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Tue, 26 Nov 2019 17:52:23 +0000 Received: from b03ledav006.gho.boulder.ibm.com (b03ledav006.gho.boulder.ibm.com [9.17.130.237]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id xAQHqLow36438320 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 26 Nov 2019 17:52:21 GMT Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C22A0C6055; Tue, 26 Nov 2019 17:52:21 +0000 (GMT) Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8E9B2C6059; Tue, 26 Nov 2019 17:52:19 +0000 (GMT) Received: from LeoBras.aus.stglabs.ibm.com (unknown [9.18.235.137]) by b03ledav006.gho.boulder.ibm.com (Postfix) with ESMTP; Tue, 26 Nov 2019 17:52:19 +0000 (GMT) From: Leonardo Bras To: Sean Christopherson , kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: [PATCH 1/1] powerpc/kvm/book3s: Fixes possible 'use after release' of kvm Date: Tue, 26 Nov 2019 14:52:12 -0300 Message-Id: <20191126175212.377171-1-leonardo@linux.ibm.com> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,18.0.572 definitions=2019-11-26_05:2019-11-26,2019-11-26 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 suspectscore=2 adultscore=0 mlxlogscore=999 impostorscore=0 clxscore=1015 priorityscore=1501 lowpriorityscore=0 bulkscore=0 malwarescore=0 spamscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1911260149 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Paolo Bonzini , Leonardo Bras Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Fixes a possible 'use after free' of kvm variable. It does use mutex_unlock(&kvm->lock) after possible freeing a variable with kvm_put_kvm(kvm). Signed-off-by: Leonardo Bras --- arch/powerpc/kvm/book3s_64_vio.c | 3 +-- virt/kvm/kvm_main.c | 8 ++++---- 2 files changed, 5 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c index 5834db0a54c6..a402ead833b6 100644 --- a/arch/powerpc/kvm/book3s_64_vio.c +++ b/arch/powerpc/kvm/book3s_64_vio.c @@ -316,14 +316,13 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, if (ret >= 0) list_add_rcu(&stt->list, &kvm->arch.spapr_tce_tables); - else - kvm_put_kvm(kvm); mutex_unlock(&kvm->lock); if (ret >= 0) return ret; + kvm_put_kvm(kvm); kfree(stt); fail_acct: account_locked_vm(current->mm, kvmppc_stt_pages(npages), false); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 13efc291b1c7..f37089b60d09 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2744,10 +2744,8 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) /* Now it's all set up, let userspace reach it */ kvm_get_kvm(kvm); r = create_vcpu_fd(vcpu); - if (r < 0) { - kvm_put_kvm(kvm); + if (r < 0) goto unlock_vcpu_destroy; - } kvm->vcpus[atomic_read(&kvm->online_vcpus)] = vcpu; @@ -2771,6 +2769,8 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) mutex_lock(&kvm->lock); kvm->created_vcpus--; mutex_unlock(&kvm->lock); + if (r < 0) + kvm_put_kvm(kvm); return r; } @@ -3183,10 +3183,10 @@ static int kvm_ioctl_create_device(struct kvm *kvm, kvm_get_kvm(kvm); ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC); if (ret < 0) { - kvm_put_kvm(kvm); mutex_lock(&kvm->lock); list_del(&dev->vm_node); mutex_unlock(&kvm->lock); + kvm_put_kvm(kvm); ops->destroy(dev); return ret; } -- 2.23.0