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 DE7F4C433EF for ; Thu, 30 Dec 2021 19:15:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241765AbhL3TPS (ORCPT ); Thu, 30 Dec 2021 14:15:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46260 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240485AbhL3TPN (ORCPT ); Thu, 30 Dec 2021 14:15:13 -0500 Received: from out2.migadu.com (out2.migadu.com [IPv6:2001:41d0:2:aacc::]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E37C3C061574 for ; Thu, 30 Dec 2021 11:15:12 -0800 (PST) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1640891711; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zMk+i6psUWRrJkriJ76ixSA3XRodREnil0b2HWyShlc=; b=hTVLkp46w7va4oaaJgM9hXUVBdrR+YwrRD1olLu1I9WemCknUMTqQKD//fIngzwPeSzuE9 R5n5ScEBoP1oX/8B8oIalASl5PRJPRweDrw7/IuK062jCumYtzWQiyPFB39ZAdDyzr6zEI 5XLxP8toHqfnKUWkgZWotmqKDtHEHR0= From: andrey.konovalov@linux.dev To: Andrew Morton Cc: Andrey Konovalov , Marco Elver , Alexander Potapenko , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, linux-mm@kvack.org, Vincenzo Frascino , Catalin Marinas , Will Deacon , Mark Rutland , linux-arm-kernel@lists.infradead.org, Peter Collingbourne , Evgenii Stepanov , linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH mm v5 23/39] kasan, arm64: reset pointer tags of vmapped stacks Date: Thu, 30 Dec 2021 20:14:48 +0100 Message-Id: In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andrey Konovalov Once tag-based KASAN modes start tagging vmalloc() allocations, kernel stacks start getting tagged if CONFIG_VMAP_STACK is enabled. Reset the tag of kernel stack pointers after allocation in arch_alloc_vmap_stack(). For SW_TAGS KASAN, when CONFIG_KASAN_STACK is enabled, the instrumentation can't handle the SP register being tagged. For HW_TAGS KASAN, there's no instrumentation-related issues. However, the impact of having a tagged SP register needs to be properly evaluated, so keep it non-tagged for now. Note, that the memory for the stack allocation still gets tagged to catch vmalloc-into-stack out-of-bounds accesses. Signed-off-by: Andrey Konovalov Acked-by: Catalin Marinas --- Changes v2->v3: - Add this patch. --- arch/arm64/include/asm/vmap_stack.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/vmap_stack.h b/arch/arm64/include/asm/vmap_stack.h index 894e031b28d2..20873099c035 100644 --- a/arch/arm64/include/asm/vmap_stack.h +++ b/arch/arm64/include/asm/vmap_stack.h @@ -17,10 +17,13 @@ */ static inline unsigned long *arch_alloc_vmap_stack(size_t stack_size, int node) { + void *p; + BUILD_BUG_ON(!IS_ENABLED(CONFIG_VMAP_STACK)); - return __vmalloc_node(stack_size, THREAD_ALIGN, THREADINFO_GFP, node, + p = __vmalloc_node(stack_size, THREAD_ALIGN, THREADINFO_GFP, node, __builtin_return_address(0)); + return kasan_reset_tag(p); } #endif /* __ASM_VMAP_STACK_H */ -- 2.25.1