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qemu-kvm/SOURCES/kvm-block-crypto-create-cip...

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From a67edfb4b591acdffc5b4987601a30224376996f Mon Sep 17 00:00:00 2001
From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Mon, 27 May 2024 11:58:50 -0400
Subject: [PATCH 4/5] block/crypto: create ciphers on demand
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RH-Author: Stefan Hajnoczi <stefanha@redhat.com>
RH-MergeRequest: 251: block/crypto: create ciphers on demand
RH-Jira: RHEL-36159
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Commit: [1/2] 22a4c87fef774cad98a6f5a79f27df50a208013d (stefanha/centos-stream-qemu-kvm)
Ciphers are pre-allocated by qcrypto_block_init_cipher() depending on
the given number of threads. The -device
virtio-blk-pci,iothread-vq-mapping= feature allows users to assign
multiple IOThreads to a virtio-blk device, but the association between
the virtio-blk device and the block driver happens after the block
driver is already open.
When the number of threads given to qcrypto_block_init_cipher() is
smaller than the actual number of threads at runtime, the
block->n_free_ciphers > 0 assertion in qcrypto_block_pop_cipher() can
fail.
Get rid of qcrypto_block_init_cipher() n_thread's argument and allocate
ciphers on demand.
Reported-by: Qing Wang <qinwang@redhat.com>
Buglink: https://issues.redhat.com/browse/RHEL-36159
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20240527155851.892885-2-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit af206c284e4c1b17cdfb0f17e898b288c0fc1751)
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
crypto/block-luks.c | 3 +-
crypto/block-qcow.c | 2 +-
crypto/block.c | 111 ++++++++++++++++++++++++++------------------
crypto/blockpriv.h | 12 +++--
4 files changed, 78 insertions(+), 50 deletions(-)
diff --git a/crypto/block-luks.c b/crypto/block-luks.c
index 3ee928fb5a..3357852c0a 100644
--- a/crypto/block-luks.c
+++ b/crypto/block-luks.c
@@ -1262,7 +1262,6 @@ qcrypto_block_luks_open(QCryptoBlock *block,
luks->cipher_mode,
masterkey,
luks->header.master_key_len,
- n_threads,
errp) < 0) {
goto fail;
}
@@ -1456,7 +1455,7 @@ qcrypto_block_luks_create(QCryptoBlock *block,
/* Setup the block device payload encryption objects */
if (qcrypto_block_init_cipher(block, luks_opts.cipher_alg,
luks_opts.cipher_mode, masterkey,
- luks->header.master_key_len, 1, errp) < 0) {
+ luks->header.master_key_len, errp) < 0) {
goto error;
}
diff --git a/crypto/block-qcow.c b/crypto/block-qcow.c
index 4d7cf36a8f..02305058e3 100644
--- a/crypto/block-qcow.c
+++ b/crypto/block-qcow.c
@@ -75,7 +75,7 @@ qcrypto_block_qcow_init(QCryptoBlock *block,
ret = qcrypto_block_init_cipher(block, QCRYPTO_CIPHER_ALG_AES_128,
QCRYPTO_CIPHER_MODE_CBC,
keybuf, G_N_ELEMENTS(keybuf),
- n_threads, errp);
+ errp);
if (ret < 0) {
ret = -ENOTSUP;
goto fail;
diff --git a/crypto/block.c b/crypto/block.c
index 506ea1d1a3..ba6d1cebc7 100644
--- a/crypto/block.c
+++ b/crypto/block.c
@@ -20,6 +20,7 @@
#include "qemu/osdep.h"
#include "qapi/error.h"
+#include "qemu/lockable.h"
#include "blockpriv.h"
#include "block-qcow.h"
#include "block-luks.h"
@@ -57,6 +58,8 @@ QCryptoBlock *qcrypto_block_open(QCryptoBlockOpenOptions *options,
{
QCryptoBlock *block = g_new0(QCryptoBlock, 1);
+ qemu_mutex_init(&block->mutex);
+
block->format = options->format;
if (options->format >= G_N_ELEMENTS(qcrypto_block_drivers) ||
@@ -76,8 +79,6 @@ QCryptoBlock *qcrypto_block_open(QCryptoBlockOpenOptions *options,
return NULL;
}
- qemu_mutex_init(&block->mutex);
-
return block;
}
@@ -92,6 +93,8 @@ QCryptoBlock *qcrypto_block_create(QCryptoBlockCreateOptions *options,
{
QCryptoBlock *block = g_new0(QCryptoBlock, 1);
+ qemu_mutex_init(&block->mutex);
+
block->format = options->format;
if (options->format >= G_N_ELEMENTS(qcrypto_block_drivers) ||
@@ -111,8 +114,6 @@ QCryptoBlock *qcrypto_block_create(QCryptoBlockCreateOptions *options,
return NULL;
}
- qemu_mutex_init(&block->mutex);
-
return block;
}
@@ -227,37 +228,42 @@ QCryptoCipher *qcrypto_block_get_cipher(QCryptoBlock *block)
* This function is used only in test with one thread (it's safe to skip
* pop/push interface), so it's enough to assert it here:
*/
- assert(block->n_ciphers <= 1);
- return block->ciphers ? block->ciphers[0] : NULL;
+ assert(block->max_free_ciphers <= 1);
+ return block->free_ciphers ? block->free_ciphers[0] : NULL;
}
-static QCryptoCipher *qcrypto_block_pop_cipher(QCryptoBlock *block)
+static QCryptoCipher *qcrypto_block_pop_cipher(QCryptoBlock *block,
+ Error **errp)
{
- QCryptoCipher *cipher;
-
- qemu_mutex_lock(&block->mutex);
-
- assert(block->n_free_ciphers > 0);
- block->n_free_ciphers--;
- cipher = block->ciphers[block->n_free_ciphers];
-
- qemu_mutex_unlock(&block->mutex);
+ /* Usually there is a free cipher available */
+ WITH_QEMU_LOCK_GUARD(&block->mutex) {
+ if (block->n_free_ciphers > 0) {
+ block->n_free_ciphers--;
+ return block->free_ciphers[block->n_free_ciphers];
+ }
+ }
- return cipher;
+ /* Otherwise allocate a new cipher */
+ return qcrypto_cipher_new(block->alg, block->mode, block->key,
+ block->nkey, errp);
}
static void qcrypto_block_push_cipher(QCryptoBlock *block,
QCryptoCipher *cipher)
{
- qemu_mutex_lock(&block->mutex);
+ QEMU_LOCK_GUARD(&block->mutex);
- assert(block->n_free_ciphers < block->n_ciphers);
- block->ciphers[block->n_free_ciphers] = cipher;
- block->n_free_ciphers++;
+ if (block->n_free_ciphers == block->max_free_ciphers) {
+ block->max_free_ciphers++;
+ block->free_ciphers = g_renew(QCryptoCipher *,
+ block->free_ciphers,
+ block->max_free_ciphers);
+ }
- qemu_mutex_unlock(&block->mutex);
+ block->free_ciphers[block->n_free_ciphers] = cipher;
+ block->n_free_ciphers++;
}
@@ -265,24 +271,31 @@ int qcrypto_block_init_cipher(QCryptoBlock *block,
QCryptoCipherAlgorithm alg,
QCryptoCipherMode mode,
const uint8_t *key, size_t nkey,
- size_t n_threads, Error **errp)
+ Error **errp)
{
- size_t i;
+ QCryptoCipher *cipher;
- assert(!block->ciphers && !block->n_ciphers && !block->n_free_ciphers);
+ assert(!block->free_ciphers && !block->max_free_ciphers &&
+ !block->n_free_ciphers);
- block->ciphers = g_new0(QCryptoCipher *, n_threads);
+ /* Stash away cipher parameters for qcrypto_block_pop_cipher() */
+ block->alg = alg;
+ block->mode = mode;
+ block->key = g_memdup2(key, nkey);
+ block->nkey = nkey;
- for (i = 0; i < n_threads; i++) {
- block->ciphers[i] = qcrypto_cipher_new(alg, mode, key, nkey, errp);
- if (!block->ciphers[i]) {
- qcrypto_block_free_cipher(block);
- return -1;
- }
- block->n_ciphers++;
- block->n_free_ciphers++;
+ /*
+ * Create a new cipher to validate the parameters now. This reduces the
+ * chance of cipher creation failing at I/O time.
+ */
+ cipher = qcrypto_block_pop_cipher(block, errp);
+ if (!cipher) {
+ g_free(block->key);
+ block->key = NULL;
+ return -1;
}
+ qcrypto_block_push_cipher(block, cipher);
return 0;
}
@@ -291,19 +304,23 @@ void qcrypto_block_free_cipher(QCryptoBlock *block)
{
size_t i;
- if (!block->ciphers) {
+ g_free(block->key);
+ block->key = NULL;
+
+ if (!block->free_ciphers) {
return;
}
- assert(block->n_ciphers == block->n_free_ciphers);
+ /* All popped ciphers were eventually pushed back */
+ assert(block->n_free_ciphers == block->max_free_ciphers);
- for (i = 0; i < block->n_ciphers; i++) {
- qcrypto_cipher_free(block->ciphers[i]);
+ for (i = 0; i < block->max_free_ciphers; i++) {
+ qcrypto_cipher_free(block->free_ciphers[i]);
}
- g_free(block->ciphers);
- block->ciphers = NULL;
- block->n_ciphers = block->n_free_ciphers = 0;
+ g_free(block->free_ciphers);
+ block->free_ciphers = NULL;
+ block->max_free_ciphers = block->n_free_ciphers = 0;
}
QCryptoIVGen *qcrypto_block_get_ivgen(QCryptoBlock *block)
@@ -311,7 +328,7 @@ QCryptoIVGen *qcrypto_block_get_ivgen(QCryptoBlock *block)
/* ivgen should be accessed under mutex. However, this function is used only
* in test with one thread, so it's enough to assert it here:
*/
- assert(block->n_ciphers <= 1);
+ assert(block->max_free_ciphers <= 1);
return block->ivgen;
}
@@ -446,7 +463,10 @@ int qcrypto_block_decrypt_helper(QCryptoBlock *block,
Error **errp)
{
int ret;
- QCryptoCipher *cipher = qcrypto_block_pop_cipher(block);
+ QCryptoCipher *cipher = qcrypto_block_pop_cipher(block, errp);
+ if (!cipher) {
+ return -1;
+ }
ret = do_qcrypto_block_cipher_encdec(cipher, block->niv, block->ivgen,
&block->mutex, sectorsize, offset, buf,
@@ -465,7 +485,10 @@ int qcrypto_block_encrypt_helper(QCryptoBlock *block,
Error **errp)
{
int ret;
- QCryptoCipher *cipher = qcrypto_block_pop_cipher(block);
+ QCryptoCipher *cipher = qcrypto_block_pop_cipher(block, errp);
+ if (!cipher) {
+ return -1;
+ }
ret = do_qcrypto_block_cipher_encdec(cipher, block->niv, block->ivgen,
&block->mutex, sectorsize, offset, buf,
diff --git a/crypto/blockpriv.h b/crypto/blockpriv.h
index 836f3b4726..4bf6043d5d 100644
--- a/crypto/blockpriv.h
+++ b/crypto/blockpriv.h
@@ -32,8 +32,14 @@ struct QCryptoBlock {
const QCryptoBlockDriver *driver;
void *opaque;
- QCryptoCipher **ciphers;
- size_t n_ciphers;
+ /* Cipher parameters */
+ QCryptoCipherAlgorithm alg;
+ QCryptoCipherMode mode;
+ uint8_t *key;
+ size_t nkey;
+
+ QCryptoCipher **free_ciphers;
+ size_t max_free_ciphers;
size_t n_free_ciphers;
QCryptoIVGen *ivgen;
QemuMutex mutex;
@@ -130,7 +136,7 @@ int qcrypto_block_init_cipher(QCryptoBlock *block,
QCryptoCipherAlgorithm alg,
QCryptoCipherMode mode,
const uint8_t *key, size_t nkey,
- size_t n_threads, Error **errp);
+ Error **errp);
void qcrypto_block_free_cipher(QCryptoBlock *block);
--
2.39.3
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