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fscrypt updates for 6.1

Browse Source 
This release contains some implementation changes, but no new features:
 
 - Rework the implementation of the fscrypt filesystem-level keyring to
   not be as tightly coupled to the keyrings subsystem.  This resolves
   several issues.
 
 - Eliminate most direct uses of struct request_queue from fs/crypto/,
   since struct request_queue is considered to be a block layer
   implementation detail.
 
 - Stop using the PG_error flag to track decryption failures.  This is a
   prerequisite for freeing up PG_error for other uses.
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Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt

Pull fscrypt updates from Eric Biggers:
 "This release contains some implementation changes, but no new
  features:

   - Rework the implementation of the fscrypt filesystem-level keyring
     to not be as tightly coupled to the keyrings subsystem. This
     resolves several issues.

   - Eliminate most direct uses of struct request_queue from fs/crypto/,
     since struct request_queue is considered to be a block layer
     implementation detail.

   - Stop using the PG_error flag to track decryption failures. This is
     a prerequisite for freeing up PG_error for other uses"

* tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt:
  fscrypt: work on block_devices instead of request_queues
  fscrypt: stop holding extra request_queue references
  fscrypt: stop using keyrings subsystem for fscrypt_master_key
  fscrypt: stop using PG_error to track error status
  fscrypt: remove fscrypt_set_test_dummy_encryption()
This commit is contained in:
Linus Torvalds 2022-10-03 20:18:34 -07:00
commit 438b2cdd17
14 changed files with 498 additions and 460 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
fs/crypto/bio.c
View File

@ -25,21 +25,25 @@
* then this function isn't applicable. This function may sleep, so it must be
* called from a workqueue rather than from the bio's bi_end_io callback.
*
* This function sets PG_error on any pages that contain any blocks that failed
* to be decrypted. The filesystem must not mark such pages uptodate.
* Return: %true on success; %false on failure. On failure, bio->bi_status is
* also set to an error status.
*/
void fscrypt_decrypt_bio(struct bio *bio)
bool fscrypt_decrypt_bio(struct bio *bio)
{
struct bio_vec *bv;
struct bvec_iter_all iter_all;
bio_for_each_segment_all(bv, bio, iter_all) {
struct page *page = bv->bv_page;
int ret = fscrypt_decrypt_pagecache_blocks(page, bv->bv_len,
int err = fscrypt_decrypt_pagecache_blocks(page, bv->bv_len,
bv->bv_offset);
if (ret)
SetPageError(page);
if (err) {
bio->bi_status = errno_to_blk_status(err);
return false;
}
}
return true;
}
EXPORT_SYMBOL(fscrypt_decrypt_bio);

82
fs/crypto/fscrypt_private.h
View File

@ -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)
{
}
@ -436,6 +438,40 @@ 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
@ -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;
@ -465,22 +504,12 @@ 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);

10
fs/crypto/hooks.c
View File

@ -5,8 +5,6 @@
* Encryption hooks for higher-level filesystem operations.
*/
#include <linux/key.h>
#include "fscrypt_private.h"
/**
@ -142,7 +140,6 @@ int fscrypt_prepare_setflags(struct inode *inode,
unsigned int oldflags, unsigned int flags)
{
struct fscrypt_info *ci;
struct key *key;
struct fscrypt_master_key *mk;
int err;
@ -158,14 +155,13 @@ int fscrypt_prepare_setflags(struct inode *inode,
ci = inode->i_crypt_info;
if (ci->ci_policy.version != FSCRYPT_POLICY_V2)
return -EINVAL;
key = ci->ci_master_key;
mk = key->payload.data[0];
down_read(&key->sem);
mk = ci->ci_master_key;
down_read(&mk->mk_sem);
if (is_master_key_secret_present(&mk->mk_secret))
err = fscrypt_derive_dirhash_key(ci, mk);
else
err = -ENOKEY;
up_read(&key->sem);
up_read(&mk->mk_sem);
return err;
}
return 0;

149
fs/crypto/inline_crypt.c
View File

@ -21,26 +21,22 @@
#include "fscrypt_private.h"
struct fscrypt_blk_crypto_key {
struct blk_crypto_key base;
int num_devs;
struct request_queue *devs[];
};
static int fscrypt_get_num_devices(struct super_block *sb)
static struct block_device **fscrypt_get_devices(struct super_block *sb,
unsigned int *num_devs)
{
if (sb->s_cop->get_num_devices)
return sb->s_cop->get_num_devices(sb);
return 1;
}
struct block_device **devs;
static void fscrypt_get_devices(struct super_block *sb, int num_devs,
struct request_queue **devs)
{
if (num_devs == 1)
devs[0] = bdev_get_queue(sb->s_bdev);
else
sb->s_cop->get_devices(sb, devs);
if (sb->s_cop->get_devices) {
devs = sb->s_cop->get_devices(sb, num_devs);
if (devs)
return devs;
}
devs = kmalloc(sizeof(*devs), GFP_KERNEL);
if (!devs)
return ERR_PTR(-ENOMEM);
devs[0] = sb->s_bdev;
*num_devs = 1;
return devs;
}
static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_info *ci)
@ -74,15 +70,17 @@ static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_info *ci)
* helpful for debugging problems where the "wrong" implementation is used.
*/
static void fscrypt_log_blk_crypto_impl(struct fscrypt_mode *mode,
struct request_queue **devs,
int num_devs,
struct block_device **devs,
unsigned int num_devs,
const struct blk_crypto_config *cfg)
{
int i;
unsigned int i;
for (i = 0; i < num_devs; i++) {
struct request_queue *q = bdev_get_queue(devs[i]);
if (!IS_ENABLED(CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK) ||
__blk_crypto_cfg_supported(devs[i]->crypto_profile, cfg)) {
__blk_crypto_cfg_supported(q->crypto_profile, cfg)) {
if (!xchg(&mode->logged_blk_crypto_native, 1))
pr_info("fscrypt: %s using blk-crypto (native)\n",
mode->friendly_name);
@ -99,9 +97,9 @@ int fscrypt_select_encryption_impl(struct fscrypt_info *ci)
const struct inode *inode = ci->ci_inode;
struct super_block *sb = inode->i_sb;
struct blk_crypto_config crypto_cfg;
int num_devs;
struct request_queue **devs;
int i;
struct block_device **devs;
unsigned int num_devs;
unsigned int i;
/* The file must need contents encryption, not filenames encryption */
if (!S_ISREG(inode->i_mode))
@ -129,20 +127,20 @@ int fscrypt_select_encryption_impl(struct fscrypt_info *ci)
return 0;
/*
* On all the filesystem's devices, blk-crypto must support the crypto
* configuration that the file would use.
* On all the filesystem's block devices, blk-crypto must support the
* crypto configuration that the file would use.
*/
crypto_cfg.crypto_mode = ci->ci_mode->blk_crypto_mode;
crypto_cfg.data_unit_size = sb->s_blocksize;
crypto_cfg.dun_bytes = fscrypt_get_dun_bytes(ci);
num_devs = fscrypt_get_num_devices(sb);
devs = kmalloc_array(num_devs, sizeof(*devs), GFP_KERNEL);
if (!devs)
return -ENOMEM;
fscrypt_get_devices(sb, num_devs, devs);
devs = fscrypt_get_devices(sb, &num_devs);
if (IS_ERR(devs))
return PTR_ERR(devs);
for (i = 0; i < num_devs; i++) {
if (!blk_crypto_config_supported(devs[i], &crypto_cfg))
if (!blk_crypto_config_supported(bdev_get_queue(devs[i]),
&crypto_cfg))
goto out_free_devs;
}
@ -162,49 +160,41 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
const struct inode *inode = ci->ci_inode;
struct super_block *sb = inode->i_sb;
enum blk_crypto_mode_num crypto_mode = ci->ci_mode->blk_crypto_mode;
int num_devs = fscrypt_get_num_devices(sb);
int queue_refs = 0;
struct fscrypt_blk_crypto_key *blk_key;
struct blk_crypto_key *blk_key;
struct block_device **devs;
unsigned int num_devs;
unsigned int i;
int err;
int i;
blk_key = kzalloc(struct_size(blk_key, devs, num_devs), GFP_KERNEL);
blk_key = kmalloc(sizeof(*blk_key), GFP_KERNEL);
if (!blk_key)
return -ENOMEM;
blk_key->num_devs = num_devs;
fscrypt_get_devices(sb, num_devs, blk_key->devs);
err = blk_crypto_init_key(&blk_key->base, raw_key, crypto_mode,
err = blk_crypto_init_key(blk_key, raw_key, crypto_mode,
fscrypt_get_dun_bytes(ci), sb->s_blocksize);
if (err) {
fscrypt_err(inode, "error %d initializing blk-crypto key", err);
goto fail;
}
/*
* We have to start using blk-crypto on all the filesystem's devices.
* We also have to save all the request_queue's for later so that the
* key can be evicted from them. This is needed because some keys
* aren't destroyed until after the filesystem was already unmounted
* (namely, the per-mode keys in struct fscrypt_master_key).
*/
for (i = 0; i < num_devs; i++) {
if (!blk_get_queue(blk_key->devs[i])) {
fscrypt_err(inode, "couldn't get request_queue");
err = -EAGAIN;
goto fail;
}
queue_refs++;
err = blk_crypto_start_using_key(&blk_key->base,
blk_key->devs[i]);
if (err) {
fscrypt_err(inode,
"error %d starting to use blk-crypto", err);
goto fail;
}
/* Start using blk-crypto on all the filesystem's block devices. */
devs = fscrypt_get_devices(sb, &num_devs);
if (IS_ERR(devs)) {
err = PTR_ERR(devs);
goto fail;
}
for (i = 0; i < num_devs; i++) {
err = blk_crypto_start_using_key(blk_key,
bdev_get_queue(devs[i]));
if (err)
break;
}
kfree(devs);
if (err) {
fscrypt_err(inode, "error %d starting to use blk-crypto", err);
goto fail;
}
/*
* Pairs with the smp_load_acquire() in fscrypt_is_key_prepared().
* I.e., here we publish ->blk_key with a RELEASE barrier so that
@ -215,24 +205,29 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
return 0;
fail:
for (i = 0; i < queue_refs; i++)
blk_put_queue(blk_key->devs[i]);
kfree_sensitive(blk_key);
return err;
}
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)
{
struct fscrypt_blk_crypto_key *blk_key = prep_key->blk_key;
int i;
struct blk_crypto_key *blk_key = prep_key->blk_key;
struct block_device **devs;
unsigned int num_devs;
unsigned int i;
if (blk_key) {
for (i = 0; i < blk_key->num_devs; i++) {
blk_crypto_evict_key(blk_key->devs[i], &blk_key->base);
blk_put_queue(blk_key->devs[i]);
}
kfree_sensitive(blk_key);
if (!blk_key)
return;
/* Evict the key from all the filesystem's block devices. */
devs = fscrypt_get_devices(sb, &num_devs);
if (!IS_ERR(devs)) {
for (i = 0; i < num_devs; i++)
blk_crypto_evict_key(bdev_get_queue(devs[i]), blk_key);
kfree(devs);
}
kfree_sensitive(blk_key);
}
bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode)
@ -282,7 +277,7 @@ void fscrypt_set_bio_crypt_ctx(struct bio *bio, const struct inode *inode,
ci = inode->i_crypt_info;
fscrypt_generate_dun(ci, first_lblk, dun);
bio_crypt_set_ctx(bio, &ci->ci_enc_key.blk_key->base, dun, gfp_mask);
bio_crypt_set_ctx(bio, ci->ci_enc_key.blk_key, dun, gfp_mask);
}
EXPORT_SYMBOL_GPL(fscrypt_set_bio_crypt_ctx);
@ -369,7 +364,7 @@ bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode,
* uses the same pointer. I.e., there's currently no need to support
* merging requests where the keys are the same but the pointers differ.
*/
if (bc->bc_key != &inode->i_crypt_info->ci_enc_key.blk_key->base)
if (bc->bc_key != inode->i_crypt_info->ci_enc_key.blk_key)
return false;
fscrypt_generate_dun(inode->i_crypt_info, next_lblk, next_dun);

497
fs/crypto/keyring.c
View File

@ -18,6 +18,7 @@
* information about these ioctls.
*/
#include <asm/unaligned.h>
#include <crypto/skcipher.h>
#include <linux/key-type.h>
#include <linux/random.h>
@ -25,6 +26,18 @@
#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)
{
fscrypt_destroy_hkdf(&secret->hkdf);
@ -38,20 +51,73 @@ static void move_master_key_secret(struct fscrypt_master_key_secret *dst,
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.
*/
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]);
fscrypt_destroy_prepared_key(
sb, &mk->mk_direct_keys[i]);
fscrypt_destroy_prepared_key(
sb, &mk->mk_iv_ino_lblk_64_keys[i]);
fscrypt_destroy_prepared_key(
sb, &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);
kfree_sensitive(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)
@ -61,44 +127,6 @@ static inline bool valid_key_spec(const struct fscrypt_key_specifier *spec)
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)
{
@ -131,32 +159,6 @@ static struct key_type key_type_fscrypt_user = {
.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, 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);
}
#define FSCRYPT_FS_KEYRING_DESCRIPTION_SIZE \
(CONST_STRLEN("fscrypt-") + sizeof_field(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)
@ -164,21 +166,6 @@ static struct key *search_fscrypt_keyring(struct key *keyring,
#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],
const u8 mk_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE])
@ -199,20 +186,15 @@ static void format_mk_user_description(
/* 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);
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
@ -222,21 +204,75 @@ static int allocate_filesystem_keyring(struct super_block *sb)
return 0;
}
void fscrypt_sb_free(struct super_block *sb)
/*
* This is called at unmount time to release all encryption keys that have been
* added to the filesystem, along with the keyring that contains them.
*
* Note that besides clearing and freeing memory, this might need to evict keys
* from the keyslots of an inline crypto engine. Therefore, this must be called
* while the filesystem's underlying block device(s) are still available.
*/
void fscrypt_sb_delete(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);
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().
@ -246,10 +282,38 @@ struct key *fscrypt_find_master_key(struct super_block *sb,
*/
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)
@ -277,17 +341,30 @@ static int allocate_master_key_users_keyring(struct fscrypt_master_key *mk)
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)
{
@ -309,7 +386,7 @@ static int add_master_key_user(struct fscrypt_master_key *mk)
/*
* 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.
*/
@ -327,63 +404,49 @@ static int remove_master_key_user(struct fscrypt_master_key *mk)
}
/*
* 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);
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;
}
@ -392,42 +455,34 @@ out_free_mk:
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)
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);
}
return 0;
}
@ -436,38 +491,36 @@ static int do_add_master_key(struct super_block *sb,
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;
}
@ -771,19 +824,19 @@ int fscrypt_verify_key_added(struct super_block *sb,
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);
@ -791,7 +844,8 @@ int fscrypt_verify_key_added(struct super_block *sb,
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;
@ -953,11 +1007,10 @@ static int do_remove_key(struct file *filp, void __user *_uarg, bool all_users)
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;
@ -977,12 +1030,10 @@ static int do_remove_key(struct file *filp, void __user *_uarg, bool all_users)
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) {
@ -991,7 +1042,7 @@ static int do_remove_key(struct file *filp, void __user *_uarg, bool all_users)
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) {
@ -1003,26 +1054,22 @@ static int do_remove_key(struct file *filp, void __user *_uarg, bool all_users)
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)) {
wipe_master_key_secret(&mk->mk_secret);
dead = refcount_dec_and_test(&mk->mk_refcount);
}
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) {
@ -1038,7 +1085,7 @@ static int do_remove_key(struct file *filp, void __user *_uarg, bool all_users)
* 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;
@ -1085,7 +1132,6 @@ int fscrypt_ioctl_get_key_status(struct file *filp, void __user *uarg)
{
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;
@ -1102,19 +1148,18 @@ int fscrypt_ioctl_get_key_status(struct file *filp, void __user *uarg)
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;
}
@ -1136,8 +1181,8 @@ int fscrypt_ioctl_get_key_status(struct file *filp, void __user *uarg)
}
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;
@ -1149,13 +1194,9 @@ int __init fscrypt_init_keyring(void)
{
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)
@ -1165,7 +1206,5 @@ int __init fscrypt_init_keyring(void)
err_unregister_fscrypt_user:
unregister_key_type(&key_type_fscrypt_user);
err_unregister_fscrypt:
unregister_key_type(&key_type_fscrypt);
return err;
}

89
fs/crypto/keysetup.c
View File

@ -9,7 +9,6 @@
*/
#include <crypto/skcipher.h>
#include <linux/key.h>
#include <linux/random.h>
#include "fscrypt_private.h"
@ -155,10 +154,12 @@ int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key,
}
/* Destroy a crypto transform object and/or blk-crypto key. */
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)
{
crypto_free_skcipher(prep_key->tfm);
fscrypt_destroy_inline_crypt_key(prep_key);
fscrypt_destroy_inline_crypt_key(sb, prep_key);
memzero_explicit(prep_key, sizeof(*prep_key));
}
/* Given a per-file encryption key, set up the file's crypto transform object */
@ -412,20 +413,18 @@ static bool fscrypt_valid_master_key_size(const struct fscrypt_master_key *mk,
/*
* Find the master key, then set up the inode's actual encryption key.
*
* If the master key is found in the filesystem-level keyring, then the
* corresponding 'struct key' is returned in *master_key_ret with its semaphore
* read-locked. This is needed to ensure that only one task links the
* fscrypt_info into ->mk_decrypted_inodes (as multiple tasks may race to create
* an fscrypt_info for the same inode), and to synchronize the master key being
* removed with a new inode starting to use it.
* If the master key is found in the filesystem-level keyring, then it is
* returned in *mk_ret with its semaphore read-locked. This is needed to ensure
* that only one task links the fscrypt_info into ->mk_decrypted_inodes (as
* multiple tasks may race to create an fscrypt_info for the same inode), and to
* synchronize the master key being removed with a new inode starting to use it.
*/
static int setup_file_encryption_key(struct fscrypt_info *ci,
bool need_dirhash_key,
struct key **master_key_ret)
struct fscrypt_master_key **mk_ret)
{
struct key *key;
struct fscrypt_master_key *mk = NULL;
struct fscrypt_key_specifier mk_spec;
struct fscrypt_master_key *mk;
int err;
err = fscrypt_select_encryption_impl(ci);
@ -436,11 +435,10 @@ static int setup_file_encryption_key(struct fscrypt_info *ci,
if (err)
return err;
key = fscrypt_find_master_key(ci->ci_inode->i_sb, &mk_spec);
if (IS_ERR(key)) {
if (key != ERR_PTR(-ENOKEY) ||
ci->ci_policy.version != FSCRYPT_POLICY_V1)
return PTR_ERR(key);
mk = fscrypt_find_master_key(ci->ci_inode->i_sb, &mk_spec);
if (!mk) {
if (ci->ci_policy.version != FSCRYPT_POLICY_V1)
return -ENOKEY;
/*
* As a legacy fallback for v1 policies, search for the key in
@ -450,9 +448,7 @@ static int setup_file_encryption_key(struct fscrypt_info *ci,
*/
return fscrypt_setup_v1_file_key_via_subscribed_keyrings(ci);
}
mk = key->payload.data[0];
down_read(&key->sem);
down_read(&mk->mk_sem);
/* Has the secret been removed (via FS_IOC_REMOVE_ENCRYPTION_KEY)? */
if (!is_master_key_secret_present(&mk->mk_secret)) {
@ -480,18 +476,18 @@ static int setup_file_encryption_key(struct fscrypt_info *ci,
if (err)
goto out_release_key;
*master_key_ret = key;
*mk_ret = mk;
return 0;
out_release_key:
up_read(&key->sem);
key_put(key);
up_read(&mk->mk_sem);
fscrypt_put_master_key(mk);
return err;
}
static void put_crypt_info(struct fscrypt_info *ci)
{
struct key *key;
struct fscrypt_master_key *mk;
if (!ci)
return;
@ -499,26 +495,21 @@ static void put_crypt_info(struct fscrypt_info *ci)
if (ci->ci_direct_key)
fscrypt_put_direct_key(ci->ci_direct_key);
else if (ci->ci_owns_key)
fscrypt_destroy_prepared_key(&ci->ci_enc_key);
key = ci->ci_master_key;
if (key) {
struct fscrypt_master_key *mk = key->payload.data[0];
fscrypt_destroy_prepared_key(ci->ci_inode->i_sb,
&ci->ci_enc_key);
mk = ci->ci_master_key;
if (mk) {
/*
* Remove this inode from the list of inodes that were unlocked
* with the master key.
*
* In addition, if we're removing the last inode from a key that
* already had its secret removed, invalidate the key so that it
* gets removed from ->s_master_keys.
* with the master key. In addition, if we're removing the last
* inode from a master key struct that already had its secret
* removed, then complete the full removal of the struct.
*/
spin_lock(&mk->mk_decrypted_inodes_lock);
list_del(&ci->ci_master_key_link);
spin_unlock(&mk->mk_decrypted_inodes_lock);
if (refcount_dec_and_test(&mk->mk_refcount))
key_invalidate(key);
key_put(key);
fscrypt_put_master_key_activeref(mk);
}
memzero_explicit(ci, sizeof(*ci));
kmem_cache_free(fscrypt_info_cachep, ci);
@ -532,7 +523,7 @@ fscrypt_setup_encryption_info(struct inode *inode,
{
struct fscrypt_info *crypt_info;
struct fscrypt_mode *mode;
struct key *master_key = NULL;
struct fscrypt_master_key *mk = NULL;
int res;
res = fscrypt_initialize(inode->i_sb->s_cop->flags);
@ -555,8 +546,7 @@ fscrypt_setup_encryption_info(struct inode *inode,
WARN_ON(mode->ivsize > FSCRYPT_MAX_IV_SIZE);
crypt_info->ci_mode = mode;
res = setup_file_encryption_key(crypt_info, need_dirhash_key,
&master_key);
res = setup_file_encryption_key(crypt_info, need_dirhash_key, &mk);
if (res)
goto out;
@ -571,12 +561,9 @@ fscrypt_setup_encryption_info(struct inode *inode,
* We won the race and set ->i_crypt_info to our crypt_info.
* Now link it into the master key's inode list.
*/
if (master_key) {
struct fscrypt_master_key *mk =
master_key->payload.data[0];
refcount_inc(&mk->mk_refcount);
crypt_info->ci_master_key = key_get(master_key);
if (mk) {
crypt_info->ci_master_key = mk;
refcount_inc(&mk->mk_active_refs);
spin_lock(&mk->mk_decrypted_inodes_lock);
list_add(&crypt_info->ci_master_key_link,
&mk->mk_decrypted_inodes);
@ -586,9 +573,9 @@ fscrypt_setup_encryption_info(struct inode *inode,
}
res = 0;
out:
if (master_key) {
up_read(&master_key->sem);
key_put(master_key);
if (mk) {
up_read(&mk->mk_sem);
fscrypt_put_master_key(mk);
}
put_crypt_info(crypt_info);
return res;
@ -753,7 +740,6 @@ EXPORT_SYMBOL(fscrypt_free_inode);
int fscrypt_drop_inode(struct inode *inode)
{
const struct fscrypt_info *ci = fscrypt_get_info(inode);
const struct fscrypt_master_key *mk;
/*
* If ci is NULL, then the inode doesn't have an encryption key set up
@ -763,7 +749,6 @@ int fscrypt_drop_inode(struct inode *inode)
*/
if (!ci || !ci->ci_master_key)
return 0;
mk = ci->ci_master_key->payload.data[0];
/*
* With proper, non-racy use of FS_IOC_REMOVE_ENCRYPTION_KEY, all inodes
@ -782,6 +767,6 @@ int fscrypt_drop_inode(struct inode *inode)
* then the thread removing the key will either evict the inode itself
* or will correctly detect that it wasn't evicted due to the race.
*/
return !is_master_key_secret_present(&mk->mk_secret);
return !is_master_key_secret_present(&ci->ci_master_key->mk_secret);
}
EXPORT_SYMBOL_GPL(fscrypt_drop_inode);

4
fs/crypto/keysetup_v1.c
View File

@ -143,6 +143,7 @@ invalid:
/* Master key referenced by DIRECT_KEY policy */
struct fscrypt_direct_key {
struct super_block *dk_sb;
struct hlist_node dk_node;
refcount_t dk_refcount;
const struct fscrypt_mode *dk_mode;
@ -154,7 +155,7 @@ struct fscrypt_direct_key {
static void free_direct_key(struct fscrypt_direct_key *dk)
{
if (dk) {
fscrypt_destroy_prepared_key(&dk->dk_key);
fscrypt_destroy_prepared_key(dk->dk_sb, &dk->dk_key);
kfree_sensitive(dk);
}
}
@ -231,6 +232,7 @@ fscrypt_get_direct_key(const struct fscrypt_info *ci, const u8 *raw_key)
dk = kzalloc(sizeof(*dk), GFP_KERNEL);
if (!dk)
return ERR_PTR(-ENOMEM);
dk->dk_sb = ci->ci_inode->i_sb;
refcount_set(&dk->dk_refcount, 1);
dk->dk_mode = ci->ci_mode;
err = fscrypt_prepare_key(&dk->dk_key, raw_key, ci);

21
fs/crypto/policy.c
View File

@ -744,12 +744,8 @@ int fscrypt_set_context(struct inode *inode, void *fs_data)
* delayed key setup that requires the inode number.
*/
if (ci->ci_policy.version == FSCRYPT_POLICY_V2 &&
(ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) {
const struct fscrypt_master_key *mk =
ci->ci_master_key->payload.data[0];
fscrypt_hash_inode_number(ci, mk);
}
(ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32))
fscrypt_hash_inode_number(ci, ci->ci_master_key);
return inode->i_sb->s_cop->set_context(inode, &ctx, ctxsize, fs_data);
}
@ -833,19 +829,6 @@ bool fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1,
}
EXPORT_SYMBOL_GPL(fscrypt_dummy_policies_equal);
/* Deprecated, do not use */
int fscrypt_set_test_dummy_encryption(struct super_block *sb, const char *arg,
struct fscrypt_dummy_policy *dummy_policy)
{
struct fs_parameter param = {
.type = fs_value_is_string,
.string = arg ? (char *)arg : "",
};
return fscrypt_parse_test_dummy_encryption(&param, dummy_policy) ?:
fscrypt_add_test_dummy_key(sb, dummy_policy);
}
EXPORT_SYMBOL_GPL(fscrypt_set_test_dummy_encryption);
/**
* fscrypt_show_test_dummy_encryption() - show '-o test_dummy_encryption'
* @seq: the seq_file to print the option to

10
fs/ext4/readpage.c
View File

@ -75,7 +75,7 @@ static void __read_end_io(struct bio *bio)
bio_for_each_segment_all(bv, bio, iter_all) {
page = bv->bv_page;
/* PG_error was set if any post_read step failed */
/* PG_error was set if verity failed. */
if (bio->bi_status || PageError(page)) {
ClearPageUptodate(page);
/* will re-read again later */
@ -96,10 +96,12 @@ static void decrypt_work(struct work_struct *work)
{
struct bio_post_read_ctx *ctx =
container_of(work, struct bio_post_read_ctx, work);
struct bio *bio = ctx->bio;
fscrypt_decrypt_bio(ctx->bio);
bio_post_read_processing(ctx);
if (fscrypt_decrypt_bio(bio))
bio_post_read_processing(ctx);
else
__read_end_io(bio);
}
static void verity_work(struct work_struct *work)

18
fs/f2fs/data.c
View File

@ -139,7 +139,7 @@ static void f2fs_finish_read_bio(struct bio *bio, bool in_task)
continue;
}
/* PG_error was set if decryption or verity failed. */
/* PG_error was set if verity failed. */
if (bio->bi_status || PageError(page)) {
ClearPageUptodate(page);
/* will re-read again later */
@ -185,7 +185,7 @@ static void f2fs_verify_bio(struct work_struct *work)
struct page *page = bv->bv_page;
if (!f2fs_is_compressed_page(page) &&
!PageError(page) && !fsverity_verify_page(page))
!fsverity_verify_page(page))
SetPageError(page);
}
} else {
@ -236,10 +236,9 @@ static void f2fs_handle_step_decompress(struct bio_post_read_ctx *ctx,
bio_for_each_segment_all(bv, ctx->bio, iter_all) {
struct page *page = bv->bv_page;
/* PG_error was set if decryption failed. */
if (f2fs_is_compressed_page(page))
f2fs_end_read_compressed_page(page, PageError(page),
blkaddr, in_task);
f2fs_end_read_compressed_page(page, false, blkaddr,
in_task);
else
all_compressed = false;
@ -259,14 +258,17 @@ static void f2fs_post_read_work(struct work_struct *work)
{
struct bio_post_read_ctx *ctx =
container_of(work, struct bio_post_read_ctx, work);
struct bio *bio = ctx->bio;
if (ctx->enabled_steps & STEP_DECRYPT)
fscrypt_decrypt_bio(ctx->bio);
if ((ctx->enabled_steps & STEP_DECRYPT) && !fscrypt_decrypt_bio(bio)) {
f2fs_finish_read_bio(bio, true);
return;
}
if (ctx->enabled_steps & STEP_DECOMPRESS)
f2fs_handle_step_decompress(ctx, true);
f2fs_verify_and_finish_bio(ctx->bio, true);
f2fs_verify_and_finish_bio(bio, true);
}
static void f2fs_read_end_io(struct bio *bio)

26
fs/f2fs/super.c
View File

@ -3039,23 +3039,24 @@ static void f2fs_get_ino_and_lblk_bits(struct super_block *sb,
*lblk_bits_ret = 8 * sizeof(block_t);
}
static int f2fs_get_num_devices(struct super_block *sb)
{
struct f2fs_sb_info *sbi = F2FS_SB(sb);
if (f2fs_is_multi_device(sbi))
return sbi->s_ndevs;
return 1;
}
static void f2fs_get_devices(struct super_block *sb,
struct request_queue **devs)
static struct block_device **f2fs_get_devices(struct super_block *sb,
unsigned int *num_devs)
{
struct f2fs_sb_info *sbi = F2FS_SB(sb);
struct block_device **devs;
int i;
if (!f2fs_is_multi_device(sbi))
return NULL;
devs = kmalloc_array(sbi->s_ndevs, sizeof(*devs), GFP_KERNEL);
if (!devs)
return ERR_PTR(-ENOMEM);
for (i = 0; i < sbi->s_ndevs; i++)
devs[i] = bdev_get_queue(FDEV(i).bdev);
devs[i] = FDEV(i).bdev;
*num_devs = sbi->s_ndevs;
return devs;
}
static const struct fscrypt_operations f2fs_cryptops = {
@ -3066,7 +3067,6 @@ static const struct fscrypt_operations f2fs_cryptops = {
.empty_dir = f2fs_empty_dir,
.has_stable_inodes = f2fs_has_stable_inodes,
.get_ino_and_lblk_bits = f2fs_get_ino_and_lblk_bits,
.get_num_devices = f2fs_get_num_devices,
.get_devices = f2fs_get_devices,
};
#endif

2
fs/super.c
View File

@ -291,7 +291,6 @@ static void __put_super(struct super_block *s)
WARN_ON(s->s_inode_lru.node);
WARN_ON(!list_empty(&s->s_mounts));
security_sb_free(s);
fscrypt_sb_free(s);
put_user_ns(s->s_user_ns);
kfree(s->s_subtype);
call_rcu(&s->rcu, destroy_super_rcu);
@ -480,6 +479,7 @@ void generic_shutdown_super(struct super_block *sb)
evict_inodes(sb);
/* only nonzero refcount inodes can have marks */
fsnotify_sb_delete(sb);
fscrypt_sb_delete(sb);
security_sb_delete(sb);
if (sb->s_dio_done_wq) {

2
include/linux/fs.h
View File

@ -1472,7 +1472,7 @@ struct super_block {
const struct xattr_handler **s_xattr;
#ifdef CONFIG_FS_ENCRYPTION
const struct fscrypt_operations *s_cop;
struct key *s_master_keys; /* master crypto keys in use */
struct fscrypt_keyring *s_master_keys; /* master crypto keys in use */
#endif
#ifdef CONFIG_FS_VERITY
const struct fsverity_operations *s_vop;

32
include/linux/fscrypt.h
View File

@ -161,24 +161,21 @@ struct fscrypt_operations {
int *ino_bits_ret, int *lblk_bits_ret);
/*
* Return the number of block devices to which the filesystem may write
* encrypted file contents.
* Return an array of pointers to the block devices to which the
* filesystem may write encrypted file contents, NULL if the filesystem
* only has a single such block device, or an ERR_PTR() on error.
*
* On successful non-NULL return, *num_devs is set to the number of
* devices in the returned array. The caller must free the returned
* array using kfree().
*
* If the filesystem can use multiple block devices (other than block
* devices that aren't used for encrypted file contents, such as
* external journal devices), and wants to support inline encryption,
* then it must implement this function. Otherwise it's not needed.
*/
int (*get_num_devices)(struct super_block *sb);
/*
* If ->get_num_devices() returns a value greater than 1, then this
* function is called to get the array of request_queues that the
* filesystem is using -- one per block device. (There may be duplicate
* entries in this array, as block devices can share a request_queue.)
*/
void (*get_devices)(struct super_block *sb,
struct request_queue **devs);
struct block_device **(*get_devices)(struct super_block *sb,
unsigned int *num_devs);
};
static inline struct fscrypt_info *fscrypt_get_info(const struct inode *inode)
@ -295,8 +292,6 @@ int fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param,
struct fscrypt_dummy_policy *dummy_policy);
bool fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1,
const struct fscrypt_dummy_policy *p2);
int fscrypt_set_test_dummy_encryption(struct super_block *sb, const char *arg,
struct fscrypt_dummy_policy *dummy_policy);
void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep,
struct super_block *sb);
static inline bool
@ -312,7 +307,7 @@ fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy)
}
/* keyring.c */
void fscrypt_sb_free(struct super_block *sb);
void fscrypt_sb_delete(struct super_block *sb);
int fscrypt_ioctl_add_key(struct file *filp, void __user *arg);
int fscrypt_add_test_dummy_key(struct super_block *sb,
const struct fscrypt_dummy_policy *dummy_policy);
@ -353,7 +348,7 @@ u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name);
int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags);
/* bio.c */
void fscrypt_decrypt_bio(struct bio *bio);
bool fscrypt_decrypt_bio(struct bio *bio);
int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
sector_t pblk, unsigned int len);
@ -526,7 +521,7 @@ fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy)
}
/* keyring.c */
static inline void fscrypt_sb_free(struct super_block *sb)
static inline void fscrypt_sb_delete(struct super_block *sb)
{
}
@ -646,8 +641,9 @@ static inline int fscrypt_d_revalidate(struct dentry *dentry,
}
/* bio.c */
static inline void fscrypt_decrypt_bio(struct bio *bio)
static inline bool fscrypt_decrypt_bio(struct bio *bio)
{
return true;
}
static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,