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Message-Id: <20220820190210.169734-3-ebiggers@kernel.org>
Date: Sat, 20 Aug 2022 12:02:10 -0700
From: Eric Biggers <ebiggers@...nel.org>
To: linux-fscrypt@...r.kernel.org
Cc: linux-fsdevel@...r.kernel.org, linux-block@...r.kernel.org,
linux-ext4@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net,
Christoph Hellwig <hch@....de>
Subject: [PATCH v2 2/2] fscrypt: stop holding extra request_queue references
From: Eric Biggers <ebiggers@...gle.com>
Now that the fscrypt_master_key lifetime has been reworked to not be
subject to the quirks of the keyrings subsystem, blk_crypto_evict_key()
no longer gets called after the filesystem has already been unmounted.
Therefore, there is no longer any need to hold extra references to the
filesystem's request_queue(s). (And these references didn't always do
their intended job anyway, as pinning a request_queue doesn't
necessarily pin the corresponding blk_crypto_profile.)
Stop taking these extra references. Instead, just pass the super_block
to fscrypt_destroy_inline_crypt_key(), and use it to get the list of
block devices the key needs to be evicted from.
Signed-off-by: Eric Biggers <ebiggers@...gle.com>
---
fs/crypto/fscrypt_private.h | 11 +++--
fs/crypto/inline_crypt.c | 83 ++++++++++++++++---------------------
fs/crypto/keyring.c | 9 ++--
fs/crypto/keysetup.c | 8 ++--
fs/crypto/keysetup_v1.c | 4 +-
5 files changed, 57 insertions(+), 58 deletions(-)
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 0e2d3b0af0f79e..dcc005e3491453 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -184,7 +184,7 @@ struct fscrypt_symlink_data {
struct fscrypt_prepared_key {
struct crypto_skcipher *tfm;
#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
- struct fscrypt_blk_crypto_key *blk_key;
+ struct blk_crypto_key *blk_key;
#endif
};
@@ -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)
{
}
@@ -600,7 +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);
diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c
index 90f3e68f166e39..a3225fe2291361 100644
--- a/fs/crypto/inline_crypt.c
+++ b/fs/crypto/inline_crypt.c
@@ -21,12 +21,6 @@
#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)
{
if (sb->s_cop->get_num_devices)
@@ -162,47 +156,37 @@ 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;
+ int num_devs;
+ struct request_queue **devs = NULL;
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;
+ goto out;
}
- /*
- * 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).
- */
+ /* Start using blk-crypto on all the filesystem's block devices. */
+ num_devs = fscrypt_get_num_devices(sb);
+ devs = kmalloc_array(num_devs, sizeof(*devs), GFP_KERNEL);
+ if (!devs) {
+ err = -ENOMEM;
+ goto out;
+ }
+ fscrypt_get_devices(sb, num_devs, devs);
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]);
+ err = blk_crypto_start_using_key(blk_key, devs[i]);
if (err) {
fscrypt_err(inode,
"error %d starting to use blk-crypto", err);
- goto fail;
+ goto out;
}
}
/*
@@ -212,27 +196,32 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
* possible for per-mode keys, not for per-file keys.
*/
smp_store_release(&prep_key->blk_key, blk_key);
- return 0;
-
-fail:
- for (i = 0; i < queue_refs; i++)
- blk_put_queue(blk_key->devs[i]);
+ blk_key = NULL;
+ err = 0;
+out:
+ kfree(devs);
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;
+ struct blk_crypto_key *blk_key = prep_key->blk_key;
+ int num_devs;
+ struct request_queue **devs;
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);
+ /* Evict the key from all the filesystem's block devices. */
+ num_devs = fscrypt_get_num_devices(sb);
+ devs = kmalloc_array(num_devs, sizeof(*devs), GFP_KERNEL);
+ if (devs) {
+ fscrypt_get_devices(sb, num_devs, devs);
+ for (i = 0; i < num_devs; i++)
+ blk_crypto_evict_key(devs[i], blk_key);
+ kfree(devs);
}
+ kfree_sensitive(blk_key);
}
bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode)
@@ -282,7 +271,7 @@ 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 +358,7 @@ 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);
diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c
index 9b98d6a576e6a0..1cca09aa43f8b3 100644
--- a/fs/crypto/keyring.c
+++ b/fs/crypto/keyring.c
@@ -105,9 +105,12 @@ void fscrypt_put_master_key_activeref(struct fscrypt_master_key *mk)
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));
diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c
index e037a7b8e9e42b..f7407071a95242 100644
--- a/fs/crypto/keysetup.c
+++ b/fs/crypto/keysetup.c
@@ -154,10 +154,11 @@ 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));
}
@@ -494,7 +495,8 @@ 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);
+ fscrypt_destroy_prepared_key(ci->ci_inode->i_sb,
+ &ci->ci_enc_key);
mk = ci->ci_master_key;
if (mk) {
diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c
index 2762c53504323f..75dabd9b27f9b6 100644
--- a/fs/crypto/keysetup_v1.c
+++ b/fs/crypto/keysetup_v1.c
@@ -143,6 +143,7 @@ find_and_lock_process_key(const char *prefix,
/* 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);
--
2.37.1
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