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 1C942C433F5 for ; Mon, 13 Dec 2021 21:54:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243348AbhLMVyU (ORCPT ); Mon, 13 Dec 2021 16:54:20 -0500 Received: from out0.migadu.com ([94.23.1.103]:19431 "EHLO out0.migadu.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243290AbhLMVyF (ORCPT ); Mon, 13 Dec 2021 16:54:05 -0500 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=1639432443; 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=td/TtoF7cXxMeVx908agEEKdFK6FpXlk5RKSWg4HTMg=; b=qtKtE2kmusrP8UhCICzGgfQ7wuB9SHDUGobGIXiPT0HT1ujU9JGrYFO0Xr4WUv+oVcF16r bIuF+IG0xlHSg6THx9BFdsoU719C1vKuNQ/2BilR3FCuWIrQOqUpF7HNicqq6YOB4Alu+3 EFc9/vHa1I0io8eZmTh57ykDgGZHjBs= From: andrey.konovalov@linux.dev To: Marco Elver , Alexander Potapenko , Andrew Morton Cc: Andrey Konovalov , 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 v3 21/38] kasan, vmalloc: reset tags in vmalloc functions Date: Mon, 13 Dec 2021 22:53:11 +0100 Message-Id: In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: andrey.konovalov@linux.dev Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andrey Konovalov In preparation for adding vmalloc support to SW/HW_TAGS KASAN, reset pointer tags in functions that use pointer values in range checks. vread() is a special case here. Despite the untagging of the addr pointer in its prologue, the accesses performed by vread() are checked. Instead of accessing the virtual mappings though addr directly, vread() recovers the physical address via page_address(vmalloc_to_page()) and acceses that. And as page_address() recovers the pointer tag, the accesses get checked. Signed-off-by: Andrey Konovalov --- Changes v1->v2: - Clarified the description of untagging in vread(). --- mm/vmalloc.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index a6b61e24a703..42406c53e2a5 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -72,7 +72,7 @@ static const bool vmap_allow_huge = false; bool is_vmalloc_addr(const void *x) { - unsigned long addr = (unsigned long)x; + unsigned long addr = (unsigned long)kasan_reset_tag(x); return addr >= VMALLOC_START && addr < VMALLOC_END; } @@ -630,7 +630,7 @@ int is_vmalloc_or_module_addr(const void *x) * just put it in the vmalloc space. */ #if defined(CONFIG_MODULES) && defined(MODULES_VADDR) - unsigned long addr = (unsigned long)x; + unsigned long addr = (unsigned long)kasan_reset_tag(x); if (addr >= MODULES_VADDR && addr < MODULES_END) return 1; #endif @@ -804,6 +804,8 @@ static struct vmap_area *find_vmap_area_exceed_addr(unsigned long addr) struct vmap_area *va = NULL; struct rb_node *n = vmap_area_root.rb_node; + addr = (unsigned long)kasan_reset_tag((void *)addr); + while (n) { struct vmap_area *tmp; @@ -825,6 +827,8 @@ static struct vmap_area *__find_vmap_area(unsigned long addr) { struct rb_node *n = vmap_area_root.rb_node; + addr = (unsigned long)kasan_reset_tag((void *)addr); + while (n) { struct vmap_area *va; @@ -2143,7 +2147,7 @@ EXPORT_SYMBOL_GPL(vm_unmap_aliases); void vm_unmap_ram(const void *mem, unsigned int count) { unsigned long size = (unsigned long)count << PAGE_SHIFT; - unsigned long addr = (unsigned long)mem; + unsigned long addr = (unsigned long)kasan_reset_tag(mem); struct vmap_area *va; might_sleep(); @@ -3394,6 +3398,8 @@ long vread(char *buf, char *addr, unsigned long count) unsigned long buflen = count; unsigned long n; + addr = kasan_reset_tag(addr); + /* Don't allow overflow */ if ((unsigned long) addr + count < count) count = -(unsigned long) addr; -- 2.25.1