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Diffstat (limited to 'fs/crypto/fscrypt_private.h')
-rw-r--r--fs/crypto/fscrypt_private.h82
1 files changed, 58 insertions, 24 deletions
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 3afdaa084773..d5f68a0c5d15 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -184,7 +184,7 @@ struct fscrypt_symlink_data {
struct fscrypt_prepared_key {
struct crypto_skcipher *tfm;
#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
- struct fscrypt_blk_crypto_key *blk_key;
+ struct blk_crypto_key *blk_key;
#endif
};
@@ -225,7 +225,7 @@ struct fscrypt_info {
* will be NULL if the master key was found in a process-subscribed
* keyring rather than in the filesystem-level keyring.
*/
- struct key *ci_master_key;
+ struct fscrypt_master_key *ci_master_key;
/*
* Link in list of inodes that were unlocked with the master key.
@@ -344,7 +344,8 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
const u8 *raw_key,
const struct fscrypt_info *ci);
-void fscrypt_destroy_inline_crypt_key(struct fscrypt_prepared_key *prep_key);
+void fscrypt_destroy_inline_crypt_key(struct super_block *sb,
+ struct fscrypt_prepared_key *prep_key);
/*
* Check whether the crypto transform or blk-crypto key has been allocated in
@@ -390,7 +391,8 @@ fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
}
static inline void
-fscrypt_destroy_inline_crypt_key(struct fscrypt_prepared_key *prep_key)
+fscrypt_destroy_inline_crypt_key(struct super_block *sb,
+ struct fscrypt_prepared_key *prep_key)
{
}
@@ -437,6 +439,40 @@ struct fscrypt_master_key_secret {
struct fscrypt_master_key {
/*
+ * Back-pointer to the super_block of the filesystem to which this
+ * master key has been added. Only valid if ->mk_active_refs > 0.
+ */
+ struct super_block *mk_sb;
+
+ /*
+ * Link in ->mk_sb->s_master_keys->key_hashtable.
+ * Only valid if ->mk_active_refs > 0.
+ */
+ struct hlist_node mk_node;
+
+ /* Semaphore that protects ->mk_secret and ->mk_users */
+ struct rw_semaphore mk_sem;
+
+ /*
+ * Active and structural reference counts. An active ref guarantees
+ * that the struct continues to exist, continues to be in the keyring
+ * ->mk_sb->s_master_keys, and that any embedded subkeys (e.g.
+ * ->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 structural ref associated with the active refcount being
+ * nonzero. Finding a key in the keyring also takes a structural ref,
+ * which is then held temporarily while the key is operated on.
+ */
+ refcount_t mk_active_refs;
+ refcount_t mk_struct_refs;
+
+ 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
@@ -444,7 +480,10 @@ struct fscrypt_master_key {
* FS_IOC_REMOVE_ENCRYPTION_KEY can be retried, or
* FS_IOC_ADD_ENCRYPTION_KEY can add the secret again.
*
- * Locking: protected by this master key's key->sem.
+ * 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.
*/
struct fscrypt_master_key_secret mk_secret;
@@ -465,23 +504,13 @@ struct fscrypt_master_key {
*
* This is NULL for v1 policy keys; those can only be added by root.
*
- * Locking: in addition to this keyring's own semaphore, this is
- * protected by this master key's key->sem, so we can do atomic
- * search+insert. It can also be searched without taking any locks, but
- * in that case the returned key may have already been removed.
+ * 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.)
*/
struct key *mk_users;
/*
- * Length of ->mk_decrypted_inodes, plus one if mk_secret is present.
- * Once this goes to 0, the master key is removed from ->s_master_keys.
- * The 'struct fscrypt_master_key' will continue to live as long as the
- * 'struct key' whose payload it is, but we won't let this reference
- * count rise again.
- */
- refcount_t mk_refcount;
-
- /*
* List of inodes that were unlocked using this key. This allows the
* inodes to be evicted efficiently if the key is removed.
*/
@@ -506,10 +535,10 @@ 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() and
- * fscrypt_key_describe(). These run in atomic context, so they can't
- * take the key semaphore and thus 'secret' can change concurrently
- * which would be a data race. But they only need to know whether the
+ * 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.
*/
return READ_ONCE(secret->size) != 0;
@@ -538,7 +567,11 @@ static inline int master_key_spec_len(const struct fscrypt_key_specifier *spec)
return 0;
}
-struct key *
+void fscrypt_put_master_key(struct fscrypt_master_key *mk);
+
+void fscrypt_put_master_key_activeref(struct fscrypt_master_key *mk);
+
+struct fscrypt_master_key *
fscrypt_find_master_key(struct super_block *sb,
const struct fscrypt_key_specifier *mk_spec);
@@ -569,7 +602,8 @@ 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);
-void fscrypt_destroy_prepared_key(struct fscrypt_prepared_key *prep_key);
+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);