From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yb1-xb33.google.com (mail-yb1-xb33.google.com [IPv6:2607:f8b0:4864:20::b33]) by sourceware.org (Postfix) with ESMTPS id 77A773858C2C for ; Wed, 20 Dec 2023 12:55:15 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 77A773858C2C Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 77A773858C2C Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=2607:f8b0:4864:20::b33 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1703076916; cv=none; b=CPmXf8zDxt1Dism5rW6Hxa+tveL3tpKVsNK5xtVRjNXFdB6cOxRAEMBX1fvZJ/FYch2iEAou1+tfxkQV5M1HIOZvP3ZCXst+AP8Fme7bKLPQBNQr7cWtmlkjg02vL5lzU7pAjWnsvBMsO+cX36aFAKvCQA4OtxuZMMXCh9DgeLw= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1703076916; c=relaxed/simple; bh=pvmMUR6YMb4j9qRaW5tOZ12dYNG0ukhOHBp1HDE83bQ=; h=DKIM-Signature:MIME-Version:From:Date:Message-ID:Subject:To; b=otHyiCF+Vx54E3gqmHPlt0Hvuftid5c8TZLD6OkqiaP4c7Iayt1pC1L6kImej3WndNYh304IoCYKRj6y0/p92vClGdo711qmGp7bdhPFkgdVE6Bgxa68HooTjx9FYHB0WgB+qW6oNKAFZ0AvZBFyN7p+neUXvUCMAnKw/6w71xk= ARC-Authentication-Results: i=1; server2.sourceware.org Received: by mail-yb1-xb33.google.com with SMTP id 3f1490d57ef6-dbd49d583e3so2173049276.2 for ; Wed, 20 Dec 2023 04:55:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1703076915; x=1703681715; darn=sourceware.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=oIe7MlMFIDcyAp9+/0ReuL6Zytj5wWn3yECJZTcyH1I=; b=f4WKodwQEgTyf3OXhAITflcod30Ld7jRWuDO+0dLNJ5/7xqZ24IhfhisISYedlvGE8 pUCf+ABJibTzU9ts7KNQMYTGxF/wlx9sUfzh3cf4aGJbuBL5SK/vvcGHgAFSQQuLeoNK PyEeP9Q5soOL0gBKQYKZvIoewp3vSZTFVj8GNELYA3YTzC8ZyJbyY5kkFZ58Uhdwp2qJ RkKsdl6Yl3BgAV4bQINfuhWk0D7TlOF5Y9icGZDTxenHfiSXdI/Mq/Us2vaouQsUJsM3 UOkfwy7f2B6q0m6nC+oOGb7b0Y4PIozfdr+tB9ti4COeWdKnxo0kED+uh1VuTmwOx9LM LJdQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1703076915; x=1703681715; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=oIe7MlMFIDcyAp9+/0ReuL6Zytj5wWn3yECJZTcyH1I=; b=wU4Zhylwwat3iUrL/Lt/pKTX+HE+sFUKkLNXp0mtix5mgDqL3We78e4uMkKo9iLGCB dLq6UBlgwNSKPT5is9XD9prhO1fg7BDGdZSpiug50QXNhYRggqxtsqTRAXDjHOeYzsSO 2H2pddAerbvCedVmwjoFpfXNlE/SxVkXlguUiwtmFvwEauAKdMefgoNNmIGR+urHdV3E 96RrxCzkfzZgOgmGibTvEpZ/CSh6LF6rSJZmquydSDuwfP1w0TvxnAP2yioX+p3RZOA6 zMCFps6xtQXoBdkC5JvI7q9UmEmw5Jyhed0pURIOT8atdYcuWtn/rzuJzoW14V1CMg/S URyA== X-Gm-Message-State: AOJu0Yw/+3nthwWo0fRZvJ7Gykq34S/oh+/dfHRpH7kR8uUFntKhnMEO Bx63y7DELcXJeDi/QvmOZFraVu0YtZ24o7eNks8= X-Google-Smtp-Source: AGHT+IFVLjuMkWaX8oE6AUq5kdJeDVo3o6TZMdtu63y15QkV6k8hFg8b8xl55nJ5hY8tzhl7iL+My0wVxWFW6ScSzag= X-Received: by 2002:a5b:4c3:0:b0:dbd:3cd0:a4c2 with SMTP id u3-20020a5b04c3000000b00dbd3cd0a4c2mr2782661ybp.73.1703076914846; Wed, 20 Dec 2023 04:55:14 -0800 (PST) MIME-Version: 1.0 References: <20231219180256.3082953-1-hjl.tools@gmail.com> <87msu6os1k.fsf@oldenburg.str.redhat.com> <87o7elz4pg.fsf@oldenburg.str.redhat.com> In-Reply-To: <87o7elz4pg.fsf@oldenburg.str.redhat.com> From: "H.J. Lu" Date: Wed, 20 Dec 2023 04:54:38 -0800 Message-ID: Subject: Re: [PATCH] tst-setcontext10.c: Undef _FORTIFY_SOURCE To: Florian Weimer Cc: libc-alpha@sourceware.org, adhemerval.zanella@linaro.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-3015.3 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Tue, Dec 19, 2023 at 11:57=E2=80=AFPM Florian Weimer wrote: > > * H. J. Lu: > > > void ____longjmp_chk (__jmp_buf env, int val) > > { > > void *this_frame =3D __builtin_frame_address (0); > > void *saved_frame =3D JB_FRAME_ADDRESS (env); > > stack_t ss; > > > > /* If "env" is from a frame that called us, we're all set. */ > > if (called_from(this_frame, saved_frame)) <<< This is false for user= context > > __longjmp (env, val); > > Why isn't this a problem without shadow stack? It is a problem without shadow stack: https://sourceware.org/pipermail/libc-alpha/2023-December/153409.html > But what I meant was: Do the longjmp checks really add value over the > checking that shadow stack longjmp inevitably does? > No, I don't think so. But IFUNC can't be used since shadow stack may be enabled after IFUNC resolver has been initialized. --=20 H.J.