From patchwork Fri Apr 18 13:44:39 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen Yufeng X-Patchwork-Id: 14057207 Received: from cstnet.cn (smtp81.cstnet.cn [159.226.251.81]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E77DF29A0 for ; Fri, 18 Apr 2025 13:45:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.81 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744983915; cv=none; b=H+q+S9VxesgT5ybgDNqaHgtOcBR2blpGvEOSt1/06ydUMrbjkaml+3DB5tk/go810X7biBIdgYM+agKRC5kvxb/bRz3r0nXLYIyAysNJ3G3hedFcuBvqV5HxSz9jvh2BHqFO+y8pMNugt0Hs5Q+vr/tao3NMuwlPPpOllZnsJDI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744983915; c=relaxed/simple; bh=eaYdj/zAC6YB0prFHSJ3DGQmAAMOIdtBvlc2Vneh/Ck=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=g+FFIlNADirCOOcoe4HM/gXTu3nmivghl3NgyMLej35mAOWK6eWYMsBV0BXVLogMEsB/VdJcPlvQd20RTps70NTo5F/0GYfs6n9l2Cc4OmWcjNnsuP1NvuJ0s26fI+bPvfZHLqWDLO/CW0aesJUq67DF9XnOuYyX9ZuRYt4qdPo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iie.ac.cn; spf=pass smtp.mailfrom=iie.ac.cn; arc=none smtp.client-ip=159.226.251.81 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iie.ac.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iie.ac.cn Received: from localhost.localdomain (unknown [159.226.95.28]) by APP-03 (Coremail) with SMTP id rQCowAD3mzhWVwJoQDHdCQ--.24362S2; Fri, 18 Apr 2025 21:44:56 +0800 (CST) From: Chen Yufeng To: pbonzini@redhat.com Cc: chenyufeng@iie.ac.cn, kvm@vger.kernel.org Subject: [PATCH v2] kvm: potential NULL pointer dereference in kvm_vm_ioctl_create_vcpu() Date: Fri, 18 Apr 2025 21:44:39 +0800 Message-ID: <20250418134440.379-1-chenyufeng@iie.ac.cn> X-Mailer: git-send-email 2.43.0.windows.1 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: rQCowAD3mzhWVwJoQDHdCQ--.24362S2 X-Coremail-Antispam: 1UD129KBjvJXoW7Wry7CFWxGF47tF13WryDWrg_yoW8Xr15pF 43Gw10qr45Jw1jy3y3G3s5ZryjganIgas7CFyjvws8ZF12yFn5ZF1Skr909r17urW8Xayf try5X3WUu3WUCw7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUyq14x267AKxVWUJVW8JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26r1I6r4UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s 0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xII jxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr 1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7MxAIw28IcxkI7VAKI48J MxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwV AFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUXVWUAwCIc40Y0x0EwIxGrwCI42IY6xIIjxv2 0xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVWUJVW8JwCI42IY6xAIw20EY4 v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AK xVWUJVW8JbIYCTnIWIevJa73UjIFyTuYvjfU5WlkUUUUU X-CM-SenderInfo: xfkh05xxih0wo6llvhldfou0/1tbiBwkQEmgCI3mOVQAAsn A patch similar to commit 5593473a1e6c ("KVM: avoid NULL pointer dereference in kvm_dirty_ring_push"). If kvm_get_vcpu_by_id() or xa_insert() failed, kvm_vm_ioctl_create_vcpu() will call kvm_dirty_ring_free(), freeing ring->dirty_gfns and setting it to NULL. Then, it calls kvm_arch_vcpu_destroy(), which may call kvm_dirty_ring_push() in specific call stack under the same conditions as previous commit said. Finally, kvm_dirty_ring_push() will use ring->dirty_gfns, leading to a NULL pointer dereference. v2: - fixed in better way by just moving the position of kvm_dirty_ring_free v1: https://lore.kernel.org/kvm/596ce9b2-aa00-4bc5-ae20-451f3176d904@redhat.com Signed-off-by: Chen Yufeng --- virt/kvm/kvm_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index e85b33a92624..089efc4d01c6 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -4178,9 +4178,9 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, unsigned long id) xa_erase(&kvm->vcpu_array, vcpu->vcpu_idx); unlock_vcpu_destroy: mutex_unlock(&kvm->lock); - kvm_dirty_ring_free(&vcpu->dirty_ring); arch_vcpu_destroy: kvm_arch_vcpu_destroy(vcpu); + kvm_dirty_ring_free(&vcpu->dirty_ring); vcpu_free_run_page: free_page((unsigned long)vcpu->run); vcpu_free: