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-rw-r--r--fs/crypto/fscrypt_private.h164
1 files changed, 109 insertions, 55 deletions
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 2d63da4863..1892356cf9 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -47,7 +47,8 @@ struct fscrypt_context_v2 {
u8 contents_encryption_mode;
u8 filenames_encryption_mode;
u8 flags;
- u8 __reserved[4];
+ u8 log2_data_unit_size;
+ u8 __reserved[3];
u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
};
@@ -165,6 +166,26 @@ fscrypt_policy_flags(const union fscrypt_policy *policy)
BUG();
}
+static inline int
+fscrypt_policy_v2_du_bits(const struct fscrypt_policy_v2 *policy,
+ const struct inode *inode)
+{
+ return policy->log2_data_unit_size ?: inode->i_blkbits;
+}
+
+static inline int
+fscrypt_policy_du_bits(const union fscrypt_policy *policy,
+ const struct inode *inode)
+{
+ switch (policy->version) {
+ case FSCRYPT_POLICY_V1:
+ return inode->i_blkbits;
+ case FSCRYPT_POLICY_V2:
+ return fscrypt_policy_v2_du_bits(&policy->v2, inode);
+ }
+ BUG();
+}
+
/*
* For encrypted symlinks, the ciphertext length is stored at the beginning
* of the string in little-endian format.
@@ -189,18 +210,18 @@ struct fscrypt_prepared_key {
};
/*
- * fscrypt_info - the "encryption key" for an inode
+ * fscrypt_inode_info - the "encryption key" for an inode
*
* When an encrypted file's key is made available, an instance of this struct is
* allocated and stored in ->i_crypt_info. Once created, it remains until the
* inode is evicted.
*/
-struct fscrypt_info {
+struct fscrypt_inode_info {
/* The key in a form prepared for actual encryption/decryption */
struct fscrypt_prepared_key ci_enc_key;
- /* True if ci_enc_key should be freed when this fscrypt_info is freed */
+ /* True if ci_enc_key should be freed when this struct is freed */
bool ci_owns_key;
#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
@@ -212,6 +233,16 @@ struct fscrypt_info {
#endif
/*
+ * log2 of the data unit size (granularity of contents encryption) of
+ * this file. This is computable from ci_policy and ci_inode but is
+ * cached here for efficiency. Only used for regular files.
+ */
+ u8 ci_data_unit_bits;
+
+ /* Cached value: log2 of number of data units per FS block */
+ u8 ci_data_units_per_block_bits;
+
+ /*
* Encryption mode used for this inode. It corresponds to either the
* contents or filenames encryption mode, depending on the inode type.
*/
@@ -263,12 +294,13 @@ typedef enum {
} fscrypt_direction_t;
/* crypto.c */
-extern struct kmem_cache *fscrypt_info_cachep;
+extern struct kmem_cache *fscrypt_inode_info_cachep;
int fscrypt_initialize(struct super_block *sb);
-int fscrypt_crypt_block(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);
+int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci,
+ fscrypt_direction_t rw, u64 index,
+ struct page *src_page, struct page *dest_page,
+ unsigned int len, unsigned int offs,
+ gfp_t gfp_flags);
struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags);
void __printf(3, 4) __cold
@@ -283,8 +315,8 @@ fscrypt_msg(const struct inode *inode, const char *level, const char *fmt, ...);
union fscrypt_iv {
struct {
- /* logical block number within the file */
- __le64 lblk_num;
+ /* zero-based index of data unit within the file */
+ __le64 index;
/* per-file nonce; only set in DIRECT_KEY mode */
u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
@@ -293,8 +325,18 @@ union fscrypt_iv {
__le64 dun[FSCRYPT_MAX_IV_SIZE / sizeof(__le64)];
};
-void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num,
- const struct fscrypt_info *ci);
+void fscrypt_generate_iv(union fscrypt_iv *iv, u64 index,
+ const struct fscrypt_inode_info *ci);
+
+/*
+ * Return the number of bits used by the maximum file data unit index that is
+ * possible on the given filesystem, using the given log2 data unit size.
+ */
+static inline int
+fscrypt_max_file_dun_bits(const struct super_block *sb, int du_bits)
+{
+ return fls64(sb->s_maxbytes - 1) - du_bits;
+}
/* fname.c */
bool __fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
@@ -332,17 +374,17 @@ void fscrypt_destroy_hkdf(struct fscrypt_hkdf *hkdf);
/* inline_crypt.c */
#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
-int fscrypt_select_encryption_impl(struct fscrypt_info *ci);
+int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci);
static inline bool
-fscrypt_using_inline_encryption(const struct fscrypt_info *ci)
+fscrypt_using_inline_encryption(const struct fscrypt_inode_info *ci)
{
return ci->ci_inlinecrypt;
}
int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
const u8 *raw_key,
- const struct fscrypt_info *ci);
+ const struct fscrypt_inode_info *ci);
void fscrypt_destroy_inline_crypt_key(struct super_block *sb,
struct fscrypt_prepared_key *prep_key);
@@ -353,7 +395,7 @@ void fscrypt_destroy_inline_crypt_key(struct super_block *sb,
*/
static inline bool
fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key,
- const struct fscrypt_info *ci)
+ const struct fscrypt_inode_info *ci)
{
/*
* The two smp_load_acquire()'s here pair with the smp_store_release()'s
@@ -370,13 +412,13 @@ fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key,
#else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
-static inline int fscrypt_select_encryption_impl(struct fscrypt_info *ci)
+static inline int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci)
{
return 0;
}
static inline bool
-fscrypt_using_inline_encryption(const struct fscrypt_info *ci)
+fscrypt_using_inline_encryption(const struct fscrypt_inode_info *ci)
{
return false;
}
@@ -384,7 +426,7 @@ fscrypt_using_inline_encryption(const struct fscrypt_info *ci)
static inline int
fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
const u8 *raw_key,
- const struct fscrypt_info *ci)
+ const struct fscrypt_inode_info *ci)
{
WARN_ON_ONCE(1);
return -EOPNOTSUPP;
@@ -398,7 +440,7 @@ fscrypt_destroy_inline_crypt_key(struct super_block *sb,
static inline bool
fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key,
- const struct fscrypt_info *ci)
+ const struct fscrypt_inode_info *ci)
{
return smp_load_acquire(&prep_key->tfm) != NULL;
}
@@ -433,8 +475,28 @@ struct fscrypt_master_key_secret {
* fscrypt_master_key - an in-use master key
*
* This represents a master encryption key which has been added to the
- * filesystem and can be used to "unlock" the encrypted files which were
- * encrypted with it.
+ * filesystem. There are three high-level states that a key can be in:
+ *
+ * FSCRYPT_KEY_STATUS_PRESENT
+ * Key is fully usable; it can be used to unlock inodes that are encrypted
+ * with it (this includes being able to create new inodes). ->mk_present
+ * indicates whether the key is in this state. ->mk_secret exists, the key
+ * is in the keyring, and ->mk_active_refs > 0 due to ->mk_present.
+ *
+ * FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED
+ * Removal of this key has been initiated, but some inodes that were
+ * unlocked with it are still in-use. Like ABSENT, ->mk_secret is wiped,
+ * and the key can no longer be used to unlock inodes. Unlike ABSENT, the
+ * key is still in the keyring; ->mk_decrypted_inodes is nonempty; and
+ * ->mk_active_refs > 0, being equal to the size of ->mk_decrypted_inodes.
+ *
+ * This state transitions to ABSENT if ->mk_decrypted_inodes becomes empty,
+ * or to PRESENT if FS_IOC_ADD_ENCRYPTION_KEY is called again for this key.
+ *
+ * FSCRYPT_KEY_STATUS_ABSENT
+ * Key is fully removed. The key is no longer in the keyring,
+ * ->mk_decrypted_inodes is empty, ->mk_active_refs == 0, ->mk_secret is
+ * wiped, and the key can no longer be used to unlock inodes.
*/
struct fscrypt_master_key {
@@ -444,7 +506,7 @@ struct fscrypt_master_key {
*/
struct hlist_node mk_node;
- /* Semaphore that protects ->mk_secret and ->mk_users */
+ /* Semaphore that protects ->mk_secret, ->mk_users, and ->mk_present */
struct rw_semaphore mk_sem;
/*
@@ -454,8 +516,8 @@ struct fscrypt_master_key {
* ->mk_direct_keys) that have been prepared continue to exist.
* A structural ref only guarantees that the struct continues to exist.
*
- * There is one active ref associated with ->mk_secret being present,
- * and one active ref for each inode in ->mk_decrypted_inodes.
+ * There is one active ref associated with ->mk_present being true, and
+ * one active ref for each inode in ->mk_decrypted_inodes.
*
* There is one structural ref associated with the active refcount being
* nonzero. Finding a key in the keyring also takes a structural ref,
@@ -467,17 +529,10 @@ struct fscrypt_master_key {
struct rcu_head mk_rcu_head;
/*
- * The secret key material. After FS_IOC_REMOVE_ENCRYPTION_KEY is
- * executed, this is wiped and no new inodes can be unlocked with this
- * key; however, there may still be inodes in ->mk_decrypted_inodes
- * which could not be evicted. As long as some inodes still remain,
- * FS_IOC_REMOVE_ENCRYPTION_KEY can be retried, or
- * FS_IOC_ADD_ENCRYPTION_KEY can add the secret again.
+ * The secret key material. Wiped as soon as it is no longer needed;
+ * for details, see the fscrypt_master_key struct comment.
*
- * While ->mk_secret is present, one ref in ->mk_active_refs is held.
- *
- * Locking: protected by ->mk_sem. The manipulation of ->mk_active_refs
- * associated with this field is protected by ->mk_sem as well.
+ * Locking: protected by ->mk_sem.
*/
struct fscrypt_master_key_secret mk_secret;
@@ -500,7 +555,7 @@ struct fscrypt_master_key {
*
* Locking: protected by ->mk_sem. (We don't just rely on the keyrings
* subsystem semaphore ->mk_users->sem, as we need support for atomic
- * search+insert along with proper synchronization with ->mk_secret.)
+ * search+insert along with proper synchronization with other fields.)
*/
struct key *mk_users;
@@ -523,20 +578,17 @@ struct fscrypt_master_key {
siphash_key_t mk_ino_hash_key;
bool mk_ino_hash_key_initialized;
-} __randomize_layout;
-
-static inline bool
-is_master_key_secret_present(const struct fscrypt_master_key_secret *secret)
-{
/*
- * The READ_ONCE() is only necessary for fscrypt_drop_inode().
- * fscrypt_drop_inode() runs in atomic context, so it can't take the key
- * semaphore and thus 'secret' can change concurrently which would be a
- * data race. But fscrypt_drop_inode() only need to know whether the
- * secret *was* present at the time of check, so READ_ONCE() suffices.
+ * Whether this key is in the "present" state, i.e. fully usable. For
+ * details, see the fscrypt_master_key struct comment.
+ *
+ * Locking: protected by ->mk_sem, but can be read locklessly using
+ * READ_ONCE(). Writers must use WRITE_ONCE() when concurrent readers
+ * are possible.
*/
- return READ_ONCE(secret->size) != 0;
-}
+ bool mk_present;
+
+} __randomize_layout;
static inline const char *master_key_spec_type(
const struct fscrypt_key_specifier *spec)
@@ -598,17 +650,18 @@ struct fscrypt_mode {
extern struct fscrypt_mode fscrypt_modes[];
int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key,
- const u8 *raw_key, const struct fscrypt_info *ci);
+ const u8 *raw_key, const struct fscrypt_inode_info *ci);
void fscrypt_destroy_prepared_key(struct super_block *sb,
struct fscrypt_prepared_key *prep_key);
-int fscrypt_set_per_file_enc_key(struct fscrypt_info *ci, const u8 *raw_key);
+int fscrypt_set_per_file_enc_key(struct fscrypt_inode_info *ci,
+ const u8 *raw_key);
-int fscrypt_derive_dirhash_key(struct fscrypt_info *ci,
+int fscrypt_derive_dirhash_key(struct fscrypt_inode_info *ci,
const struct fscrypt_master_key *mk);
-void fscrypt_hash_inode_number(struct fscrypt_info *ci,
+void fscrypt_hash_inode_number(struct fscrypt_inode_info *ci,
const struct fscrypt_master_key *mk);
int fscrypt_get_encryption_info(struct inode *inode, bool allow_unsupported);
@@ -643,10 +696,11 @@ static inline int fscrypt_require_key(struct inode *inode)
void fscrypt_put_direct_key(struct fscrypt_direct_key *dk);
-int fscrypt_setup_v1_file_key(struct fscrypt_info *ci,
+int fscrypt_setup_v1_file_key(struct fscrypt_inode_info *ci,
const u8 *raw_master_key);
-int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci);
+int fscrypt_setup_v1_file_key_via_subscribed_keyrings(
+ struct fscrypt_inode_info *ci);
/* policy.c */