2010-11-19 15:45:48

by David Howells

[permalink] [raw]
Subject: Re: [PATCH v1.4 3/5] key: add tpm_send command

Mimi Zohar <[email protected]> wrote:

> +int tpm_send(u32 chip_num, void *cmd, int buflen)

I'd recommend size_t for buflen; apart from that:

Acked-by: David Howells <[email protected]>

2010-11-19 16:05:27

by David Safford

[permalink] [raw]
Subject: Re: [PATCH v1.4 3/5] key: add tpm_send command

On Fri, 2010-11-19 at 15:45 +0000, David Howells wrote:
> Mimi Zohar <[email protected]> wrote:
>
> > +int tpm_send(u32 chip_num, void *cmd, int buflen)
>
> I'd recommend size_t for buflen; apart from that:
>
> Acked-by: David Howells <[email protected]>

right - that would be better.

Currently transmit_command() in tpm.c expects an int,
but it changes it to size_t for the actual tpm_transmit().
We will work with Rajiv to do a cleanup, as this touches
a number of calls.

thanks!
dave

2010-11-19 16:23:44

by David Howells

[permalink] [raw]
Subject: Re: [PATCH v1.4 4/5] keys: add new trusted key-type

Mimi Zohar <[email protected]> wrote:

> +keyctl print returns an ascii hex copy of the sealed key, which is in standard

I'd quote 'keyctl print' just so it's obvious where the command ends and the
descriptive text starts.

> +Usage:
> + keyctl add encrypted name "new key-type:master-key-name keylen" ring
> + keyctl add encrypted name "load key-type:master-key-name keylen hex_blob" ring
> + keyctl update keyid "update key-type:master-key-name"
> +
> +where 'key-type' is either 'trusted' or 'user'.

I recommend adding some example commands with all the arguments substituted.
Nothing helps get to grip with an API like knowing what a command is supposed
to look like when it's actually used.

> +static int trusted_tpm_send(u32 chip_num, unsigned char *cmd, int buflen)

There are still a lot of places in here where you should probably be using
const and size_t.

> +static int my_get_random(unsigned char *buf, int len)
> +{
> + struct tpm_buf *tb;
> + int ret;
> +
> + tb = kzalloc(sizeof *tb, GFP_KERNEL);
> + if (!tb)
> + return -ENOMEM;
> + ret = tpm_get_random(tb, buf, len);

Using kzalloc() rather than kmalloc() is a waste of time, I'd've thought.
It's a temporary buffer. Does it really need to be precleared?

> + ret = tpm_pcr_extend(TPM_ANY_NUM, pcrnum, hash);
> + return ret;

Merge.

> +static int trusted_update(struct key *key, const void *data, size_t datalen)
> +{
> ...
> + *(datablob + datalen) = '\0';

That's what [] is for.

> + if (new_o)
> + kfree(new_o);

kfree() can handle a NULL pointer.

> + if (new_o->pcrlock)
> + ret = pcrlock(new_o->pcrlock);
> + rcu_assign_pointer(key->payload.data, new_p);
> + call_rcu(&p->rcu, trusted_rcu_free);

Should there be a check for pcrlock() failure?

> +/* not already defined in tpm.h - specific to this use */
> +#define TPM_TAG_RQU_COMMAND 193
> +#define TPM_TAG_RQU_AUTH1_COMMAND 194
> ...

Values defined for TPM hardware access really ought to be in a separate file
in include/linux/. They aren't strictly specific to the trusted key
implementation here; that may be the only user currently in the kernel, but
that doesn't mean there can't be another user.

David

2010-11-19 16:43:20

by David Howells

[permalink] [raw]
Subject: Re: [PATCH v1.4 5/5] keys: add new key-type encrypted

Mimi Zohar <[email protected]> wrote:

> +static int datablob_format(char __user *buffer,
> + struct encrypted_key_payload *epayload,
> + int asciiblob_len)

size_t? There are other instances where you should be using size_t too.

> + index = strcspn(epayload->master_desc, ":");
> + if (index == strlen(epayload->master_desc))
> + goto out;

For single chars, use strchr() rather than strcspn(), and if you happen to
know the length too, use memchr(). This also means you don't need to do the
strlen() again to check the result.

> + memset(derived_key, 0, sizeof derived_key);
> + ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen)

Is the memset() actually necessary?

> + decrypted_datalen = (unsigned short)dlen;

Unnecessary cast.

> + *(datablob + datalen) = 0;
> + *(buf + datalen) = 0;

Use [].

> + if (index == strlen(new_master_desc)
> + || (strncmp(new_master_desc, epayload->master_desc, index) != 0)) {

Superfluous brackets.

Mimi Zohar <[email protected]> wrote:

> + mkey = request_master_key(epayload, &master_key, &master_keylen);
> + if (IS_ERR(mkey))
> + return PTR_ERR(mkey);
> +
> + memset(derived_key, 0, sizeof derived_key);
> + ret = get_derived_key(derived_key, ENC_KEY, master_key, master_keylen);
> + if (ret < 0)
> + goto out;
> +
> + ret = derived_key_encrypt(epayload, derived_key, sizeof derived_key);
> + if (ret < 0)
> + goto out;
> +
> + ret = datablob_hmac_append(epayload, master_key, master_keylen);
> + if (ret < 0)
> + goto out;
> +
> + ret = datablob_format(buffer, epayload, asciiblob_len);
> + if (ret < 0)
> + goto out;
> +
> + rcu_read_unlock();

NAK! This is not safe. You may not sleep whilst you hold the RCU read lock
on the master key. At the very least, datablob_format() may sleep as it
writes to userspace.

I think what you should do is ignore RCU entirely and read lock the master
key's semaphore.

> + ret = aes_get_sizes();
> + return ret;

Merge.

David

2010-11-19 16:45:44

by David Howells

[permalink] [raw]
Subject: Re: [PATCH v1.4 3/5] key: add tpm_send command

David Safford <[email protected]> wrote:

> Currently transmit_command() in tpm.c expects an int,
> but it changes it to size_t for the actual tpm_transmit().
> We will work with Rajiv to do a cleanup, as this touches
> a number of calls.

You can pass a size_t value to an int. The compiler will cast automatically.

David

2010-11-19 18:00:45

by David Safford

[permalink] [raw]
Subject: Re: [PATCH v1.4 4/5] keys: add new trusted key-type

On Fri, 2010-11-19 at 16:23 +0000, David Howells wrote:
> Mimi Zohar <[email protected]> wrote:

thanks for the review! - getting closer...

> > +keyctl print returns an ascii hex copy of the sealed key, which is in standard
>
> I'd quote 'keyctl print' just so it's obvious where the command ends and the
> descriptive text starts.

ok

> > +Usage:
> > + keyctl add encrypted name "new key-type:master-key-name keylen" ring
> > + keyctl add encrypted name "load key-type:master-key-name keylen hex_blob" ring
> > + keyctl update keyid "update key-type:master-key-name"
> > +
> > +where 'key-type' is either 'trusted' or 'user'.
>
> I recommend adding some example commands with all the arguments substituted.
> Nothing helps get to grip with an API like knowing what a command is supposed
> to look like when it's actually used.

now that this is moved to documentation, you are right, more examples
would be nice... willdo.

> > +static int trusted_tpm_send(u32 chip_num, unsigned char *cmd, int buflen)
>
> There are still a lot of places in here where you should probably be using
> const and size_t.

will clean up.

> > +static int my_get_random(unsigned char *buf, int len)
> > +{
> > + struct tpm_buf *tb;
> > + int ret;
> > +
> > + tb = kzalloc(sizeof *tb, GFP_KERNEL);
> > + if (!tb)
> > + return -ENOMEM;
> > + ret = tpm_get_random(tb, buf, len);
>
> Using kzalloc() rather than kmalloc() is a waste of time, I'd've thought.
> It's a temporary buffer. Does it really need to be precleared?

In this case, none need to be precleared. Will fix.

> > + ret = tpm_pcr_extend(TPM_ANY_NUM, pcrnum, hash);
> > + return ret;
>
> Merge.

agreed

> > +static int trusted_update(struct key *key, const void *data, size_t datalen)
> > +{
> > ...
> > + *(datablob + datalen) = '\0';
>
> That's what [] is for.

agreed.

> > + if (new_o)
> > + kfree(new_o);
>
> kfree() can handle a NULL pointer.

agreed.

> > + if (new_o->pcrlock)
> > + ret = pcrlock(new_o->pcrlock);
> > + rcu_assign_pointer(key->payload.data, new_p);
> > + call_rcu(&p->rcu, trusted_rcu_free);
>
> Should there be a check for pcrlock() failure?

yes, because if the pcrlock failed, even though the key
was successfully created, it is not safe to use.
Will correct.

> > +/* not already defined in tpm.h - specific to this use */
> > +#define TPM_TAG_RQU_COMMAND 193
> > +#define TPM_TAG_RQU_AUTH1_COMMAND 194
> > ...
>
> Values defined for TPM hardware access really ought to be in a separate file
> in include/linux/. They aren't strictly specific to the trusted key
> implementation here; that may be the only user currently in the kernel, but
> that doesn't mean there can't be another user.

Currently tpm request packet defines are private to the tpm driver.
With the opening of a tpm_send() interface, perhaps it does make
sense for an include/linux/tpm_packet.h for everyone (including tpm.c)
to use, even though there is little overlap currently.

We could create that with these current defines to start,
and then do a cleanup patch for tpm.c to take advantage.

dave

2010-11-22 12:16:07

by Mimi Zohar

[permalink] [raw]
Subject: Re: [PATCH v1.4 5/5] keys: add new key-type encrypted

On Fri, 2010-11-19 at 16:43 +0000, David Howells wrote:
> Mimi Zohar <[email protected]> wrote:
>
> > +static int datablob_format(char __user *buffer,
> > + struct encrypted_key_payload *epayload,
> > + int asciiblob_len)
>
> size_t? There are other instances where you should be using size_t too.

Most of the crypto library calls use "unsigned int". Obviously didn't
quite get everything else. Will look again. thanks.

> > + index = strcspn(epayload->master_desc, ":");
> > + if (index == strlen(epayload->master_desc))
> > + goto out;
>
> For single chars, use strchr() rather than strcspn(), and if you happen to
> know the length too, use memchr(). This also means you don't need to do the
> strlen() again to check the result.

Don't have the length, but getting it once and then using strchr/memchr,
should work. thanks.

> > + memset(derived_key, 0, sizeof derived_key);
> > + ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen)
>
> Is the memset() actually necessary?

not sure, will check.

> > + decrypted_datalen = (unsigned short)dlen;
>
> Unnecessary cast.

ok

> > + *(datablob + datalen) = 0;
> > + *(buf + datalen) = 0;
>
> Use [].

> > + if (index == strlen(new_master_desc)
> > + || (strncmp(new_master_desc, epayload->master_desc, index) != 0)) {
>
> Superfluous brackets.
>
> Mimi Zohar <[email protected]> wrote:
>
> > + mkey = request_master_key(epayload, &master_key, &master_keylen);
> > + if (IS_ERR(mkey))
> > + return PTR_ERR(mkey);
> > +
> > + memset(derived_key, 0, sizeof derived_key);
> > + ret = get_derived_key(derived_key, ENC_KEY, master_key, master_keylen);
> > + if (ret < 0)
> > + goto out;
> > +
> > + ret = derived_key_encrypt(epayload, derived_key, sizeof derived_key);
> > + if (ret < 0)
> > + goto out;
> > +
> > + ret = datablob_hmac_append(epayload, master_key, master_keylen);
> > + if (ret < 0)
> > + goto out;
> > +
> > + ret = datablob_format(buffer, epayload, asciiblob_len);
> > + if (ret < 0)
> > + goto out;
> > +
> > + rcu_read_unlock();
>
> NAK! This is not safe. You may not sleep whilst you hold the RCU read lock
> on the master key. At the very least, datablob_format() may sleep as it
> writes to userspace.

datablob_format() could be split up into formatting the string returned
to userspace and copying it userspace, releasing the lock before copying
it, but that wouldn't resolve the other places it may sleep, like alloc.

> I think what you should do is ignore RCU entirely and read lock the master
> key's semaphore.

thanks, will do.

> > + ret = aes_get_sizes();
> > + return ret;
>
> Merge.
>
> David

ok

thanks,

Mimi