From: Mimi Zohar Subject: [PATCH v1.1 4/4] keys: add new key-type encrypted Date: Mon, 11 Oct 2010 16:11:43 -0400 Message-ID: <1286827903-3066-5-git-send-email-zohar@linux.vnet.ibm.com> References: <1286827903-3066-1-git-send-email-zohar@linux.vnet.ibm.com> Cc: Mimi Zohar , linux-security-module@vger.kernel.org, keyrings@linux-nfs.org, linux-crypto@vger.kernel.org, David Howells , James Morris , David Safford , Rajiv Andrade , Mimi Zohar To: linux-kernel@vger.kernel.org Return-path: In-Reply-To: <1286827903-3066-1-git-send-email-zohar@linux.vnet.ibm.com> Sender: linux-security-module-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org 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 - 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. Signed-off-by: Mimi Zohar Signed-off-by: David Safford Reviewed-by: Roberto Sassu --- include/keys/encrypted-type.h | 30 ++ security/Kconfig | 16 + security/keys/Makefile | 1 + security/keys/encrypted_defined.c | 804 +++++++++++++++++++++++++++++++++++++ security/keys/encrypted_defined.h | 52 +++ 5 files changed, 903 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 + * + * 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 +#include + +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..5331925 --- /dev/null +++ b/security/keys/encrypted_defined.c @@ -0,0 +1,804 @@ +/* + * Copyright (C) 2010 IBM Corporation + * + * Author: + * Mimi Zohar + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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 MAX_DATA_SIZE = 4096; +static int MIN_DATA_SIZE = 20; + +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_update, Opt_NEW, Opt_LOAD, Opt_UPDATE +}; + +static match_table_t key_tokens = { + {Opt_new, "new"}, + {Opt_NEW, "NEW"}, + {Opt_load, "load"}, + {Opt_LOAD, "LOAD"}, + {Opt_update, "update"}, + {Opt_UPDATE, "UPDATE"}, + {Opt_err, NULL} +}; + +/* + * datablob_parse - parse the keyctl data + * + * datablob format: + * NEW + * LOAD + * UPDATE + * + * 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; + + if (decrypted_datalen) { + *decrypted_datalen = strsep(&datablob, " \t"); + if (!*decrypted_datalen) + goto out; + } + + switch (key_cmd) { + case Opt_new: + case Opt_NEW: + if (!decrypted_datalen) + break; + ret = 0; + break; + case Opt_load: + 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: + 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; + 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 < 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, + 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); + if (ret) { + 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; + 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); + ret = datablob_parse(buf, &new_master_desc, NULL, NULL, NULL); + if (ret < 0) + 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: + * + * + * 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; +} + +/* + * 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