diff options
| -rw-r--r-- | fs/f2fs/Makefile | 2 | ||||
| -rw-r--r-- | fs/f2fs/crypto.c | 560 | ||||
| -rw-r--r-- | fs/f2fs/f2fs.h | 25 | ||||
| -rw-r--r-- | fs/f2fs/super.c | 3 |
4 files changed, 589 insertions, 1 deletions
diff --git a/fs/f2fs/Makefile b/fs/f2fs/Makefile index 7864f4f02ca6..a79907b4f9f5 100644 --- a/fs/f2fs/Makefile +++ b/fs/f2fs/Makefile @@ -6,4 +6,4 @@ f2fs-$(CONFIG_F2FS_STAT_FS) += debug.o f2fs-$(CONFIG_F2FS_FS_XATTR) += xattr.o f2fs-$(CONFIG_F2FS_FS_POSIX_ACL) += acl.o f2fs-$(CONFIG_F2FS_IO_TRACE) += trace.o -f2fs-$(CONFIG_F2FS_FS_ENCRYPTION) += crypto_policy.o +f2fs-$(CONFIG_F2FS_FS_ENCRYPTION) += crypto_policy.o crypto.o diff --git a/fs/f2fs/crypto.c b/fs/f2fs/crypto.c new file mode 100644 index 000000000000..c910fa722e5c --- /dev/null +++ b/fs/f2fs/crypto.c @@ -0,0 +1,560 @@ +/* + * 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); + +struct workqueue_struct *f2fs_read_workqueue; +static DEFINE_MUTEX(crypto_init); + +/** + * 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->bounce_page) { + if (ctx->flags & F2FS_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL) + __free_page(ctx->bounce_page); + else + mempool_free(ctx->bounce_page, f2fs_bounce_page_pool); + ctx->bounce_page = NULL; + } + ctx->control_page = NULL; + if (ctx->flags & F2FS_CTX_REQUIRES_FREE_ENCRYPT_FL) { + if (ctx->tfm) + crypto_free_tfm(ctx->tfm); + kfree(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_alloc_and_init_crypto_ctx() - Allocates and inits an encryption context + * @mask: The allocation mask. + * + * Return: An allocated and initialized encryption context on success. An error + * value or NULL otherwise. + */ +static struct f2fs_crypto_ctx *f2fs_alloc_and_init_crypto_ctx(gfp_t mask) +{ + struct f2fs_crypto_ctx *ctx = kzalloc(sizeof(struct f2fs_crypto_ctx), + mask); + + if (!ctx) + return ERR_PTR(-ENOMEM); + return ctx; +} + +/** + * 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; + int res = 0; + unsigned long flags; + struct f2fs_crypt_info *ci = F2FS_I(inode)->i_crypt_info; + + BUG_ON(ci == NULL); + /* + * 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 = f2fs_alloc_and_init_crypto_ctx(GFP_NOFS); + if (IS_ERR(ctx)) { + res = PTR_ERR(ctx); + goto out; + } + ctx->flags |= F2FS_CTX_REQUIRES_FREE_ENCRYPT_FL; + } else { + ctx->flags &= ~F2FS_CTX_REQUIRES_FREE_ENCRYPT_FL; + } + + /* + * Allocate a new Crypto API context if we don't already have + * one or if it isn't the right mode. + */ + BUG_ON(ci->ci_mode == F2FS_ENCRYPTION_MODE_INVALID); + if (ctx->tfm && (ctx->mode != ci->ci_mode)) { + crypto_free_tfm(ctx->tfm); + ctx->tfm = NULL; + ctx->mode = F2FS_ENCRYPTION_MODE_INVALID; + } + if (!ctx->tfm) { + switch (ci->ci_mode) { + case F2FS_ENCRYPTION_MODE_AES_256_XTS: + ctx->tfm = crypto_ablkcipher_tfm( + crypto_alloc_ablkcipher("xts(aes)", 0, 0)); + break; + case F2FS_ENCRYPTION_MODE_AES_256_GCM: + /* + * TODO(mhalcrow): AEAD w/ gcm(aes); + * crypto_aead_setauthsize() + */ + ctx->tfm = ERR_PTR(-ENOTSUPP); + break; + default: + BUG(); + } + if (IS_ERR_OR_NULL(ctx->tfm)) { + res = PTR_ERR(ctx->tfm); + ctx->tfm = NULL; + goto out; + } + ctx->mode = ci->ci_mode; + } + BUG_ON(ci->ci_size != f2fs_encryption_key_size(ci->ci_mode)); + + /* + * There shouldn't be a bounce page attached to the crypto + * context at this point. + */ + BUG_ON(ctx->bounce_page); + +out: + if (res) { + if (!IS_ERR_OR_NULL(ctx)) + f2fs_release_crypto_ctx(ctx); + ctx = ERR_PTR(res); + } + 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, work); + struct bio *bio = ctx->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(ctx, 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->work, completion_pages); + ctx->bio = bio; + queue_work(f2fs_read_workqueue, &ctx->work); +} + +/** + * f2fs_exit_crypto() - Shutdown the f2fs encryption system + */ +void f2fs_exit_crypto(void) +{ + struct f2fs_crypto_ctx *pos, *n; + + list_for_each_entry_safe(pos, n, &f2fs_free_crypto_ctxs, free_list) { + if (pos->bounce_page) { + if (pos->flags & + F2FS_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL) + __free_page(pos->bounce_page); + else + mempool_free(pos->bounce_page, + f2fs_bounce_page_pool); + } + if (pos->tfm) + crypto_free_tfm(pos->tfm); + kfree(pos); + } + INIT_LIST_HEAD(&f2fs_free_crypto_ctxs); + if (f2fs_bounce_page_pool) + mempool_destroy(f2fs_bounce_page_pool); + f2fs_bounce_page_pool = NULL; + if (f2fs_read_workqueue) + destroy_workqueue(f2fs_read_workqueue); + f2fs_read_workqueue = NULL; +} + +/** + * f2fs_init_crypto() - 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_init_crypto(void) +{ + int i, res; + + mutex_lock(&crypto_init); + if (f2fs_read_workqueue) + goto already_initialized; + + f2fs_read_workqueue = alloc_workqueue("f2fs_crypto", WQ_HIGHPRI, 0); + if (!f2fs_read_workqueue) { + res = -ENOMEM; + goto fail; + } + + for (i = 0; i < num_prealloc_crypto_ctxs; i++) { + struct f2fs_crypto_ctx *ctx; + + ctx = f2fs_alloc_and_init_crypto_ctx(GFP_KERNEL); + if (IS_ERR(ctx)) { + res = PTR_ERR(ctx); + goto fail; + } + list_add(&ctx->free_list, &f2fs_free_crypto_ctxs); + } + + f2fs_bounce_page_pool = + mempool_create_page_pool(num_prealloc_crypto_pages, 0); + if (!f2fs_bounce_page_pool) { + res = -ENOMEM; + goto fail; + } +already_initialized: + mutex_unlock(&crypto_init); + return 0; +fail: + f2fs_exit_crypto(); + mutex_unlock(&crypto_init); + 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->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 f2fs_crypto_ctx *ctx, + 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_inode_info *fi = F2FS_I(inode); + struct crypto_ablkcipher *atfm = __crypto_ablkcipher_cast(ctx->tfm); + int res = 0; + + BUG_ON(!ctx->tfm); + BUG_ON(ctx->mode != fi->i_crypt_info->ci_mode); + + if (ctx->mode != F2FS_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, fi->i_crypt_info->ci_raw, + fi->i_crypt_info->ci_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, + 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) { + 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; +} + +/** + * 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_page(GFP_NOFS); + if (!ciphertext_page) { + /* + * This is a potential bottleneck, but at least we'll have + * forward progress. + */ + ciphertext_page = mempool_alloc(f2fs_bounce_page_pool, + GFP_NOFS); + if (WARN_ON_ONCE(!ciphertext_page)) + ciphertext_page = mempool_alloc(f2fs_bounce_page_pool, + GFP_NOFS | __GFP_WAIT); + ctx->flags &= ~F2FS_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL; + } else { + ctx->flags |= F2FS_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL; + } + ctx->bounce_page = ciphertext_page; + ctx->control_page = plaintext_page; + err = f2fs_page_crypto(ctx, inode, F2FS_ENCRYPT, plaintext_page->index, + plaintext_page, ciphertext_page); + if (err) { + f2fs_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; +} + +/** + * 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 f2fs_crypto_ctx *ctx, struct page *page) +{ + BUG_ON(!PageLocked(page)); + + return f2fs_page_crypto(ctx, page->mapping->host, + F2FS_DECRYPT, page->index, page, page); +} + +/* + * Convenience function which takes care of allocating and + * deallocating the encryption context + */ +int f2fs_decrypt_one(struct inode *inode, struct page *page) +{ + struct f2fs_crypto_ctx *ctx = f2fs_get_crypto_ctx(inode); + int ret; + + if (!ctx) + return -ENOMEM; + ret = f2fs_decrypt(ctx, page); + f2fs_release_crypto_ctx(ctx); + return ret; +} + +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; +} diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 709660bd926a..b0490cb58b97 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -1962,4 +1962,29 @@ int f2fs_is_child_context_consistent_with_parent(struct inode *, int f2fs_inherit_context(struct inode *, struct inode *, struct page *); int f2fs_process_policy(const struct f2fs_encryption_policy *, struct inode *); int f2fs_get_policy(struct inode *, struct f2fs_encryption_policy *); + +/* crypt.c */ +extern struct workqueue_struct *f2fs_read_workqueue; +bool f2fs_valid_contents_enc_mode(uint32_t); +uint32_t f2fs_validate_encryption_key_size(uint32_t, uint32_t); +struct f2fs_crypto_ctx *f2fs_get_crypto_ctx(struct inode *); +void f2fs_release_crypto_ctx(struct f2fs_crypto_ctx *); +struct page *f2fs_encrypt(struct inode *, struct page *); +int f2fs_decrypt(struct f2fs_crypto_ctx *, struct page *); +int f2fs_decrypt_one(struct inode *, struct page *); +void f2fs_end_io_crypto_work(struct f2fs_crypto_ctx *, struct bio *); + +#ifdef CONFIG_F2FS_FS_ENCRYPTION +void f2fs_restore_and_release_control_page(struct page **); +void f2fs_restore_control_page(struct page *); + +int f2fs_init_crypto(void); +void f2fs_exit_crypto(void); +#else +static inline void f2fs_restore_and_release_control_page(struct page **p) { } +static inline void f2fs_restore_control_page(struct page *p) { } + +static inline int f2fs_init_crypto(void) { return 0; } +static inline void f2fs_exit_crypto(void) { } +#endif #endif diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 138fa938c291..d61f74ab4a03 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -416,6 +416,9 @@ static struct inode *f2fs_alloc_inode(struct super_block *sb) /* Will be used by directory only */ fi->i_dir_level = F2FS_SB(sb)->dir_level; +#ifdef CONFIG_F2FS_FS_ENCRYPTION + fi->i_crypt_info = NULL; +#endif return &fi->vfs_inode; } |