From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DD1C8CDB465 for ; Mon, 16 Oct 2023 08:48:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232719AbjJPIss (ORCPT ); Mon, 16 Oct 2023 04:48:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41930 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232618AbjJPIsr (ORCPT ); Mon, 16 Oct 2023 04:48:47 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BBBDDB4 for ; Mon, 16 Oct 2023 01:48:45 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7B87FC433C8; Mon, 16 Oct 2023 08:48:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1697446125; bh=zSwoDARdqXy9TAIOMMj5HivSPCW7M/9iNK2FMS5WAk4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0F5WfJCm+w5S8gFLvNG4H1i32kyllJygXGrtFP5GiA/jyvXMCNgG8AtLPWtDkQy2u OB8wngqy1rV+zDnkaPIkCPLFGmZF0Rb21Rwn8GN+xzCD/I8SmEw1/DqGgdjrfJjAm3 8ZwAzjCfzJcRVBOYla5hSj4ikoFm+vgOXsKliUM8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Rijo Thomas , Sumit Garg , Jens Wiklander Subject: [PATCH 5.15 073/102] tee: amdtee: fix use-after-free vulnerability in amdtee_close_session Date: Mon, 16 Oct 2023 10:41:12 +0200 Message-ID: <20231016083955.645189532@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231016083953.689300946@linuxfoundation.org> References: <20231016083953.689300946@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Rijo Thomas commit f4384b3e54ea813868bb81a861bf5b2406e15d8f upstream. There is a potential race condition in amdtee_close_session that may cause use-after-free in amdtee_open_session. For instance, if a session has refcount == 1, and one thread tries to free this session via: kref_put(&sess->refcount, destroy_session); the reference count will get decremented, and the next step would be to call destroy_session(). However, if in another thread, amdtee_open_session() is called before destroy_session() has completed execution, alloc_session() may return 'sess' that will be freed up later in destroy_session() leading to use-after-free in amdtee_open_session. To fix this issue, treat decrement of sess->refcount and removal of 'sess' from session list in destroy_session() as a critical section, so that it is executed atomically. Fixes: 757cc3e9ff1d ("tee: add AMD-TEE driver") Cc: stable@vger.kernel.org Signed-off-by: Rijo Thomas Reviewed-by: Sumit Garg Signed-off-by: Jens Wiklander Signed-off-by: Greg Kroah-Hartman --- drivers/tee/amdtee/core.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/drivers/tee/amdtee/core.c +++ b/drivers/tee/amdtee/core.c @@ -217,12 +217,12 @@ unlock: return rc; } +/* mutex must be held by caller */ static void destroy_session(struct kref *ref) { struct amdtee_session *sess = container_of(ref, struct amdtee_session, refcount); - mutex_lock(&session_list_mutex); list_del(&sess->list_node); mutex_unlock(&session_list_mutex); kfree(sess); @@ -272,7 +272,8 @@ int amdtee_open_session(struct tee_conte if (arg->ret != TEEC_SUCCESS) { pr_err("open_session failed %d\n", arg->ret); handle_unload_ta(ta_handle); - kref_put(&sess->refcount, destroy_session); + kref_put_mutex(&sess->refcount, destroy_session, + &session_list_mutex); goto out; } @@ -290,7 +291,8 @@ int amdtee_open_session(struct tee_conte pr_err("reached maximum session count %d\n", TEE_NUM_SESSIONS); handle_close_session(ta_handle, session_info); handle_unload_ta(ta_handle); - kref_put(&sess->refcount, destroy_session); + kref_put_mutex(&sess->refcount, destroy_session, + &session_list_mutex); rc = -ENOMEM; goto out; } @@ -331,7 +333,7 @@ int amdtee_close_session(struct tee_cont handle_close_session(ta_handle, session_info); handle_unload_ta(ta_handle); - kref_put(&sess->refcount, destroy_session); + kref_put_mutex(&sess->refcount, destroy_session, &session_list_mutex); return 0; }