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Tsirkin" , "Gonglei (Arei)" References: <87cyemoeiw.fsf@pond.sub.org> Content-Language: en-US From: zhenwei pi In-Reply-To: <87cyemoeiw.fsf@pond.sub.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::636; envelope-from=pizhenwei@bytedance.com; helo=mail-pl1-x636.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 3/12/25 16:10, Markus Armbruster wrote: > scripts/coccinelle/error-use-after-free.cocci led me to this function: > > static void cryptodev_lkcf_execute_task(CryptoDevLKCFTask *task) > { > CryptoDevBackendLKCFSession *session = task->sess; > CryptoDevBackendAsymOpInfo *asym_op_info; > bool kick = false; > int ret, status, op_code = task->op_info->op_code; > size_t p8info_len; > g_autofree uint8_t *p8info = NULL; > Error *local_error = NULL; > key_serial_t key_id = INVALID_KEY_ID; > char op_desc[64]; > g_autoptr(QCryptoAkCipher) akcipher = NULL; > > /** > * We only offload private key session: > * 1. currently, the Linux kernel can only accept public key wrapped > * with X.509 certificates, but unfortunately the cost of making a > * ceritificate with public key is too expensive. > * 2. generally, public key related compution is fast, just compute it with > * thread-pool. > */ > if (session->keytype == QCRYPTO_AK_CIPHER_KEY_TYPE_PRIVATE) { > if (qcrypto_akcipher_export_p8info(&session->akcipher_opts, > session->key, session->keylen, > &p8info, &p8info_len, > &local_error) != 0 || > cryptodev_lkcf_set_op_desc(&session->akcipher_opts, op_desc, > sizeof(op_desc), &local_error) != 0) { > error_report_err(local_error); > > Reporting an error, but continue anyway. This is suspicious. > > Note for later: @local_error is now non-null. > > } else { > key_id = add_key(KCTL_KEY_TYPE_PKEY, "lkcf-backend-priv-key", > p8info, p8info_len, KCTL_KEY_RING); > } > } > > if (key_id < 0) { > if (!qcrypto_akcipher_supports(&session->akcipher_opts)) { > status = -VIRTIO_CRYPTO_NOTSUPP; > goto out; > } > akcipher = qcrypto_akcipher_new(&session->akcipher_opts, > session->keytype, > session->key, session->keylen, > &local_error); > > Passing non-null @local_error to qcrypto_akcipher_new(). This is wrong. > When qcrypto_akcipher_new() fails and passes &local_error to > error_setg(), error_setv()'s assertion will fail. > > Two possible fixes: > > 1. If continuing after cryptodev_lkcf_set_op_desc() is correct, we need > to clear @local_error there. Since it's not actually an error then, we > should almost certainly not use error_report_err() there. *Maybe* > warn_report_err(). > > 2. If continuing is wrong, we probably need set @status (to what?) and > goto out. > > What is the correct fix? > Hi, It's fatal error of a crypto task, so it should not continue. setting status as VIRTIO_CRYPTO_ERR should be fine. Thanks! [remove Lei He from cc list, he has already resigned from bytedance] > if (!akcipher) { > status = -VIRTIO_CRYPTO_ERR; > goto out; > } > } > > [...] > > out: > if (key_id >= 0) { > keyctl_unlink(key_id, KCTL_KEY_RING); > } > task->status = status; > > qemu_mutex_lock(&task->lkcf->rsp_mutex); > if (QSIMPLEQ_EMPTY(&task->lkcf->responses)) { > kick = true; > } > QSIMPLEQ_INSERT_TAIL(&task->lkcf->responses, task, queue); > qemu_mutex_unlock(&task->lkcf->rsp_mutex); > > if (kick) { > eventfd_write(task->lkcf->eventfd, 1); > } > } >