From: Eric Biggers <ebiggers@xxxxxxxxxx>
In preparation for introducing a filesystem-level keyring which will
contain fscrypt master keys, rename the existing 'struct
fscrypt_master_key' to 'struct fscrypt_direct_key'. This is the
structure in the existing table of master keys that's maintained to
deduplicate the crypto transforms for v1 DIRECT_KEY policies.
I've chosen to keep this table as-is rather than make it automagically
add/remove the keys to/from the filesystem-level keyring, since that
would add a lot of extra complexity to the filesystem-level keyring.
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
fs/crypto/fscrypt_private.h | 7 +-
fs/crypto/keyinfo.c | 130 ++++++++++++++++++------------------
2 files changed, 68 insertions(+), 69 deletions(-)
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index d345a7d28df8c2..80d15a1bf60685 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -77,11 +77,10 @@ struct fscrypt_info {
struct inode *ci_inode;
/*
- * If non-NULL, then this inode uses a master key directly rather than a
- * derived key, and ci_ctfm will equal ci_master_key->mk_ctfm.
- * Otherwise, this inode uses a derived key.
+ * If non-NULL, then encryption is done using the master key directly
+ * and ci_ctfm will equal ci_direct_key->dk_ctfm.
*/
- struct fscrypt_master_key *ci_master_key;
+ struct fscrypt_direct_key *ci_direct_key;
/* fields from the fscrypt_context */
u8 ci_data_mode;
diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c
index 2d45a86f09db25..c4650071df2772 100644
--- a/fs/crypto/keyinfo.c
+++ b/fs/crypto/keyinfo.c
@@ -21,8 +21,8 @@
static struct crypto_shash *essiv_hash_tfm;
/* Table of keys referenced by DIRECT_KEY policies */
-static DEFINE_HASHTABLE(fscrypt_master_keys, 6); /* 6 bits = 64 buckets */
-static DEFINE_SPINLOCK(fscrypt_master_keys_lock);
+static DEFINE_HASHTABLE(fscrypt_direct_keys, 6); /* 6 bits = 64 buckets */
+static DEFINE_SPINLOCK(fscrypt_direct_keys_lock);
/*
* Key derivation function. This generates the derived key by encrypting the
@@ -273,46 +273,46 @@ allocate_skcipher_for_mode(struct fscrypt_mode *mode, const u8 *raw_key,
}
/* Master key referenced by DIRECT_KEY policy */
-struct fscrypt_master_key {
- struct hlist_node mk_node;
- refcount_t mk_refcount;
- const struct fscrypt_mode *mk_mode;
- struct crypto_skcipher *mk_ctfm;
- u8 mk_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
- u8 mk_raw[FSCRYPT_MAX_KEY_SIZE];
+struct fscrypt_direct_key {
+ struct hlist_node dk_node;
+ refcount_t dk_refcount;
+ const struct fscrypt_mode *dk_mode;
+ struct crypto_skcipher *dk_ctfm;
+ u8 dk_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
+ u8 dk_raw[FSCRYPT_MAX_KEY_SIZE];
};
-static void free_master_key(struct fscrypt_master_key *mk)
+static void free_direct_key(struct fscrypt_direct_key *dk)
{
- if (mk) {
- crypto_free_skcipher(mk->mk_ctfm);
- kzfree(mk);
+ if (dk) {
+ crypto_free_skcipher(dk->dk_ctfm);
+ kzfree(dk);
}
}
-static void put_master_key(struct fscrypt_master_key *mk)
+static void put_direct_key(struct fscrypt_direct_key *dk)
{
- if (!refcount_dec_and_lock(&mk->mk_refcount, &fscrypt_master_keys_lock))
+ if (!refcount_dec_and_lock(&dk->dk_refcount, &fscrypt_direct_keys_lock))
return;
- hash_del(&mk->mk_node);
- spin_unlock(&fscrypt_master_keys_lock);
+ hash_del(&dk->dk_node);
+ spin_unlock(&fscrypt_direct_keys_lock);
- free_master_key(mk);
+ free_direct_key(dk);
}
/*
- * Find/insert the given master key into the fscrypt_master_keys table. If
- * found, it is returned with elevated refcount, and 'to_insert' is freed if
- * non-NULL. If not found, 'to_insert' is inserted and returned if it's
- * non-NULL; otherwise NULL is returned.
+ * Find/insert the given key into the fscrypt_direct_keys table. If found, it
+ * is returned with elevated refcount, and 'to_insert' is freed if non-NULL. If
+ * not found, 'to_insert' is inserted and returned if it's non-NULL; otherwise
+ * NULL is returned.
*/
-static struct fscrypt_master_key *
-find_or_insert_master_key(struct fscrypt_master_key *to_insert,
+static struct fscrypt_direct_key *
+find_or_insert_direct_key(struct fscrypt_direct_key *to_insert,
const u8 *raw_key, const struct fscrypt_mode *mode,
const struct fscrypt_info *ci)
{
unsigned long hash_key;
- struct fscrypt_master_key *mk;
+ struct fscrypt_direct_key *dk;
/*
* Careful: to avoid potentially leaking secret key bytes via timing
@@ -323,60 +323,60 @@ find_or_insert_master_key(struct fscrypt_master_key *to_insert,
BUILD_BUG_ON(sizeof(hash_key) > FSCRYPT_KEY_DESCRIPTOR_SIZE);
memcpy(&hash_key, ci->ci_master_key_descriptor, sizeof(hash_key));
- spin_lock(&fscrypt_master_keys_lock);
- hash_for_each_possible(fscrypt_master_keys, mk, mk_node, hash_key) {
- if (memcmp(ci->ci_master_key_descriptor, mk->mk_descriptor,
+ spin_lock(&fscrypt_direct_keys_lock);
+ hash_for_each_possible(fscrypt_direct_keys, dk, dk_node, hash_key) {
+ if (memcmp(ci->ci_master_key_descriptor, dk->dk_descriptor,
FSCRYPT_KEY_DESCRIPTOR_SIZE) != 0)
continue;
- if (mode != mk->mk_mode)
+ if (mode != dk->dk_mode)
continue;
- if (crypto_memneq(raw_key, mk->mk_raw, mode->keysize))
+ if (crypto_memneq(raw_key, dk->dk_raw, mode->keysize))
continue;
/* using existing tfm with same (descriptor, mode, raw_key) */
- refcount_inc(&mk->mk_refcount);
- spin_unlock(&fscrypt_master_keys_lock);
- free_master_key(to_insert);
- return mk;
+ refcount_inc(&dk->dk_refcount);
+ spin_unlock(&fscrypt_direct_keys_lock);
+ free_direct_key(to_insert);
+ return dk;
}
if (to_insert)
- hash_add(fscrypt_master_keys, &to_insert->mk_node, hash_key);
- spin_unlock(&fscrypt_master_keys_lock);
+ hash_add(fscrypt_direct_keys, &to_insert->dk_node, hash_key);
+ spin_unlock(&fscrypt_direct_keys_lock);
return to_insert;
}
/* Prepare to encrypt directly using the master key in the given mode */
-static struct fscrypt_master_key *
-fscrypt_get_master_key(const struct fscrypt_info *ci, struct fscrypt_mode *mode,
+static struct fscrypt_direct_key *
+fscrypt_get_direct_key(const struct fscrypt_info *ci, struct fscrypt_mode *mode,
const u8 *raw_key, const struct inode *inode)
{
- struct fscrypt_master_key *mk;
+ struct fscrypt_direct_key *dk;
int err;
/* Is there already a tfm for this key? */
- mk = find_or_insert_master_key(NULL, raw_key, mode, ci);
- if (mk)
- return mk;
+ dk = find_or_insert_direct_key(NULL, raw_key, mode, ci);
+ if (dk)
+ return dk;
/* Nope, allocate one. */
- mk = kzalloc(sizeof(*mk), GFP_NOFS);
- if (!mk)
+ dk = kzalloc(sizeof(*dk), GFP_NOFS);
+ if (!dk)
return ERR_PTR(-ENOMEM);
- refcount_set(&mk->mk_refcount, 1);
- mk->mk_mode = mode;
- mk->mk_ctfm = allocate_skcipher_for_mode(mode, raw_key, inode);
- if (IS_ERR(mk->mk_ctfm)) {
- err = PTR_ERR(mk->mk_ctfm);
- mk->mk_ctfm = NULL;
- goto err_free_mk;
+ refcount_set(&dk->dk_refcount, 1);
+ dk->dk_mode = mode;
+ dk->dk_ctfm = allocate_skcipher_for_mode(mode, raw_key, inode);
+ if (IS_ERR(dk->dk_ctfm)) {
+ err = PTR_ERR(dk->dk_ctfm);
+ dk->dk_ctfm = NULL;
+ goto err_free_dk;
}
- memcpy(mk->mk_descriptor, ci->ci_master_key_descriptor,
+ memcpy(dk->dk_descriptor, ci->ci_master_key_descriptor,
FSCRYPT_KEY_DESCRIPTOR_SIZE);
- memcpy(mk->mk_raw, raw_key, mode->keysize);
+ memcpy(dk->dk_raw, raw_key, mode->keysize);
- return find_or_insert_master_key(mk, raw_key, mode, ci);
+ return find_or_insert_direct_key(dk, raw_key, mode, ci);
-err_free_mk:
- free_master_key(mk);
+err_free_dk:
+ free_direct_key(dk);
return ERR_PTR(err);
}
@@ -455,22 +455,22 @@ static int setup_crypto_transform(struct fscrypt_info *ci,
struct fscrypt_mode *mode,
const u8 *raw_key, const struct inode *inode)
{
- struct fscrypt_master_key *mk;
+ struct fscrypt_direct_key *dk;
struct crypto_skcipher *ctfm;
int err;
if (ci->ci_flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) {
- mk = fscrypt_get_master_key(ci, mode, raw_key, inode);
- if (IS_ERR(mk))
- return PTR_ERR(mk);
- ctfm = mk->mk_ctfm;
+ dk = fscrypt_get_direct_key(ci, mode, raw_key, inode);
+ if (IS_ERR(dk))
+ return PTR_ERR(dk);
+ ctfm = dk->dk_ctfm;
} else {
- mk = NULL;
+ dk = NULL;
ctfm = allocate_skcipher_for_mode(mode, raw_key, inode);
if (IS_ERR(ctfm))
return PTR_ERR(ctfm);
}
- ci->ci_master_key = mk;
+ ci->ci_direct_key = dk;
ci->ci_ctfm = ctfm;
if (mode->needs_essiv) {
@@ -494,8 +494,8 @@ static void put_crypt_info(struct fscrypt_info *ci)
if (!ci)
return;
- if (ci->ci_master_key) {
- put_master_key(ci->ci_master_key);
+ if (ci->ci_direct_key) {
+ put_direct_key(ci->ci_direct_key);
} else {
crypto_free_skcipher(ci->ci_ctfm);
crypto_free_cipher(ci->ci_essiv_tfm);
--
2.22.0.770.g0f2c4a37fd-goog
