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f2fs crypto: add encryption key management facilities
This patch copies from encrypt_key.c in ext4, and modifies for f2fs. Use GFP_NOFS, since _f2fs_get_encryption_info is called under f2fs_lock_op. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <muslukhovi@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Jaegeuk Kim
parent
57e5055b0a
commit
0adda907f2
@ -6,4 +6,4 @@ f2fs-$(CONFIG_F2FS_STAT_FS) += debug.o
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f2fs-$(CONFIG_F2FS_FS_XATTR) += xattr.o
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f2fs-$(CONFIG_F2FS_FS_POSIX_ACL) += acl.o
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f2fs-$(CONFIG_F2FS_IO_TRACE) += trace.o
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f2fs-$(CONFIG_F2FS_FS_ENCRYPTION) += crypto_policy.o crypto.o
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f2fs-$(CONFIG_F2FS_FS_ENCRYPTION) += crypto_policy.o crypto.o crypto_key.o
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206
fs/f2fs/crypto_key.c
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206
fs/f2fs/crypto_key.c
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@ -0,0 +1,206 @@
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/*
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* linux/fs/f2fs/crypto_key.c
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*
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* Copied from linux/fs/f2fs/crypto_key.c
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*
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* Copyright (C) 2015, Google, Inc.
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*
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* This contains encryption key functions for f2fs
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*
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* Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
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*/
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#include <keys/encrypted-type.h>
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#include <keys/user-type.h>
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#include <linux/random.h>
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#include <linux/scatterlist.h>
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#include <uapi/linux/keyctl.h>
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#include <crypto/hash.h>
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#include <linux/f2fs_fs.h>
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#include "f2fs.h"
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#include "xattr.h"
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static void derive_crypt_complete(struct crypto_async_request *req, int rc)
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{
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struct f2fs_completion_result *ecr = req->data;
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if (rc == -EINPROGRESS)
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return;
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ecr->res = rc;
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complete(&ecr->completion);
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}
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/**
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* f2fs_derive_key_aes() - Derive a key using AES-128-ECB
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* @deriving_key: Encryption key used for derivatio.
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* @source_key: Source key to which to apply derivation.
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* @derived_key: Derived key.
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*
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* Return: Zero on success; non-zero otherwise.
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*/
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static int f2fs_derive_key_aes(char deriving_key[F2FS_AES_128_ECB_KEY_SIZE],
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char source_key[F2FS_AES_256_XTS_KEY_SIZE],
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char derived_key[F2FS_AES_256_XTS_KEY_SIZE])
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{
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int res = 0;
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struct ablkcipher_request *req = NULL;
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DECLARE_F2FS_COMPLETION_RESULT(ecr);
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struct scatterlist src_sg, dst_sg;
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struct crypto_ablkcipher *tfm = crypto_alloc_ablkcipher("ecb(aes)", 0,
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0);
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if (IS_ERR(tfm)) {
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res = PTR_ERR(tfm);
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tfm = NULL;
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goto out;
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}
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crypto_ablkcipher_set_flags(tfm, CRYPTO_TFM_REQ_WEAK_KEY);
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req = ablkcipher_request_alloc(tfm, GFP_NOFS);
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if (!req) {
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res = -ENOMEM;
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goto out;
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}
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ablkcipher_request_set_callback(req,
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CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
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derive_crypt_complete, &ecr);
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res = crypto_ablkcipher_setkey(tfm, deriving_key,
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F2FS_AES_128_ECB_KEY_SIZE);
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if (res < 0)
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goto out;
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sg_init_one(&src_sg, source_key, F2FS_AES_256_XTS_KEY_SIZE);
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sg_init_one(&dst_sg, derived_key, F2FS_AES_256_XTS_KEY_SIZE);
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ablkcipher_request_set_crypt(req, &src_sg, &dst_sg,
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F2FS_AES_256_XTS_KEY_SIZE, NULL);
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res = crypto_ablkcipher_encrypt(req);
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if (res == -EINPROGRESS || res == -EBUSY) {
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BUG_ON(req->base.data != &ecr);
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wait_for_completion(&ecr.completion);
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res = ecr.res;
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}
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out:
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if (req)
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ablkcipher_request_free(req);
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if (tfm)
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crypto_free_ablkcipher(tfm);
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return res;
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}
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void f2fs_free_encryption_info(struct inode *inode)
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{
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struct f2fs_inode_info *fi = F2FS_I(inode);
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struct f2fs_crypt_info *ci = fi->i_crypt_info;
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if (!ci)
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return;
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if (ci->ci_keyring_key)
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key_put(ci->ci_keyring_key);
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crypto_free_ablkcipher(ci->ci_ctfm);
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memzero_explicit(&ci->ci_raw, sizeof(ci->ci_raw));
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kfree(ci);
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fi->i_crypt_info = NULL;
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}
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int _f2fs_get_encryption_info(struct inode *inode)
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{
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struct f2fs_inode_info *fi = F2FS_I(inode);
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struct f2fs_crypt_info *crypt_info;
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char full_key_descriptor[F2FS_KEY_DESC_PREFIX_SIZE +
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(F2FS_KEY_DESCRIPTOR_SIZE * 2) + 1];
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struct key *keyring_key = NULL;
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struct f2fs_encryption_key *master_key;
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struct f2fs_encryption_context ctx;
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struct user_key_payload *ukp;
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int res;
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if (!f2fs_read_workqueue) {
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res = f2fs_init_crypto();
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if (res)
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return res;
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}
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if (fi->i_crypt_info) {
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if (!fi->i_crypt_info->ci_keyring_key ||
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key_validate(fi->i_crypt_info->ci_keyring_key) == 0)
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return 0;
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f2fs_free_encryption_info(inode);
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}
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res = f2fs_getxattr(inode, F2FS_XATTR_INDEX_ENCRYPTION,
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F2FS_XATTR_NAME_ENCRYPTION_CONTEXT,
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&ctx, sizeof(ctx), NULL);
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if (res < 0)
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return res;
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else if (res != sizeof(ctx))
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return -EINVAL;
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res = 0;
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crypt_info = kmalloc(sizeof(struct f2fs_crypt_info), GFP_NOFS);
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if (!crypt_info)
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return -ENOMEM;
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crypt_info->ci_flags = ctx.flags;
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crypt_info->ci_data_mode = ctx.contents_encryption_mode;
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crypt_info->ci_filename_mode = ctx.filenames_encryption_mode;
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crypt_info->ci_ctfm = NULL;
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memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor,
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sizeof(crypt_info->ci_master_key));
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if (S_ISREG(inode->i_mode))
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crypt_info->ci_mode = ctx.contents_encryption_mode;
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else if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
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crypt_info->ci_mode = ctx.filenames_encryption_mode;
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else {
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printk(KERN_ERR "f2fs crypto: Unsupported inode type.\n");
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BUG();
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}
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crypt_info->ci_size = f2fs_encryption_key_size(crypt_info->ci_mode);
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BUG_ON(!crypt_info->ci_size);
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memcpy(full_key_descriptor, F2FS_KEY_DESC_PREFIX,
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F2FS_KEY_DESC_PREFIX_SIZE);
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sprintf(full_key_descriptor + F2FS_KEY_DESC_PREFIX_SIZE,
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"%*phN", F2FS_KEY_DESCRIPTOR_SIZE,
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ctx.master_key_descriptor);
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full_key_descriptor[F2FS_KEY_DESC_PREFIX_SIZE +
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(2 * F2FS_KEY_DESCRIPTOR_SIZE)] = '\0';
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keyring_key = request_key(&key_type_logon, full_key_descriptor, NULL);
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if (IS_ERR(keyring_key)) {
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res = PTR_ERR(keyring_key);
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keyring_key = NULL;
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goto out;
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}
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BUG_ON(keyring_key->type != &key_type_logon);
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ukp = ((struct user_key_payload *)keyring_key->payload.data);
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if (ukp->datalen != sizeof(struct f2fs_encryption_key)) {
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res = -EINVAL;
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goto out;
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}
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master_key = (struct f2fs_encryption_key *)ukp->data;
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BUILD_BUG_ON(F2FS_AES_128_ECB_KEY_SIZE !=
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F2FS_KEY_DERIVATION_NONCE_SIZE);
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BUG_ON(master_key->size != F2FS_AES_256_XTS_KEY_SIZE);
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res = f2fs_derive_key_aes(ctx.nonce, master_key->raw,
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crypt_info->ci_raw);
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out:
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if (res < 0) {
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if (res == -ENOKEY)
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res = 0;
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kfree(crypt_info);
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} else {
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fi->i_crypt_info = crypt_info;
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crypt_info->ci_keyring_key = keyring_key;
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keyring_key = NULL;
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}
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if (keyring_key)
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key_put(keyring_key);
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return res;
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}
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int f2fs_has_encryption_key(struct inode *inode)
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{
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struct f2fs_inode_info *fi = F2FS_I(inode);
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return (fi->i_crypt_info != NULL);
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}
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@ -1974,17 +1974,39 @@ int f2fs_decrypt(struct f2fs_crypto_ctx *, struct page *);
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int f2fs_decrypt_one(struct inode *, struct page *);
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void f2fs_end_io_crypto_work(struct f2fs_crypto_ctx *, struct bio *);
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/* crypto_key.c */
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void f2fs_free_encryption_info(struct inode *);
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int _f2fs_get_encryption_info(struct inode *inode);
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#ifdef CONFIG_F2FS_FS_ENCRYPTION
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void f2fs_restore_and_release_control_page(struct page **);
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void f2fs_restore_control_page(struct page *);
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int f2fs_init_crypto(void);
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void f2fs_exit_crypto(void);
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int f2fs_has_encryption_key(struct inode *);
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static inline int f2fs_get_encryption_info(struct inode *inode)
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{
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struct f2fs_crypt_info *ci = F2FS_I(inode)->i_crypt_info;
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if (!ci ||
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(ci->ci_keyring_key &&
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(ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) |
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(1 << KEY_FLAG_REVOKED) |
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(1 << KEY_FLAG_DEAD)))))
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return _f2fs_get_encryption_info(inode);
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return 0;
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}
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#else
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static inline void f2fs_restore_and_release_control_page(struct page **p) { }
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static inline void f2fs_restore_control_page(struct page *p) { }
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static inline int f2fs_init_crypto(void) { return 0; }
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static inline void f2fs_exit_crypto(void) { }
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static inline int f2fs_has_encryption_key(struct inode *i) { return 0; }
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static inline int f2fs_get_encryption_info(struct inode *i) { return 0; }
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#endif
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#endif
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@ -65,6 +65,9 @@ struct f2fs_encryption_context {
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#define F2FS_AES_256_XTS_KEY_SIZE 64
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#define F2FS_MAX_KEY_SIZE 64
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#define F2FS_KEY_DESC_PREFIX "f2fs:"
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#define F2FS_KEY_DESC_PREFIX_SIZE 5
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struct f2fs_encryption_key {
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__u32 mode;
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char raw[F2FS_MAX_KEY_SIZE];
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