From nobody Mon Feb 9 09:08:16 2026 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 D0A43EB64DC for ; Tue, 4 Jul 2023 00:57:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230397AbjGDA5f (ORCPT ); Mon, 3 Jul 2023 20:57:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229622AbjGDA5d (ORCPT ); Mon, 3 Jul 2023 20:57:33 -0400 X-Greylist: delayed 320 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Mon, 03 Jul 2023 17:57:32 PDT Received: from out-8.mta1.migadu.com (out-8.mta1.migadu.com [95.215.58.8]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 80956137 for ; Mon, 3 Jul 2023 17:57:32 -0700 (PDT) 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=1688431928; 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; bh=9PvMF+hM/tczQlWv3CZcoKeqGsQQ6VNHOk9FPhNfzNc=; b=QYXS2UfB9fTOuQpIwrkK8of/jfOc1fLqLKs6PHdxgbFg8nLcpk3/ConRj1BiU7j0WCo28n daS2Mm1suhkZfCV9ZqOjFCpyOONbNFubKyg6htLLwJBilt9OjYbjTlOpmT57JWEevu0M2T nWPQm6VALEzldSnhheqDa/Q0KUbBky0= From: andrey.konovalov@linux.dev To: Marco Elver Cc: Andrey Konovalov , Alexander Potapenko , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, Andrew Morton , linux-mm@kvack.org, Arnd Bergmann , stable@vger.kernel.org, linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH] kasan: fix type cast in memory_is_poisoned_n Date: Tue, 4 Jul 2023 02:52:05 +0200 Message-Id: <8c9e0251c2b8b81016255709d4ec42942dcaf018.1688431866.git.andreyknvl@google.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Andrey Konovalov Commit bb6e04a173f0 ("kasan: use internal prototypes matching gcc-13 builtins") introduced a bug into the memory_is_poisoned_n implementation: it effectively removed the cast to a signed integer type after applying KASAN_GRANULE_MASK. As a result, KASAN started failing to properly check memset, memcpy, and other similar functions. Fix the bug by adding the cast back (through an additional signed integer variable to make the code more readable). Fixes: bb6e04a173f0 ("kasan: use internal prototypes matching gcc-13 builti= ns") Cc: Signed-off-by: Andrey Konovalov --- mm/kasan/generic.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c index 5b4c97baa656..4d837ab83f08 100644 --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -130,9 +130,10 @@ static __always_inline bool memory_is_poisoned_n(const= void *addr, size_t size) if (unlikely(ret)) { const void *last_byte =3D addr + size - 1; s8 *last_shadow =3D (s8 *)kasan_mem_to_shadow(last_byte); + s8 last_accessible_byte =3D (unsigned long)last_byte & KASAN_GRANULE_MAS= K; =20 if (unlikely(ret !=3D (unsigned long)last_shadow || - (((long)last_byte & KASAN_GRANULE_MASK) >=3D *last_shadow))) + last_accessible_byte >=3D *last_shadow)) return true; } return false; --=20 2.25.1