From patchwork Fri Mar 11 13:22:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiaoguang Wang X-Patchwork-Id: 550705 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 DC210C433FE for ; Fri, 11 Mar 2022 13:22:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347714AbiCKNXO (ORCPT ); Fri, 11 Mar 2022 08:23:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33488 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236044AbiCKNXN (ORCPT ); Fri, 11 Mar 2022 08:23:13 -0500 Received: from out30-57.freemail.mail.aliyun.com (out30-57.freemail.mail.aliyun.com [115.124.30.57]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9ABE81C2F7E; Fri, 11 Mar 2022 05:22:09 -0800 (PST) X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R921e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=e01e04400; MF=xiaoguang.wang@linux.alibaba.com; NM=1; PH=DS; RN=3; SR=0; TI=SMTPD_---0V6uG0i8_1647004926; Received: from localhost(mailfrom:xiaoguang.wang@linux.alibaba.com fp:SMTPD_---0V6uG0i8_1647004926) by smtp.aliyun-inc.com(127.0.0.1); Fri, 11 Mar 2022 21:22:06 +0800 From: Xiaoguang Wang To: linux-scsi@vger.kernel.org, target-devel@vger.kernel.org Cc: bostroesser@gmail.com Subject: [PATCH 1/2] scsi: target: tcmu: Fix possible page UAF Date: Fri, 11 Mar 2022 21:22:05 +0800 Message-Id: <20220311132206.24515-1-xiaoguang.wang@linux.alibaba.com> X-Mailer: git-send-email 2.17.2 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org tcmu_try_get_data_page() looks up pages under cmdr_lock, but it don't take refcount properly and just return page pointer. When tcmu_try_get_data_page() returns, the returned page may have been freed by tcmu_blocks_release(), need to get_page() under cmdr_lock to avoid concurrent tcmu_blocks_release(). Signed-off-by: Xiaoguang Wang Reviewed-by: Bodo Stroesser --- 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 7b2a89a67cdb..06a5c4086551 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -1820,6 +1820,7 @@ static struct page *tcmu_try_get_data_page(struct tcmu_dev *udev, uint32_t dpi) mutex_lock(&udev->cmdr_lock); page = xa_load(&udev->data_pages, dpi); if (likely(page)) { + get_page(page); mutex_unlock(&udev->cmdr_lock); return page; } @@ -1876,6 +1877,7 @@ 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 dpi; @@ -1886,7 +1888,6 @@ static vm_fault_t tcmu_vma_fault(struct vm_fault *vmf) return VM_FAULT_SIGBUS; } - get_page(page); vmf->page = page; return 0; } From patchwork Fri Mar 11 13:22:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiaoguang Wang X-Patchwork-Id: 550886 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 4A246C4332F for ; Fri, 11 Mar 2022 13:22:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347909AbiCKNXP (ORCPT ); Fri, 11 Mar 2022 08:23:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33490 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242718AbiCKNXN (ORCPT ); Fri, 11 Mar 2022 08:23:13 -0500 Received: from out30-130.freemail.mail.aliyun.com (out30-130.freemail.mail.aliyun.com [115.124.30.130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52AE21C3D08; Fri, 11 Mar 2022 05:22:10 -0800 (PST) X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R191e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=e01e04423; MF=xiaoguang.wang@linux.alibaba.com; NM=1; PH=DS; RN=3; SR=0; TI=SMTPD_---0V6uG0iM_1647004927; Received: from localhost(mailfrom:xiaoguang.wang@linux.alibaba.com fp:SMTPD_---0V6uG0iM_1647004927) by smtp.aliyun-inc.com(127.0.0.1); Fri, 11 Mar 2022 21:22:07 +0800 From: Xiaoguang Wang To: linux-scsi@vger.kernel.org, target-devel@vger.kernel.org Cc: bostroesser@gmail.com Subject: [PATCH 2/2] scsi: target: tcmu: Use address_space->invalidate_lock Date: Fri, 11 Mar 2022 21:22:06 +0800 Message-Id: <20220311132206.24515-2-xiaoguang.wang@linux.alibaba.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20220311132206.24515-1-xiaoguang.wang@linux.alibaba.com> References: <20220311132206.24515-1-xiaoguang.wang@linux.alibaba.com> Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Currently tcmu_vma_fault() uses udev->cmdr_lock to avoid concurrent find_free_blocks(), which unmaps idle pages and truncates them. This work is really like many filesystem's truncate operations, but they use address_space->invalidate_lock to protect race. This patch replaces cmdr_lock with address_space->invalidate_lock in tcmu fault procedure, which will also make page-fault have concurrency. Signed-off-by: Xiaoguang Wang --- drivers/target/target_core_user.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index 06a5c4086551..e0a62623ccd7 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -1815,13 +1815,14 @@ static int tcmu_find_mem_index(struct vm_area_struct *vma) static struct page *tcmu_try_get_data_page(struct tcmu_dev *udev, uint32_t dpi) { + struct address_space *mapping = udev->inode->i_mapping; struct page *page; - mutex_lock(&udev->cmdr_lock); + filemap_invalidate_lock_shared(mapping); page = xa_load(&udev->data_pages, dpi); if (likely(page)) { get_page(page); - mutex_unlock(&udev->cmdr_lock); + filemap_invalidate_unlock_shared(mapping); return page; } @@ -1831,7 +1832,7 @@ static struct page *tcmu_try_get_data_page(struct tcmu_dev *udev, uint32_t dpi) */ pr_err("Invalid addr to data page mapping (dpi %u) on device %s\n", dpi, udev->name); - mutex_unlock(&udev->cmdr_lock); + filemap_invalidate_unlock_shared(mapping); return NULL; } @@ -3111,6 +3112,7 @@ static void find_free_blocks(void) loff_t off; u32 pages_freed, total_pages_freed = 0; u32 start, end, block, total_blocks_freed = 0; + struct address_space *mapping; if (atomic_read(&global_page_count) <= tcmu_global_max_pages) return; @@ -3134,6 +3136,7 @@ static void find_free_blocks(void) continue; } + mapping = udev->inode->i_mapping; end = udev->dbi_max + 1; block = find_last_bit(udev->data_bitmap, end); if (block == udev->dbi_max) { @@ -3152,12 +3155,14 @@ static void find_free_blocks(void) udev->dbi_max = block; } + filemap_invalidate_lock(mapping); /* Here will truncate the data area from off */ off = udev->data_off + (loff_t)start * udev->data_blk_size; - unmap_mapping_range(udev->inode->i_mapping, off, 0, 1); + unmap_mapping_range(mapping, off, 0, 1); /* Release the block pages */ pages_freed = tcmu_blocks_release(udev, start, end - 1); + filemap_invalidate_unlock(mapping); mutex_unlock(&udev->cmdr_lock); total_pages_freed += pages_freed;