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@xxxxxxxxxx>
Signed-off-by: David Safford <safford@xxxxxxxxxxxxxx>
---
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@xxxxxxxxxx>
+ *
+ * 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@xxxxxxxxxx>
+ *
+ * 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
--
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