From patchwork Tue Apr 5 07:28:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 557825 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 BDE65C3A589 for ; Tue, 5 Apr 2022 08:56:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245313AbiDEIyx (ORCPT ); Tue, 5 Apr 2022 04:54:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60902 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240915AbiDEIci (ORCPT ); Tue, 5 Apr 2022 04:32:38 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D00D8D688; Tue, 5 Apr 2022 01:25:19 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 5A8CD60FFC; Tue, 5 Apr 2022 08:25:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 68B84C385A1; Tue, 5 Apr 2022 08:25:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649147118; bh=Ytr58gnACPtIgX8wj6A+Rgu50Y/LfhHdm8jAbP6A5yc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bHBnmKL/AySjloMP3Y4tECs50M9+efQFOXPGXndCiYCGmjr3AC9MjDIhGcHLXsFJU XdT9CJ6O1HK0F2fMPQ42pw0LvJpZnrRP81uqMgWXir+tyBlPJyd0QBN+1+fLFmijDV 7x9T96BPSh24QOcUrHIl1OAwLOf1y95VkvEQi5ZI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chen Jingwen , Christophe Leroy , Michael Ellerman Subject: [PATCH 5.17 0960/1126] powerpc/kasan: Fix early region not updated correctly Date: Tue, 5 Apr 2022 09:28:27 +0200 Message-Id: <20220405070435.684837161@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220405070407.513532867@linuxfoundation.org> References: <20220405070407.513532867@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Chen Jingwen commit dd75080aa8409ce10d50fb58981c6b59bf8707d3 upstream. The shadow's page table is not updated when PTE_RPN_SHIFT is 24 and PAGE_SHIFT is 12. It not only causes false positives but also false negative as shown the following text. Fix it by bringing the logic of kasan_early_shadow_page_entry here. 1. False Positive: ================================================================== BUG: KASAN: vmalloc-out-of-bounds in pcpu_alloc+0x508/0xa50 Write of size 16 at addr f57f3be0 by task swapper/0/1 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.15.0-12267-gdebe436e77c7 #1 Call Trace: [c80d1c20] [c07fe7b8] dump_stack_lvl+0x4c/0x6c (unreliable) [c80d1c40] [c02ff668] print_address_description.constprop.0+0x88/0x300 [c80d1c70] [c02ff45c] kasan_report+0x1ec/0x200 [c80d1cb0] [c0300b20] kasan_check_range+0x160/0x2f0 [c80d1cc0] [c03018a4] memset+0x34/0x90 [c80d1ce0] [c0280108] pcpu_alloc+0x508/0xa50 [c80d1d40] [c02fd7bc] __kmem_cache_create+0xfc/0x570 [c80d1d70] [c0283d64] kmem_cache_create_usercopy+0x274/0x3e0 [c80d1db0] [c2036580] init_sd+0xc4/0x1d0 [c80d1de0] [c00044a0] do_one_initcall+0xc0/0x33c [c80d1eb0] [c2001624] kernel_init_freeable+0x2c8/0x384 [c80d1ef0] [c0004b14] kernel_init+0x24/0x170 [c80d1f10] [c001b26c] ret_from_kernel_thread+0x5c/0x64 Memory state around the buggy address: f57f3a80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f57f3b00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 >f57f3b80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ f57f3c00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f57f3c80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ================================================================== 2. False Negative (with KASAN tests): ================================================================== Before fix: ok 45 - kmalloc_double_kzfree # vmalloc_oob: EXPECTATION FAILED at lib/test_kasan.c:1039 KASAN failure expected in "((volatile char *)area)[3100]", but none occurred not ok 46 - vmalloc_oob not ok 1 - kasan ================================================================== After fix: ok 1 - kasan Fixes: cbd18991e24fe ("powerpc/mm: Fix an Oops in kasan_mmu_init()") Cc: stable@vger.kernel.org # 5.4.x Signed-off-by: Chen Jingwen Reviewed-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20211229035226.59159-1-chenjingwen6@huawei.com Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/mm/kasan/kasan_init_32.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/arch/powerpc/mm/kasan/kasan_init_32.c +++ b/arch/powerpc/mm/kasan/kasan_init_32.c @@ -83,13 +83,12 @@ void __init kasan_update_early_region(unsigned long k_start, unsigned long k_end, pte_t pte) { unsigned long k_cur; - phys_addr_t pa = __pa(kasan_early_shadow_page); for (k_cur = k_start; k_cur != k_end; k_cur += PAGE_SIZE) { pmd_t *pmd = pmd_off_k(k_cur); pte_t *ptep = pte_offset_kernel(pmd, k_cur); - if ((pte_val(*ptep) & PTE_RPN_MASK) != pa) + if (pte_page(*ptep) != virt_to_page(lm_alias(kasan_early_shadow_page))) continue; __set_pte_at(&init_mm, k_cur, ptep, pte, 0);