diff options
Diffstat (limited to 'include/linux/fscrypt.h')
| -rw-r--r-- | include/linux/fscrypt.h | 220 |
1 files changed, 160 insertions, 60 deletions
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index c895b12737a1..516aba5b858b 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -31,7 +31,7 @@ #define FSCRYPT_CONTENTS_ALIGNMENT 16 union fscrypt_policy; -struct fscrypt_info; +struct fscrypt_inode_info; struct fs_parameter; struct seq_file; @@ -59,26 +59,61 @@ struct fscrypt_name { #ifdef CONFIG_FS_ENCRYPTION -/* - * If set, the fscrypt bounce page pool won't be allocated (unless another - * filesystem needs it). Set this if the filesystem always uses its own bounce - * pages for writes and therefore won't need the fscrypt bounce page pool. - */ -#define FS_CFLG_OWN_PAGES (1U << 1) - /* Crypto operations for filesystems */ struct fscrypt_operations { + /* + * The offset of the pointer to struct fscrypt_inode_info in the + * filesystem-specific part of the inode, relative to the beginning of + * the common part of the inode (the 'struct inode'). + */ + ptrdiff_t inode_info_offs; + + /* + * If set, then fs/crypto/ will allocate a global bounce page pool the + * first time an encryption key is set up for a file. The bounce page + * pool is required by the following functions: + * + * - fscrypt_encrypt_pagecache_blocks() + * - fscrypt_zeroout_range() for files not using inline crypto + * + * If the filesystem doesn't use those, it doesn't need to set this. + */ + unsigned int needs_bounce_pages : 1; + + /* + * If set, then fs/crypto/ will allow the use of encryption settings + * that assume inode numbers fit in 32 bits (i.e. + * FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64}), provided that the other + * prerequisites for these settings are also met. This is only useful + * if the filesystem wants to support inline encryption hardware that is + * limited to 32-bit or 64-bit data unit numbers and where programming + * keyslots is very slow. + */ + unsigned int has_32bit_inodes : 1; - /* Set of optional flags; see above for allowed flags */ - unsigned int flags; + /* + * If set, then fs/crypto/ will allow users to select a crypto data unit + * size that is less than the filesystem block size. This is done via + * the log2_data_unit_size field of the fscrypt policy. This flag is + * not compatible with filesystems that encrypt variable-length blocks + * (i.e. blocks that aren't all equal to filesystem's block size), for + * example as a result of compression. It's also not compatible with + * the fscrypt_encrypt_block_inplace() and + * fscrypt_decrypt_block_inplace() functions. + */ + unsigned int supports_subblock_data_units : 1; /* - * If set, this is a filesystem-specific key description prefix that - * will be accepted for "logon" keys for v1 fscrypt policies, in - * addition to the generic prefix "fscrypt:". This functionality is - * deprecated, so new filesystems shouldn't set this field. + * This field exists only for backwards compatibility reasons and should + * only be set by the filesystems that are setting it already. It + * contains the filesystem-specific key description prefix that is + * accepted for "logon" keys for v1 fscrypt policies. This + * functionality is deprecated in favor of the generic prefix + * "fscrypt:", which itself is deprecated in favor of the filesystem + * keyring ioctls such as FS_IOC_ADD_ENCRYPTION_KEY. Filesystems that + * are newly adding fscrypt support should not set this field. */ - const char *key_prefix; + const char *legacy_key_prefix; /* * Get the fscrypt context of the given inode. @@ -146,21 +181,6 @@ struct fscrypt_operations { bool (*has_stable_inodes)(struct super_block *sb); /* - * Get the number of bits that the filesystem uses to represent inode - * numbers and file logical block numbers. - * - * By default, both of these are assumed to be 64-bit. This function - * can be implemented to declare that either or both of these numbers is - * shorter, which may allow the use of the - * FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64} flags and/or the use of - * inline crypto hardware whose maximum DUN length is less than 64 bits - * (e.g., eMMC v5.2 spec compliant hardware). This function only needs - * to be implemented if support for one of these features is needed. - */ - void (*get_ino_and_lblk_bits)(struct super_block *sb, - int *ino_bits_ret, int *lblk_bits_ret); - - /* * Return an array of pointers to the block devices to which the * filesystem may write encrypted file contents, NULL if the filesystem * only has a single such block device, or an ERR_PTR() on error. @@ -178,15 +198,47 @@ struct fscrypt_operations { unsigned int *num_devs); }; -static inline struct fscrypt_info *fscrypt_get_info(const struct inode *inode) +int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name, + struct dentry *dentry, unsigned int flags); + +/* + * Returns the address of the fscrypt info pointer within the + * filesystem-specific part of the inode. (To save memory on filesystems that + * don't support fscrypt, a field in 'struct inode' itself is no longer used.) + */ +static inline struct fscrypt_inode_info ** +fscrypt_inode_info_addr(const struct inode *inode) +{ + VFS_WARN_ON_ONCE(inode->i_sb->s_cop->inode_info_offs == 0); + return (void *)inode + inode->i_sb->s_cop->inode_info_offs; +} + +/* + * Load the inode's fscrypt info pointer, using a raw dereference. Since this + * uses a raw dereference with no memory barrier, it is appropriate to use only + * when the caller knows the inode's key setup already happened, resulting in + * non-NULL fscrypt info. E.g., the file contents en/decryption functions use + * this, since fscrypt_file_open() set up the key. + */ +static inline struct fscrypt_inode_info * +fscrypt_get_inode_info_raw(const struct inode *inode) +{ + struct fscrypt_inode_info *ci = *fscrypt_inode_info_addr(inode); + + VFS_WARN_ON_ONCE(ci == NULL); + return ci; +} + +static inline struct fscrypt_inode_info * +fscrypt_get_inode_info(const struct inode *inode) { /* * Pairs with the cmpxchg_release() in fscrypt_setup_encryption_info(). - * I.e., another task may publish ->i_crypt_info concurrently, executing - * a RELEASE barrier. We need to use smp_load_acquire() here to safely + * I.e., another task may publish the fscrypt info concurrently, + * executing a RELEASE barrier. Use smp_load_acquire() here to safely * ACQUIRE the memory the other task published. */ - return smp_load_acquire(&inode->i_crypt_info); + return smp_load_acquire(fscrypt_inode_info_addr(inode)); } /** @@ -206,15 +258,29 @@ static inline bool fscrypt_needs_contents_encryption(const struct inode *inode) } /* - * When d_splice_alias() moves a directory's no-key alias to its plaintext alias - * as a result of the encryption key being added, DCACHE_NOKEY_NAME must be - * cleared. Note that we don't have to support arbitrary moves of this flag - * because fscrypt doesn't allow no-key names to be the source or target of a - * rename(). + * When d_splice_alias() moves a directory's no-key alias to its + * plaintext alias as a result of the encryption key being added, + * DCACHE_NOKEY_NAME must be cleared and there might be an opportunity + * to disable d_revalidate. Note that we don't have to support the + * inverse operation because fscrypt doesn't allow no-key names to be + * the source or target of a rename(). */ static inline void fscrypt_handle_d_move(struct dentry *dentry) { - dentry->d_flags &= ~DCACHE_NOKEY_NAME; + /* + * VFS calls fscrypt_handle_d_move even for non-fscrypt + * filesystems. + */ + if (dentry->d_flags & DCACHE_NOKEY_NAME) { + dentry->d_flags &= ~DCACHE_NOKEY_NAME; + + /* + * Other filesystem features might be handling dentry + * revalidation, in which case it cannot be disabled. + */ + if (dentry->d_op->d_revalidate == fscrypt_d_revalidate) + dentry->d_flags &= ~DCACHE_OP_REVALIDATE; + } } /** @@ -246,16 +312,43 @@ static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) return dentry->d_flags & DCACHE_NOKEY_NAME; } +static inline void fscrypt_prepare_dentry(struct dentry *dentry, + bool is_nokey_name) +{ + /* + * This code tries to only take ->d_lock when necessary to write + * to ->d_flags. We shouldn't be peeking on d_flags for + * DCACHE_OP_REVALIDATE unlocked, but in the unlikely case + * there is a race, the worst it can happen is that we fail to + * unset DCACHE_OP_REVALIDATE and pay the cost of an extra + * d_revalidate. + */ + if (is_nokey_name) { + spin_lock(&dentry->d_lock); + dentry->d_flags |= DCACHE_NOKEY_NAME; + spin_unlock(&dentry->d_lock); + } else if (dentry->d_flags & DCACHE_OP_REVALIDATE && + dentry->d_op->d_revalidate == fscrypt_d_revalidate) { + /* + * Unencrypted dentries and encrypted dentries where the + * key is available are always valid from fscrypt + * perspective. Avoid the cost of calling + * fscrypt_d_revalidate unnecessarily. + */ + spin_lock(&dentry->d_lock); + dentry->d_flags &= ~DCACHE_OP_REVALIDATE; + spin_unlock(&dentry->d_lock); + } +} + /* crypto.c */ void fscrypt_enqueue_decrypt_work(struct work_struct *); -struct page *fscrypt_encrypt_pagecache_blocks(struct page *page, - unsigned int len, - unsigned int offs, - gfp_t gfp_flags); +struct page *fscrypt_encrypt_pagecache_blocks(struct folio *folio, + size_t len, size_t offs, gfp_t gfp_flags); int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page, unsigned int len, unsigned int offs, - u64 lblk_num, gfp_t gfp_flags); + u64 lblk_num); int fscrypt_decrypt_pagecache_blocks(struct folio *folio, size_t len, size_t offs); @@ -273,12 +366,13 @@ static inline struct page *fscrypt_pagecache_page(struct page *bounce_page) return (struct page *)page_private(bounce_page); } -static inline bool fscrypt_is_bounce_folio(struct folio *folio) +static inline bool fscrypt_is_bounce_folio(const struct folio *folio) { return folio->mapping == NULL; } -static inline struct folio *fscrypt_pagecache_folio(struct folio *bounce_folio) +static inline +struct folio *fscrypt_pagecache_folio(const struct folio *bounce_folio) { return bounce_folio->private; } @@ -353,7 +447,6 @@ int fscrypt_fname_disk_to_usr(const struct inode *inode, bool fscrypt_match_name(const struct fscrypt_name *fname, const u8 *de_name, u32 de_name_len); u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name); -int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags); /* bio.c */ bool fscrypt_decrypt_bio(struct bio *bio); @@ -390,7 +483,8 @@ static inline void fscrypt_set_ops(struct super_block *sb, } #else /* !CONFIG_FS_ENCRYPTION */ -static inline struct fscrypt_info *fscrypt_get_info(const struct inode *inode) +static inline struct fscrypt_inode_info * +fscrypt_get_inode_info(const struct inode *inode) { return NULL; } @@ -409,15 +503,18 @@ static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) return false; } +static inline void fscrypt_prepare_dentry(struct dentry *dentry, + bool is_nokey_name) +{ +} + /* crypto.c */ static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work) { } -static inline struct page *fscrypt_encrypt_pagecache_blocks(struct page *page, - unsigned int len, - unsigned int offs, - gfp_t gfp_flags) +static inline struct page *fscrypt_encrypt_pagecache_blocks(struct folio *folio, + size_t len, size_t offs, gfp_t gfp_flags) { return ERR_PTR(-EOPNOTSUPP); } @@ -425,8 +522,7 @@ static inline struct page *fscrypt_encrypt_pagecache_blocks(struct page *page, static inline int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page, unsigned int len, - unsigned int offs, u64 lblk_num, - gfp_t gfp_flags) + unsigned int offs, u64 lblk_num) { return -EOPNOTSUPP; } @@ -456,12 +552,13 @@ static inline struct page *fscrypt_pagecache_page(struct page *bounce_page) return ERR_PTR(-EINVAL); } -static inline bool fscrypt_is_bounce_folio(struct folio *folio) +static inline bool fscrypt_is_bounce_folio(const struct folio *folio) { return false; } -static inline struct folio *fscrypt_pagecache_folio(struct folio *bounce_folio) +static inline +struct folio *fscrypt_pagecache_folio(const struct folio *bounce_folio) { WARN_ON_ONCE(1); return ERR_PTR(-EINVAL); @@ -646,8 +743,8 @@ static inline u64 fscrypt_fname_siphash(const struct inode *dir, return 0; } -static inline int fscrypt_d_revalidate(struct dentry *dentry, - unsigned int flags) +static inline int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name, + struct dentry *dentry, unsigned int flags) { return 1; } @@ -868,7 +965,7 @@ static inline bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode) */ static inline bool fscrypt_has_encryption_key(const struct inode *inode) { - return fscrypt_get_info(inode) != NULL; + return fscrypt_get_inode_info(inode) != NULL; } /** @@ -966,6 +1063,9 @@ static inline int fscrypt_prepare_lookup(struct inode *dir, fname->usr_fname = &dentry->d_name; fname->disk_name.name = (unsigned char *)dentry->d_name.name; fname->disk_name.len = dentry->d_name.len; + + fscrypt_prepare_dentry(dentry, false); + return 0; } |