diff options
Diffstat (limited to 'fs/f2fs/crypto.c')
| -rw-r--r-- | fs/f2fs/crypto.c | 473 |
1 files changed, 0 insertions, 473 deletions
diff --git a/fs/f2fs/crypto.c b/fs/f2fs/crypto.c deleted file mode 100644 index 3ef37868d0c7..000000000000 --- a/fs/f2fs/crypto.c +++ /dev/null @@ -1,473 +0,0 @@ -/* - * linux/fs/f2fs/crypto.c - * - * Copied from linux/fs/ext4/crypto.c - * - * Copyright (C) 2015, Google, Inc. - * Copyright (C) 2015, Motorola Mobility - * - * This contains encryption functions for f2fs - * - * Written by Michael Halcrow, 2014. - * - * Filename encryption additions - * Uday Savagaonkar, 2014 - * Encryption policy handling additions - * Ildar Muslukhov, 2014 - * Remove ext4_encrypted_zeroout(), - * add f2fs_restore_and_release_control_page() - * Jaegeuk Kim, 2015. - * - * This has not yet undergone a rigorous security audit. - * - * The usage of AES-XTS should conform to recommendations in NIST - * Special Publication 800-38E and IEEE P1619/D16. - */ -#include <crypto/hash.h> -#include <crypto/sha.h> -#include <keys/user-type.h> -#include <keys/encrypted-type.h> -#include <linux/crypto.h> -#include <linux/ecryptfs.h> -#include <linux/gfp.h> -#include <linux/kernel.h> -#include <linux/key.h> -#include <linux/list.h> -#include <linux/mempool.h> -#include <linux/module.h> -#include <linux/mutex.h> -#include <linux/random.h> -#include <linux/scatterlist.h> -#include <linux/spinlock_types.h> -#include <linux/f2fs_fs.h> -#include <linux/ratelimit.h> -#include <linux/bio.h> - -#include "f2fs.h" -#include "xattr.h" - -/* Encryption added and removed here! (L: */ - -static unsigned int num_prealloc_crypto_pages = 32; -static unsigned int num_prealloc_crypto_ctxs = 128; - -module_param(num_prealloc_crypto_pages, uint, 0444); -MODULE_PARM_DESC(num_prealloc_crypto_pages, - "Number of crypto pages to preallocate"); -module_param(num_prealloc_crypto_ctxs, uint, 0444); -MODULE_PARM_DESC(num_prealloc_crypto_ctxs, - "Number of crypto contexts to preallocate"); - -static mempool_t *f2fs_bounce_page_pool; - -static LIST_HEAD(f2fs_free_crypto_ctxs); -static DEFINE_SPINLOCK(f2fs_crypto_ctx_lock); - -static struct workqueue_struct *f2fs_read_workqueue; -static DEFINE_MUTEX(crypto_init); - -static struct kmem_cache *f2fs_crypto_ctx_cachep; -struct kmem_cache *f2fs_crypt_info_cachep; - -/** - * f2fs_release_crypto_ctx() - Releases an encryption context - * @ctx: The encryption context to release. - * - * If the encryption context was allocated from the pre-allocated pool, returns - * it to that pool. Else, frees it. - * - * If there's a bounce page in the context, this frees that. - */ -void f2fs_release_crypto_ctx(struct f2fs_crypto_ctx *ctx) -{ - unsigned long flags; - - if (ctx->flags & F2FS_WRITE_PATH_FL && ctx->w.bounce_page) { - mempool_free(ctx->w.bounce_page, f2fs_bounce_page_pool); - ctx->w.bounce_page = NULL; - } - ctx->w.control_page = NULL; - if (ctx->flags & F2FS_CTX_REQUIRES_FREE_ENCRYPT_FL) { - kmem_cache_free(f2fs_crypto_ctx_cachep, ctx); - } else { - spin_lock_irqsave(&f2fs_crypto_ctx_lock, flags); - list_add(&ctx->free_list, &f2fs_free_crypto_ctxs); - spin_unlock_irqrestore(&f2fs_crypto_ctx_lock, flags); - } -} - -/** - * f2fs_get_crypto_ctx() - Gets an encryption context - * @inode: The inode for which we are doing the crypto - * - * Allocates and initializes an encryption context. - * - * Return: An allocated and initialized encryption context on success; error - * value or NULL otherwise. - */ -struct f2fs_crypto_ctx *f2fs_get_crypto_ctx(struct inode *inode) -{ - struct f2fs_crypto_ctx *ctx = NULL; - unsigned long flags; - struct f2fs_crypt_info *ci = F2FS_I(inode)->i_crypt_info; - - if (ci == NULL) - return ERR_PTR(-ENOKEY); - - /* - * We first try getting the ctx from a free list because in - * the common case the ctx will have an allocated and - * initialized crypto tfm, so it's probably a worthwhile - * optimization. For the bounce page, we first try getting it - * from the kernel allocator because that's just about as fast - * as getting it from a list and because a cache of free pages - * should generally be a "last resort" option for a filesystem - * to be able to do its job. - */ - spin_lock_irqsave(&f2fs_crypto_ctx_lock, flags); - ctx = list_first_entry_or_null(&f2fs_free_crypto_ctxs, - struct f2fs_crypto_ctx, free_list); - if (ctx) - list_del(&ctx->free_list); - spin_unlock_irqrestore(&f2fs_crypto_ctx_lock, flags); - if (!ctx) { - ctx = kmem_cache_zalloc(f2fs_crypto_ctx_cachep, GFP_NOFS); - if (!ctx) - return ERR_PTR(-ENOMEM); - ctx->flags |= F2FS_CTX_REQUIRES_FREE_ENCRYPT_FL; - } else { - ctx->flags &= ~F2FS_CTX_REQUIRES_FREE_ENCRYPT_FL; - } - ctx->flags &= ~F2FS_WRITE_PATH_FL; - return ctx; -} - -/* - * Call f2fs_decrypt on every single page, reusing the encryption - * context. - */ -static void completion_pages(struct work_struct *work) -{ - struct f2fs_crypto_ctx *ctx = - container_of(work, struct f2fs_crypto_ctx, r.work); - struct bio *bio = ctx->r.bio; - struct bio_vec *bv; - int i; - - bio_for_each_segment_all(bv, bio, i) { - struct page *page = bv->bv_page; - int ret = f2fs_decrypt(page); - - if (ret) { - WARN_ON_ONCE(1); - SetPageError(page); - } else - SetPageUptodate(page); - unlock_page(page); - } - f2fs_release_crypto_ctx(ctx); - bio_put(bio); -} - -void f2fs_end_io_crypto_work(struct f2fs_crypto_ctx *ctx, struct bio *bio) -{ - INIT_WORK(&ctx->r.work, completion_pages); - ctx->r.bio = bio; - queue_work(f2fs_read_workqueue, &ctx->r.work); -} - -static void f2fs_crypto_destroy(void) -{ - struct f2fs_crypto_ctx *pos, *n; - - list_for_each_entry_safe(pos, n, &f2fs_free_crypto_ctxs, free_list) - kmem_cache_free(f2fs_crypto_ctx_cachep, pos); - INIT_LIST_HEAD(&f2fs_free_crypto_ctxs); - if (f2fs_bounce_page_pool) - mempool_destroy(f2fs_bounce_page_pool); - f2fs_bounce_page_pool = NULL; -} - -/** - * f2fs_crypto_initialize() - Set up for f2fs encryption. - * - * We only call this when we start accessing encrypted files, since it - * results in memory getting allocated that wouldn't otherwise be used. - * - * Return: Zero on success, non-zero otherwise. - */ -int f2fs_crypto_initialize(void) -{ - int i, res = -ENOMEM; - - if (f2fs_bounce_page_pool) - return 0; - - mutex_lock(&crypto_init); - if (f2fs_bounce_page_pool) - goto already_initialized; - - for (i = 0; i < num_prealloc_crypto_ctxs; i++) { - struct f2fs_crypto_ctx *ctx; - - ctx = kmem_cache_zalloc(f2fs_crypto_ctx_cachep, GFP_KERNEL); - if (!ctx) - goto fail; - list_add(&ctx->free_list, &f2fs_free_crypto_ctxs); - } - - /* must be allocated at the last step to avoid race condition above */ - f2fs_bounce_page_pool = - mempool_create_page_pool(num_prealloc_crypto_pages, 0); - if (!f2fs_bounce_page_pool) - goto fail; - -already_initialized: - mutex_unlock(&crypto_init); - return 0; -fail: - f2fs_crypto_destroy(); - mutex_unlock(&crypto_init); - return res; -} - -/** - * f2fs_exit_crypto() - Shutdown the f2fs encryption system - */ -void f2fs_exit_crypto(void) -{ - f2fs_crypto_destroy(); - - if (f2fs_read_workqueue) - destroy_workqueue(f2fs_read_workqueue); - if (f2fs_crypto_ctx_cachep) - kmem_cache_destroy(f2fs_crypto_ctx_cachep); - if (f2fs_crypt_info_cachep) - kmem_cache_destroy(f2fs_crypt_info_cachep); -} - -int __init f2fs_init_crypto(void) -{ - int res = -ENOMEM; - - f2fs_read_workqueue = alloc_workqueue("f2fs_crypto", WQ_HIGHPRI, 0); - if (!f2fs_read_workqueue) - goto fail; - - f2fs_crypto_ctx_cachep = KMEM_CACHE(f2fs_crypto_ctx, - SLAB_RECLAIM_ACCOUNT); - if (!f2fs_crypto_ctx_cachep) - goto fail; - - f2fs_crypt_info_cachep = KMEM_CACHE(f2fs_crypt_info, - SLAB_RECLAIM_ACCOUNT); - if (!f2fs_crypt_info_cachep) - goto fail; - - return 0; -fail: - f2fs_exit_crypto(); - return res; -} - -void f2fs_restore_and_release_control_page(struct page **page) -{ - struct f2fs_crypto_ctx *ctx; - struct page *bounce_page; - - /* The bounce data pages are unmapped. */ - if ((*page)->mapping) - return; - - /* The bounce data page is unmapped. */ - bounce_page = *page; - ctx = (struct f2fs_crypto_ctx *)page_private(bounce_page); - - /* restore control page */ - *page = ctx->w.control_page; - - f2fs_restore_control_page(bounce_page); -} - -void f2fs_restore_control_page(struct page *data_page) -{ - struct f2fs_crypto_ctx *ctx = - (struct f2fs_crypto_ctx *)page_private(data_page); - - set_page_private(data_page, (unsigned long)NULL); - ClearPagePrivate(data_page); - unlock_page(data_page); - f2fs_release_crypto_ctx(ctx); -} - -/** - * f2fs_crypt_complete() - The completion callback for page encryption - * @req: The asynchronous encryption request context - * @res: The result of the encryption operation - */ -static void f2fs_crypt_complete(struct crypto_async_request *req, int res) -{ - struct f2fs_completion_result *ecr = req->data; - - if (res == -EINPROGRESS) - return; - ecr->res = res; - complete(&ecr->completion); -} - -typedef enum { - F2FS_DECRYPT = 0, - F2FS_ENCRYPT, -} f2fs_direction_t; - -static int f2fs_page_crypto(struct inode *inode, - f2fs_direction_t rw, - pgoff_t index, - struct page *src_page, - struct page *dest_page) -{ - u8 xts_tweak[F2FS_XTS_TWEAK_SIZE]; - struct ablkcipher_request *req = NULL; - DECLARE_F2FS_COMPLETION_RESULT(ecr); - struct scatterlist dst, src; - struct f2fs_crypt_info *ci = F2FS_I(inode)->i_crypt_info; - struct crypto_ablkcipher *tfm = ci->ci_ctfm; - int res = 0; - - req = ablkcipher_request_alloc(tfm, 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, - f2fs_crypt_complete, &ecr); - - BUILD_BUG_ON(F2FS_XTS_TWEAK_SIZE < sizeof(index)); - memcpy(xts_tweak, &index, sizeof(index)); - memset(&xts_tweak[sizeof(index)], 0, - F2FS_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 == F2FS_DECRYPT) - res = crypto_ablkcipher_decrypt(req); - else - res = crypto_ablkcipher_encrypt(req); - if (res == -EINPROGRESS || res == -EBUSY) { - 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; -} - -static struct page *alloc_bounce_page(struct f2fs_crypto_ctx *ctx) -{ - ctx->w.bounce_page = mempool_alloc(f2fs_bounce_page_pool, GFP_NOWAIT); - if (ctx->w.bounce_page == NULL) - return ERR_PTR(-ENOMEM); - ctx->flags |= F2FS_WRITE_PATH_FL; - return ctx->w.bounce_page; -} - -/** - * f2fs_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 - * f2fs_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 *f2fs_encrypt(struct inode *inode, - struct page *plaintext_page) -{ - struct f2fs_crypto_ctx *ctx; - struct page *ciphertext_page = NULL; - int err; - - BUG_ON(!PageLocked(plaintext_page)); - - ctx = f2fs_get_crypto_ctx(inode); - if (IS_ERR(ctx)) - return (struct page *)ctx; - - /* The encryption operation will require a bounce page. */ - ciphertext_page = alloc_bounce_page(ctx); - if (IS_ERR(ciphertext_page)) - goto err_out; - - ctx->w.control_page = plaintext_page; - err = f2fs_page_crypto(inode, F2FS_ENCRYPT, plaintext_page->index, - plaintext_page, ciphertext_page); - if (err) { - ciphertext_page = ERR_PTR(err); - goto err_out; - } - - SetPagePrivate(ciphertext_page); - set_page_private(ciphertext_page, (unsigned long)ctx); - lock_page(ciphertext_page); - return ciphertext_page; - -err_out: - f2fs_release_crypto_ctx(ctx); - return ciphertext_page; -} - -/** - * f2fs_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 f2fs_decrypt(struct page *page) -{ - BUG_ON(!PageLocked(page)); - - return f2fs_page_crypto(page->mapping->host, - F2FS_DECRYPT, page->index, page, page); -} - -bool f2fs_valid_contents_enc_mode(uint32_t mode) -{ - return (mode == F2FS_ENCRYPTION_MODE_AES_256_XTS); -} - -/** - * f2fs_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 f2fs_validate_encryption_key_size(uint32_t mode, uint32_t size) -{ - if (size == f2fs_encryption_key_size(mode)) - return size; - return 0; -} |