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-rw-r--r--fs/crypto/keyinfo.c387
1 files changed, 0 insertions, 387 deletions
diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c
deleted file mode 100644
index a38630214058..000000000000
--- a/fs/crypto/keyinfo.c
+++ /dev/null
@@ -1,387 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * key management facility for FS encryption support.
- *
- * Copyright (C) 2015, Google, Inc.
- *
- * This contains encryption key functions.
- *
- * Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
- */
-
-#include <keys/user-type.h>
-#include <linux/scatterlist.h>
-#include <linux/ratelimit.h>
-#include <crypto/aes.h>
-#include <crypto/sha.h>
-#include "fscrypt_private.h"
-
-static struct crypto_shash *essiv_hash_tfm;
-
-static void derive_crypt_complete(struct crypto_async_request *req, int rc)
-{
- struct fscrypt_completion_result *ecr = req->data;
-
- if (rc == -EINPROGRESS)
- return;
-
- ecr->res = rc;
- complete(&ecr->completion);
-}
-
-/**
- * derive_key_aes() - Derive a key using AES-128-ECB
- * @deriving_key: Encryption key used for derivation.
- * @source_key: Source key to which to apply derivation.
- * @derived_raw_key: Derived raw key.
- *
- * Return: Zero on success; non-zero otherwise.
- */
-static int derive_key_aes(u8 deriving_key[FS_AES_128_ECB_KEY_SIZE],
- const struct fscrypt_key *source_key,
- u8 derived_raw_key[FS_MAX_KEY_SIZE])
-{
- int res = 0;
- struct skcipher_request *req = NULL;
- DECLARE_FS_COMPLETION_RESULT(ecr);
- struct scatterlist src_sg, dst_sg;
- struct crypto_skcipher *tfm = crypto_alloc_skcipher("ecb(aes)", 0, 0);
-
- if (IS_ERR(tfm)) {
- res = PTR_ERR(tfm);
- tfm = NULL;
- goto out;
- }
- crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_WEAK_KEY);
- req = skcipher_request_alloc(tfm, GFP_NOFS);
- if (!req) {
- res = -ENOMEM;
- goto out;
- }
- skcipher_request_set_callback(req,
- CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
- derive_crypt_complete, &ecr);
- res = crypto_skcipher_setkey(tfm, deriving_key,
- FS_AES_128_ECB_KEY_SIZE);
- if (res < 0)
- goto out;
-
- sg_init_one(&src_sg, source_key->raw, source_key->size);
- sg_init_one(&dst_sg, derived_raw_key, source_key->size);
- skcipher_request_set_crypt(req, &src_sg, &dst_sg, source_key->size,
- NULL);
- res = crypto_skcipher_encrypt(req);
- if (res == -EINPROGRESS || res == -EBUSY) {
- wait_for_completion(&ecr.completion);
- res = ecr.res;
- }
-out:
- skcipher_request_free(req);
- crypto_free_skcipher(tfm);
- return res;
-}
-
-static int validate_user_key(struct fscrypt_info *crypt_info,
- struct fscrypt_context *ctx, u8 *raw_key,
- const char *prefix, int min_keysize)
-{
- char *description;
- struct key *keyring_key;
- struct fscrypt_key *master_key;
- const struct user_key_payload *ukp;
- int res;
-
- description = kasprintf(GFP_NOFS, "%s%*phN", prefix,
- FS_KEY_DESCRIPTOR_SIZE,
- ctx->master_key_descriptor);
- if (!description)
- return -ENOMEM;
-
- keyring_key = request_key(&key_type_logon, description, NULL);
- kfree(description);
- if (IS_ERR(keyring_key))
- return PTR_ERR(keyring_key);
- down_read(&keyring_key->sem);
-
- if (keyring_key->type != &key_type_logon) {
- printk_once(KERN_WARNING
- "%s: key type must be logon\n", __func__);
- res = -ENOKEY;
- goto out;
- }
- ukp = user_key_payload_locked(keyring_key);
- if (!ukp) {
- /* key was revoked before we acquired its semaphore */
- res = -EKEYREVOKED;
- goto out;
- }
- if (ukp->datalen != sizeof(struct fscrypt_key)) {
- res = -EINVAL;
- goto out;
- }
- master_key = (struct fscrypt_key *)ukp->data;
- BUILD_BUG_ON(FS_AES_128_ECB_KEY_SIZE != FS_KEY_DERIVATION_NONCE_SIZE);
-
- if (master_key->size < min_keysize || master_key->size > FS_MAX_KEY_SIZE
- || master_key->size % AES_BLOCK_SIZE != 0) {
- printk_once(KERN_WARNING
- "%s: key size incorrect: %d\n",
- __func__, master_key->size);
- res = -ENOKEY;
- goto out;
- }
- res = derive_key_aes(ctx->nonce, master_key, raw_key);
-out:
- up_read(&keyring_key->sem);
- key_put(keyring_key);
- return res;
-}
-
-static const struct {
- const char *cipher_str;
- int keysize;
-} available_modes[] = {
- [FS_ENCRYPTION_MODE_AES_256_XTS] = { "xts(aes)",
- FS_AES_256_XTS_KEY_SIZE },
- [FS_ENCRYPTION_MODE_AES_256_CTS] = { "cts(cbc(aes))",
- FS_AES_256_CTS_KEY_SIZE },
- [FS_ENCRYPTION_MODE_AES_128_CBC] = { "cbc(aes)",
- FS_AES_128_CBC_KEY_SIZE },
- [FS_ENCRYPTION_MODE_AES_128_CTS] = { "cts(cbc(aes))",
- FS_AES_128_CTS_KEY_SIZE },
-};
-
-static int determine_cipher_type(struct fscrypt_info *ci, struct inode *inode,
- const char **cipher_str_ret, int *keysize_ret)
-{
- u32 mode;
-
- if (!fscrypt_valid_enc_modes(ci->ci_data_mode, ci->ci_filename_mode)) {
- pr_warn_ratelimited("fscrypt: inode %lu uses unsupported encryption modes (contents mode %d, filenames mode %d)\n",
- inode->i_ino,
- ci->ci_data_mode, ci->ci_filename_mode);
- return -EINVAL;
- }
-
- if (S_ISREG(inode->i_mode)) {
- mode = ci->ci_data_mode;
- } else if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) {
- mode = ci->ci_filename_mode;
- } else {
- WARN_ONCE(1, "fscrypt: filesystem tried to load encryption info for inode %lu, which is not encryptable (file type %d)\n",
- inode->i_ino, (inode->i_mode & S_IFMT));
- return -EINVAL;
- }
-
- *cipher_str_ret = available_modes[mode].cipher_str;
- *keysize_ret = available_modes[mode].keysize;
- return 0;
-}
-
-static void put_crypt_info(struct fscrypt_info *ci)
-{
- if (!ci)
- return;
-
- crypto_free_skcipher(ci->ci_ctfm);
- crypto_free_cipher(ci->ci_essiv_tfm);
- kmem_cache_free(fscrypt_info_cachep, ci);
-}
-
-static int derive_essiv_salt(const u8 *key, int keysize, u8 *salt)
-{
- struct crypto_shash *tfm = READ_ONCE(essiv_hash_tfm);
-
- /* init hash transform on demand */
- if (unlikely(!tfm)) {
- struct crypto_shash *prev_tfm;
-
- tfm = crypto_alloc_shash("sha256", 0, 0);
- if (IS_ERR(tfm)) {
- pr_warn_ratelimited("fscrypt: error allocating SHA-256 transform: %ld\n",
- PTR_ERR(tfm));
- return PTR_ERR(tfm);
- }
- prev_tfm = cmpxchg(&essiv_hash_tfm, NULL, tfm);
- if (prev_tfm) {
- crypto_free_shash(tfm);
- tfm = prev_tfm;
- }
- }
-
- {
- SHASH_DESC_ON_STACK(desc, tfm);
- desc->tfm = tfm;
- desc->flags = 0;
-
- return crypto_shash_digest(desc, key, keysize, salt);
- }
-}
-
-static int init_essiv_generator(struct fscrypt_info *ci, const u8 *raw_key,
- int keysize)
-{
- int err;
- struct crypto_cipher *essiv_tfm;
- u8 salt[SHA256_DIGEST_SIZE];
-
- essiv_tfm = crypto_alloc_cipher("aes", 0, 0);
- if (IS_ERR(essiv_tfm))
- return PTR_ERR(essiv_tfm);
-
- ci->ci_essiv_tfm = essiv_tfm;
-
- err = derive_essiv_salt(raw_key, keysize, salt);
- if (err)
- goto out;
-
- /*
- * Using SHA256 to derive the salt/key will result in AES-256 being
- * used for IV generation. File contents encryption will still use the
- * configured keysize (AES-128) nevertheless.
- */
- err = crypto_cipher_setkey(essiv_tfm, salt, sizeof(salt));
- if (err)
- goto out;
-
-out:
- memzero_explicit(salt, sizeof(salt));
- return err;
-}
-
-void __exit fscrypt_essiv_cleanup(void)
-{
- crypto_free_shash(essiv_hash_tfm);
-}
-
-int fscrypt_get_encryption_info(struct inode *inode)
-{
- struct fscrypt_info *crypt_info;
- struct fscrypt_context ctx;
- struct crypto_skcipher *ctfm;
- const char *cipher_str;
- int keysize;
- u8 *raw_key = NULL;
- int res;
-
- if (inode->i_crypt_info)
- return 0;
-
- res = fscrypt_initialize(inode->i_sb->s_cop->flags);
- if (res)
- return res;
-
- res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
- if (res < 0) {
- if (!fscrypt_dummy_context_enabled(inode) ||
- inode->i_sb->s_cop->is_encrypted(inode))
- return res;
- /* Fake up a context for an unencrypted directory */
- memset(&ctx, 0, sizeof(ctx));
- ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
- ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
- ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
- memset(ctx.master_key_descriptor, 0x42, FS_KEY_DESCRIPTOR_SIZE);
- } else if (res != sizeof(ctx)) {
- return -EINVAL;
- }
-
- if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1)
- return -EINVAL;
-
- if (ctx.flags & ~FS_POLICY_FLAGS_VALID)
- return -EINVAL;
-
- crypt_info = kmem_cache_alloc(fscrypt_info_cachep, GFP_NOFS);
- if (!crypt_info)
- return -ENOMEM;
-
- crypt_info->ci_flags = ctx.flags;
- crypt_info->ci_data_mode = ctx.contents_encryption_mode;
- crypt_info->ci_filename_mode = ctx.filenames_encryption_mode;
- crypt_info->ci_ctfm = NULL;
- crypt_info->ci_essiv_tfm = NULL;
- memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor,
- sizeof(crypt_info->ci_master_key));
-
- res = determine_cipher_type(crypt_info, inode, &cipher_str, &keysize);
- if (res)
- goto out;
-
- /*
- * This cannot be a stack buffer because it is passed to the scatterlist
- * crypto API as part of key derivation.
- */
- res = -ENOMEM;
- raw_key = kmalloc(FS_MAX_KEY_SIZE, GFP_NOFS);
- if (!raw_key)
- goto out;
-
- res = validate_user_key(crypt_info, &ctx, raw_key, FS_KEY_DESC_PREFIX,
- keysize);
- if (res && inode->i_sb->s_cop->key_prefix) {
- int res2 = validate_user_key(crypt_info, &ctx, raw_key,
- inode->i_sb->s_cop->key_prefix,
- keysize);
- if (res2) {
- if (res2 == -ENOKEY)
- res = -ENOKEY;
- goto out;
- }
- } else if (res) {
- goto out;
- }
- ctfm = crypto_alloc_skcipher(cipher_str, 0, 0);
- if (!ctfm || IS_ERR(ctfm)) {
- res = ctfm ? PTR_ERR(ctfm) : -ENOMEM;
- pr_debug("%s: error %d (inode %lu) allocating crypto tfm\n",
- __func__, res, inode->i_ino);
- goto out;
- }
- crypt_info->ci_ctfm = ctfm;
- crypto_skcipher_clear_flags(ctfm, ~0);
- crypto_skcipher_set_flags(ctfm, CRYPTO_TFM_REQ_WEAK_KEY);
- /*
- * if the provided key is longer than keysize, we use the first
- * keysize bytes of the derived key only
- */
- res = crypto_skcipher_setkey(ctfm, raw_key, keysize);
- if (res)
- goto out;
-
- if (S_ISREG(inode->i_mode) &&
- crypt_info->ci_data_mode == FS_ENCRYPTION_MODE_AES_128_CBC) {
- res = init_essiv_generator(crypt_info, raw_key, keysize);
- if (res) {
- pr_debug("%s: error %d (inode %lu) allocating essiv tfm\n",
- __func__, res, inode->i_ino);
- goto out;
- }
- }
- if (cmpxchg(&inode->i_crypt_info, NULL, crypt_info) == NULL)
- crypt_info = NULL;
-out:
- if (res == -ENOKEY)
- res = 0;
- put_crypt_info(crypt_info);
- kzfree(raw_key);
- return res;
-}
-EXPORT_SYMBOL(fscrypt_get_encryption_info);
-
-void fscrypt_put_encryption_info(struct inode *inode, struct fscrypt_info *ci)
-{
- struct fscrypt_info *prev;
-
- if (ci == NULL)
- ci = ACCESS_ONCE(inode->i_crypt_info);
- if (ci == NULL)
- return;
-
- prev = cmpxchg(&inode->i_crypt_info, ci, NULL);
- if (prev != ci)
- return;
-
- put_crypt_info(ci);
-}
-EXPORT_SYMBOL(fscrypt_put_encryption_info);