Message-Id: <1286484734-3119-5-git-send-email-zohar@linux.vnet.ibm.com>
Date:	Thu,  7 Oct 2010 16:52:14 -0400
From:	Mimi Zohar <zohar@...ux.vnet.ibm.com>
To:	linux-kernel@...r.kernel.org
Cc:	Mimi Zohar <zohar@...ux.vnet.ibm.com>,
	linux-security-module@...r.kernel.org, keyrings@...ux-nfs.org,
	linux-crypto@...r.kernel.org, David Howells <dhowells@...hat.com>,
	James Morris <jmorris@...ei.org>,
	David Safford <safford@...son.ibm.com>,
	Rajiv Andrade <srajiv@...ux.vnet.ibm.com>,
	Mimi Zohar <zohar@...ibm.com>
Subject: [PATCH v1 4/4] keys: add new key-type encrypted

Defines 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:
- wait until late_initcall for crypto libraries to be registered
- cleanup security/Kconfig

Signed-off-by: Mimi Zohar <zohar@...ibm.com>
Signed-off-by: David Safford <safford@...son.ibm.com>
---
 include/keys/encrypted-type.h     |   30 ++
 security/Kconfig                  |   16 +
 security/keys/Makefile            |    1 +
 security/keys/encrypted_defined.c |  782 +++++++++++++++++++++++++++++++++++++
 security/keys/encrypted_defined.h |   52 +++
 5 files changed, 881 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..e2312e0
--- /dev/null
+++ b/include/keys/encrypted-type.h
@@ -0,0 +1,30 @@
+/* encrypted-type.h: encrypted-defined key type
+ *
+ * Copyright (C) 2010 IBM Corporation
+ * Author: Mimi Zohar <zohar@...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_ENCRYPTED_TYPE_H
+#define _KEYS_ENCRYPTED_TYPE_H
+
+#include <linux/key.h>
+#include <linux/rcupdate.h>
+
+struct encrypted_key_payload {
+	struct rcu_head rcu;	/* RCU destructor */
+	char *master_desc;	/* datablob: master key name */
+	char *datalen;		/* datablob: decrypted key length */
+	void *iv;		/* datablob: iv */
+	void *encrypted_data;	/* datablob: encrypted key */
+	unsigned short datablob_len;	/* length of datablob */
+	unsigned short decrypted_datalen;	/* decrypted data length */
+	char 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 38fdaf6..d591398 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..68fff82
--- /dev/null
+++ b/security/keys/encrypted_defined.c
@@ -0,0 +1,782 @@
+/*
+ * Copyright (C) 2010 IBM Corporation
+ *
+ * Author:
+ * Mimi Zohar <zohar@...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.
+ *
+ * File: encrypted_defined.c
+ *
+ * Defines a new kernel key-type called 'encrypted'. Encrypted keys
+ * are kernel generated random numbers, which are encrypted/decrypted
+ * using a 'master' key. The 'master' key can either be a trusted-key or
+ * user-key type. Encrypted keys are created/encrypted/decrypted in the
+ * kernel. Userspace ever only sees/stores encrypted blobs.
+ *
+ * keyctl add "encrypted" "name" "NEW master-key-name keylen" ring
+ * keyctl add "encrypted" "name" "LOAD master-key-name keylen hex_blob" ring
+ * keyctl update keyid "UPDATE master-key-name"
+ */
+
+#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/sha.h>
+#include <crypto/aes.h>
+
+#include "encrypted_defined.h"
+
+static char hash_alg[] = "sha256";
+static char hmac_alg[] = "hmac(sha256)";
+static int hash_size = SHA256_DIGEST_SIZE;
+static char blkcipher_alg[] = "cbc(aes)";
+static int ivsize;
+static int blksize;
+
+static int aes_get_sizes(int *ivsize, int *blksize)
+{
+	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 = 1, Opt_load, Opt_NEW, Opt_LOAD
+};
+
+static match_table_t key_tokens = {
+	{Opt_new, "new"},
+	{Opt_NEW, "NEW"},
+	{Opt_load, "load"},
+	{Opt_LOAD, "LOAD"},
+	{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>
+ *
+ * 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;
+	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;
+	*decrypted_datalen = strsep(&datablob, " \t");
+	if (!*decrypted_datalen)
+		goto out;
+
+	switch (key_cmd) {
+	case Opt_new:
+	case Opt_NEW:
+		ret = 0;
+		break;
+	case Opt_load:
+	case Opt_LOAD:
+		*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_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;
+	char *iv = (char *)epayload->iv;
+	int ret = 0;
+	int len;
+	int i;
+
+	ascii_buf = kzalloc(asciiblob_len + 1, GFP_KERNEL);
+	if (!ascii_buf)
+		return -ENOMEM;
+
+	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(char *trusted_desc, void **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;
+
+	tpayload = 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(char *master_desc, void **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;
+
+	upayload = ukey->payload.data;
+	*master_key = upayload->data;
+	*master_keylen = (unsigned int)upayload->datalen;
+error:
+	return ukey;
+}
+
+static int init_desc(struct hash_desc *desc, char *alg)
+{
+	int ret;
+
+	desc->tfm = crypto_alloc_hash(alg, 0, CRYPTO_ALG_ASYNC);
+	if (IS_ERR(desc->tfm)) {
+		pr_info("encrypted_key: failed to load %s transform: %ld\n",
+			alg, PTR_ERR(desc->tfm));
+		ret = PTR_ERR(desc->tfm);
+		return ret;
+	}
+	desc->flags = 0;
+	ret = crypto_hash_init(desc);
+	if (ret)
+		crypto_free_hash(desc->tfm);
+	return ret;
+}
+
+static int calc_hmac(char *digest, char *key, int keylen,
+		     char *buf, size_t buflen)
+{
+	struct hash_desc desc;
+	struct scatterlist sg[1];
+	int ret;
+
+	ret = init_desc(&desc, hmac_alg);
+	if (ret)
+		return ret;
+
+	crypto_hash_setkey(desc.tfm, key, keylen);
+	ret = crypto_hash_init(&desc);
+	if (ret)
+		goto out;
+
+	sg_init_one(sg, buf, buflen);
+	ret = crypto_hash_update(&desc, sg, buflen);
+	if (!ret)
+		ret = crypto_hash_final(&desc, digest);
+out:
+	crypto_free_hash(desc.tfm);
+	return ret;
+}
+
+static int calc_hash(char *digest, void *buf, int buflen)
+{
+	struct hash_desc desc;
+	struct scatterlist sg[1];
+	int ret;
+
+	ret = init_desc(&desc, hash_alg);
+	if (ret)
+		return ret;
+
+	sg_init_one(sg, buf, buflen);
+	ret = crypto_hash_update(&desc, sg, buflen);
+	if (!ret)
+		ret = crypto_hash_final(&desc, digest);
+	crypto_free_hash(desc.tfm);
+	return ret;
+}
+
+enum derived_key_type { ENC_KEY, AUTH_KEY };
+
+/* Derive authentication/encryption key from trusted key */
+static int get_derived_key(char *derived_key, enum derived_key_type key_type,
+			   void *master_key, unsigned int master_keylen)
+{
+	char derived_buf[hash_size + 10];
+	int ret;
+
+	memset(derived_buf, 0, sizeof derived_buf);
+	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, sizeof derived_buf);
+	return ret;
+}
+
+static int init_blkcipher_desc(struct blkcipher_desc *desc, const void *key,
+			       unsigned int key_len, void *iv, 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) {
+		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,
+				      void **master_key,
+				      unsigned int *master_keylen)
+{
+	struct key *mkey;
+
+	mkey = request_trusted_key(epayload->master_desc,
+				   master_key, master_keylen);
+	if (IS_ERR(mkey)) {
+		mkey = request_user_key(epayload->master_desc,
+					master_key, master_keylen);
+		if (IS_ERR(mkey)) {
+			pr_info("encrypted_key: trusted/user key %s not found",
+				epayload->master_desc);
+			return mkey;
+		}
+	}
+	dump_master_key(*master_key, *master_keylen);
+	return mkey;
+}
+
+/* Before returning data to userspace, encrypt decrypted data. */
+static int derived_key_encrypt(struct encrypted_key_payload *epayload,
+			       void *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)
+		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)
+		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,
+				void *master_key, unsigned int master_keylen)
+{
+	char derived_key[hash_size];
+	char *digest;
+	int ret;
+
+	memset(derived_key, 0, sizeof derived_key);
+	ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen);
+	if (ret)
+		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,
+				void *master_key, unsigned int master_keylen)
+{
+	char derived_key[hash_size];
+	char 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)
+		goto out;
+
+	memset(digest, 0, sizeof digest);
+	ret = calc_hmac(digest, derived_key, sizeof derived_key,
+			epayload->master_desc, epayload->datablob_len);
+	if (ret)
+		goto out;
+	ret = memcmp(digest, epayload->master_desc + epayload->datablob_len,
+		     sizeof digest);
+	if (ret) {
+		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,
+			       void *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)
+		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)
+		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;
+	size_t encrypted_datalen;
+	long dlen;
+	int ret;
+
+	ret = strict_strtol(datalen, 10, &dlen);
+	if (ret < 0 || dlen < 20 || dlen > hash_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,
+				 char *hex_encoded_iv, char *hex_encoded_data)
+{
+	char derived_key[hash_size];
+	struct key *mkey;
+	void *master_key;
+	unsigned int master_keylen;
+	size_t encrypted_datalen;
+	char *hmac;
+	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) {
+		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)
+		goto out;
+
+	ret = derived_key_decrypt(epayload, derived_key, sizeof derived_key);
+	if (ret)
+		pr_err("encrypted_key: failed to decrypt key (%d)\n", ret);
+out:
+	key_put(mkey);
+	return ret;
+}
+
+static void __ekey_init(struct encrypted_key_payload *epayload,
+			char *master_desc, 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,
+			  char *master_desc, char *datalen,
+			  char *hex_encoded_iv, 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 = kzalloc(datalen + 1, GFP_KERNEL);
+	if (!datablob)
+		return -ENOMEM;
+
+	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);
+	rcu_assign_pointer(key->payload.data, epayload);
+out:
+	kfree(datablob);
+	return ret > 0 ? -EINVAL : 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;
+	int ret = 0;
+
+	if (datalen <= 0 || datalen > 32767 || !data)
+		return -EINVAL;
+
+	buf = kzalloc(datalen + 1, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	memcpy(buf, data, datalen);
+	new_master_desc = strsep(&buf, " \t");
+	if (!*new_master_desc) {
+		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;
+	void *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)
+		goto out;
+
+	ret = derived_key_encrypt(epayload, derived_key, sizeof derived_key);
+	if (ret)
+		goto out;
+
+	ret = datablob_hmac_append(epayload, master_key, master_keylen);
+	if (ret)
+		goto out;
+
+	ret = datablob_format(buffer, epayload, asciiblob_len);
+	if (ret < 0)
+		goto out;
+
+	key_put(mkey);
+	return asciiblob_len;
+out:
+	key_put(mkey);
+	return ret > 0 ? -EINVAL : 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 int __init init_encrypted(void)
+{
+	int ret;
+
+	ret = register_key_type(&key_type_encrypted);
+	if (ret < 0)
+		return ret;
+	ret = aes_get_sizes(&ivsize, &blksize);
+	return ret;
+}
+
+static void __exit cleanup_encrypted(void)
+{
+	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..4e0b6e5
--- /dev/null
+++ b/security/keys/encrypted_defined.h
@@ -0,0 +1,52 @@
+#ifndef __ENCRYPTED_KEY_H
+#define __ENCRYPTED_KEY_H
+
+#define ENCRYPTED_DEBUG 0
+
+#if ENCRYPTED_DEBUG
+static inline void dump_master_key(void *master_key, unsigned int master_keylen)
+{
+	print_hex_dump(KERN_ERR, "master key: ", DUMP_PREFIX_NONE, 32, 1,
+		       master_key, (size_t) 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, (size_t) encrypted_datalen, 0);
+}
+
+static inline void dump_hmac(char *str, void *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,
+		       (size_t) hmac_size, 0);
+}
+#else
+static inline void dump_master_key(void *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(char *str, void *digest, int hmac_size)
+{
+}
+#endif
+#endif
-- 
1.7.2.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists