From a67edfb4b591acdffc5b4987601a30224376996f Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi 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 RH-MergeRequest: 251: block/crypto: create ciphers on demand RH-Jira: RHEL-36159 RH-Acked-by: Kevin Wolf RH-Acked-by: Miroslav Rezanina 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 Buglink: https://issues.redhat.com/browse/RHEL-36159 Signed-off-by: Stefan Hajnoczi Message-ID: <20240527155851.892885-2-stefanha@redhat.com> Reviewed-by: Kevin Wolf Acked-by: Daniel P. Berrangé Signed-off-by: Kevin Wolf (cherry picked from commit af206c284e4c1b17cdfb0f17e898b288c0fc1751) Signed-off-by: Stefan Hajnoczi --- 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