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c3917fd9df
This patch replaces uses of blkcipher with skcipher. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
1063 lines
27 KiB
C
1063 lines
27 KiB
C
/*
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* Copyright (C) 2010 IBM Corporation
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* Copyright (C) 2010 Politecnico di Torino, Italy
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* TORSEC group -- http://security.polito.it
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*
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* Authors:
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* Mimi Zohar <zohar@us.ibm.com>
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* Roberto Sassu <roberto.sassu@polito.it>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, version 2 of the License.
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*
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* See Documentation/security/keys-trusted-encrypted.txt
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*/
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#include <linux/uaccess.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/parser.h>
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#include <linux/string.h>
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#include <linux/err.h>
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#include <keys/user-type.h>
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#include <keys/trusted-type.h>
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#include <keys/encrypted-type.h>
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#include <linux/key-type.h>
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#include <linux/random.h>
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#include <linux/rcupdate.h>
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#include <linux/scatterlist.h>
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#include <linux/ctype.h>
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#include <crypto/hash.h>
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#include <crypto/sha.h>
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#include <crypto/skcipher.h>
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#include "encrypted.h"
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#include "ecryptfs_format.h"
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static const char KEY_TRUSTED_PREFIX[] = "trusted:";
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static const char KEY_USER_PREFIX[] = "user:";
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static const char hash_alg[] = "sha256";
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static const char hmac_alg[] = "hmac(sha256)";
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static const char blkcipher_alg[] = "cbc(aes)";
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static const char key_format_default[] = "default";
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static const char key_format_ecryptfs[] = "ecryptfs";
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static unsigned int ivsize;
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static int blksize;
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#define KEY_TRUSTED_PREFIX_LEN (sizeof (KEY_TRUSTED_PREFIX) - 1)
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#define KEY_USER_PREFIX_LEN (sizeof (KEY_USER_PREFIX) - 1)
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#define KEY_ECRYPTFS_DESC_LEN 16
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#define HASH_SIZE SHA256_DIGEST_SIZE
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#define MAX_DATA_SIZE 4096
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#define MIN_DATA_SIZE 20
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struct sdesc {
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struct shash_desc shash;
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char ctx[];
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};
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static struct crypto_shash *hashalg;
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static struct crypto_shash *hmacalg;
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enum {
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Opt_err = -1, Opt_new, Opt_load, Opt_update
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};
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enum {
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Opt_error = -1, Opt_default, Opt_ecryptfs
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};
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static const match_table_t key_format_tokens = {
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{Opt_default, "default"},
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{Opt_ecryptfs, "ecryptfs"},
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{Opt_error, NULL}
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};
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static const match_table_t key_tokens = {
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{Opt_new, "new"},
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{Opt_load, "load"},
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{Opt_update, "update"},
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{Opt_err, NULL}
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};
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static int aes_get_sizes(void)
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{
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struct crypto_skcipher *tfm;
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tfm = crypto_alloc_skcipher(blkcipher_alg, 0, CRYPTO_ALG_ASYNC);
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if (IS_ERR(tfm)) {
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pr_err("encrypted_key: failed to alloc_cipher (%ld)\n",
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PTR_ERR(tfm));
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return PTR_ERR(tfm);
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}
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ivsize = crypto_skcipher_ivsize(tfm);
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blksize = crypto_skcipher_blocksize(tfm);
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crypto_free_skcipher(tfm);
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return 0;
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}
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/*
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* valid_ecryptfs_desc - verify the description of a new/loaded encrypted key
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*
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* The description of a encrypted key with format 'ecryptfs' must contain
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* exactly 16 hexadecimal characters.
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*
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*/
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static int valid_ecryptfs_desc(const char *ecryptfs_desc)
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{
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int i;
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if (strlen(ecryptfs_desc) != KEY_ECRYPTFS_DESC_LEN) {
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pr_err("encrypted_key: key description must be %d hexadecimal "
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"characters long\n", KEY_ECRYPTFS_DESC_LEN);
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return -EINVAL;
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}
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for (i = 0; i < KEY_ECRYPTFS_DESC_LEN; i++) {
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if (!isxdigit(ecryptfs_desc[i])) {
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pr_err("encrypted_key: key description must contain "
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"only hexadecimal characters\n");
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return -EINVAL;
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}
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}
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return 0;
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}
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/*
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* valid_master_desc - verify the 'key-type:desc' of a new/updated master-key
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*
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* key-type:= "trusted:" | "user:"
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* desc:= master-key description
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*
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* Verify that 'key-type' is valid and that 'desc' exists. On key update,
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* only the master key description is permitted to change, not the key-type.
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* The key-type remains constant.
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*
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* On success returns 0, otherwise -EINVAL.
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*/
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static int valid_master_desc(const char *new_desc, const char *orig_desc)
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{
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if (!memcmp(new_desc, KEY_TRUSTED_PREFIX, KEY_TRUSTED_PREFIX_LEN)) {
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if (strlen(new_desc) == KEY_TRUSTED_PREFIX_LEN)
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goto out;
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if (orig_desc)
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if (memcmp(new_desc, orig_desc, KEY_TRUSTED_PREFIX_LEN))
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goto out;
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} else if (!memcmp(new_desc, KEY_USER_PREFIX, KEY_USER_PREFIX_LEN)) {
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if (strlen(new_desc) == KEY_USER_PREFIX_LEN)
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goto out;
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if (orig_desc)
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if (memcmp(new_desc, orig_desc, KEY_USER_PREFIX_LEN))
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goto out;
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} else
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goto out;
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return 0;
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out:
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return -EINVAL;
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}
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/*
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* datablob_parse - parse the keyctl data
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*
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* datablob format:
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* new [<format>] <master-key name> <decrypted data length>
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* load [<format>] <master-key name> <decrypted data length>
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* <encrypted iv + data>
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* update <new-master-key name>
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*
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* Tokenizes a copy of the keyctl data, returning a pointer to each token,
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* which is null terminated.
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*
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* On success returns 0, otherwise -EINVAL.
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*/
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static int datablob_parse(char *datablob, const char **format,
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char **master_desc, char **decrypted_datalen,
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char **hex_encoded_iv)
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{
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substring_t args[MAX_OPT_ARGS];
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int ret = -EINVAL;
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int key_cmd;
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int key_format;
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char *p, *keyword;
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keyword = strsep(&datablob, " \t");
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if (!keyword) {
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pr_info("encrypted_key: insufficient parameters specified\n");
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return ret;
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}
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key_cmd = match_token(keyword, key_tokens, args);
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/* Get optional format: default | ecryptfs */
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p = strsep(&datablob, " \t");
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if (!p) {
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pr_err("encrypted_key: insufficient parameters specified\n");
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return ret;
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}
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key_format = match_token(p, key_format_tokens, args);
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switch (key_format) {
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case Opt_ecryptfs:
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case Opt_default:
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*format = p;
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*master_desc = strsep(&datablob, " \t");
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break;
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case Opt_error:
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*master_desc = p;
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break;
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}
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if (!*master_desc) {
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pr_info("encrypted_key: master key parameter is missing\n");
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goto out;
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}
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if (valid_master_desc(*master_desc, NULL) < 0) {
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pr_info("encrypted_key: master key parameter \'%s\' "
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"is invalid\n", *master_desc);
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goto out;
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}
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if (decrypted_datalen) {
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*decrypted_datalen = strsep(&datablob, " \t");
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if (!*decrypted_datalen) {
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pr_info("encrypted_key: keylen parameter is missing\n");
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goto out;
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}
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}
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switch (key_cmd) {
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case Opt_new:
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if (!decrypted_datalen) {
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pr_info("encrypted_key: keyword \'%s\' not allowed "
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"when called from .update method\n", keyword);
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break;
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}
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ret = 0;
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break;
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case Opt_load:
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if (!decrypted_datalen) {
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pr_info("encrypted_key: keyword \'%s\' not allowed "
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"when called from .update method\n", keyword);
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break;
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}
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*hex_encoded_iv = strsep(&datablob, " \t");
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if (!*hex_encoded_iv) {
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pr_info("encrypted_key: hex blob is missing\n");
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break;
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}
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ret = 0;
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break;
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case Opt_update:
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if (decrypted_datalen) {
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pr_info("encrypted_key: keyword \'%s\' not allowed "
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"when called from .instantiate method\n",
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keyword);
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break;
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}
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ret = 0;
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break;
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case Opt_err:
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pr_info("encrypted_key: keyword \'%s\' not recognized\n",
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keyword);
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break;
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}
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out:
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return ret;
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}
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/*
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* datablob_format - format as an ascii string, before copying to userspace
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*/
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static char *datablob_format(struct encrypted_key_payload *epayload,
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size_t asciiblob_len)
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{
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char *ascii_buf, *bufp;
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u8 *iv = epayload->iv;
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int len;
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int i;
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ascii_buf = kmalloc(asciiblob_len + 1, GFP_KERNEL);
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if (!ascii_buf)
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goto out;
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ascii_buf[asciiblob_len] = '\0';
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/* copy datablob master_desc and datalen strings */
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len = sprintf(ascii_buf, "%s %s %s ", epayload->format,
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epayload->master_desc, epayload->datalen);
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/* convert the hex encoded iv, encrypted-data and HMAC to ascii */
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bufp = &ascii_buf[len];
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for (i = 0; i < (asciiblob_len - len) / 2; i++)
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bufp = hex_byte_pack(bufp, iv[i]);
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out:
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return ascii_buf;
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}
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/*
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* request_user_key - request the user key
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*
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* Use a user provided key to encrypt/decrypt an encrypted-key.
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*/
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static struct key *request_user_key(const char *master_desc, const u8 **master_key,
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size_t *master_keylen)
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{
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const struct user_key_payload *upayload;
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struct key *ukey;
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ukey = request_key(&key_type_user, master_desc, NULL);
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if (IS_ERR(ukey))
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goto error;
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down_read(&ukey->sem);
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upayload = user_key_payload(ukey);
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*master_key = upayload->data;
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*master_keylen = upayload->datalen;
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error:
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return ukey;
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}
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static struct sdesc *alloc_sdesc(struct crypto_shash *alg)
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{
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struct sdesc *sdesc;
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int size;
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size = sizeof(struct shash_desc) + crypto_shash_descsize(alg);
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sdesc = kmalloc(size, GFP_KERNEL);
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if (!sdesc)
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return ERR_PTR(-ENOMEM);
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sdesc->shash.tfm = alg;
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sdesc->shash.flags = 0x0;
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return sdesc;
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}
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static int calc_hmac(u8 *digest, const u8 *key, unsigned int keylen,
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const u8 *buf, unsigned int buflen)
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{
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struct sdesc *sdesc;
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int ret;
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sdesc = alloc_sdesc(hmacalg);
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if (IS_ERR(sdesc)) {
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pr_info("encrypted_key: can't alloc %s\n", hmac_alg);
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return PTR_ERR(sdesc);
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}
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ret = crypto_shash_setkey(hmacalg, key, keylen);
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if (!ret)
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ret = crypto_shash_digest(&sdesc->shash, buf, buflen, digest);
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kfree(sdesc);
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return ret;
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}
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static int calc_hash(u8 *digest, const u8 *buf, unsigned int buflen)
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{
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struct sdesc *sdesc;
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int ret;
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sdesc = alloc_sdesc(hashalg);
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if (IS_ERR(sdesc)) {
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pr_info("encrypted_key: can't alloc %s\n", hash_alg);
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return PTR_ERR(sdesc);
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}
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ret = crypto_shash_digest(&sdesc->shash, buf, buflen, digest);
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kfree(sdesc);
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return ret;
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}
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enum derived_key_type { ENC_KEY, AUTH_KEY };
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/* Derive authentication/encryption key from trusted key */
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static int get_derived_key(u8 *derived_key, enum derived_key_type key_type,
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const u8 *master_key, size_t master_keylen)
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{
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u8 *derived_buf;
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unsigned int derived_buf_len;
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int ret;
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derived_buf_len = strlen("AUTH_KEY") + 1 + master_keylen;
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if (derived_buf_len < HASH_SIZE)
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derived_buf_len = HASH_SIZE;
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derived_buf = kzalloc(derived_buf_len, GFP_KERNEL);
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if (!derived_buf) {
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pr_err("encrypted_key: out of memory\n");
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return -ENOMEM;
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}
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if (key_type)
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strcpy(derived_buf, "AUTH_KEY");
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else
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strcpy(derived_buf, "ENC_KEY");
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memcpy(derived_buf + strlen(derived_buf) + 1, master_key,
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master_keylen);
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ret = calc_hash(derived_key, derived_buf, derived_buf_len);
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kfree(derived_buf);
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return ret;
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}
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static struct skcipher_request *init_skcipher_req(const u8 *key,
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unsigned int key_len)
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{
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struct skcipher_request *req;
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struct crypto_skcipher *tfm;
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int ret;
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tfm = crypto_alloc_skcipher(blkcipher_alg, 0, CRYPTO_ALG_ASYNC);
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if (IS_ERR(tfm)) {
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pr_err("encrypted_key: failed to load %s transform (%ld)\n",
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blkcipher_alg, PTR_ERR(tfm));
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return ERR_CAST(tfm);
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}
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|
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ret = crypto_skcipher_setkey(tfm, key, key_len);
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if (ret < 0) {
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pr_err("encrypted_key: failed to setkey (%d)\n", ret);
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crypto_free_skcipher(tfm);
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return ERR_PTR(ret);
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}
|
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|
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req = skcipher_request_alloc(tfm, GFP_KERNEL);
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if (!req) {
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pr_err("encrypted_key: failed to allocate request for %s\n",
|
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blkcipher_alg);
|
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crypto_free_skcipher(tfm);
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return ERR_PTR(-ENOMEM);
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}
|
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|
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skcipher_request_set_callback(req, 0, NULL, NULL);
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return req;
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}
|
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|
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static struct key *request_master_key(struct encrypted_key_payload *epayload,
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const u8 **master_key, size_t *master_keylen)
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{
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struct key *mkey = NULL;
|
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|
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if (!strncmp(epayload->master_desc, KEY_TRUSTED_PREFIX,
|
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KEY_TRUSTED_PREFIX_LEN)) {
|
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mkey = request_trusted_key(epayload->master_desc +
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KEY_TRUSTED_PREFIX_LEN,
|
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master_key, master_keylen);
|
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} else if (!strncmp(epayload->master_desc, KEY_USER_PREFIX,
|
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KEY_USER_PREFIX_LEN)) {
|
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mkey = request_user_key(epayload->master_desc +
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KEY_USER_PREFIX_LEN,
|
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master_key, master_keylen);
|
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} else
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goto out;
|
|
|
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if (IS_ERR(mkey)) {
|
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int ret = PTR_ERR(mkey);
|
|
|
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if (ret == -ENOTSUPP)
|
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pr_info("encrypted_key: key %s not supported",
|
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epayload->master_desc);
|
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else
|
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pr_info("encrypted_key: key %s not found",
|
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epayload->master_desc);
|
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goto out;
|
|
}
|
|
|
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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,
|
|
const u8 *derived_key,
|
|
unsigned int derived_keylen)
|
|
{
|
|
struct scatterlist sg_in[2];
|
|
struct scatterlist sg_out[1];
|
|
struct crypto_skcipher *tfm;
|
|
struct skcipher_request *req;
|
|
unsigned int encrypted_datalen;
|
|
unsigned int padlen;
|
|
char pad[16];
|
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int ret;
|
|
|
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encrypted_datalen = roundup(epayload->decrypted_datalen, blksize);
|
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padlen = encrypted_datalen - epayload->decrypted_datalen;
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|
|
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req = init_skcipher_req(derived_key, derived_keylen);
|
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ret = PTR_ERR(req);
|
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if (IS_ERR(req))
|
|
goto out;
|
|
dump_decrypted_data(epayload);
|
|
|
|
memset(pad, 0, sizeof pad);
|
|
sg_init_table(sg_in, 2);
|
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sg_set_buf(&sg_in[0], epayload->decrypted_data,
|
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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);
|
|
|
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skcipher_request_set_crypt(req, sg_in, sg_out, encrypted_datalen,
|
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epayload->iv);
|
|
ret = crypto_skcipher_encrypt(req);
|
|
tfm = crypto_skcipher_reqtfm(req);
|
|
skcipher_request_free(req);
|
|
crypto_free_skcipher(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, size_t master_keylen)
|
|
{
|
|
u8 derived_key[HASH_SIZE];
|
|
u8 *digest;
|
|
int ret;
|
|
|
|
ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen);
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
digest = epayload->format + epayload->datablob_len;
|
|
ret = calc_hmac(digest, derived_key, sizeof derived_key,
|
|
epayload->format, 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 *format, const u8 *master_key,
|
|
size_t master_keylen)
|
|
{
|
|
u8 derived_key[HASH_SIZE];
|
|
u8 digest[HASH_SIZE];
|
|
int ret;
|
|
char *p;
|
|
unsigned short len;
|
|
|
|
ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen);
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
len = epayload->datablob_len;
|
|
if (!format) {
|
|
p = epayload->master_desc;
|
|
len -= strlen(epayload->format) + 1;
|
|
} else
|
|
p = epayload->format;
|
|
|
|
ret = calc_hmac(digest, derived_key, sizeof derived_key, p, len);
|
|
if (ret < 0)
|
|
goto out;
|
|
ret = memcmp(digest, epayload->format + epayload->datablob_len,
|
|
sizeof digest);
|
|
if (ret) {
|
|
ret = -EINVAL;
|
|
dump_hmac("datablob",
|
|
epayload->format + 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 crypto_skcipher *tfm;
|
|
struct skcipher_request *req;
|
|
unsigned int encrypted_datalen;
|
|
char pad[16];
|
|
int ret;
|
|
|
|
encrypted_datalen = roundup(epayload->decrypted_datalen, blksize);
|
|
req = init_skcipher_req(derived_key, derived_keylen);
|
|
ret = PTR_ERR(req);
|
|
if (IS_ERR(req))
|
|
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,
|
|
epayload->decrypted_datalen);
|
|
sg_set_buf(&sg_out[1], pad, sizeof pad);
|
|
|
|
skcipher_request_set_crypt(req, sg_in, sg_out, encrypted_datalen,
|
|
epayload->iv);
|
|
ret = crypto_skcipher_decrypt(req);
|
|
tfm = crypto_skcipher_reqtfm(req);
|
|
skcipher_request_free(req);
|
|
crypto_free_skcipher(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 *format,
|
|
const char *master_desc,
|
|
const char *datalen)
|
|
{
|
|
struct encrypted_key_payload *epayload = NULL;
|
|
unsigned short datablob_len;
|
|
unsigned short decrypted_datalen;
|
|
unsigned short payload_datalen;
|
|
unsigned int encrypted_datalen;
|
|
unsigned int format_len;
|
|
long dlen;
|
|
int ret;
|
|
|
|
ret = kstrtol(datalen, 10, &dlen);
|
|
if (ret < 0 || dlen < MIN_DATA_SIZE || dlen > MAX_DATA_SIZE)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
format_len = (!format) ? strlen(key_format_default) : strlen(format);
|
|
decrypted_datalen = dlen;
|
|
payload_datalen = decrypted_datalen;
|
|
if (format && !strcmp(format, key_format_ecryptfs)) {
|
|
if (dlen != ECRYPTFS_MAX_KEY_BYTES) {
|
|
pr_err("encrypted_key: keylen for the ecryptfs format "
|
|
"must be equal to %d bytes\n",
|
|
ECRYPTFS_MAX_KEY_BYTES);
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
decrypted_datalen = ECRYPTFS_MAX_KEY_BYTES;
|
|
payload_datalen = sizeof(struct ecryptfs_auth_tok);
|
|
}
|
|
|
|
encrypted_datalen = roundup(decrypted_datalen, blksize);
|
|
|
|
datablob_len = format_len + 1 + strlen(master_desc) + 1
|
|
+ strlen(datalen) + 1 + ivsize + 1 + encrypted_datalen;
|
|
|
|
ret = key_payload_reserve(key, payload_datalen + datablob_len
|
|
+ HASH_SIZE + 1);
|
|
if (ret < 0)
|
|
return ERR_PTR(ret);
|
|
|
|
epayload = kzalloc(sizeof(*epayload) + payload_datalen +
|
|
datablob_len + HASH_SIZE + 1, GFP_KERNEL);
|
|
if (!epayload)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
epayload->payload_datalen = payload_datalen;
|
|
epayload->decrypted_datalen = decrypted_datalen;
|
|
epayload->datablob_len = datablob_len;
|
|
return epayload;
|
|
}
|
|
|
|
static int encrypted_key_decrypt(struct encrypted_key_payload *epayload,
|
|
const char *format, const char *hex_encoded_iv)
|
|
{
|
|
struct key *mkey;
|
|
u8 derived_key[HASH_SIZE];
|
|
const u8 *master_key;
|
|
u8 *hmac;
|
|
const char *hex_encoded_data;
|
|
unsigned int encrypted_datalen;
|
|
size_t master_keylen;
|
|
size_t asciilen;
|
|
int ret;
|
|
|
|
encrypted_datalen = roundup(epayload->decrypted_datalen, blksize);
|
|
asciilen = (ivsize + 1 + encrypted_datalen + HASH_SIZE) * 2;
|
|
if (strlen(hex_encoded_iv) != asciilen)
|
|
return -EINVAL;
|
|
|
|
hex_encoded_data = hex_encoded_iv + (2 * ivsize) + 2;
|
|
ret = hex2bin(epayload->iv, hex_encoded_iv, ivsize);
|
|
if (ret < 0)
|
|
return -EINVAL;
|
|
ret = hex2bin(epayload->encrypted_data, hex_encoded_data,
|
|
encrypted_datalen);
|
|
if (ret < 0)
|
|
return -EINVAL;
|
|
|
|
hmac = epayload->format + epayload->datablob_len;
|
|
ret = hex2bin(hmac, hex_encoded_data + (encrypted_datalen * 2),
|
|
HASH_SIZE);
|
|
if (ret < 0)
|
|
return -EINVAL;
|
|
|
|
mkey = request_master_key(epayload, &master_key, &master_keylen);
|
|
if (IS_ERR(mkey))
|
|
return PTR_ERR(mkey);
|
|
|
|
ret = datablob_hmac_verify(epayload, format, master_key, master_keylen);
|
|
if (ret < 0) {
|
|
pr_err("encrypted_key: bad hmac (%d)\n", ret);
|
|
goto out;
|
|
}
|
|
|
|
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:
|
|
up_read(&mkey->sem);
|
|
key_put(mkey);
|
|
return ret;
|
|
}
|
|
|
|
static void __ekey_init(struct encrypted_key_payload *epayload,
|
|
const char *format, const char *master_desc,
|
|
const char *datalen)
|
|
{
|
|
unsigned int format_len;
|
|
|
|
format_len = (!format) ? strlen(key_format_default) : strlen(format);
|
|
epayload->format = epayload->payload_data + epayload->payload_datalen;
|
|
epayload->master_desc = epayload->format + format_len + 1;
|
|
epayload->datalen = epayload->master_desc + strlen(master_desc) + 1;
|
|
epayload->iv = epayload->datalen + strlen(datalen) + 1;
|
|
epayload->encrypted_data = epayload->iv + ivsize + 1;
|
|
epayload->decrypted_data = epayload->payload_data;
|
|
|
|
if (!format)
|
|
memcpy(epayload->format, key_format_default, format_len);
|
|
else {
|
|
if (!strcmp(format, key_format_ecryptfs))
|
|
epayload->decrypted_data =
|
|
ecryptfs_get_auth_tok_key((struct ecryptfs_auth_tok *)epayload->payload_data);
|
|
|
|
memcpy(epayload->format, format, format_len);
|
|
}
|
|
|
|
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 *key_desc, const char *format,
|
|
const char *master_desc, const char *datalen,
|
|
const char *hex_encoded_iv)
|
|
{
|
|
int ret = 0;
|
|
|
|
if (format && !strcmp(format, key_format_ecryptfs)) {
|
|
ret = valid_ecryptfs_desc(key_desc);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
ecryptfs_fill_auth_tok((struct ecryptfs_auth_tok *)epayload->payload_data,
|
|
key_desc);
|
|
}
|
|
|
|
__ekey_init(epayload, format, master_desc, datalen);
|
|
if (!hex_encoded_iv) {
|
|
get_random_bytes(epayload->iv, ivsize);
|
|
|
|
get_random_bytes(epayload->decrypted_data,
|
|
epayload->decrypted_datalen);
|
|
} else
|
|
ret = encrypted_key_decrypt(epayload, format, hex_encoded_iv);
|
|
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,
|
|
struct key_preparsed_payload *prep)
|
|
{
|
|
struct encrypted_key_payload *epayload = NULL;
|
|
char *datablob = NULL;
|
|
const char *format = NULL;
|
|
char *master_desc = NULL;
|
|
char *decrypted_datalen = NULL;
|
|
char *hex_encoded_iv = NULL;
|
|
size_t datalen = prep->datalen;
|
|
int ret;
|
|
|
|
if (datalen <= 0 || datalen > 32767 || !prep->data)
|
|
return -EINVAL;
|
|
|
|
datablob = kmalloc(datalen + 1, GFP_KERNEL);
|
|
if (!datablob)
|
|
return -ENOMEM;
|
|
datablob[datalen] = 0;
|
|
memcpy(datablob, prep->data, datalen);
|
|
ret = datablob_parse(datablob, &format, &master_desc,
|
|
&decrypted_datalen, &hex_encoded_iv);
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
epayload = encrypted_key_alloc(key, format, master_desc,
|
|
decrypted_datalen);
|
|
if (IS_ERR(epayload)) {
|
|
ret = PTR_ERR(epayload);
|
|
goto out;
|
|
}
|
|
ret = encrypted_init(epayload, key->description, format, master_desc,
|
|
decrypted_datalen, hex_encoded_iv);
|
|
if (ret < 0) {
|
|
kfree(epayload);
|
|
goto out;
|
|
}
|
|
|
|
rcu_assign_keypointer(key, 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, struct key_preparsed_payload *prep)
|
|
{
|
|
struct encrypted_key_payload *epayload = key->payload.data[0];
|
|
struct encrypted_key_payload *new_epayload;
|
|
char *buf;
|
|
char *new_master_desc = NULL;
|
|
const char *format = NULL;
|
|
size_t datalen = prep->datalen;
|
|
int ret = 0;
|
|
|
|
if (test_bit(KEY_FLAG_NEGATIVE, &key->flags))
|
|
return -ENOKEY;
|
|
if (datalen <= 0 || datalen > 32767 || !prep->data)
|
|
return -EINVAL;
|
|
|
|
buf = kmalloc(datalen + 1, GFP_KERNEL);
|
|
if (!buf)
|
|
return -ENOMEM;
|
|
|
|
buf[datalen] = 0;
|
|
memcpy(buf, prep->data, datalen);
|
|
ret = datablob_parse(buf, &format, &new_master_desc, NULL, NULL);
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
ret = valid_master_desc(new_master_desc, epayload->master_desc);
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
new_epayload = encrypted_key_alloc(key, epayload->format,
|
|
new_master_desc, epayload->datalen);
|
|
if (IS_ERR(new_epayload)) {
|
|
ret = PTR_ERR(new_epayload);
|
|
goto out;
|
|
}
|
|
|
|
__ekey_init(new_epayload, epayload->format, new_master_desc,
|
|
epayload->datalen);
|
|
|
|
memcpy(new_epayload->iv, epayload->iv, ivsize);
|
|
memcpy(new_epayload->payload_data, epayload->payload_data,
|
|
epayload->payload_datalen);
|
|
|
|
rcu_assign_keypointer(key, 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;
|
|
const u8 *master_key;
|
|
size_t master_keylen;
|
|
char derived_key[HASH_SIZE];
|
|
char *ascii_buf;
|
|
size_t asciiblob_len;
|
|
int ret;
|
|
|
|
epayload = rcu_dereference_key(key);
|
|
|
|
/* 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 < asciiblob_len)
|
|
return asciiblob_len;
|
|
|
|
mkey = request_master_key(epayload, &master_key, &master_keylen);
|
|
if (IS_ERR(mkey))
|
|
return PTR_ERR(mkey);
|
|
|
|
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;
|
|
|
|
ascii_buf = datablob_format(epayload, asciiblob_len);
|
|
if (!ascii_buf) {
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
up_read(&mkey->sem);
|
|
key_put(mkey);
|
|
|
|
if (copy_to_user(buffer, ascii_buf, asciiblob_len) != 0)
|
|
ret = -EFAULT;
|
|
kfree(ascii_buf);
|
|
|
|
return asciiblob_len;
|
|
out:
|
|
up_read(&mkey->sem);
|
|
key_put(mkey);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* encrypted_destroy - before freeing the key, clear the decrypted data
|
|
*
|
|
* Before freeing the key, clear the memory containing the decrypted
|
|
* key data.
|
|
*/
|
|
static void encrypted_destroy(struct key *key)
|
|
{
|
|
struct encrypted_key_payload *epayload = key->payload.data[0];
|
|
|
|
if (!epayload)
|
|
return;
|
|
|
|
memset(epayload->decrypted_data, 0, epayload->decrypted_datalen);
|
|
kfree(key->payload.data[0]);
|
|
}
|
|
|
|
struct key_type key_type_encrypted = {
|
|
.name = "encrypted",
|
|
.instantiate = encrypted_instantiate,
|
|
.update = encrypted_update,
|
|
.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 = aes_get_sizes();
|
|
if (ret < 0)
|
|
goto out;
|
|
ret = register_key_type(&key_type_encrypted);
|
|
if (ret < 0)
|
|
goto out;
|
|
return 0;
|
|
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");
|