From patchwork Mon Jan 24 18:04:56 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: andrey.konovalov@linux.dev X-Patchwork-Id: 12722792 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7EF63C433EF for ; Mon, 24 Jan 2022 18:55:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=pAuyZkZiCPEifyy1KycKK37nMA/SFjgN6x79TPXBFZc=; b=ciAqPLWESKblvS NqVdpQP2qNQT+hh1GX7tS21smGeIBesR2VEwRuVW6oXTR2pI3M8bEu/FpUaAdeIoRWnp6qtL7L4hg lCAm5F27Z75Ti/3q4sNs+xuw7c3nIhDwW9dxL4tNb4khEVGXwPZkO5nRglCM83aDPeSecvMikk2IS h4bUyl2KWWJbUU1BfpoBZjXFLWXBevY1AKOb20cBeK72BBva/viQ2t6gUPsWXXvrgLIre4zq03/Tz dapPmQJOjltJuemyyw9h1NAFauhT8ryKnKmSb+6bDxq6JiIgt1sUlpFQuGnexGn1CyulpfEp2xTvL +jS6/KrUZKtE33kWhD/A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nC4TI-004eWa-Lp; Mon, 24 Jan 2022 18:53:45 +0000 Received: from out2.migadu.com ([2001:41d0:2:aacc::]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nC3iT-004Mnv-HX for linux-arm-kernel@lists.infradead.org; Mon, 24 Jan 2022 18:05:23 +0000 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=1643047519; 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=/XjTstEAGTMnS2cfhATsR9x5w6K0TN8X9h4vHjvkVrw=; b=IyNV3VAB/t0xjLzGOgv309VybgWXRFeywRGdKZZV4iWmY3e4kmKdNicqqTqZ0zN6pNo8pb Dz0IPusOEJkjC1XcK7aZ0CY5vehv5/xzm45oSN0+WTwFS1+6OxePIrkEnh8zjQNUZ/2XdF maXcYOD2z9VsCMIHn0R0EO1mtu8+Iuw= 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 v6 22/39] kasan, fork: reset pointer tags of vmapped stacks Date: Mon, 24 Jan 2022 19:04:56 +0100 Message-Id: In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220124_100521_790857_1C5FBC7B X-CRM114-Status: GOOD ( 10.68 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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 alloc_thread_stack_node(). 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 Reviewed-by: Alexander Potapenko --- Changes v2->v3: - Update patch description. --- kernel/fork.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/fork.c b/kernel/fork.c index d75a528f7b21..57d624f05182 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -254,6 +254,7 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node) * so cache the vm_struct. */ if (stack) { + stack = kasan_reset_tag(stack); tsk->stack_vm_area = find_vm_area(stack); tsk->stack = stack; }