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 3B1BEC4332F for ; Tue, 12 Apr 2022 01:08:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346050AbiDLBHm (ORCPT ); Mon, 11 Apr 2022 21:07:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34896 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346502AbiDLA64 (ORCPT ); Mon, 11 Apr 2022 20:58:56 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F74735DCF; Mon, 11 Apr 2022 17:51:58 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 0B55CB81996; Tue, 12 Apr 2022 00:51:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF49DC385AE; Tue, 12 Apr 2022 00:51:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1649724715; bh=o7YxnEC1EUE/sxcXqD6+pc915/hcy+Zkz6Z/qMlcCKE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lhibbUhZE2MSHclzSKo8wcM783cXuUKrIoSpb3hIwMK0OjoxrYXDEHA07oRN0xl/E lZ0Pnaobc28r8lF6jdbqifvjXV/OF/E+XZhN/j7MK/pmypvDUUUq3RnpIVrtPDd+yo cOLb1NMPD5OBnhR/kixPQpp/6O75ZkIY1VRT6OI5EY340MWXAlJZ9qrgiEWGiKWKa+ ZoLXseyM9UN4DsoooPg2v4Mog+166i/LOTQGV2X6Cr48sKNh8iqtC9caCKXkxnaVzL EMFJrWT7oLys5oaBjS0BUOiyXwcYGrhN8kIek7WM0woRwnnGUU8ycaOQArSzFWdiqM uprzlfu3vw3Ig== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Xiaoguang Wang , Bodo Stroesser , "Martin K . Petersen" , Sasha Levin , linux-scsi@vger.kernel.org, target-devel@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 04/12] scsi: target: tcmu: Fix possible page UAF Date: Mon, 11 Apr 2022 20:51:37 -0400 Message-Id: <20220412005148.351391-4-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220412005148.351391-1-sashal@kernel.org> References: <20220412005148.351391-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Xiaoguang Wang [ Upstream commit a6968f7a367f128d120447360734344d5a3d5336 ] tcmu_try_get_data_page() looks up pages under cmdr_lock, but it does not take refcount properly and just returns page pointer. When tcmu_try_get_data_page() returns, the returned page may have been freed by tcmu_blocks_release(). We need to get_page() under cmdr_lock to avoid concurrent tcmu_blocks_release(). Link: https://lore.kernel.org/r/20220311132206.24515-1-xiaoguang.wang@linux.alibaba.com Reviewed-by: Bodo Stroesser Signed-off-by: Xiaoguang Wang Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/target/target_core_user.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index dd7307375504..f29d600357f3 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -1499,6 +1499,7 @@ static struct page *tcmu_try_get_block_page(struct tcmu_dev *udev, uint32_t dbi) mutex_lock(&udev->cmdr_lock); page = tcmu_get_block_page(udev, dbi); if (likely(page)) { + get_page(page); mutex_unlock(&udev->cmdr_lock); return page; } @@ -1537,6 +1538,7 @@ static vm_fault_t tcmu_vma_fault(struct vm_fault *vmf) /* For the vmalloc()ed cmd area pages */ addr = (void *)(unsigned long)info->mem[mi].addr + offset; page = vmalloc_to_page(addr); + get_page(page); } else { uint32_t dbi; @@ -1547,7 +1549,6 @@ static vm_fault_t tcmu_vma_fault(struct vm_fault *vmf) return VM_FAULT_SIGBUS; } - get_page(page); vmf->page = page; return 0; } -- 2.35.1