ext4 crypto: add ext4 encryption facilities
On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Michael Halcrow
Theodore Ts'o
Родитель
9bd8212f98
Коммит
b30ab0e034
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@ -12,4 +12,4 @@ ext4-y := balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o page-io.o \
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ext4-$(CONFIG_EXT4_FS_POSIX_ACL) += acl.o
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ext4-$(CONFIG_EXT4_FS_POSIX_ACL) += acl.o
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ext4-$(CONFIG_EXT4_FS_SECURITY) += xattr_security.o
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ext4-$(CONFIG_EXT4_FS_SECURITY) += xattr_security.o
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ext4-$(CONFIG_EXT4_FS_ENCRYPTION) += crypto_policy.o
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ext4-$(CONFIG_EXT4_FS_ENCRYPTION) += crypto_policy.o crypto.o
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@ -0,0 +1,558 @@
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/*
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* linux/fs/ext4/crypto.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 functions for ext4
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*
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* Written by Michael Halcrow, 2014.
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*
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* Filename encryption additions
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* Uday Savagaonkar, 2014
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* Encryption policy handling additions
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* Ildar Muslukhov, 2014
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*
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* This has not yet undergone a rigorous security audit.
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*
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* The usage of AES-XTS should conform to recommendations in NIST
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* Special Publication 800-38E and IEEE P1619/D16.
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*/
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#include <crypto/hash.h>
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#include <crypto/sha.h>
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#include <keys/user-type.h>
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#include <keys/encrypted-type.h>
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#include <linux/crypto.h>
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#include <linux/ecryptfs.h>
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#include <linux/gfp.h>
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#include <linux/kernel.h>
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#include <linux/key.h>
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#include <linux/list.h>
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#include <linux/mempool.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/random.h>
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#include <linux/scatterlist.h>
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#include <linux/spinlock_types.h>
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#include "ext4_extents.h"
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#include "xattr.h"
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/* Encryption added and removed here! (L: */
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static unsigned int num_prealloc_crypto_pages = 32;
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static unsigned int num_prealloc_crypto_ctxs = 128;
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module_param(num_prealloc_crypto_pages, uint, 0444);
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MODULE_PARM_DESC(num_prealloc_crypto_pages,
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"Number of crypto pages to preallocate");
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module_param(num_prealloc_crypto_ctxs, uint, 0444);
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MODULE_PARM_DESC(num_prealloc_crypto_ctxs,
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"Number of crypto contexts to preallocate");
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static mempool_t *ext4_bounce_page_pool;
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static LIST_HEAD(ext4_free_crypto_ctxs);
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static DEFINE_SPINLOCK(ext4_crypto_ctx_lock);
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/**
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* ext4_release_crypto_ctx() - Releases an encryption context
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* @ctx: The encryption context to release.
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*
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* If the encryption context was allocated from the pre-allocated pool, returns
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* it to that pool. Else, frees it.
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*
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* If there's a bounce page in the context, this frees that.
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*/
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void ext4_release_crypto_ctx(struct ext4_crypto_ctx *ctx)
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{
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unsigned long flags;
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if (ctx->bounce_page) {
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if (ctx->flags & EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL)
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__free_page(ctx->bounce_page);
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else
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mempool_free(ctx->bounce_page, ext4_bounce_page_pool);
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ctx->bounce_page = NULL;
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}
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ctx->control_page = NULL;
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if (ctx->flags & EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL) {
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if (ctx->tfm)
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crypto_free_tfm(ctx->tfm);
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kfree(ctx);
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} else {
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spin_lock_irqsave(&ext4_crypto_ctx_lock, flags);
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list_add(&ctx->free_list, &ext4_free_crypto_ctxs);
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spin_unlock_irqrestore(&ext4_crypto_ctx_lock, flags);
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}
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}
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/**
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* ext4_alloc_and_init_crypto_ctx() - Allocates and inits an encryption context
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* @mask: The allocation mask.
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*
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* Return: An allocated and initialized encryption context on success. An error
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* value or NULL otherwise.
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*/
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static struct ext4_crypto_ctx *ext4_alloc_and_init_crypto_ctx(gfp_t mask)
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{
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struct ext4_crypto_ctx *ctx = kzalloc(sizeof(struct ext4_crypto_ctx),
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mask);
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if (!ctx)
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return ERR_PTR(-ENOMEM);
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return ctx;
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}
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/**
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* ext4_get_crypto_ctx() - Gets an encryption context
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* @inode: The inode for which we are doing the crypto
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*
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* Allocates and initializes an encryption context.
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*
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* Return: An allocated and initialized encryption context on success; error
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* value or NULL otherwise.
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*/
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struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode)
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{
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struct ext4_crypto_ctx *ctx = NULL;
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int res = 0;
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unsigned long flags;
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struct ext4_encryption_key *key = &EXT4_I(inode)->i_encryption_key;
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if (!ext4_read_workqueue)
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ext4_init_crypto();
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/*
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* We first try getting the ctx from a free list because in
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* the common case the ctx will have an allocated and
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* initialized crypto tfm, so it's probably a worthwhile
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* optimization. For the bounce page, we first try getting it
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* from the kernel allocator because that's just about as fast
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* as getting it from a list and because a cache of free pages
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* should generally be a "last resort" option for a filesystem
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* to be able to do its job.
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*/
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spin_lock_irqsave(&ext4_crypto_ctx_lock, flags);
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ctx = list_first_entry_or_null(&ext4_free_crypto_ctxs,
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struct ext4_crypto_ctx, free_list);
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if (ctx)
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list_del(&ctx->free_list);
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spin_unlock_irqrestore(&ext4_crypto_ctx_lock, flags);
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if (!ctx) {
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ctx = ext4_alloc_and_init_crypto_ctx(GFP_NOFS);
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if (IS_ERR(ctx)) {
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res = PTR_ERR(ctx);
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goto out;
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}
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ctx->flags |= EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL;
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} else {
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ctx->flags &= ~EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL;
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}
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/* Allocate a new Crypto API context if we don't already have
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* one or if it isn't the right mode. */
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BUG_ON(key->mode == EXT4_ENCRYPTION_MODE_INVALID);
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if (ctx->tfm && (ctx->mode != key->mode)) {
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crypto_free_tfm(ctx->tfm);
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ctx->tfm = NULL;
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ctx->mode = EXT4_ENCRYPTION_MODE_INVALID;
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}
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if (!ctx->tfm) {
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switch (key->mode) {
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case EXT4_ENCRYPTION_MODE_AES_256_XTS:
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ctx->tfm = crypto_ablkcipher_tfm(
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crypto_alloc_ablkcipher("xts(aes)", 0, 0));
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break;
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case EXT4_ENCRYPTION_MODE_AES_256_GCM:
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/* TODO(mhalcrow): AEAD w/ gcm(aes);
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* crypto_aead_setauthsize() */
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ctx->tfm = ERR_PTR(-ENOTSUPP);
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break;
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default:
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BUG();
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}
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if (IS_ERR_OR_NULL(ctx->tfm)) {
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res = PTR_ERR(ctx->tfm);
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ctx->tfm = NULL;
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goto out;
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}
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ctx->mode = key->mode;
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}
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BUG_ON(key->size != ext4_encryption_key_size(key->mode));
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/* There shouldn't be a bounce page attached to the crypto
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* context at this point. */
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BUG_ON(ctx->bounce_page);
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out:
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if (res) {
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if (!IS_ERR_OR_NULL(ctx))
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ext4_release_crypto_ctx(ctx);
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ctx = ERR_PTR(res);
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}
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return ctx;
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}
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struct workqueue_struct *ext4_read_workqueue;
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static DEFINE_MUTEX(crypto_init);
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/**
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* ext4_exit_crypto() - Shutdown the ext4 encryption system
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*/
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void ext4_exit_crypto(void)
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{
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struct ext4_crypto_ctx *pos, *n;
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list_for_each_entry_safe(pos, n, &ext4_free_crypto_ctxs, free_list) {
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if (pos->bounce_page) {
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if (pos->flags &
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EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL) {
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__free_page(pos->bounce_page);
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} else {
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mempool_free(pos->bounce_page,
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ext4_bounce_page_pool);
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}
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}
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if (pos->tfm)
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crypto_free_tfm(pos->tfm);
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kfree(pos);
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}
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INIT_LIST_HEAD(&ext4_free_crypto_ctxs);
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if (ext4_bounce_page_pool)
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mempool_destroy(ext4_bounce_page_pool);
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ext4_bounce_page_pool = NULL;
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if (ext4_read_workqueue)
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destroy_workqueue(ext4_read_workqueue);
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ext4_read_workqueue = NULL;
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}
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/**
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* ext4_init_crypto() - Set up for ext4 encryption.
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*
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* We only call this when we start accessing encrypted files, since it
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* results in memory getting allocated that wouldn't otherwise be used.
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*
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* Return: Zero on success, non-zero otherwise.
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*/
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int ext4_init_crypto(void)
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{
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int i, res;
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mutex_lock(&crypto_init);
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if (ext4_read_workqueue)
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goto already_initialized;
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ext4_read_workqueue = alloc_workqueue("ext4_crypto", WQ_HIGHPRI, 0);
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if (!ext4_read_workqueue) {
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res = -ENOMEM;
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goto fail;
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}
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for (i = 0; i < num_prealloc_crypto_ctxs; i++) {
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struct ext4_crypto_ctx *ctx;
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ctx = ext4_alloc_and_init_crypto_ctx(GFP_KERNEL);
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if (IS_ERR(ctx)) {
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res = PTR_ERR(ctx);
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goto fail;
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|
}
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list_add(&ctx->free_list, &ext4_free_crypto_ctxs);
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}
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ext4_bounce_page_pool =
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mempool_create_page_pool(num_prealloc_crypto_pages, 0);
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if (!ext4_bounce_page_pool) {
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res = -ENOMEM;
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|
goto fail;
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|
}
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|
already_initialized:
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|
mutex_unlock(&crypto_init);
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return 0;
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|
fail:
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ext4_exit_crypto();
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mutex_unlock(&crypto_init);
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|
return res;
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|
}
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|
|
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void ext4_restore_control_page(struct page *data_page)
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|
{
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struct ext4_crypto_ctx *ctx =
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(struct ext4_crypto_ctx *)page_private(data_page);
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|
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set_page_private(data_page, (unsigned long)NULL);
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|
ClearPagePrivate(data_page);
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|
unlock_page(data_page);
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|
ext4_release_crypto_ctx(ctx);
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|
}
|
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|
|
||||||
|
/**
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|
* ext4_crypt_complete() - The completion callback for page encryption
|
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* @req: The asynchronous encryption request context
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* @res: The result of the encryption operation
|
||||||
|
*/
|
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static void ext4_crypt_complete(struct crypto_async_request *req, int res)
|
||||||
|
{
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|
struct ext4_completion_result *ecr = req->data;
|
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|
|
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|
if (res == -EINPROGRESS)
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|
return;
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|
ecr->res = res;
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|
complete(&ecr->completion);
|
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|
}
|
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|
|
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|
typedef enum {
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|
EXT4_DECRYPT = 0,
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|
EXT4_ENCRYPT,
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|
} ext4_direction_t;
|
||||||
|
|
||||||
|
static int ext4_page_crypto(struct ext4_crypto_ctx *ctx,
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|
struct inode *inode,
|
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|
ext4_direction_t rw,
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|
pgoff_t index,
|
||||||
|
struct page *src_page,
|
||||||
|
struct page *dest_page)
|
||||||
|
|
||||||
|
{
|
||||||
|
u8 xts_tweak[EXT4_XTS_TWEAK_SIZE];
|
||||||
|
struct ablkcipher_request *req = NULL;
|
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|
DECLARE_EXT4_COMPLETION_RESULT(ecr);
|
||||||
|
struct scatterlist dst, src;
|
||||||
|
struct ext4_inode_info *ei = EXT4_I(inode);
|
||||||
|
struct crypto_ablkcipher *atfm = __crypto_ablkcipher_cast(ctx->tfm);
|
||||||
|
int res = 0;
|
||||||
|
|
||||||
|
BUG_ON(!ctx->tfm);
|
||||||
|
BUG_ON(ctx->mode != ei->i_encryption_key.mode);
|
||||||
|
|
||||||
|
if (ctx->mode != EXT4_ENCRYPTION_MODE_AES_256_XTS) {
|
||||||
|
printk_ratelimited(KERN_ERR
|
||||||
|
"%s: unsupported crypto algorithm: %d\n",
|
||||||
|
__func__, ctx->mode);
|
||||||
|
return -ENOTSUPP;
|
||||||
|
}
|
||||||
|
|
||||||
|
crypto_ablkcipher_clear_flags(atfm, ~0);
|
||||||
|
crypto_tfm_set_flags(ctx->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
|
||||||
|
|
||||||
|
res = crypto_ablkcipher_setkey(atfm, ei->i_encryption_key.raw,
|
||||||
|
ei->i_encryption_key.size);
|
||||||
|
if (res) {
|
||||||
|
printk_ratelimited(KERN_ERR
|
||||||
|
"%s: crypto_ablkcipher_setkey() failed\n",
|
||||||
|
__func__);
|
||||||
|
return res;
|
||||||
|
}
|
||||||
|
req = ablkcipher_request_alloc(atfm, GFP_NOFS);
|
||||||
|
if (!req) {
|
||||||
|
printk_ratelimited(KERN_ERR
|
||||||
|
"%s: crypto_request_alloc() failed\n",
|
||||||
|
__func__);
|
||||||
|
return -ENOMEM;
|
||||||
|
}
|
||||||
|
ablkcipher_request_set_callback(
|
||||||
|
req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
|
||||||
|
ext4_crypt_complete, &ecr);
|
||||||
|
|
||||||
|
BUILD_BUG_ON(EXT4_XTS_TWEAK_SIZE < sizeof(index));
|
||||||
|
memcpy(xts_tweak, &index, sizeof(index));
|
||||||
|
memset(&xts_tweak[sizeof(index)], 0,
|
||||||
|
EXT4_XTS_TWEAK_SIZE - sizeof(index));
|
||||||
|
|
||||||
|
sg_init_table(&dst, 1);
|
||||||
|
sg_set_page(&dst, dest_page, PAGE_CACHE_SIZE, 0);
|
||||||
|
sg_init_table(&src, 1);
|
||||||
|
sg_set_page(&src, src_page, PAGE_CACHE_SIZE, 0);
|
||||||
|
ablkcipher_request_set_crypt(req, &src, &dst, PAGE_CACHE_SIZE,
|
||||||
|
xts_tweak);
|
||||||
|
if (rw == EXT4_DECRYPT)
|
||||||
|
res = crypto_ablkcipher_decrypt(req);
|
||||||
|
else
|
||||||
|
res = crypto_ablkcipher_encrypt(req);
|
||||||
|
if (res == -EINPROGRESS || res == -EBUSY) {
|
||||||
|
BUG_ON(req->base.data != &ecr);
|
||||||
|
wait_for_completion(&ecr.completion);
|
||||||
|
res = ecr.res;
|
||||||
|
}
|
||||||
|
ablkcipher_request_free(req);
|
||||||
|
if (res) {
|
||||||
|
printk_ratelimited(
|
||||||
|
KERN_ERR
|
||||||
|
"%s: crypto_ablkcipher_encrypt() returned %d\n",
|
||||||
|
__func__, res);
|
||||||
|
return res;
|
||||||
|
}
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
/**
|
||||||
|
* ext4_encrypt() - Encrypts a page
|
||||||
|
* @inode: The inode for which the encryption should take place
|
||||||
|
* @plaintext_page: The page to encrypt. Must be locked.
|
||||||
|
*
|
||||||
|
* Allocates a ciphertext page and encrypts plaintext_page into it using the ctx
|
||||||
|
* encryption context.
|
||||||
|
*
|
||||||
|
* Called on the page write path. The caller must call
|
||||||
|
* ext4_restore_control_page() on the returned ciphertext page to
|
||||||
|
* release the bounce buffer and the encryption context.
|
||||||
|
*
|
||||||
|
* Return: An allocated page with the encrypted content on success. Else, an
|
||||||
|
* error value or NULL.
|
||||||
|
*/
|
||||||
|
struct page *ext4_encrypt(struct inode *inode,
|
||||||
|
struct page *plaintext_page)
|
||||||
|
{
|
||||||
|
struct ext4_crypto_ctx *ctx;
|
||||||
|
struct page *ciphertext_page = NULL;
|
||||||
|
int err;
|
||||||
|
|
||||||
|
BUG_ON(!PageLocked(plaintext_page));
|
||||||
|
|
||||||
|
ctx = ext4_get_crypto_ctx(inode);
|
||||||
|
if (IS_ERR(ctx))
|
||||||
|
return (struct page *) ctx;
|
||||||
|
|
||||||
|
/* The encryption operation will require a bounce page. */
|
||||||
|
ciphertext_page = alloc_page(GFP_NOFS);
|
||||||
|
if (!ciphertext_page) {
|
||||||
|
/* This is a potential bottleneck, but at least we'll have
|
||||||
|
* forward progress. */
|
||||||
|
ciphertext_page = mempool_alloc(ext4_bounce_page_pool,
|
||||||
|
GFP_NOFS);
|
||||||
|
if (WARN_ON_ONCE(!ciphertext_page)) {
|
||||||
|
ciphertext_page = mempool_alloc(ext4_bounce_page_pool,
|
||||||
|
GFP_NOFS | __GFP_WAIT);
|
||||||
|
}
|
||||||
|
ctx->flags &= ~EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
|
||||||
|
} else {
|
||||||
|
ctx->flags |= EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
|
||||||
|
}
|
||||||
|
ctx->bounce_page = ciphertext_page;
|
||||||
|
ctx->control_page = plaintext_page;
|
||||||
|
err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, plaintext_page->index,
|
||||||
|
plaintext_page, ciphertext_page);
|
||||||
|
if (err) {
|
||||||
|
ext4_release_crypto_ctx(ctx);
|
||||||
|
return ERR_PTR(err);
|
||||||
|
}
|
||||||
|
SetPagePrivate(ciphertext_page);
|
||||||
|
set_page_private(ciphertext_page, (unsigned long)ctx);
|
||||||
|
lock_page(ciphertext_page);
|
||||||
|
return ciphertext_page;
|
||||||
|
}
|
||||||
|
|
||||||
|
/**
|
||||||
|
* ext4_decrypt() - Decrypts a page in-place
|
||||||
|
* @ctx: The encryption context.
|
||||||
|
* @page: The page to decrypt. Must be locked.
|
||||||
|
*
|
||||||
|
* Decrypts page in-place using the ctx encryption context.
|
||||||
|
*
|
||||||
|
* Called from the read completion callback.
|
||||||
|
*
|
||||||
|
* Return: Zero on success, non-zero otherwise.
|
||||||
|
*/
|
||||||
|
int ext4_decrypt(struct ext4_crypto_ctx *ctx, struct page *page)
|
||||||
|
{
|
||||||
|
BUG_ON(!PageLocked(page));
|
||||||
|
|
||||||
|
return ext4_page_crypto(ctx, page->mapping->host,
|
||||||
|
EXT4_DECRYPT, page->index, page, page);
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Convenience function which takes care of allocating and
|
||||||
|
* deallocating the encryption context
|
||||||
|
*/
|
||||||
|
int ext4_decrypt_one(struct inode *inode, struct page *page)
|
||||||
|
{
|
||||||
|
int ret;
|
||||||
|
|
||||||
|
struct ext4_crypto_ctx *ctx = ext4_get_crypto_ctx(inode);
|
||||||
|
|
||||||
|
if (!ctx)
|
||||||
|
return -ENOMEM;
|
||||||
|
ret = ext4_decrypt(ctx, page);
|
||||||
|
ext4_release_crypto_ctx(ctx);
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
|
||||||
|
int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex)
|
||||||
|
{
|
||||||
|
struct ext4_crypto_ctx *ctx;
|
||||||
|
struct page *ciphertext_page = NULL;
|
||||||
|
struct bio *bio;
|
||||||
|
ext4_lblk_t lblk = ex->ee_block;
|
||||||
|
ext4_fsblk_t pblk = ext4_ext_pblock(ex);
|
||||||
|
unsigned int len = ext4_ext_get_actual_len(ex);
|
||||||
|
int err = 0;
|
||||||
|
|
||||||
|
BUG_ON(inode->i_sb->s_blocksize != PAGE_CACHE_SIZE);
|
||||||
|
|
||||||
|
ctx = ext4_get_crypto_ctx(inode);
|
||||||
|
if (IS_ERR(ctx))
|
||||||
|
return PTR_ERR(ctx);
|
||||||
|
|
||||||
|
ciphertext_page = alloc_page(GFP_NOFS);
|
||||||
|
if (!ciphertext_page) {
|
||||||
|
/* This is a potential bottleneck, but at least we'll have
|
||||||
|
* forward progress. */
|
||||||
|
ciphertext_page = mempool_alloc(ext4_bounce_page_pool,
|
||||||
|
GFP_NOFS);
|
||||||
|
if (WARN_ON_ONCE(!ciphertext_page)) {
|
||||||
|
ciphertext_page = mempool_alloc(ext4_bounce_page_pool,
|
||||||
|
GFP_NOFS | __GFP_WAIT);
|
||||||
|
}
|
||||||
|
ctx->flags &= ~EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
|
||||||
|
} else {
|
||||||
|
ctx->flags |= EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
|
||||||
|
}
|
||||||
|
ctx->bounce_page = ciphertext_page;
|
||||||
|
|
||||||
|
while (len--) {
|
||||||
|
err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, lblk,
|
||||||
|
ZERO_PAGE(0), ciphertext_page);
|
||||||
|
if (err)
|
||||||
|
goto errout;
|
||||||
|
|
||||||
|
bio = bio_alloc(GFP_KERNEL, 1);
|
||||||
|
if (!bio) {
|
||||||
|
err = -ENOMEM;
|
||||||
|
goto errout;
|
||||||
|
}
|
||||||
|
bio->bi_bdev = inode->i_sb->s_bdev;
|
||||||
|
bio->bi_iter.bi_sector = pblk;
|
||||||
|
err = bio_add_page(bio, ciphertext_page,
|
||||||
|
inode->i_sb->s_blocksize, 0);
|
||||||
|
if (err) {
|
||||||
|
bio_put(bio);
|
||||||
|
goto errout;
|
||||||
|
}
|
||||||
|
err = submit_bio_wait(WRITE, bio);
|
||||||
|
if (err)
|
||||||
|
goto errout;
|
||||||
|
}
|
||||||
|
err = 0;
|
||||||
|
errout:
|
||||||
|
ext4_release_crypto_ctx(ctx);
|
||||||
|
return err;
|
||||||
|
}
|
||||||
|
|
||||||
|
bool ext4_valid_contents_enc_mode(uint32_t mode)
|
||||||
|
{
|
||||||
|
return (mode == EXT4_ENCRYPTION_MODE_AES_256_XTS);
|
||||||
|
}
|
||||||
|
|
||||||
|
/**
|
||||||
|
* ext4_validate_encryption_key_size() - Validate the encryption key size
|
||||||
|
* @mode: The key mode.
|
||||||
|
* @size: The key size to validate.
|
||||||
|
*
|
||||||
|
* Return: The validated key size for @mode. Zero if invalid.
|
||||||
|
*/
|
||||||
|
uint32_t ext4_validate_encryption_key_size(uint32_t mode, uint32_t size)
|
||||||
|
{
|
||||||
|
if (size == ext4_encryption_key_size(mode))
|
||||||
|
return size;
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
@ -52,6 +52,13 @@ static int ext4_create_encryption_context_from_policy(
|
||||||
ctx.format = EXT4_ENCRYPTION_CONTEXT_FORMAT_V1;
|
ctx.format = EXT4_ENCRYPTION_CONTEXT_FORMAT_V1;
|
||||||
memcpy(ctx.master_key_descriptor, policy->master_key_descriptor,
|
memcpy(ctx.master_key_descriptor, policy->master_key_descriptor,
|
||||||
EXT4_KEY_DESCRIPTOR_SIZE);
|
EXT4_KEY_DESCRIPTOR_SIZE);
|
||||||
|
if (!ext4_valid_contents_enc_mode(policy->contents_encryption_mode)) {
|
||||||
|
printk(KERN_WARNING
|
||||||
|
"%s: Invalid contents encryption mode %d\n", __func__,
|
||||||
|
policy->contents_encryption_mode);
|
||||||
|
res = -EINVAL;
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
ctx.contents_encryption_mode = policy->contents_encryption_mode;
|
ctx.contents_encryption_mode = policy->contents_encryption_mode;
|
||||||
ctx.filenames_encryption_mode = policy->filenames_encryption_mode;
|
ctx.filenames_encryption_mode = policy->filenames_encryption_mode;
|
||||||
BUILD_BUG_ON(sizeof(ctx.nonce) != EXT4_KEY_DERIVATION_NONCE_SIZE);
|
BUILD_BUG_ON(sizeof(ctx.nonce) != EXT4_KEY_DERIVATION_NONCE_SIZE);
|
||||||
|
|
@ -60,6 +67,7 @@ static int ext4_create_encryption_context_from_policy(
|
||||||
res = ext4_xattr_set(inode, EXT4_XATTR_INDEX_ENCRYPTION,
|
res = ext4_xattr_set(inode, EXT4_XATTR_INDEX_ENCRYPTION,
|
||||||
EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, &ctx,
|
EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, &ctx,
|
||||||
sizeof(ctx), 0);
|
sizeof(ctx), 0);
|
||||||
|
out:
|
||||||
if (!res)
|
if (!res)
|
||||||
ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
|
ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
|
||||||
return res;
|
return res;
|
||||||
|
|
|
||||||
|
|
@ -951,6 +951,11 @@ struct ext4_inode_info {
|
||||||
|
|
||||||
/* Precomputed uuid+inum+igen checksum for seeding inode checksums */
|
/* Precomputed uuid+inum+igen checksum for seeding inode checksums */
|
||||||
__u32 i_csum_seed;
|
__u32 i_csum_seed;
|
||||||
|
|
||||||
|
#ifdef CONFIG_EXT4_FS_ENCRYPTION
|
||||||
|
/* Encryption params */
|
||||||
|
struct ext4_encryption_key i_encryption_key;
|
||||||
|
#endif
|
||||||
};
|
};
|
||||||
|
|
||||||
/*
|
/*
|
||||||
|
|
@ -1366,6 +1371,12 @@ struct ext4_sb_info {
|
||||||
struct ratelimit_state s_err_ratelimit_state;
|
struct ratelimit_state s_err_ratelimit_state;
|
||||||
struct ratelimit_state s_warning_ratelimit_state;
|
struct ratelimit_state s_warning_ratelimit_state;
|
||||||
struct ratelimit_state s_msg_ratelimit_state;
|
struct ratelimit_state s_msg_ratelimit_state;
|
||||||
|
|
||||||
|
#ifdef CONFIG_EXT4_FS_ENCRYPTION
|
||||||
|
/* Encryption */
|
||||||
|
uint32_t s_file_encryption_mode;
|
||||||
|
uint32_t s_dir_encryption_mode;
|
||||||
|
#endif
|
||||||
};
|
};
|
||||||
|
|
||||||
static inline struct ext4_sb_info *EXT4_SB(struct super_block *sb)
|
static inline struct ext4_sb_info *EXT4_SB(struct super_block *sb)
|
||||||
|
|
@ -1481,6 +1492,18 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei)
|
||||||
#define EXT4_SB(sb) (sb)
|
#define EXT4_SB(sb) (sb)
|
||||||
#endif
|
#endif
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Returns true if the inode is inode is encrypted
|
||||||
|
*/
|
||||||
|
static inline int ext4_encrypted_inode(struct inode *inode)
|
||||||
|
{
|
||||||
|
#ifdef CONFIG_EXT4_FS_ENCRYPTION
|
||||||
|
return ext4_test_inode_flag(inode, EXT4_INODE_ENCRYPT);
|
||||||
|
#else
|
||||||
|
return 0;
|
||||||
|
#endif
|
||||||
|
}
|
||||||
|
|
||||||
#define NEXT_ORPHAN(inode) EXT4_I(inode)->i_dtime
|
#define NEXT_ORPHAN(inode) EXT4_I(inode)->i_dtime
|
||||||
|
|
||||||
/*
|
/*
|
||||||
|
|
@ -2026,6 +2049,35 @@ int ext4_process_policy(const struct ext4_encryption_policy *policy,
|
||||||
int ext4_get_policy(struct inode *inode,
|
int ext4_get_policy(struct inode *inode,
|
||||||
struct ext4_encryption_policy *policy);
|
struct ext4_encryption_policy *policy);
|
||||||
|
|
||||||
|
/* crypto.c */
|
||||||
|
bool ext4_valid_contents_enc_mode(uint32_t mode);
|
||||||
|
uint32_t ext4_validate_encryption_key_size(uint32_t mode, uint32_t size);
|
||||||
|
extern struct workqueue_struct *ext4_read_workqueue;
|
||||||
|
struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode);
|
||||||
|
void ext4_release_crypto_ctx(struct ext4_crypto_ctx *ctx);
|
||||||
|
void ext4_restore_control_page(struct page *data_page);
|
||||||
|
struct page *ext4_encrypt(struct inode *inode,
|
||||||
|
struct page *plaintext_page);
|
||||||
|
int ext4_decrypt(struct ext4_crypto_ctx *ctx, struct page *page);
|
||||||
|
int ext4_decrypt_one(struct inode *inode, struct page *page);
|
||||||
|
int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex);
|
||||||
|
|
||||||
|
#ifdef CONFIG_EXT4_FS_ENCRYPTION
|
||||||
|
int ext4_init_crypto(void);
|
||||||
|
void ext4_exit_crypto(void);
|
||||||
|
static inline int ext4_sb_has_crypto(struct super_block *sb)
|
||||||
|
{
|
||||||
|
return EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_ENCRYPT);
|
||||||
|
}
|
||||||
|
#else
|
||||||
|
static inline int ext4_init_crypto(void) { return 0; }
|
||||||
|
static inline void ext4_exit_crypto(void) { }
|
||||||
|
static inline int ext4_sb_has_crypto(struct super_block *sb)
|
||||||
|
{
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
#endif
|
||||||
|
|
||||||
/* dir.c */
|
/* dir.c */
|
||||||
extern int __ext4_check_dir_entry(const char *, unsigned int, struct inode *,
|
extern int __ext4_check_dir_entry(const char *, unsigned int, struct inode *,
|
||||||
struct file *,
|
struct file *,
|
||||||
|
|
|
||||||
|
|
@ -46,4 +46,59 @@ struct ext4_encryption_context {
|
||||||
char nonce[EXT4_KEY_DERIVATION_NONCE_SIZE];
|
char nonce[EXT4_KEY_DERIVATION_NONCE_SIZE];
|
||||||
} __attribute__((__packed__));
|
} __attribute__((__packed__));
|
||||||
|
|
||||||
|
/* Encryption parameters */
|
||||||
|
#define EXT4_XTS_TWEAK_SIZE 16
|
||||||
|
#define EXT4_AES_128_ECB_KEY_SIZE 16
|
||||||
|
#define EXT4_AES_256_GCM_KEY_SIZE 32
|
||||||
|
#define EXT4_AES_256_CBC_KEY_SIZE 32
|
||||||
|
#define EXT4_AES_256_CTS_KEY_SIZE 32
|
||||||
|
#define EXT4_AES_256_XTS_KEY_SIZE 64
|
||||||
|
#define EXT4_MAX_KEY_SIZE 64
|
||||||
|
|
||||||
|
struct ext4_encryption_key {
|
||||||
|
uint32_t mode;
|
||||||
|
char raw[EXT4_MAX_KEY_SIZE];
|
||||||
|
uint32_t size;
|
||||||
|
};
|
||||||
|
|
||||||
|
#define EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001
|
||||||
|
#define EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL 0x00000002
|
||||||
|
|
||||||
|
struct ext4_crypto_ctx {
|
||||||
|
struct crypto_tfm *tfm; /* Crypto API context */
|
||||||
|
struct page *bounce_page; /* Ciphertext page on write path */
|
||||||
|
struct page *control_page; /* Original page on write path */
|
||||||
|
struct bio *bio; /* The bio for this context */
|
||||||
|
struct work_struct work; /* Work queue for read complete path */
|
||||||
|
struct list_head free_list; /* Free list */
|
||||||
|
int flags; /* Flags */
|
||||||
|
int mode; /* Encryption mode for tfm */
|
||||||
|
};
|
||||||
|
|
||||||
|
struct ext4_completion_result {
|
||||||
|
struct completion completion;
|
||||||
|
int res;
|
||||||
|
};
|
||||||
|
|
||||||
|
#define DECLARE_EXT4_COMPLETION_RESULT(ecr) \
|
||||||
|
struct ext4_completion_result ecr = { \
|
||||||
|
COMPLETION_INITIALIZER((ecr).completion), 0 }
|
||||||
|
|
||||||
|
static inline int ext4_encryption_key_size(int mode)
|
||||||
|
{
|
||||||
|
switch (mode) {
|
||||||
|
case EXT4_ENCRYPTION_MODE_AES_256_XTS:
|
||||||
|
return EXT4_AES_256_XTS_KEY_SIZE;
|
||||||
|
case EXT4_ENCRYPTION_MODE_AES_256_GCM:
|
||||||
|
return EXT4_AES_256_GCM_KEY_SIZE;
|
||||||
|
case EXT4_ENCRYPTION_MODE_AES_256_CBC:
|
||||||
|
return EXT4_AES_256_CBC_KEY_SIZE;
|
||||||
|
case EXT4_ENCRYPTION_MODE_AES_256_CTS:
|
||||||
|
return EXT4_AES_256_CTS_KEY_SIZE;
|
||||||
|
default:
|
||||||
|
BUG();
|
||||||
|
}
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
#endif /* _EXT4_CRYPTO_H */
|
#endif /* _EXT4_CRYPTO_H */
|
||||||
|
|
|
||||||
|
|
@ -876,6 +876,9 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)
|
||||||
atomic_set(&ei->i_ioend_count, 0);
|
atomic_set(&ei->i_ioend_count, 0);
|
||||||
atomic_set(&ei->i_unwritten, 0);
|
atomic_set(&ei->i_unwritten, 0);
|
||||||
INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work);
|
INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work);
|
||||||
|
#ifdef CONFIG_EXT4_FS_ENCRYPTION
|
||||||
|
ei->i_encryption_key.mode = EXT4_ENCRYPTION_MODE_INVALID;
|
||||||
|
#endif
|
||||||
|
|
||||||
return &ei->vfs_inode;
|
return &ei->vfs_inode;
|
||||||
}
|
}
|
||||||
|
|
@ -3431,6 +3434,11 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
|
||||||
if (sb->s_bdev->bd_part)
|
if (sb->s_bdev->bd_part)
|
||||||
sbi->s_sectors_written_start =
|
sbi->s_sectors_written_start =
|
||||||
part_stat_read(sb->s_bdev->bd_part, sectors[1]);
|
part_stat_read(sb->s_bdev->bd_part, sectors[1]);
|
||||||
|
#ifdef CONFIG_EXT4_FS_ENCRYPTION
|
||||||
|
/* Modes of operations for file and directory encryption. */
|
||||||
|
sbi->s_file_encryption_mode = EXT4_ENCRYPTION_MODE_AES_256_XTS;
|
||||||
|
sbi->s_dir_encryption_mode = EXT4_ENCRYPTION_MODE_INVALID;
|
||||||
|
#endif
|
||||||
|
|
||||||
/* Cleanup superblock name */
|
/* Cleanup superblock name */
|
||||||
for (cp = sb->s_id; (cp = strchr(cp, '/'));)
|
for (cp = sb->s_id; (cp = strchr(cp, '/'));)
|
||||||
|
|
|
||||||
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