From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/fs/crypto/fscrypt_private.h | 196 +++++++++++++++++++++++++++++++++----------------
1 files changed, 132 insertions(+), 64 deletions(-)
diff --git a/kernel/fs/crypto/fscrypt_private.h b/kernel/fs/crypto/fscrypt_private.h
index beb3a61..f5f0567 100644
--- a/kernel/fs/crypto/fscrypt_private.h
+++ b/kernel/fs/crypto/fscrypt_private.h
@@ -14,17 +14,21 @@
#include <linux/fscrypt.h>
#include <linux/siphash.h>
#include <crypto/hash.h>
-#include <linux/bio-crypt-ctx.h>
+#include <linux/blk-crypto.h>
#define CONST_STRLEN(str) (sizeof(str) - 1)
-#define FS_KEY_DERIVATION_NONCE_SIZE 16
+#define FSCRYPT_FILE_NONCE_SIZE 16
-#define FSCRYPT_MIN_KEY_SIZE 16
+#define FSCRYPT_MIN_KEY_SIZE 16
+
#define FSCRYPT_MAX_HW_WRAPPED_KEY_SIZE 128
#define FSCRYPT_CONTEXT_V1 1
#define FSCRYPT_CONTEXT_V2 2
+
+/* Keep this in sync with include/uapi/linux/fscrypt.h */
+#define FSCRYPT_MODE_MAX FSCRYPT_MODE_ADIANTUM
struct fscrypt_context_v1 {
u8 version; /* FSCRYPT_CONTEXT_V1 */
@@ -32,7 +36,7 @@
u8 filenames_encryption_mode;
u8 flags;
u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
- u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
+ u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
};
struct fscrypt_context_v2 {
@@ -42,7 +46,7 @@
u8 flags;
u8 __reserved[4];
u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
- u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
+ u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
};
/*
@@ -98,7 +102,6 @@
return NULL;
}
-#undef fscrypt_policy
union fscrypt_policy {
u8 version;
struct fscrypt_policy_v1 v1;
@@ -192,9 +195,9 @@
struct fscrypt_info {
/* The key in a form prepared for actual encryption/decryption */
- struct fscrypt_prepared_key ci_key;
+ struct fscrypt_prepared_key ci_enc_key;
- /* True if the key should be freed when this fscrypt_info is freed */
+ /* True if ci_enc_key should be freed when this fscrypt_info is freed */
bool ci_owns_key;
#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
@@ -219,7 +222,16 @@
* will be NULL if the master key was found in a process-subscribed
* keyring rather than in the filesystem-level keyring.
*/
+#ifdef __GENKSYMS__
+ /*
+ * Android ABI CRC preservation due to commit 391cceee6d43 ("fscrypt:
+ * stop using keyrings subsystem for fscrypt_master_key") changing this
+ * type. Size is the same, this is a private field.
+ */
struct key *ci_master_key;
+#else
+ struct fscrypt_master_key *ci_master_key;
+#endif
/*
* Link in list of inodes that were unlocked with the master key.
@@ -229,7 +241,7 @@
/*
* If non-NULL, then encryption is done using the master key directly
- * and ci_key will equal ci_direct_key->dk_key.
+ * and ci_enc_key will equal ci_direct_key->dk_key.
*/
struct fscrypt_direct_key *ci_direct_key;
@@ -245,7 +257,7 @@
union fscrypt_policy ci_policy;
/* This inode's nonce, copied from the fscrypt_context */
- u8 ci_nonce[FS_KEY_DERIVATION_NONCE_SIZE];
+ u8 ci_nonce[FSCRYPT_FILE_NONCE_SIZE];
/* Hashed inode number. Only set for IV_INO_LBLK_32 */
u32 ci_hashed_ino;
@@ -281,7 +293,7 @@
__le64 lblk_num;
/* per-file nonce; only set in DIRECT_KEY mode */
- u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
+ u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
};
u8 raw[FSCRYPT_MAX_IV_SIZE];
__le64 dun[FSCRYPT_MAX_IV_SIZE / sizeof(__le64)];
@@ -293,8 +305,9 @@
/* fname.c */
int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
u8 *out, unsigned int olen);
-bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len,
- u32 max_len, u32 *encrypted_len_ret);
+bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
+ u32 orig_len, u32 max_len,
+ u32 *encrypted_len_ret);
/* hkdf.c */
@@ -312,13 +325,13 @@
* outputs are unique and cryptographically isolated, i.e. knowledge of one
* output doesn't reveal another.
*/
-#define HKDF_CONTEXT_KEY_IDENTIFIER 1
-#define HKDF_CONTEXT_PER_FILE_ENC_KEY 2
-#define HKDF_CONTEXT_DIRECT_KEY 3
-#define HKDF_CONTEXT_IV_INO_LBLK_64_KEY 4
-#define HKDF_CONTEXT_DIRHASH_KEY 5
-#define HKDF_CONTEXT_IV_INO_LBLK_32_KEY 6
-#define HKDF_CONTEXT_INODE_HASH_KEY 7
+#define HKDF_CONTEXT_KEY_IDENTIFIER 1 /* info=<empty> */
+#define HKDF_CONTEXT_PER_FILE_ENC_KEY 2 /* info=file_nonce */
+#define HKDF_CONTEXT_DIRECT_KEY 3 /* info=mode_num */
+#define HKDF_CONTEXT_IV_INO_LBLK_64_KEY 4 /* info=mode_num||fs_uuid */
+#define HKDF_CONTEXT_DIRHASH_KEY 5 /* info=file_nonce */
+#define HKDF_CONTEXT_IV_INO_LBLK_32_KEY 6 /* info=mode_num||fs_uuid */
+#define HKDF_CONTEXT_INODE_HASH_KEY 7 /* info=<empty> */
int fscrypt_hkdf_expand(const struct fscrypt_hkdf *hkdf, u8 context,
const u8 *info, unsigned int infolen,
@@ -328,8 +341,8 @@
/* inline_crypt.c */
#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
-extern int fscrypt_select_encryption_impl(struct fscrypt_info *ci,
- bool is_hw_wrapped_key);
+int fscrypt_select_encryption_impl(struct fscrypt_info *ci,
+ bool is_hw_wrapped_key);
static inline bool
fscrypt_using_inline_encryption(const struct fscrypt_info *ci)
@@ -337,15 +350,13 @@
return ci->ci_inlinecrypt;
}
-extern int fscrypt_prepare_inline_crypt_key(
- struct fscrypt_prepared_key *prep_key,
- const u8 *raw_key,
- unsigned int raw_key_size,
- bool is_hw_wrapped,
- const struct fscrypt_info *ci);
+int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
+ const u8 *raw_key,
+ unsigned int raw_key_size,
+ bool is_hw_wrapped,
+ const struct fscrypt_info *ci);
-extern void fscrypt_destroy_inline_crypt_key(
- struct fscrypt_prepared_key *prep_key);
+void fscrypt_destroy_inline_crypt_key(struct fscrypt_prepared_key *prep_key);
extern int fscrypt_derive_raw_secret(struct super_block *sb,
const u8 *wrapped_key,
@@ -382,8 +393,8 @@
return 0;
}
-static inline bool fscrypt_using_inline_encryption(
- const struct fscrypt_info *ci)
+static inline bool
+fscrypt_using_inline_encryption(const struct fscrypt_info *ci)
{
return false;
}
@@ -460,6 +471,40 @@
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
@@ -467,16 +512,12 @@
* FS_IOC_REMOVE_ENCRYPTION_KEY can be retried, or
* FS_IOC_ADD_ENCRYPTION_KEY can add the secret again.
*
- * Locking: protected by key->sem (outer) and mk_secret_sem (inner).
- * The reason for two locks is that key->sem also protects modifying
- * mk_users, which ranks it above the semaphore for the keyring key
- * type, which is in turn above page faults (via keyring_read). But
- * sometimes filesystems call fscrypt_get_encryption_info() from within
- * a transaction, which ranks it below page faults. So we need a
- * separate lock which protects mk_secret but not also mk_users.
+ * 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;
- struct rw_semaphore mk_secret_sem;
/*
* For v1 policy keys: an arbitrary key descriptor which was assigned by
@@ -495,21 +536,11 @@
*
* This is NULL for v1 policy keys; those can only be added by root.
*
- * Locking: in addition to this keyrings own semaphore, this is
- * protected by the 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
@@ -522,9 +553,9 @@
* Per-mode encryption keys for the various types of encryption policies
* that use them. Allocated and derived on-demand.
*/
- struct fscrypt_prepared_key mk_direct_keys[__FSCRYPT_MODE_MAX + 1];
- struct fscrypt_prepared_key mk_iv_ino_lblk_64_keys[__FSCRYPT_MODE_MAX + 1];
- struct fscrypt_prepared_key mk_iv_ino_lblk_32_keys[__FSCRYPT_MODE_MAX + 1];
+ struct fscrypt_prepared_key mk_direct_keys[FSCRYPT_MODE_MAX + 1];
+ struct fscrypt_prepared_key mk_iv_ino_lblk_64_keys[FSCRYPT_MODE_MAX + 1];
+ struct fscrypt_prepared_key mk_iv_ino_lblk_32_keys[FSCRYPT_MODE_MAX + 1];
/* Hash key for inode numbers. Initialized only when needed. */
siphash_key_t mk_ino_hash_key;
@@ -536,11 +567,11 @@
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 ->mk_secret_sem and thus 'secret' can change concurrently which
- * would be a data race. But they only need to know whether the secret
- * *was* present at the time of check, so READ_ONCE() suffices.
+ * 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;
}
@@ -568,7 +599,11 @@
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);
@@ -585,8 +620,9 @@
struct fscrypt_mode {
const char *friendly_name;
const char *cipher_str;
- int keysize;
- int ivsize;
+ int keysize; /* key size in bytes */
+ int security_strength; /* security strength in bytes */
+ int ivsize; /* IV size in bytes */
int logged_impl_name;
enum blk_crypto_mode_num blk_crypto_mode;
};
@@ -603,6 +639,37 @@
int fscrypt_derive_dirhash_key(struct fscrypt_info *ci,
const struct fscrypt_master_key *mk);
+
+void fscrypt_hash_inode_number(struct fscrypt_info *ci,
+ const struct fscrypt_master_key *mk);
+
+int fscrypt_get_encryption_info(struct inode *inode, bool allow_unsupported);
+
+/**
+ * fscrypt_require_key() - require an inode's encryption key
+ * @inode: the inode we need the key for
+ *
+ * If the inode is encrypted, set up its encryption key if not already done.
+ * Then require that the key be present and return -ENOKEY otherwise.
+ *
+ * No locks are needed, and the key will live as long as the struct inode --- so
+ * it won't go away from under you.
+ *
+ * Return: 0 on success, -ENOKEY if the key is missing, or another -errno code
+ * if a problem occurred while setting up the encryption key.
+ */
+static inline int fscrypt_require_key(struct inode *inode)
+{
+ if (IS_ENCRYPTED(inode)) {
+ int err = fscrypt_get_encryption_info(inode, false);
+
+ if (err)
+ return err;
+ if (!fscrypt_has_encryption_key(inode))
+ return -ENOKEY;
+ }
+ return 0;
+}
/* keysetup_v1.c */
@@ -622,5 +689,6 @@
int fscrypt_policy_from_context(union fscrypt_policy *policy_u,
const union fscrypt_context *ctx_u,
int ctx_size);
+const union fscrypt_policy *fscrypt_policy_to_inherit(struct inode *dir);
#endif /* _FSCRYPT_PRIVATE_H */
--
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