diff options
Diffstat (limited to 'fs/crypto')
| -rw-r--r-- | fs/crypto/Kconfig | 2 | ||||
| -rw-r--r-- | fs/crypto/crypto.c | 123 | ||||
| -rw-r--r-- | fs/crypto/fname.c | 8 | ||||
| -rw-r--r-- | fs/crypto/fscrypt_private.h | 93 | ||||
| -rw-r--r-- | fs/crypto/keyinfo.c | 8 | ||||
| -rw-r--r-- | fs/crypto/policy.c | 36 |
6 files changed, 208 insertions, 62 deletions
diff --git a/fs/crypto/Kconfig b/fs/crypto/Kconfig index 92348faf9865..f514978f6688 100644 --- a/fs/crypto/Kconfig +++ b/fs/crypto/Kconfig @@ -8,9 +8,7 @@ config FS_ENCRYPTION select CRYPTO_XTS select CRYPTO_CTS select CRYPTO_CTR - select CRYPTO_SHA256 select KEYS - select ENCRYPTED_KEYS help Enable encryption of files and directories. This feature is similar to ecryptfs, but it is more memory diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c index 98f87fe8f186..ac8e4f6a3773 100644 --- a/fs/crypto/crypto.c +++ b/fs/crypto/crypto.c @@ -27,7 +27,7 @@ #include <linux/bio.h> #include <linux/dcache.h> #include <linux/namei.h> -#include <linux/fscrypto.h> +#include "fscrypt_private.h" static unsigned int num_prealloc_crypto_pages = 32; static unsigned int num_prealloc_crypto_ctxs = 128; @@ -63,7 +63,7 @@ void fscrypt_release_ctx(struct fscrypt_ctx *ctx) { unsigned long flags; - if (ctx->flags & FS_WRITE_PATH_FL && ctx->w.bounce_page) { + if (ctx->flags & FS_CTX_HAS_BOUNCE_BUFFER_FL && ctx->w.bounce_page) { mempool_free(ctx->w.bounce_page, fscrypt_bounce_page_pool); ctx->w.bounce_page = NULL; } @@ -88,7 +88,7 @@ EXPORT_SYMBOL(fscrypt_release_ctx); * Return: An allocated and initialized encryption context on success; error * value or NULL otherwise. */ -struct fscrypt_ctx *fscrypt_get_ctx(struct inode *inode, gfp_t gfp_flags) +struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *inode, gfp_t gfp_flags) { struct fscrypt_ctx *ctx = NULL; struct fscrypt_info *ci = inode->i_crypt_info; @@ -121,7 +121,7 @@ struct fscrypt_ctx *fscrypt_get_ctx(struct inode *inode, gfp_t gfp_flags) } else { ctx->flags &= ~FS_CTX_REQUIRES_FREE_ENCRYPT_FL; } - ctx->flags &= ~FS_WRITE_PATH_FL; + ctx->flags &= ~FS_CTX_HAS_BOUNCE_BUFFER_FL; return ctx; } EXPORT_SYMBOL(fscrypt_get_ctx); @@ -146,9 +146,10 @@ typedef enum { FS_ENCRYPT, } fscrypt_direction_t; -static int do_page_crypto(struct inode *inode, - fscrypt_direction_t rw, pgoff_t index, +static int do_page_crypto(const struct inode *inode, + fscrypt_direction_t rw, u64 lblk_num, struct page *src_page, struct page *dest_page, + unsigned int len, unsigned int offs, gfp_t gfp_flags) { struct { @@ -162,6 +163,8 @@ static int do_page_crypto(struct inode *inode, struct crypto_skcipher *tfm = ci->ci_ctfm; int res = 0; + BUG_ON(len == 0); + req = skcipher_request_alloc(tfm, gfp_flags); if (!req) { printk_ratelimited(KERN_ERR @@ -175,14 +178,14 @@ static int do_page_crypto(struct inode *inode, page_crypt_complete, &ecr); BUILD_BUG_ON(sizeof(xts_tweak) != FS_XTS_TWEAK_SIZE); - xts_tweak.index = cpu_to_le64(index); + xts_tweak.index = cpu_to_le64(lblk_num); memset(xts_tweak.padding, 0, sizeof(xts_tweak.padding)); sg_init_table(&dst, 1); - sg_set_page(&dst, dest_page, PAGE_SIZE, 0); + sg_set_page(&dst, dest_page, len, offs); sg_init_table(&src, 1); - sg_set_page(&src, src_page, PAGE_SIZE, 0); - skcipher_request_set_crypt(req, &src, &dst, PAGE_SIZE, &xts_tweak); + sg_set_page(&src, src_page, len, offs); + skcipher_request_set_crypt(req, &src, &dst, len, &xts_tweak); if (rw == FS_DECRYPT) res = crypto_skcipher_decrypt(req); else @@ -207,34 +210,66 @@ static struct page *alloc_bounce_page(struct fscrypt_ctx *ctx, gfp_t gfp_flags) ctx->w.bounce_page = mempool_alloc(fscrypt_bounce_page_pool, gfp_flags); if (ctx->w.bounce_page == NULL) return ERR_PTR(-ENOMEM); - ctx->flags |= FS_WRITE_PATH_FL; + ctx->flags |= FS_CTX_HAS_BOUNCE_BUFFER_FL; return ctx->w.bounce_page; } /** * fscypt_encrypt_page() - Encrypts a page - * @inode: The inode for which the encryption should take place - * @plaintext_page: The page to encrypt. Must be locked. - * @gfp_flags: The gfp flag for memory allocation + * @inode: The inode for which the encryption should take place + * @page: The page to encrypt. Must be locked for bounce-page + * encryption. + * @len: Length of data to encrypt in @page and encrypted + * data in returned page. + * @offs: Offset of data within @page and returned + * page holding encrypted data. + * @lblk_num: Logical block number. This must be unique for multiple + * calls with same inode, except when overwriting + * previously written data. + * @gfp_flags: The gfp flag for memory allocation * - * Allocates a ciphertext page and encrypts plaintext_page into it using the ctx - * encryption context. + * Encrypts @page using the ctx encryption context. Performs encryption + * either in-place or into a newly allocated bounce page. + * Called on the page write path. * - * Called on the page write path. The caller must call + * Bounce page allocation is the default. + * In this case, the contents of @page are encrypted and stored in an + * allocated bounce page. @page has to be locked and the caller must call * fscrypt_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 + * In-place encryption is used by setting the FS_CFLG_OWN_PAGES flag in + * fscrypt_operations. Here, the input-page is returned with its content + * encrypted. + * + * Return: A page with the encrypted content on success. Else, an * error value or NULL. */ -struct page *fscrypt_encrypt_page(struct inode *inode, - struct page *plaintext_page, gfp_t gfp_flags) +struct page *fscrypt_encrypt_page(const struct inode *inode, + struct page *page, + unsigned int len, + unsigned int offs, + u64 lblk_num, gfp_t gfp_flags) + { struct fscrypt_ctx *ctx; - struct page *ciphertext_page = NULL; + struct page *ciphertext_page = page; int err; - BUG_ON(!PageLocked(plaintext_page)); + BUG_ON(len % FS_CRYPTO_BLOCK_SIZE != 0); + + if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) { + /* with inplace-encryption we just encrypt the page */ + err = do_page_crypto(inode, FS_ENCRYPT, lblk_num, + page, ciphertext_page, + len, offs, gfp_flags); + if (err) + return ERR_PTR(err); + + return ciphertext_page; + } + + BUG_ON(!PageLocked(page)); ctx = fscrypt_get_ctx(inode, gfp_flags); if (IS_ERR(ctx)) @@ -245,10 +280,10 @@ struct page *fscrypt_encrypt_page(struct inode *inode, if (IS_ERR(ciphertext_page)) goto errout; - ctx->w.control_page = plaintext_page; - err = do_page_crypto(inode, FS_ENCRYPT, plaintext_page->index, - plaintext_page, ciphertext_page, - gfp_flags); + ctx->w.control_page = page; + err = do_page_crypto(inode, FS_ENCRYPT, lblk_num, + page, ciphertext_page, + len, offs, gfp_flags); if (err) { ciphertext_page = ERR_PTR(err); goto errout; @@ -265,8 +300,13 @@ errout: EXPORT_SYMBOL(fscrypt_encrypt_page); /** - * f2crypt_decrypt_page() - Decrypts a page in-place - * @page: The page to decrypt. Must be locked. + * fscrypt_decrypt_page() - Decrypts a page in-place + * @inode: The corresponding inode for the page to decrypt. + * @page: The page to decrypt. Must be locked in case + * it is a writeback page (FS_CFLG_OWN_PAGES unset). + * @len: Number of bytes in @page to be decrypted. + * @offs: Start of data in @page. + * @lblk_num: Logical block number. * * Decrypts page in-place using the ctx encryption context. * @@ -274,16 +314,18 @@ EXPORT_SYMBOL(fscrypt_encrypt_page); * * Return: Zero on success, non-zero otherwise. */ -int fscrypt_decrypt_page(struct page *page) +int fscrypt_decrypt_page(const struct inode *inode, struct page *page, + unsigned int len, unsigned int offs, u64 lblk_num) { - BUG_ON(!PageLocked(page)); + if (!(inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES)) + BUG_ON(!PageLocked(page)); - return do_page_crypto(page->mapping->host, - FS_DECRYPT, page->index, page, page, GFP_NOFS); + return do_page_crypto(inode, FS_DECRYPT, lblk_num, page, page, len, + offs, GFP_NOFS); } EXPORT_SYMBOL(fscrypt_decrypt_page); -int fscrypt_zeroout_range(struct inode *inode, pgoff_t lblk, +int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, sector_t pblk, unsigned int len) { struct fscrypt_ctx *ctx; @@ -306,7 +348,7 @@ int fscrypt_zeroout_range(struct inode *inode, pgoff_t lblk, while (len--) { err = do_page_crypto(inode, FS_ENCRYPT, lblk, ZERO_PAGE(0), ciphertext_page, - GFP_NOFS); + PAGE_SIZE, 0, GFP_NOFS); if (err) goto errout; @@ -414,7 +456,8 @@ static void completion_pages(struct work_struct *work) bio_for_each_segment_all(bv, bio, i) { struct page *page = bv->bv_page; - int ret = fscrypt_decrypt_page(page); + int ret = fscrypt_decrypt_page(page->mapping->host, page, + PAGE_SIZE, 0, page->index); if (ret) { WARN_ON_ONCE(1); @@ -482,17 +525,22 @@ static void fscrypt_destroy(void) /** * fscrypt_initialize() - allocate major buffers for fs encryption. + * @cop_flags: fscrypt operations flags * * 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 fscrypt_initialize(void) +int fscrypt_initialize(unsigned int cop_flags) { int i, res = -ENOMEM; - if (fscrypt_bounce_page_pool) + /* + * No need to allocate a bounce page pool if there already is one or + * this FS won't use it. + */ + if (cop_flags & FS_CFLG_OWN_PAGES || fscrypt_bounce_page_pool) return 0; mutex_lock(&fscrypt_init_mutex); @@ -521,7 +569,6 @@ fail: mutex_unlock(&fscrypt_init_mutex); return res; } -EXPORT_SYMBOL(fscrypt_initialize); /** * fscrypt_init() - Set up for fs encryption. diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index 9b774f4b50c8..56ad9d195f18 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -12,7 +12,7 @@ #include <linux/scatterlist.h> #include <linux/ratelimit.h> -#include <linux/fscrypto.h> +#include "fscrypt_private.h" /** * fname_crypt_complete() - completion callback for filename crypto @@ -209,7 +209,7 @@ static int digest_decode(const char *src, int len, char *dst) return cp - dst; } -u32 fscrypt_fname_encrypted_size(struct inode *inode, u32 ilen) +u32 fscrypt_fname_encrypted_size(const struct inode *inode, u32 ilen) { int padding = 32; struct fscrypt_info *ci = inode->i_crypt_info; @@ -227,7 +227,7 @@ EXPORT_SYMBOL(fscrypt_fname_encrypted_size); * Allocates an output buffer that is sufficient for the crypto operation * specified by the context and the direction. */ -int fscrypt_fname_alloc_buffer(struct inode *inode, +int fscrypt_fname_alloc_buffer(const struct inode *inode, u32 ilen, struct fscrypt_str *crypto_str) { unsigned int olen = fscrypt_fname_encrypted_size(inode, ilen); @@ -350,7 +350,7 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname, fname->disk_name.len = iname->len; return 0; } - ret = get_crypt_info(dir); + ret = fscrypt_get_crypt_info(dir); if (ret && ret != -EOPNOTSUPP) return ret; diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h new file mode 100644 index 000000000000..aeab032d7d35 --- /dev/null +++ b/fs/crypto/fscrypt_private.h @@ -0,0 +1,93 @@ +/* + * fscrypt_private.h + * + * Copyright (C) 2015, Google, Inc. + * + * This contains encryption key functions. + * + * Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015. + */ + +#ifndef _FSCRYPT_PRIVATE_H +#define _FSCRYPT_PRIVATE_H + +#include <linux/fscrypto.h> + +#define FS_FNAME_CRYPTO_DIGEST_SIZE 32 + +/* Encryption parameters */ +#define FS_XTS_TWEAK_SIZE 16 +#define FS_AES_128_ECB_KEY_SIZE 16 +#define FS_AES_256_GCM_KEY_SIZE 32 +#define FS_AES_256_CBC_KEY_SIZE 32 +#define FS_AES_256_CTS_KEY_SIZE 32 +#define FS_AES_256_XTS_KEY_SIZE 64 +#define FS_MAX_KEY_SIZE 64 + +#define FS_KEY_DESC_PREFIX "fscrypt:" +#define FS_KEY_DESC_PREFIX_SIZE 8 + +#define FS_KEY_DERIVATION_NONCE_SIZE 16 + +/** + * Encryption context for inode + * + * Protector format: + * 1 byte: Protector format (1 = this version) + * 1 byte: File contents encryption mode + * 1 byte: File names encryption mode + * 1 byte: Flags + * 8 bytes: Master Key descriptor + * 16 bytes: Encryption Key derivation nonce + */ +struct fscrypt_context { + u8 format; + u8 contents_encryption_mode; + u8 filenames_encryption_mode; + u8 flags; + u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE]; + u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE]; +} __packed; + +#define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1 + +/* This is passed in from userspace into the kernel keyring */ +struct fscrypt_key { + u32 mode; + u8 raw[FS_MAX_KEY_SIZE]; + u32 size; +} __packed; + +/* + * A pointer to this structure is stored in the file system's in-core + * representation of an inode. + */ +struct fscrypt_info { + u8 ci_data_mode; + u8 ci_filename_mode; + u8 ci_flags; + struct crypto_skcipher *ci_ctfm; + struct key *ci_keyring_key; + u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE]; +}; + +#define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001 +#define FS_CTX_HAS_BOUNCE_BUFFER_FL 0x00000002 + +struct fscrypt_completion_result { + struct completion completion; + int res; +}; + +#define DECLARE_FS_COMPLETION_RESULT(ecr) \ + struct fscrypt_completion_result ecr = { \ + COMPLETION_INITIALIZER((ecr).completion), 0 } + + +/* crypto.c */ +int fscrypt_initialize(unsigned int cop_flags); + +/* keyinfo.c */ +extern int fscrypt_get_crypt_info(struct inode *); + +#endif /* _FSCRYPT_PRIVATE_H */ diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c index 67fb6d8876d0..6eeea1dcba41 100644 --- a/fs/crypto/keyinfo.c +++ b/fs/crypto/keyinfo.c @@ -10,7 +10,7 @@ #include <keys/user-type.h> #include <linux/scatterlist.h> -#include <linux/fscrypto.h> +#include "fscrypt_private.h" static void derive_crypt_complete(struct crypto_async_request *req, int rc) { @@ -178,7 +178,7 @@ static void put_crypt_info(struct fscrypt_info *ci) kmem_cache_free(fscrypt_info_cachep, ci); } -int get_crypt_info(struct inode *inode) +int fscrypt_get_crypt_info(struct inode *inode) { struct fscrypt_info *crypt_info; struct fscrypt_context ctx; @@ -188,7 +188,7 @@ int get_crypt_info(struct inode *inode) u8 *raw_key = NULL; int res; - res = fscrypt_initialize(); + res = fscrypt_initialize(inode->i_sb->s_cop->flags); if (res) return res; @@ -327,7 +327,7 @@ int fscrypt_get_encryption_info(struct inode *inode) (ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) | (1 << KEY_FLAG_REVOKED) | (1 << KEY_FLAG_DEAD))))) - return get_crypt_info(inode); + return fscrypt_get_crypt_info(inode); return 0; } EXPORT_SYMBOL(fscrypt_get_encryption_info); diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index 6865663aac69..6ed7c2eebeec 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -10,8 +10,8 @@ #include <linux/random.h> #include <linux/string.h> -#include <linux/fscrypto.h> #include <linux/mount.h> +#include "fscrypt_private.h" static int inode_has_encryption_context(struct inode *inode) { @@ -93,16 +93,19 @@ static int create_encryption_context_from_policy(struct inode *inode, return inode->i_sb->s_cop->set_context(inode, &ctx, sizeof(ctx), NULL); } -int fscrypt_process_policy(struct file *filp, - const struct fscrypt_policy *policy) +int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg) { + struct fscrypt_policy policy; struct inode *inode = file_inode(filp); int ret; + if (copy_from_user(&policy, arg, sizeof(policy))) + return -EFAULT; + if (!inode_owner_or_capable(inode)) return -EACCES; - if (policy->version != 0) + if (policy.version != 0) return -EINVAL; ret = mnt_want_write_file(filp); @@ -120,9 +123,9 @@ int fscrypt_process_policy(struct file *filp, ret = -ENOTEMPTY; else ret = create_encryption_context_from_policy(inode, - policy); + &policy); } else if (!is_encryption_context_consistent_with_policy(inode, - policy)) { + &policy)) { printk(KERN_WARNING "%s: Policy inconsistent with encryption context\n", __func__); @@ -134,11 +137,13 @@ int fscrypt_process_policy(struct file *filp, mnt_drop_write_file(filp); return ret; } -EXPORT_SYMBOL(fscrypt_process_policy); +EXPORT_SYMBOL(fscrypt_ioctl_set_policy); -int fscrypt_get_policy(struct inode *inode, struct fscrypt_policy *policy) +int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg) { + struct inode *inode = file_inode(filp); struct fscrypt_context ctx; + struct fscrypt_policy policy; int res; if (!inode->i_sb->s_cop->get_context || @@ -151,15 +156,18 @@ int fscrypt_get_policy(struct inode *inode, struct fscrypt_policy *policy) if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1) return -EINVAL; - policy->version = 0; - policy->contents_encryption_mode = ctx.contents_encryption_mode; - policy->filenames_encryption_mode = ctx.filenames_encryption_mode; - policy->flags = ctx.flags; - memcpy(&policy->master_key_descriptor, ctx.master_key_descriptor, + policy.version = 0; + policy.contents_encryption_mode = ctx.contents_encryption_mode; + policy.filenames_encryption_mode = ctx.filenames_encryption_mode; + policy.flags = ctx.flags; + memcpy(policy.master_key_descriptor, ctx.master_key_descriptor, FS_KEY_DESCRIPTOR_SIZE); + + if (copy_to_user(arg, &policy, sizeof(policy))) + return -EFAULT; return 0; } -EXPORT_SYMBOL(fscrypt_get_policy); +EXPORT_SYMBOL(fscrypt_ioctl_get_policy); int fscrypt_has_permitted_context(struct inode *parent, struct inode *child) { |
