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/keyring.c | 549 ++++++++++++++++++++++++++++--------------------------
1 files changed, 288 insertions(+), 261 deletions(-)
diff --git a/kernel/fs/crypto/keyring.c b/kernel/fs/crypto/keyring.c
index ae081f0..eb7b904 100644
--- a/kernel/fs/crypto/keyring.c
+++ b/kernel/fs/crypto/keyring.c
@@ -18,12 +18,25 @@
* information about these ioctls.
*/
+#include <asm/unaligned.h>
#include <crypto/skcipher.h>
#include <linux/key-type.h>
#include <linux/random.h>
#include <linux/seq_file.h>
#include "fscrypt_private.h"
+
+/* The master encryption keys for a filesystem (->s_master_keys) */
+struct fscrypt_keyring {
+ /*
+ * Lock that protects ->key_hashtable. It does *not* protect the
+ * fscrypt_master_key structs themselves.
+ */
+ spinlock_t lock;
+
+ /* Hash table that maps fscrypt_key_specifier to fscrypt_master_key */
+ struct hlist_head key_hashtable[128];
+};
static void wipe_master_key_secret(struct fscrypt_master_key_secret *secret)
{
@@ -38,20 +51,70 @@
memzero_explicit(src, sizeof(*src));
}
-static void free_master_key(struct fscrypt_master_key *mk)
+static void fscrypt_free_master_key(struct rcu_head *head)
{
+ struct fscrypt_master_key *mk =
+ container_of(head, struct fscrypt_master_key, mk_rcu_head);
+ /*
+ * The master key secret and any embedded subkeys should have already
+ * been wiped when the last active reference to the fscrypt_master_key
+ * struct was dropped; doing it here would be unnecessarily late.
+ * Nevertheless, use kfree_sensitive() in case anything was missed.
+ */
+ kfree_sensitive(mk);
+}
+
+void fscrypt_put_master_key(struct fscrypt_master_key *mk)
+{
+ if (!refcount_dec_and_test(&mk->mk_struct_refs))
+ return;
+ /*
+ * No structural references left, so free ->mk_users, and also free the
+ * fscrypt_master_key struct itself after an RCU grace period ensures
+ * that concurrent keyring lookups can no longer find it.
+ */
+ WARN_ON(refcount_read(&mk->mk_active_refs) != 0);
+ key_put(mk->mk_users);
+ mk->mk_users = NULL;
+ call_rcu(&mk->mk_rcu_head, fscrypt_free_master_key);
+}
+
+void fscrypt_put_master_key_activeref(struct fscrypt_master_key *mk)
+{
+ struct super_block *sb = mk->mk_sb;
+ struct fscrypt_keyring *keyring = sb->s_master_keys;
size_t i;
- wipe_master_key_secret(&mk->mk_secret);
+ if (!refcount_dec_and_test(&mk->mk_active_refs))
+ return;
+ /*
+ * No active references left, so complete the full removal of this
+ * fscrypt_master_key struct by removing it from the keyring and
+ * destroying any subkeys embedded in it.
+ */
- for (i = 0; i <= __FSCRYPT_MODE_MAX; i++) {
+ spin_lock(&keyring->lock);
+ hlist_del_rcu(&mk->mk_node);
+ spin_unlock(&keyring->lock);
+
+ /*
+ * ->mk_active_refs == 0 implies that ->mk_secret is not present and
+ * that ->mk_decrypted_inodes is empty.
+ */
+ WARN_ON(is_master_key_secret_present(&mk->mk_secret));
+ WARN_ON(!list_empty(&mk->mk_decrypted_inodes));
+
+ for (i = 0; i <= FSCRYPT_MODE_MAX; i++) {
fscrypt_destroy_prepared_key(&mk->mk_direct_keys[i]);
fscrypt_destroy_prepared_key(&mk->mk_iv_ino_lblk_64_keys[i]);
fscrypt_destroy_prepared_key(&mk->mk_iv_ino_lblk_32_keys[i]);
}
+ memzero_explicit(&mk->mk_ino_hash_key,
+ sizeof(mk->mk_ino_hash_key));
+ mk->mk_ino_hash_key_initialized = false;
- key_put(mk->mk_users);
- kzfree(mk);
+ /* Drop the structural ref associated with the active refs. */
+ fscrypt_put_master_key(mk);
}
static inline bool valid_key_spec(const struct fscrypt_key_specifier *spec)
@@ -60,44 +123,6 @@
return false;
return master_key_spec_len(spec) != 0;
}
-
-static int fscrypt_key_instantiate(struct key *key,
- struct key_preparsed_payload *prep)
-{
- key->payload.data[0] = (struct fscrypt_master_key *)prep->data;
- return 0;
-}
-
-static void fscrypt_key_destroy(struct key *key)
-{
- free_master_key(key->payload.data[0]);
-}
-
-static void fscrypt_key_describe(const struct key *key, struct seq_file *m)
-{
- seq_puts(m, key->description);
-
- if (key_is_positive(key)) {
- const struct fscrypt_master_key *mk = key->payload.data[0];
-
- if (!is_master_key_secret_present(&mk->mk_secret))
- seq_puts(m, ": secret removed");
- }
-}
-
-/*
- * Type of key in ->s_master_keys. Each key of this type represents a master
- * key which has been added to the filesystem. Its payload is a
- * 'struct fscrypt_master_key'. The "." prefix in the key type name prevents
- * users from adding keys of this type via the keyrings syscalls rather than via
- * the intended method of FS_IOC_ADD_ENCRYPTION_KEY.
- */
-static struct key_type key_type_fscrypt = {
- .name = "._fscrypt",
- .instantiate = fscrypt_key_instantiate,
- .destroy = fscrypt_key_destroy,
- .describe = fscrypt_key_describe,
-};
static int fscrypt_user_key_instantiate(struct key *key,
struct key_preparsed_payload *prep)
@@ -131,53 +156,12 @@
.describe = fscrypt_user_key_describe,
};
-/* Search ->s_master_keys or ->mk_users */
-static struct key *search_fscrypt_keyring(struct key *keyring,
- struct key_type *type,
- const char *description)
-{
- /*
- * We need to mark the keyring reference as "possessed" so that we
- * acquire permission to search it, via the KEY_POS_SEARCH permission.
- */
- key_ref_t keyref = make_key_ref(keyring, true /* possessed */);
-
- keyref = keyring_search(keyref, type, description);
- if (IS_ERR(keyref)) {
- if (PTR_ERR(keyref) == -EAGAIN || /* not found */
- PTR_ERR(keyref) == -EKEYREVOKED) /* recently invalidated */
- keyref = ERR_PTR(-ENOKEY);
- return ERR_CAST(keyref);
- }
- return key_ref_to_ptr(keyref);
-}
-
-#define FSCRYPT_FS_KEYRING_DESCRIPTION_SIZE \
- (CONST_STRLEN("fscrypt-") + FIELD_SIZEOF(struct super_block, s_id))
-
-#define FSCRYPT_MK_DESCRIPTION_SIZE (2 * FSCRYPT_KEY_IDENTIFIER_SIZE + 1)
-
#define FSCRYPT_MK_USERS_DESCRIPTION_SIZE \
(CONST_STRLEN("fscrypt-") + 2 * FSCRYPT_KEY_IDENTIFIER_SIZE + \
CONST_STRLEN("-users") + 1)
#define FSCRYPT_MK_USER_DESCRIPTION_SIZE \
(2 * FSCRYPT_KEY_IDENTIFIER_SIZE + CONST_STRLEN(".uid.") + 10 + 1)
-
-static void format_fs_keyring_description(
- char description[FSCRYPT_FS_KEYRING_DESCRIPTION_SIZE],
- const struct super_block *sb)
-{
- sprintf(description, "fscrypt-%s", sb->s_id);
-}
-
-static void format_mk_description(
- char description[FSCRYPT_MK_DESCRIPTION_SIZE],
- const struct fscrypt_key_specifier *mk_spec)
-{
- sprintf(description, "%*phN",
- master_key_spec_len(mk_spec), (u8 *)&mk_spec->u);
-}
static void format_mk_users_keyring_description(
char description[FSCRYPT_MK_USERS_DESCRIPTION_SIZE],
@@ -199,48 +183,139 @@
/* Create ->s_master_keys if needed. Synchronized by fscrypt_add_key_mutex. */
static int allocate_filesystem_keyring(struct super_block *sb)
{
- char description[FSCRYPT_FS_KEYRING_DESCRIPTION_SIZE];
- struct key *keyring;
+ struct fscrypt_keyring *keyring;
if (sb->s_master_keys)
return 0;
- format_fs_keyring_description(description, sb);
- keyring = keyring_alloc(description, GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
- current_cred(), KEY_POS_SEARCH |
- KEY_USR_SEARCH | KEY_USR_READ | KEY_USR_VIEW,
- KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
- if (IS_ERR(keyring))
- return PTR_ERR(keyring);
-
- /* Pairs with READ_ONCE() in fscrypt_find_master_key() */
+ keyring = kzalloc(sizeof(*keyring), GFP_KERNEL);
+ if (!keyring)
+ return -ENOMEM;
+ spin_lock_init(&keyring->lock);
+ /*
+ * Pairs with the smp_load_acquire() in fscrypt_find_master_key().
+ * I.e., here we publish ->s_master_keys with a RELEASE barrier so that
+ * concurrent tasks can ACQUIRE it.
+ */
smp_store_release(&sb->s_master_keys, keyring);
return 0;
}
-void fscrypt_sb_free(struct super_block *sb)
+/*
+ * Release all encryption keys that have been added to the filesystem, along
+ * with the keyring that contains them.
+ *
+ * This is called at unmount time. The filesystem's underlying block device(s)
+ * are still available at this time; this is important because after user file
+ * accesses have been allowed, this function may need to evict keys from the
+ * keyslots of an inline crypto engine, which requires the block device(s).
+ *
+ * This is also called when the super_block is being freed. This is needed to
+ * avoid a memory leak if mounting fails after the "test_dummy_encryption"
+ * option was processed, as in that case the unmount-time call isn't made.
+ */
+void fscrypt_destroy_keyring(struct super_block *sb)
{
- key_put(sb->s_master_keys);
+ struct fscrypt_keyring *keyring = sb->s_master_keys;
+ size_t i;
+
+ if (!keyring)
+ return;
+
+ for (i = 0; i < ARRAY_SIZE(keyring->key_hashtable); i++) {
+ struct hlist_head *bucket = &keyring->key_hashtable[i];
+ struct fscrypt_master_key *mk;
+ struct hlist_node *tmp;
+
+ hlist_for_each_entry_safe(mk, tmp, bucket, mk_node) {
+ /*
+ * Since all inodes were already evicted, every key
+ * remaining in the keyring should have an empty inode
+ * list, and should only still be in the keyring due to
+ * the single active ref associated with ->mk_secret.
+ * There should be no structural refs beyond the one
+ * associated with the active ref.
+ */
+ WARN_ON(refcount_read(&mk->mk_active_refs) != 1);
+ WARN_ON(refcount_read(&mk->mk_struct_refs) != 1);
+ WARN_ON(!is_master_key_secret_present(&mk->mk_secret));
+ wipe_master_key_secret(&mk->mk_secret);
+ fscrypt_put_master_key_activeref(mk);
+ }
+ }
+ kfree_sensitive(keyring);
sb->s_master_keys = NULL;
}
-/*
- * Find the specified master key in ->s_master_keys.
- * Returns ERR_PTR(-ENOKEY) if not found.
- */
-struct key *fscrypt_find_master_key(struct super_block *sb,
- const struct fscrypt_key_specifier *mk_spec)
+static struct hlist_head *
+fscrypt_mk_hash_bucket(struct fscrypt_keyring *keyring,
+ const struct fscrypt_key_specifier *mk_spec)
{
- struct key *keyring;
- char description[FSCRYPT_MK_DESCRIPTION_SIZE];
+ /*
+ * Since key specifiers should be "random" values, it is sufficient to
+ * use a trivial hash function that just takes the first several bits of
+ * the key specifier.
+ */
+ unsigned long i = get_unaligned((unsigned long *)&mk_spec->u);
- /* pairs with smp_store_release() in allocate_filesystem_keyring() */
- keyring = READ_ONCE(sb->s_master_keys);
+ return &keyring->key_hashtable[i % ARRAY_SIZE(keyring->key_hashtable)];
+}
+
+/*
+ * Find the specified master key struct in ->s_master_keys and take a structural
+ * ref to it. The structural ref guarantees that the key struct continues to
+ * exist, but it does *not* guarantee that ->s_master_keys continues to contain
+ * the key struct. The structural ref needs to be dropped by
+ * fscrypt_put_master_key(). Returns NULL if the key struct is not found.
+ */
+struct fscrypt_master_key *
+fscrypt_find_master_key(struct super_block *sb,
+ const struct fscrypt_key_specifier *mk_spec)
+{
+ struct fscrypt_keyring *keyring;
+ struct hlist_head *bucket;
+ struct fscrypt_master_key *mk;
+
+ /*
+ * Pairs with the smp_store_release() in allocate_filesystem_keyring().
+ * I.e., another task can publish ->s_master_keys concurrently,
+ * executing a RELEASE barrier. We need to use smp_load_acquire() here
+ * to safely ACQUIRE the memory the other task published.
+ */
+ keyring = smp_load_acquire(&sb->s_master_keys);
if (keyring == NULL)
- return ERR_PTR(-ENOKEY); /* No keyring yet, so no keys yet. */
+ return NULL; /* No keyring yet, so no keys yet. */
- format_mk_description(description, mk_spec);
- return search_fscrypt_keyring(keyring, &key_type_fscrypt, description);
+ bucket = fscrypt_mk_hash_bucket(keyring, mk_spec);
+ rcu_read_lock();
+ switch (mk_spec->type) {
+ case FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR:
+ hlist_for_each_entry_rcu(mk, bucket, mk_node) {
+ if (mk->mk_spec.type ==
+ FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR &&
+ memcmp(mk->mk_spec.u.descriptor,
+ mk_spec->u.descriptor,
+ FSCRYPT_KEY_DESCRIPTOR_SIZE) == 0 &&
+ refcount_inc_not_zero(&mk->mk_struct_refs))
+ goto out;
+ }
+ break;
+ case FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER:
+ hlist_for_each_entry_rcu(mk, bucket, mk_node) {
+ if (mk->mk_spec.type ==
+ FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER &&
+ memcmp(mk->mk_spec.u.identifier,
+ mk_spec->u.identifier,
+ FSCRYPT_KEY_IDENTIFIER_SIZE) == 0 &&
+ refcount_inc_not_zero(&mk->mk_struct_refs))
+ goto out;
+ }
+ break;
+ }
+ mk = NULL;
+out:
+ rcu_read_unlock();
+ return mk;
}
static int allocate_master_key_users_keyring(struct fscrypt_master_key *mk)
@@ -268,17 +343,30 @@
static struct key *find_master_key_user(struct fscrypt_master_key *mk)
{
char description[FSCRYPT_MK_USER_DESCRIPTION_SIZE];
+ key_ref_t keyref;
format_mk_user_description(description, mk->mk_spec.u.identifier);
- return search_fscrypt_keyring(mk->mk_users, &key_type_fscrypt_user,
- description);
+
+ /*
+ * We need to mark the keyring reference as "possessed" so that we
+ * acquire permission to search it, via the KEY_POS_SEARCH permission.
+ */
+ keyref = keyring_search(make_key_ref(mk->mk_users, true /*possessed*/),
+ &key_type_fscrypt_user, description, false);
+ if (IS_ERR(keyref)) {
+ if (PTR_ERR(keyref) == -EAGAIN || /* not found */
+ PTR_ERR(keyref) == -EKEYREVOKED) /* recently invalidated */
+ keyref = ERR_PTR(-ENOKEY);
+ return ERR_CAST(keyref);
+ }
+ return key_ref_to_ptr(keyref);
}
/*
* Give the current user a "key" in ->mk_users. This charges the user's quota
* and marks the master key as added by the current user, so that it cannot be
- * removed by another user with the key. Either the master key's key->sem must
- * be held for write, or the master key must be still undergoing initialization.
+ * removed by another user with the key. Either ->mk_sem must be held for
+ * write, or the master key must be still undergoing initialization.
*/
static int add_master_key_user(struct fscrypt_master_key *mk)
{
@@ -300,7 +388,7 @@
/*
* Remove the current user's "key" from ->mk_users.
- * The master key's key->sem must be held for write.
+ * ->mk_sem must be held for write.
*
* Returns 0 if removed, -ENOKEY if not found, or another -errno code.
*/
@@ -318,64 +406,49 @@
}
/*
- * Allocate a new fscrypt_master_key which contains the given secret, set it as
- * the payload of a new 'struct key' of type fscrypt, and link the 'struct key'
- * into the given keyring. Synchronized by fscrypt_add_key_mutex.
+ * Allocate a new fscrypt_master_key, transfer the given secret over to it, and
+ * insert it into sb->s_master_keys.
*/
-static int add_new_master_key(struct fscrypt_master_key_secret *secret,
- const struct fscrypt_key_specifier *mk_spec,
- struct key *keyring)
+static int add_new_master_key(struct super_block *sb,
+ struct fscrypt_master_key_secret *secret,
+ const struct fscrypt_key_specifier *mk_spec)
{
+ struct fscrypt_keyring *keyring = sb->s_master_keys;
struct fscrypt_master_key *mk;
- char description[FSCRYPT_MK_DESCRIPTION_SIZE];
- struct key *key;
int err;
mk = kzalloc(sizeof(*mk), GFP_KERNEL);
if (!mk)
return -ENOMEM;
+ mk->mk_sb = sb;
+ init_rwsem(&mk->mk_sem);
+ refcount_set(&mk->mk_struct_refs, 1);
mk->mk_spec = *mk_spec;
- move_master_key_secret(&mk->mk_secret, secret);
- init_rwsem(&mk->mk_secret_sem);
-
- refcount_set(&mk->mk_refcount, 1); /* secret is present */
INIT_LIST_HEAD(&mk->mk_decrypted_inodes);
spin_lock_init(&mk->mk_decrypted_inodes_lock);
if (mk_spec->type == FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER) {
err = allocate_master_key_users_keyring(mk);
if (err)
- goto out_free_mk;
+ goto out_put;
err = add_master_key_user(mk);
if (err)
- goto out_free_mk;
+ goto out_put;
}
- /*
- * Note that we don't charge this key to anyone's quota, since when
- * ->mk_users is in use those keys are charged instead, and otherwise
- * (when ->mk_users isn't in use) only root can add these keys.
- */
- format_mk_description(description, mk_spec);
- key = key_alloc(&key_type_fscrypt, description,
- GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(),
- KEY_POS_SEARCH | KEY_USR_SEARCH | KEY_USR_VIEW,
- KEY_ALLOC_NOT_IN_QUOTA, NULL);
- if (IS_ERR(key)) {
- err = PTR_ERR(key);
- goto out_free_mk;
- }
- err = key_instantiate_and_link(key, mk, sizeof(*mk), keyring, NULL);
- key_put(key);
- if (err)
- goto out_free_mk;
+ move_master_key_secret(&mk->mk_secret, secret);
+ refcount_set(&mk->mk_active_refs, 1); /* ->mk_secret is present */
+ spin_lock(&keyring->lock);
+ hlist_add_head_rcu(&mk->mk_node,
+ fscrypt_mk_hash_bucket(keyring, mk_spec));
+ spin_unlock(&keyring->lock);
return 0;
-out_free_mk:
- free_master_key(mk);
+out_put:
+ fscrypt_put_master_key(mk);
return err;
}
@@ -384,45 +457,34 @@
static int add_existing_master_key(struct fscrypt_master_key *mk,
struct fscrypt_master_key_secret *secret)
{
- struct key *mk_user;
- bool rekey;
int err;
/*
* If the current user is already in ->mk_users, then there's nothing to
- * do. (Not applicable for v1 policy keys, which have NULL ->mk_users.)
+ * do. Otherwise, we need to add the user to ->mk_users. (Neither is
+ * applicable for v1 policy keys, which have NULL ->mk_users.)
*/
if (mk->mk_users) {
- mk_user = find_master_key_user(mk);
+ struct key *mk_user = find_master_key_user(mk);
+
if (mk_user != ERR_PTR(-ENOKEY)) {
if (IS_ERR(mk_user))
return PTR_ERR(mk_user);
key_put(mk_user);
return 0;
}
- }
-
- /* If we'll be re-adding ->mk_secret, try to take the reference. */
- rekey = !is_master_key_secret_present(&mk->mk_secret);
- if (rekey && !refcount_inc_not_zero(&mk->mk_refcount))
- return KEY_DEAD;
-
- /* Add the current user to ->mk_users, if applicable. */
- if (mk->mk_users) {
err = add_master_key_user(mk);
- if (err) {
- if (rekey && refcount_dec_and_test(&mk->mk_refcount))
- return KEY_DEAD;
+ if (err)
return err;
- }
}
/* Re-add the secret if needed. */
- if (rekey) {
- down_write(&mk->mk_secret_sem);
+ if (!is_master_key_secret_present(&mk->mk_secret)) {
+ if (!refcount_inc_not_zero(&mk->mk_active_refs))
+ return KEY_DEAD;
move_master_key_secret(&mk->mk_secret, secret);
- up_write(&mk->mk_secret_sem);
}
+
return 0;
}
@@ -431,38 +493,36 @@
const struct fscrypt_key_specifier *mk_spec)
{
static DEFINE_MUTEX(fscrypt_add_key_mutex);
- struct key *key;
+ struct fscrypt_master_key *mk;
int err;
mutex_lock(&fscrypt_add_key_mutex); /* serialize find + link */
-retry:
- key = fscrypt_find_master_key(sb, mk_spec);
- if (IS_ERR(key)) {
- err = PTR_ERR(key);
- if (err != -ENOKEY)
- goto out_unlock;
+
+ mk = fscrypt_find_master_key(sb, mk_spec);
+ if (!mk) {
/* Didn't find the key in ->s_master_keys. Add it. */
err = allocate_filesystem_keyring(sb);
- if (err)
- goto out_unlock;
- err = add_new_master_key(secret, mk_spec, sb->s_master_keys);
+ if (!err)
+ err = add_new_master_key(sb, secret, mk_spec);
} else {
/*
* Found the key in ->s_master_keys. Re-add the secret if
* needed, and add the user to ->mk_users if needed.
*/
- down_write(&key->sem);
- err = add_existing_master_key(key->payload.data[0], secret);
- up_write(&key->sem);
+ down_write(&mk->mk_sem);
+ err = add_existing_master_key(mk, secret);
+ up_write(&mk->mk_sem);
if (err == KEY_DEAD) {
- /* Key being removed or needs to be removed */
- key_invalidate(key);
- key_put(key);
- goto retry;
+ /*
+ * We found a key struct, but it's already been fully
+ * removed. Ignore the old struct and add a new one.
+ * fscrypt_add_key_mutex means we don't need to worry
+ * about concurrent adds.
+ */
+ err = add_new_master_key(sb, secret, mk_spec);
}
- key_put(key);
+ fscrypt_put_master_key(mk);
}
-out_unlock:
mutex_unlock(&fscrypt_add_key_mutex);
return err;
}
@@ -538,7 +598,7 @@
static void fscrypt_provisioning_key_free_preparse(
struct key_preparsed_payload *prep)
{
- kzfree(prep->payload.data[0]);
+ kfree_sensitive(prep->payload.data[0]);
}
static void fscrypt_provisioning_key_describe(const struct key *key,
@@ -555,7 +615,7 @@
static void fscrypt_provisioning_key_destroy(struct key *key)
{
- kzfree(key->payload.data[0]);
+ kfree_sensitive(key->payload.data[0]);
}
static struct key_type key_type_fscrypt_provisioning = {
@@ -756,19 +816,19 @@
const u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE])
{
struct fscrypt_key_specifier mk_spec;
- struct key *key, *mk_user;
struct fscrypt_master_key *mk;
+ struct key *mk_user;
int err;
mk_spec.type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER;
memcpy(mk_spec.u.identifier, identifier, FSCRYPT_KEY_IDENTIFIER_SIZE);
- key = fscrypt_find_master_key(sb, &mk_spec);
- if (IS_ERR(key)) {
- err = PTR_ERR(key);
+ mk = fscrypt_find_master_key(sb, &mk_spec);
+ if (!mk) {
+ err = -ENOKEY;
goto out;
}
- mk = key->payload.data[0];
+ down_read(&mk->mk_sem);
mk_user = find_master_key_user(mk);
if (IS_ERR(mk_user)) {
err = PTR_ERR(mk_user);
@@ -776,7 +836,8 @@
key_put(mk_user);
err = 0;
}
- key_put(key);
+ up_read(&mk->mk_sem);
+ fscrypt_put_master_key(mk);
out:
if (err == -ENOKEY && capable(CAP_FOWNER))
err = 0;
@@ -838,6 +899,7 @@
struct list_head *pos;
size_t busy_count = 0;
unsigned long ino;
+ char ino_str[50] = "";
spin_lock(&mk->mk_decrypted_inodes_lock);
@@ -859,41 +921,23 @@
}
spin_unlock(&mk->mk_decrypted_inodes_lock);
+ /* If the inode is currently being created, ino may still be 0. */
+ if (ino)
+ snprintf(ino_str, sizeof(ino_str), ", including ino %lu", ino);
+
fscrypt_warn(NULL,
- "%s: %zu inode(s) still busy after removing key with %s %*phN, including ino %lu",
+ "%s: %zu inode(s) still busy after removing key with %s %*phN%s",
sb->s_id, busy_count, master_key_spec_type(&mk->mk_spec),
master_key_spec_len(&mk->mk_spec), (u8 *)&mk->mk_spec.u,
- ino);
+ ino_str);
return -EBUSY;
}
-
-static BLOCKING_NOTIFIER_HEAD(fscrypt_key_removal_notifiers);
-
-/*
- * Register a function to be executed when the FS_IOC_REMOVE_ENCRYPTION_KEY
- * ioctl has removed a key and is about to try evicting inodes.
- */
-int fscrypt_register_key_removal_notifier(struct notifier_block *nb)
-{
- return blocking_notifier_chain_register(&fscrypt_key_removal_notifiers,
- nb);
-}
-EXPORT_SYMBOL_GPL(fscrypt_register_key_removal_notifier);
-
-int fscrypt_unregister_key_removal_notifier(struct notifier_block *nb)
-{
- return blocking_notifier_chain_unregister(&fscrypt_key_removal_notifiers,
- nb);
-}
-EXPORT_SYMBOL_GPL(fscrypt_unregister_key_removal_notifier);
static int try_to_lock_encrypted_files(struct super_block *sb,
struct fscrypt_master_key *mk)
{
int err1;
int err2;
-
- blocking_notifier_call_chain(&fscrypt_key_removal_notifiers, 0, NULL);
/*
* An inode can't be evicted while it is dirty or has dirty pages.
@@ -955,11 +999,10 @@
struct super_block *sb = file_inode(filp)->i_sb;
struct fscrypt_remove_key_arg __user *uarg = _uarg;
struct fscrypt_remove_key_arg arg;
- struct key *key;
struct fscrypt_master_key *mk;
u32 status_flags = 0;
int err;
- bool dead;
+ bool inodes_remain;
if (copy_from_user(&arg, uarg, sizeof(arg)))
return -EFAULT;
@@ -979,12 +1022,10 @@
return -EACCES;
/* Find the key being removed. */
- key = fscrypt_find_master_key(sb, &arg.key_spec);
- if (IS_ERR(key))
- return PTR_ERR(key);
- mk = key->payload.data[0];
-
- down_write(&key->sem);
+ mk = fscrypt_find_master_key(sb, &arg.key_spec);
+ if (!mk)
+ return -ENOKEY;
+ down_write(&mk->mk_sem);
/* If relevant, remove current user's (or all users) claim to the key */
if (mk->mk_users && mk->mk_users->keys.nr_leaves_on_tree != 0) {
@@ -993,7 +1034,7 @@
else
err = remove_master_key_user(mk);
if (err) {
- up_write(&key->sem);
+ up_write(&mk->mk_sem);
goto out_put_key;
}
if (mk->mk_users->keys.nr_leaves_on_tree != 0) {
@@ -1005,28 +1046,22 @@
status_flags |=
FSCRYPT_KEY_REMOVAL_STATUS_FLAG_OTHER_USERS;
err = 0;
- up_write(&key->sem);
+ up_write(&mk->mk_sem);
goto out_put_key;
}
}
/* No user claims remaining. Go ahead and wipe the secret. */
- dead = false;
+ err = -ENOKEY;
if (is_master_key_secret_present(&mk->mk_secret)) {
- down_write(&mk->mk_secret_sem);
wipe_master_key_secret(&mk->mk_secret);
- dead = refcount_dec_and_test(&mk->mk_refcount);
- up_write(&mk->mk_secret_sem);
- }
- up_write(&key->sem);
- if (dead) {
- /*
- * No inodes reference the key, and we wiped the secret, so the
- * key object is free to be removed from the keyring.
- */
- key_invalidate(key);
+ fscrypt_put_master_key_activeref(mk);
err = 0;
- } else {
+ }
+ inodes_remain = refcount_read(&mk->mk_active_refs) > 0;
+ up_write(&mk->mk_sem);
+
+ if (inodes_remain) {
/* Some inodes still reference this key; try to evict them. */
err = try_to_lock_encrypted_files(sb, mk);
if (err == -EBUSY) {
@@ -1042,7 +1077,7 @@
* has been fully removed including all files locked.
*/
out_put_key:
- key_put(key);
+ fscrypt_put_master_key(mk);
if (err == 0)
err = put_user(status_flags, &uarg->removal_status_flags);
return err;
@@ -1089,7 +1124,6 @@
{
struct super_block *sb = file_inode(filp)->i_sb;
struct fscrypt_get_key_status_arg arg;
- struct key *key;
struct fscrypt_master_key *mk;
int err;
@@ -1106,19 +1140,18 @@
arg.user_count = 0;
memset(arg.__out_reserved, 0, sizeof(arg.__out_reserved));
- key = fscrypt_find_master_key(sb, &arg.key_spec);
- if (IS_ERR(key)) {
- if (key != ERR_PTR(-ENOKEY))
- return PTR_ERR(key);
+ mk = fscrypt_find_master_key(sb, &arg.key_spec);
+ if (!mk) {
arg.status = FSCRYPT_KEY_STATUS_ABSENT;
err = 0;
goto out;
}
- mk = key->payload.data[0];
- down_read(&key->sem);
+ down_read(&mk->mk_sem);
if (!is_master_key_secret_present(&mk->mk_secret)) {
- arg.status = FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED;
+ arg.status = refcount_read(&mk->mk_active_refs) > 0 ?
+ FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED :
+ FSCRYPT_KEY_STATUS_ABSENT /* raced with full removal */;
err = 0;
goto out_release_key;
}
@@ -1140,8 +1173,8 @@
}
err = 0;
out_release_key:
- up_read(&key->sem);
- key_put(key);
+ up_read(&mk->mk_sem);
+ fscrypt_put_master_key(mk);
out:
if (!err && copy_to_user(uarg, &arg, sizeof(arg)))
err = -EFAULT;
@@ -1153,13 +1186,9 @@
{
int err;
- err = register_key_type(&key_type_fscrypt);
- if (err)
- return err;
-
err = register_key_type(&key_type_fscrypt_user);
if (err)
- goto err_unregister_fscrypt;
+ return err;
err = register_key_type(&key_type_fscrypt_provisioning);
if (err)
@@ -1169,7 +1198,5 @@
err_unregister_fscrypt_user:
unregister_key_type(&key_type_fscrypt_user);
-err_unregister_fscrypt:
- unregister_key_type(&key_type_fscrypt);
return err;
}
--
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