diff options
Diffstat (limited to 'fs/crypto')
| -rw-r--r-- | fs/crypto/Kconfig | 3 | ||||
| -rw-r--r-- | fs/crypto/Makefile | 1 | ||||
| -rw-r--r-- | fs/crypto/bio.c | 145 | ||||
| -rw-r--r-- | fs/crypto/crypto.c | 260 | ||||
| -rw-r--r-- | fs/crypto/fname.c | 12 | ||||
| -rw-r--r-- | fs/crypto/fscrypt_private.h | 103 | ||||
| -rw-r--r-- | fs/crypto/keyinfo.c | 102 | ||||
| -rw-r--r-- | fs/crypto/policy.c | 141 |
8 files changed, 430 insertions, 337 deletions
diff --git a/fs/crypto/Kconfig b/fs/crypto/Kconfig index 92348faf9865..08b46e6e3995 100644 --- a/fs/crypto/Kconfig +++ b/fs/crypto/Kconfig @@ -1,6 +1,5 @@ config FS_ENCRYPTION tristate "FS Encryption (Per-file encryption)" - depends on BLOCK select CRYPTO select CRYPTO_AES select CRYPTO_CBC @@ -8,9 +7,7 @@ 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/Makefile b/fs/crypto/Makefile index f17684c48739..9f6607f17b53 100644 --- a/fs/crypto/Makefile +++ b/fs/crypto/Makefile @@ -1,3 +1,4 @@ obj-$(CONFIG_FS_ENCRYPTION) += fscrypto.o fscrypto-y := crypto.o fname.o policy.o keyinfo.o +fscrypto-$(CONFIG_BLOCK) += bio.o diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c new file mode 100644 index 000000000000..a409a84f1bca --- /dev/null +++ b/fs/crypto/bio.c @@ -0,0 +1,145 @@ +/* + * This contains encryption functions for per-file encryption. + * + * Copyright (C) 2015, Google, Inc. + * Copyright (C) 2015, Motorola Mobility + * + * Written by Michael Halcrow, 2014. + * + * Filename encryption additions + * Uday Savagaonkar, 2014 + * Encryption policy handling additions + * Ildar Muslukhov, 2014 + * Add fscrypt_pullback_bio_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 <linux/pagemap.h> +#include <linux/module.h> +#include <linux/bio.h> +#include <linux/namei.h> +#include "fscrypt_private.h" + +/* + * Call fscrypt_decrypt_page on every single page, reusing the encryption + * context. + */ +static void completion_pages(struct work_struct *work) +{ + struct fscrypt_ctx *ctx = + container_of(work, struct fscrypt_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 = fscrypt_decrypt_page(page->mapping->host, page, + PAGE_SIZE, 0, page->index); + + if (ret) { + WARN_ON_ONCE(1); + SetPageError(page); + } else { + SetPageUptodate(page); + } + unlock_page(page); + } + fscrypt_release_ctx(ctx); + bio_put(bio); +} + +void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *ctx, struct bio *bio) +{ + INIT_WORK(&ctx->r.work, completion_pages); + ctx->r.bio = bio; + queue_work(fscrypt_read_workqueue, &ctx->r.work); +} +EXPORT_SYMBOL(fscrypt_decrypt_bio_pages); + +void fscrypt_pullback_bio_page(struct page **page, bool restore) +{ + struct fscrypt_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 fscrypt_ctx *)page_private(bounce_page); + + /* restore control page */ + *page = ctx->w.control_page; + + if (restore) + fscrypt_restore_control_page(bounce_page); +} +EXPORT_SYMBOL(fscrypt_pullback_bio_page); + +int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, + sector_t pblk, unsigned int len) +{ + struct fscrypt_ctx *ctx; + struct page *ciphertext_page = NULL; + struct bio *bio; + int ret, err = 0; + + BUG_ON(inode->i_sb->s_blocksize != PAGE_SIZE); + + ctx = fscrypt_get_ctx(inode, GFP_NOFS); + if (IS_ERR(ctx)) + return PTR_ERR(ctx); + + ciphertext_page = fscrypt_alloc_bounce_page(ctx, GFP_NOWAIT); + if (IS_ERR(ciphertext_page)) { + err = PTR_ERR(ciphertext_page); + goto errout; + } + + while (len--) { + err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk, + ZERO_PAGE(0), ciphertext_page, + PAGE_SIZE, 0, GFP_NOFS); + if (err) + goto errout; + + bio = bio_alloc(GFP_NOWAIT, 1); + if (!bio) { + err = -ENOMEM; + goto errout; + } + bio->bi_bdev = inode->i_sb->s_bdev; + bio->bi_iter.bi_sector = + pblk << (inode->i_sb->s_blocksize_bits - 9); + bio_set_op_attrs(bio, REQ_OP_WRITE, 0); + ret = bio_add_page(bio, ciphertext_page, + inode->i_sb->s_blocksize, 0); + if (ret != inode->i_sb->s_blocksize) { + /* should never happen! */ + WARN_ON(1); + bio_put(bio); + err = -EIO; + goto errout; + } + err = submit_bio_wait(bio); + if ((err == 0) && bio->bi_error) + err = -EIO; + bio_put(bio); + if (err) + goto errout; + lblk++; + pblk++; + } + err = 0; +errout: + fscrypt_release_ctx(ctx); + return err; +} +EXPORT_SYMBOL(fscrypt_zeroout_range); diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c index 98f87fe8f186..6d6eca394d4d 100644 --- a/fs/crypto/crypto.c +++ b/fs/crypto/crypto.c @@ -24,10 +24,9 @@ #include <linux/module.h> #include <linux/scatterlist.h> #include <linux/ratelimit.h> -#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; @@ -44,7 +43,7 @@ static mempool_t *fscrypt_bounce_page_pool = NULL; static LIST_HEAD(fscrypt_free_ctxs); static DEFINE_SPINLOCK(fscrypt_ctx_lock); -static struct workqueue_struct *fscrypt_read_workqueue; +struct workqueue_struct *fscrypt_read_workqueue; static DEFINE_MUTEX(fscrypt_init_mutex); static struct kmem_cache *fscrypt_ctx_cachep; @@ -63,7 +62,7 @@ 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 +87,7 @@ 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 +120,7 @@ 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); @@ -141,15 +140,10 @@ static void page_crypt_complete(struct crypto_async_request *req, int res) complete(&ecr->completion); } -typedef enum { - FS_DECRYPT = 0, - FS_ENCRYPT, -} fscrypt_direction_t; - -static int do_page_crypto(struct inode *inode, - fscrypt_direction_t rw, pgoff_t index, - struct page *src_page, struct page *dest_page, - gfp_t gfp_flags) +int fscrypt_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 { __le64 index; @@ -162,6 +156,8 @@ 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 +171,14 @@ 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 @@ -202,53 +198,86 @@ static int do_page_crypto(struct inode *inode, return 0; } -static struct page *alloc_bounce_page(struct fscrypt_ctx *ctx, gfp_t gfp_flags) +struct page *fscrypt_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 = fscrypt_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)) return (struct page *)ctx; /* The encryption operation will require a bounce page. */ - ciphertext_page = alloc_bounce_page(ctx, gfp_flags); + ciphertext_page = fscrypt_alloc_bounce_page(ctx, gfp_flags); 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 = fscrypt_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 +294,13 @@ 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. * @@ -274,76 +308,17 @@ 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 fscrypt_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, - sector_t pblk, unsigned int len) -{ - struct fscrypt_ctx *ctx; - struct page *ciphertext_page = NULL; - struct bio *bio; - int ret, err = 0; - - BUG_ON(inode->i_sb->s_blocksize != PAGE_SIZE); - - ctx = fscrypt_get_ctx(inode, GFP_NOFS); - if (IS_ERR(ctx)) - return PTR_ERR(ctx); - - ciphertext_page = alloc_bounce_page(ctx, GFP_NOWAIT); - if (IS_ERR(ciphertext_page)) { - err = PTR_ERR(ciphertext_page); - goto errout; - } - - while (len--) { - err = do_page_crypto(inode, FS_ENCRYPT, lblk, - ZERO_PAGE(0), ciphertext_page, - GFP_NOFS); - if (err) - goto errout; - - bio = bio_alloc(GFP_NOWAIT, 1); - if (!bio) { - err = -ENOMEM; - goto errout; - } - bio->bi_bdev = inode->i_sb->s_bdev; - bio->bi_iter.bi_sector = - pblk << (inode->i_sb->s_blocksize_bits - 9); - bio_set_op_attrs(bio, REQ_OP_WRITE, 0); - ret = bio_add_page(bio, ciphertext_page, - inode->i_sb->s_blocksize, 0); - if (ret != inode->i_sb->s_blocksize) { - /* should never happen! */ - WARN_ON(1); - bio_put(bio); - err = -EIO; - goto errout; - } - err = submit_bio_wait(bio); - if ((err == 0) && bio->bi_error) - err = -EIO; - bio_put(bio); - if (err) - goto errout; - lblk++; - pblk++; - } - err = 0; -errout: - fscrypt_release_ctx(ctx); - return err; -} -EXPORT_SYMBOL(fscrypt_zeroout_range); - /* * Validate dentries for encrypted directories to make sure we aren't * potentially caching stale data after a key has been added or @@ -352,7 +327,6 @@ EXPORT_SYMBOL(fscrypt_zeroout_range); static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags) { struct dentry *dir; - struct fscrypt_info *ci; int dir_has_key, cached_with_key; if (flags & LOOKUP_RCU) @@ -364,18 +338,11 @@ static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags) return 0; } - ci = d_inode(dir)->i_crypt_info; - if (ci && ci->ci_keyring_key && - (ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) | - (1 << KEY_FLAG_REVOKED) | - (1 << KEY_FLAG_DEAD)))) - ci = NULL; - /* this should eventually be an flag in d_flags */ spin_lock(&dentry->d_lock); cached_with_key = dentry->d_flags & DCACHE_ENCRYPTED_WITH_KEY; spin_unlock(&dentry->d_lock); - dir_has_key = (ci != NULL); + dir_has_key = (d_inode(dir)->i_crypt_info != NULL); dput(dir); /* @@ -400,63 +367,6 @@ const struct dentry_operations fscrypt_d_ops = { }; EXPORT_SYMBOL(fscrypt_d_ops); -/* - * Call fscrypt_decrypt_page on every single page, reusing the encryption - * context. - */ -static void completion_pages(struct work_struct *work) -{ - struct fscrypt_ctx *ctx = - container_of(work, struct fscrypt_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 = fscrypt_decrypt_page(page); - - if (ret) { - WARN_ON_ONCE(1); - SetPageError(page); - } else { - SetPageUptodate(page); - } - unlock_page(page); - } - fscrypt_release_ctx(ctx); - bio_put(bio); -} - -void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *ctx, struct bio *bio) -{ - INIT_WORK(&ctx->r.work, completion_pages); - ctx->r.bio = bio; - queue_work(fscrypt_read_workqueue, &ctx->r.work); -} -EXPORT_SYMBOL(fscrypt_decrypt_bio_pages); - -void fscrypt_pullback_bio_page(struct page **page, bool restore) -{ - struct fscrypt_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 fscrypt_ctx *)page_private(bounce_page); - - /* restore control page */ - *page = ctx->w.control_page; - - if (restore) - fscrypt_restore_control_page(bounce_page); -} -EXPORT_SYMBOL(fscrypt_pullback_bio_page); - void fscrypt_restore_control_page(struct page *page) { struct fscrypt_ctx *ctx; @@ -482,17 +392,22 @@ 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 +436,6 @@ 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..37b49894c762 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); @@ -332,7 +332,7 @@ int fscrypt_fname_usr_to_disk(struct inode *inode, * in a directory. Consequently, a user space name cannot be mapped to * a disk-space name */ - return -EACCES; + return -ENOKEY; } EXPORT_SYMBOL(fscrypt_fname_usr_to_disk); @@ -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_encryption_info(dir); if (ret && ret != -EOPNOTSUPP) return ret; @@ -367,7 +367,7 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname, return 0; } if (!lookup) - return -EACCES; + return -ENOKEY; /* * We don't have the key and we are doing a lookup; decode the diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h new file mode 100644 index 000000000000..e39696e64494 --- /dev/null +++ b/fs/crypto/fscrypt_private.h @@ -0,0 +1,103 @@ +/* + * 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/fscrypt_supp.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; + u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE]; +}; + +typedef enum { + FS_DECRYPT = 0, + FS_ENCRYPT, +} fscrypt_direction_t; + +#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_ONSTACK((ecr).completion), 0 } + + +/* crypto.c */ +extern int fscrypt_initialize(unsigned int cop_flags); +extern struct workqueue_struct *fscrypt_read_workqueue; +extern int fscrypt_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); +extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx, + gfp_t gfp_flags); + +#endif /* _FSCRYPT_PRIVATE_H */ diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c index 67fb6d8876d0..8cdfddce2b34 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) { @@ -77,28 +77,25 @@ out: static int validate_user_key(struct fscrypt_info *crypt_info, struct fscrypt_context *ctx, u8 *raw_key, - u8 *prefix, int prefix_size) + const char *prefix) { - u8 *full_key_descriptor; + char *description; struct key *keyring_key; struct fscrypt_key *master_key; const struct user_key_payload *ukp; - int full_key_len = prefix_size + (FS_KEY_DESCRIPTOR_SIZE * 2) + 1; int res; - full_key_descriptor = kmalloc(full_key_len, GFP_NOFS); - if (!full_key_descriptor) + description = kasprintf(GFP_NOFS, "%s%*phN", prefix, + FS_KEY_DESCRIPTOR_SIZE, + ctx->master_key_descriptor); + if (!description) return -ENOMEM; - memcpy(full_key_descriptor, prefix, prefix_size); - sprintf(full_key_descriptor + prefix_size, - "%*phN", FS_KEY_DESCRIPTOR_SIZE, - ctx->master_key_descriptor); - full_key_descriptor[full_key_len - 1] = '\0'; - keyring_key = request_key(&key_type_logon, full_key_descriptor, NULL); - kfree(full_key_descriptor); + keyring_key = request_key(&key_type_logon, description, NULL); + kfree(description); if (IS_ERR(keyring_key)) return PTR_ERR(keyring_key); + down_read(&keyring_key->sem); if (keyring_key->type != &key_type_logon) { printk_once(KERN_WARNING @@ -106,11 +103,9 @@ static int validate_user_key(struct fscrypt_info *crypt_info, res = -ENOKEY; goto out; } - down_read(&keyring_key->sem); - ukp = user_key_payload(keyring_key); + ukp = user_key_payload_locked(keyring_key); if (ukp->datalen != sizeof(struct fscrypt_key)) { res = -EINVAL; - up_read(&keyring_key->sem); goto out; } master_key = (struct fscrypt_key *)ukp->data; @@ -121,17 +116,11 @@ static int validate_user_key(struct fscrypt_info *crypt_info, "%s: key size incorrect: %d\n", __func__, master_key->size); res = -ENOKEY; - up_read(&keyring_key->sem); goto out; } res = derive_key_aes(ctx->nonce, master_key->raw, raw_key); - up_read(&keyring_key->sem); - if (res) - goto out; - - crypt_info->ci_keyring_key = keyring_key; - return 0; out: + up_read(&keyring_key->sem); key_put(keyring_key); return res; } @@ -173,12 +162,11 @@ static void put_crypt_info(struct fscrypt_info *ci) if (!ci) return; - key_put(ci->ci_keyring_key); crypto_free_skcipher(ci->ci_ctfm); kmem_cache_free(fscrypt_info_cachep, ci); } -int get_crypt_info(struct inode *inode) +int fscrypt_get_encryption_info(struct inode *inode) { struct fscrypt_info *crypt_info; struct fscrypt_context ctx; @@ -188,30 +176,27 @@ int get_crypt_info(struct inode *inode) u8 *raw_key = NULL; int res; - res = fscrypt_initialize(); + if (inode->i_crypt_info) + return 0; + + res = fscrypt_initialize(inode->i_sb->s_cop->flags); if (res) return res; if (!inode->i_sb->s_cop->get_context) return -EOPNOTSUPP; -retry: - crypt_info = ACCESS_ONCE(inode->i_crypt_info); - if (crypt_info) { - if (!crypt_info->ci_keyring_key || - key_validate(crypt_info->ci_keyring_key) == 0) - return 0; - fscrypt_put_encryption_info(inode, crypt_info); - goto retry; - } res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx)); if (res < 0) { - if (!fscrypt_dummy_context_enabled(inode)) + if (!fscrypt_dummy_context_enabled(inode) || + inode->i_sb->s_cop->is_encrypted(inode)) return res; + /* Fake up a context for an unencrypted directory */ + memset(&ctx, 0, sizeof(ctx)); ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1; ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS; ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS; - ctx.flags = 0; + memset(ctx.master_key_descriptor, 0x42, FS_KEY_DESCRIPTOR_SIZE); } else if (res != sizeof(ctx)) { return -EINVAL; } @@ -230,7 +215,6 @@ retry: crypt_info->ci_data_mode = ctx.contents_encryption_mode; crypt_info->ci_filename_mode = ctx.filenames_encryption_mode; crypt_info->ci_ctfm = NULL; - crypt_info->ci_keyring_key = NULL; memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor, sizeof(crypt_info->ci_master_key)); @@ -247,20 +231,10 @@ retry: if (!raw_key) goto out; - if (fscrypt_dummy_context_enabled(inode)) { - memset(raw_key, 0x42, FS_AES_256_XTS_KEY_SIZE); - goto got_key; - } - - res = validate_user_key(crypt_info, &ctx, raw_key, - FS_KEY_DESC_PREFIX, FS_KEY_DESC_PREFIX_SIZE); + res = validate_user_key(crypt_info, &ctx, raw_key, FS_KEY_DESC_PREFIX); if (res && inode->i_sb->s_cop->key_prefix) { - u8 *prefix = NULL; - int prefix_size, res2; - - prefix_size = inode->i_sb->s_cop->key_prefix(inode, &prefix); - res2 = validate_user_key(crypt_info, &ctx, raw_key, - prefix, prefix_size); + int res2 = validate_user_key(crypt_info, &ctx, raw_key, + inode->i_sb->s_cop->key_prefix); if (res2) { if (res2 == -ENOKEY) res = -ENOKEY; @@ -269,7 +243,6 @@ retry: } else if (res) { goto out; } -got_key: ctfm = crypto_alloc_skcipher(cipher_str, 0, 0); if (!ctfm || IS_ERR(ctfm)) { res = ctfm ? PTR_ERR(ctfm) : -ENOMEM; @@ -285,14 +258,8 @@ got_key: if (res) goto out; - kzfree(raw_key); - raw_key = NULL; - if (cmpxchg(&inode->i_crypt_info, NULL, crypt_info) != NULL) { - put_crypt_info(crypt_info); - goto retry; - } - return 0; - + if (cmpxchg(&inode->i_crypt_info, NULL, crypt_info) == NULL) + crypt_info = NULL; out: if (res == -ENOKEY) res = 0; @@ -300,6 +267,7 @@ out: kzfree(raw_key); return res; } +EXPORT_SYMBOL(fscrypt_get_encryption_info); void fscrypt_put_encryption_info(struct inode *inode, struct fscrypt_info *ci) { @@ -317,17 +285,3 @@ void fscrypt_put_encryption_info(struct inode *inode, struct fscrypt_info *ci) put_crypt_info(ci); } EXPORT_SYMBOL(fscrypt_put_encryption_info); - -int fscrypt_get_encryption_info(struct inode *inode) -{ - struct fscrypt_info *ci = inode->i_crypt_info; - - if (!ci || - (ci->ci_keyring_key && - (ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) | - (1 << KEY_FLAG_REVOKED) | - (1 << KEY_FLAG_DEAD))))) - return 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..4908906d54d5 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -10,76 +10,44 @@ #include <linux/random.h> #include <linux/string.h> -#include <linux/fscrypto.h> #include <linux/mount.h> - -static int inode_has_encryption_context(struct inode *inode) -{ - if (!inode->i_sb->s_cop->get_context) - return 0; - return (inode->i_sb->s_cop->get_context(inode, NULL, 0L) > 0); -} +#include "fscrypt_private.h" /* - * check whether the policy is consistent with the encryption context - * for the inode + * check whether an encryption policy is consistent with an encryption context */ -static int is_encryption_context_consistent_with_policy(struct inode *inode, +static bool is_encryption_context_consistent_with_policy( + const struct fscrypt_context *ctx, const struct fscrypt_policy *policy) { - struct fscrypt_context ctx; - int res; - - if (!inode->i_sb->s_cop->get_context) - return 0; - - res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx)); - if (res != sizeof(ctx)) - return 0; - - return (memcmp(ctx.master_key_descriptor, policy->master_key_descriptor, - FS_KEY_DESCRIPTOR_SIZE) == 0 && - (ctx.flags == policy->flags) && - (ctx.contents_encryption_mode == - policy->contents_encryption_mode) && - (ctx.filenames_encryption_mode == - policy->filenames_encryption_mode)); + return memcmp(ctx->master_key_descriptor, policy->master_key_descriptor, + FS_KEY_DESCRIPTOR_SIZE) == 0 && + (ctx->flags == policy->flags) && + (ctx->contents_encryption_mode == + policy->contents_encryption_mode) && + (ctx->filenames_encryption_mode == + policy->filenames_encryption_mode); } static int create_encryption_context_from_policy(struct inode *inode, const struct fscrypt_policy *policy) { struct fscrypt_context ctx; - int res; if (!inode->i_sb->s_cop->set_context) return -EOPNOTSUPP; - if (inode->i_sb->s_cop->prepare_context) { - res = inode->i_sb->s_cop->prepare_context(inode); - if (res) - return res; - } - ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1; memcpy(ctx.master_key_descriptor, policy->master_key_descriptor, FS_KEY_DESCRIPTOR_SIZE); if (!fscrypt_valid_contents_enc_mode( - policy->contents_encryption_mode)) { - printk(KERN_WARNING - "%s: Invalid contents encryption mode %d\n", __func__, - policy->contents_encryption_mode); + policy->contents_encryption_mode)) return -EINVAL; - } if (!fscrypt_valid_filenames_enc_mode( - policy->filenames_encryption_mode)) { - printk(KERN_WARNING - "%s: Invalid filenames encryption mode %d\n", __func__, - policy->filenames_encryption_mode); + policy->filenames_encryption_mode)) return -EINVAL; - } if (policy->flags & ~FS_POLICY_FLAGS_VALID) return -EINVAL; @@ -93,16 +61,20 @@ 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; + struct fscrypt_context ctx; + + 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); @@ -111,22 +83,25 @@ int fscrypt_process_policy(struct file *filp, inode_lock(inode); - if (!inode_has_encryption_context(inode)) { + ret = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx)); + if (ret == -ENODATA) { if (!S_ISDIR(inode->i_mode)) - ret = -EINVAL; + ret = -ENOTDIR; else if (!inode->i_sb->s_cop->empty_dir) ret = -EOPNOTSUPP; else if (!inode->i_sb->s_cop->empty_dir(inode)) ret = -ENOTEMPTY; else ret = create_encryption_context_from_policy(inode, - policy); - } else if (!is_encryption_context_consistent_with_policy(inode, - policy)) { - printk(KERN_WARNING - "%s: Policy inconsistent with encryption context\n", - __func__); - ret = -EINVAL; + &policy); + } else if (ret == sizeof(ctx) && + is_encryption_context_consistent_with_policy(&ctx, + &policy)) { + /* The file already uses the same encryption policy. */ + ret = 0; + } else if (ret >= 0 || ret == -ERANGE) { + /* The file already uses a different encryption policy. */ + ret = -EEXIST; } inode_unlock(inode); @@ -134,11 +109,13 @@ 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 || @@ -146,20 +123,25 @@ int fscrypt_get_policy(struct inode *inode, struct fscrypt_policy *policy) return -ENODATA; res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx)); + if (res < 0 && res != -ERANGE) + return res; if (res != sizeof(ctx)) - return -ENODATA; + return -EINVAL; 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) { @@ -171,6 +153,11 @@ int fscrypt_has_permitted_context(struct inode *parent, struct inode *child) BUG_ON(1); } + /* No restrictions on file types which are never encrypted */ + if (!S_ISREG(child->i_mode) && !S_ISDIR(child->i_mode) && + !S_ISLNK(child->i_mode)) + return 1; + /* no restrictions if the parent directory is not encrypted */ if (!parent->i_sb->s_cop->is_encrypted(parent)) return 1; @@ -204,9 +191,9 @@ EXPORT_SYMBOL(fscrypt_has_permitted_context); * @parent: Parent inode from which the context is inherited. * @child: Child inode that inherits the context from @parent. * @fs_data: private data given by FS. - * @preload: preload child i_crypt_info + * @preload: preload child i_crypt_info if true * - * Return: Zero on success, non-zero otherwise + * Return: 0 on success, -errno on failure */ int fscrypt_inherit_context(struct inode *parent, struct inode *child, void *fs_data, bool preload) @@ -227,19 +214,11 @@ int fscrypt_inherit_context(struct inode *parent, struct inode *child, return -ENOKEY; ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1; - if (fscrypt_dummy_context_enabled(parent)) { - ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS; - ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS; - ctx.flags = 0; - memset(ctx.master_key_descriptor, 0x42, FS_KEY_DESCRIPTOR_SIZE); - res = 0; - } else { - ctx.contents_encryption_mode = ci->ci_data_mode; - ctx.filenames_encryption_mode = ci->ci_filename_mode; - ctx.flags = ci->ci_flags; - memcpy(ctx.master_key_descriptor, ci->ci_master_key, - FS_KEY_DESCRIPTOR_SIZE); - } + ctx.contents_encryption_mode = ci->ci_data_mode; + ctx.filenames_encryption_mode = ci->ci_filename_mode; + ctx.flags = ci->ci_flags; + memcpy(ctx.master_key_descriptor, ci->ci_master_key, + FS_KEY_DESCRIPTOR_SIZE); get_random_bytes(ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE); res = parent->i_sb->s_cop->set_context(child, &ctx, sizeof(ctx), fs_data); |
