From patchwork Fri Apr 18 04:24:21 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen Yufeng X-Patchwork-Id: 14056699 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 965871CD15 for ; Fri, 18 Apr 2025 04:24:44 +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=1744950293; cv=none; b=HVW9EgBLmCQm8NzZicKWVil7917efDJvreCLTJlYoYm397ci7PgpGYUVxr9IyYd50yMy9/1y3Dzmv63E3t+DOmXG8g8SsUYULKEHDjNUpnKoz51E4OVBW51rbcG5LVuLhJevJT141u/hjkLJIp/pgsykx6MoQ+6s5RZ7h1KNrQ4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744950293; c=relaxed/simple; bh=UcLzApWTlaZJZCVj5dnmGM9ilFck9GmUfJn9wymEXFM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=dPWI62PmT2fupyfZG0phS7IPpblTW6b5KWVf17vuL8dwBsL4Lu9MBSaR7lX3OeTNv8sFmPDGwIaG5Ac9iZlClH7H6MCgyJV3yLNvttR/6I4Z4JLVwj3+Kgy/BJOEF10pMuT08t8yta9+peu024PsYyiEO1jgo6REnGL7n7oTP8o= 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 rQCowAAnzTkH1AFo0fa9CQ--.20162S2; Fri, 18 Apr 2025 12:24:41 +0800 (CST) From: Chen Yufeng To: pbonzini@redhat.com Cc: kvm@vger.kernel.org, chenyufeng@iie.ac.cn Subject: [PATCH] kvm: potential NULL pointer dereference in kvm_vm_ioctl_create_vcpu() Date: Fri, 18 Apr 2025 12:24:21 +0800 Message-ID: <20250418042421.1393-1-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: rQCowAAnzTkH1AFo0fa9CQ--.20162S2 X-Coremail-Antispam: 1UD129KBjvJXoWrZr17trW7CF1UCF18Xw13Arb_yoW8Jr4xpF 43Gw40qws8Ja1Dt3y7Cw1kZr18tanIgas7CFyUZw45ZF12yFn5uFyfKr909ry7CrW0qa93 try5X3WUu3W5Cw7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUym14x267AKxVWUJVW8JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26r4j6ryUM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gc CE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E 2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJV W8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1l42xK82IYc2Ij64vI r41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8Gjc xK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1Y6r17MIIYrxkI7VAKI48JMIIF0xvE2Ix0 cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r1j6r4UMIIF0xvE42xK8V AvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E 14v26r1j6r4UYxBIdaVFxhVjvjDU0xZFpf9x0JUywZ7UUUUU= X-CM-SenderInfo: xfkh05xxih0wo6llvhldfou0/1tbiDAcQEmgBm-fewQAAsT 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. Signed-off-by: Chen Yufeng --- virt/kvm/kvm_main.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index e85b33a92624..3c97e598d866 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -4178,7 +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_arch_vcpu_destroy(vcpu); kvm_dirty_ring_free(&vcpu->dirty_ring); + goto vcpu_free_run_page; arch_vcpu_destroy: kvm_arch_vcpu_destroy(vcpu); vcpu_free_run_page: