From patchwork Tue Aug 10 17:30:14 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 495890 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CEDB1C4320A for ; Tue, 10 Aug 2021 17:36:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AE7F660FC4 for ; Tue, 10 Aug 2021 17:36:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233429AbhHJRgb (ORCPT ); Tue, 10 Aug 2021 13:36:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:41904 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233424AbhHJRfV (ORCPT ); Tue, 10 Aug 2021 13:35:21 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 12E9E610A0; Tue, 10 Aug 2021 17:34:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1628616899; bh=6ymvbabE/HvGsbg4DBodrxLMvzr8aNPkhKkpFjWnC98=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nFDRYFj8j7vJ8n0RnHSZRjiI8ZPnU5TLnjef8iV8Gf79nf4bzunPyNuoU0FGSLY5l /eS5Fwzymynl5+G7MXT9d6Cleeiee5MJnxg9CKRvdFl5AyAgK/t3NCXvFmD/3Hm+Oy uxNgQwcQwRRt/hKMikN20zRF/E/yymBaF+He7Rqg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+de271708674e2093097b@syzkaller.appspotmail.com, Shuah Khan , Luis Chamberlain , Anirudh Rayabharam Subject: [PATCH 5.4 41/85] firmware_loader: fix use-after-free in firmware_fallback_sysfs Date: Tue, 10 Aug 2021 19:30:14 +0200 Message-Id: <20210810172949.609281721@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210810172948.192298392@linuxfoundation.org> References: <20210810172948.192298392@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Anirudh Rayabharam commit 75d95e2e39b27f733f21e6668af1c9893a97de5e upstream. This use-after-free happens when a fw_priv object has been freed but hasn't been removed from the pending list (pending_fw_head). The next time fw_load_sysfs_fallback tries to insert into the list, it ends up accessing the pending_list member of the previously freed fw_priv. The root cause here is that all code paths that abort the fw load don't delete it from the pending list. For example: _request_firmware() -> fw_abort_batch_reqs() -> fw_state_aborted() To fix this, delete the fw_priv from the list in __fw_set_state() if the new state is DONE or ABORTED. This way, all aborts will remove the fw_priv from the list. Accordingly, remove calls to list_del_init that were being made before calling fw_state_(aborted|done). Also, in fw_load_sysfs_fallback, don't add the fw_priv to the pending list if it is already aborted. Instead, just jump out and return early. Fixes: bcfbd3523f3c ("firmware: fix a double abort case with fw_load_sysfs_fallback") Cc: stable Reported-by: syzbot+de271708674e2093097b@syzkaller.appspotmail.com Tested-by: syzbot+de271708674e2093097b@syzkaller.appspotmail.com Reviewed-by: Shuah Khan Acked-by: Luis Chamberlain Signed-off-by: Anirudh Rayabharam Link: https://lore.kernel.org/r/20210728085107.4141-3-mail@anirudhrb.com Signed-off-by: Greg Kroah-Hartman --- drivers/base/firmware_loader/fallback.c | 12 ++++++++---- drivers/base/firmware_loader/firmware.h | 10 +++++++++- drivers/base/firmware_loader/main.c | 2 ++ 3 files changed, 19 insertions(+), 5 deletions(-) --- a/drivers/base/firmware_loader/fallback.c +++ b/drivers/base/firmware_loader/fallback.c @@ -86,12 +86,11 @@ static void __fw_load_abort(struct fw_pr { /* * There is a small window in which user can write to 'loading' - * between loading done and disappearance of 'loading' + * between loading done/aborted and disappearance of 'loading' */ - if (fw_sysfs_done(fw_priv)) + if (fw_state_is_aborted(fw_priv) || fw_sysfs_done(fw_priv)) return; - list_del_init(&fw_priv->pending_list); fw_state_aborted(fw_priv); } @@ -277,7 +276,6 @@ static ssize_t firmware_loading_store(st * Same logic as fw_load_abort, only the DONE bit * is ignored and we set ABORT only on failure. */ - list_del_init(&fw_priv->pending_list); if (rc) { fw_state_aborted(fw_priv); written = rc; @@ -512,6 +510,11 @@ static int fw_load_sysfs_fallback(struct } mutex_lock(&fw_lock); + if (fw_state_is_aborted(fw_priv)) { + mutex_unlock(&fw_lock); + retval = -EINTR; + goto out; + } list_add(&fw_priv->pending_list, &pending_fw_head); mutex_unlock(&fw_lock); @@ -537,6 +540,7 @@ static int fw_load_sysfs_fallback(struct } else if (fw_priv->is_paged_buf && !fw_priv->data) retval = -ENOMEM; +out: device_del(f_dev); err_put_dev: put_device(f_dev); --- a/drivers/base/firmware_loader/firmware.h +++ b/drivers/base/firmware_loader/firmware.h @@ -108,8 +108,16 @@ static inline void __fw_state_set(struct WRITE_ONCE(fw_st->status, status); - if (status == FW_STATUS_DONE || status == FW_STATUS_ABORTED) + if (status == FW_STATUS_DONE || status == FW_STATUS_ABORTED) { +#ifdef CONFIG_FW_LOADER_USER_HELPER + /* + * Doing this here ensures that the fw_priv is deleted from + * the pending list in all abort/done paths. + */ + list_del_init(&fw_priv->pending_list); +#endif complete_all(&fw_st->completion); + } } static inline void fw_state_aborted(struct fw_priv *fw_priv) --- a/drivers/base/firmware_loader/main.c +++ b/drivers/base/firmware_loader/main.c @@ -747,8 +747,10 @@ static void fw_abort_batch_reqs(struct f return; fw_priv = fw->priv; + mutex_lock(&fw_lock); if (!fw_state_is_aborted(fw_priv)) fw_state_aborted(fw_priv); + mutex_unlock(&fw_lock); } /* called from request_firmware() and request_firmware_work_func() */