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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 95CA0C4360D for ; Sun, 8 Sep 2019 12:47:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6899F2190F for ; Sun, 8 Sep 2019 12:47:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567946862; bh=VQW4JxtBSA8uCuI6Kk12pcVkUqkLC1Wx3tvKKIQOyxg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=WD5vkQsnyn2eawRMcj1a25obZgl3ofGocpg5ftm7eRv4v/7wIRQdjst5fcE0x5+ok lCJA7Hz/5PCtYaE9JrNBY6ObpIxke41GFmUg/Ov6bmf8Qlq+y9U7Io9Iutp1VTPWDh PH2dPczijNAgwDJpEj6l2fJ097JnOgAaDcMnxUGM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730766AbfIHMrl (ORCPT ); Sun, 8 Sep 2019 08:47:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:36130 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730756AbfIHMri (ORCPT ); Sun, 8 Sep 2019 08:47:38 -0400 Received: from localhost (unknown [62.28.240.114]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4F132218AF; Sun, 8 Sep 2019 12:47:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567946857; bh=VQW4JxtBSA8uCuI6Kk12pcVkUqkLC1Wx3tvKKIQOyxg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q1JGD/E+234v8Lhkb6+/ZYPBoVHJoLoqHg66zRanilKQPuFNV7sKEgh3z/HbR51Pq l31jf6TmwHt7RKZZiHOwY0L0LMHgXlUBwk3xCPfKCn2ImqOjaKD15RkmyiT3Vp0SRi PXzT8oA5Ic+w7WlYE0JGNz6yQs2knOP4x5sQxwu0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dmitry Fomichev , Mike Christie , Damien Le Moal , "Martin K. Petersen" , Sasha Levin Subject: [PATCH 4.19 26/57] scsi: target: tcmu: avoid use-after-free after command timeout Date: Sun, 8 Sep 2019 13:41:50 +0100 Message-Id: <20190908121136.330463012@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190908121125.608195329@linuxfoundation.org> References: <20190908121125.608195329@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit a86a75865ff4d8c05f355d1750a5250aec89ab15 ] In tcmu_handle_completion() function, the variable called read_len is always initialized with a value taken from se_cmd structure. If this function is called to complete an expired (timed out) out command, the session command pointed by se_cmd is likely to be already deallocated by the target core at that moment. As the result, this access triggers a use-after-free warning from KASAN. This patch fixes the code not to touch se_cmd when completing timed out TCMU commands. It also resets the pointer to se_cmd at the time when the TCMU_CMD_BIT_EXPIRED flag is set because it is going to become invalid after calling target_complete_cmd() later in the same function, tcmu_check_expired_cmd(). Signed-off-by: Dmitry Fomichev Acked-by: Mike Christie Reviewed-by: Damien Le Moal Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/target/target_core_user.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index c46efa47d68a5..7159e8363b83b 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -1143,14 +1143,16 @@ static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry * struct se_cmd *se_cmd = cmd->se_cmd; struct tcmu_dev *udev = cmd->tcmu_dev; bool read_len_valid = false; - uint32_t read_len = se_cmd->data_length; + uint32_t read_len; /* * cmd has been completed already from timeout, just reclaim * data area space and free cmd */ - if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) + if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) { + WARN_ON_ONCE(se_cmd); goto out; + } list_del_init(&cmd->queue_entry); @@ -1163,6 +1165,7 @@ static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry * goto done; } + read_len = se_cmd->data_length; if (se_cmd->data_direction == DMA_FROM_DEVICE && (entry->hdr.uflags & TCMU_UFLAG_READ_LEN) && entry->rsp.read_len) { read_len_valid = true; @@ -1318,6 +1321,7 @@ static int tcmu_check_expired_cmd(int id, void *p, void *data) */ scsi_status = SAM_STAT_CHECK_CONDITION; list_del_init(&cmd->queue_entry); + cmd->se_cmd = NULL; } else { list_del_init(&cmd->queue_entry); idr_remove(&udev->commands, id); @@ -2036,6 +2040,7 @@ static void tcmu_reset_ring(struct tcmu_dev *udev, u8 err_level) idr_remove(&udev->commands, i); if (!test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) { + WARN_ON(!cmd->se_cmd); list_del_init(&cmd->queue_entry); if (err_level == 1) { /* -- 2.20.1