From patchwork Tue Jul 2 08:01:58 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 168285 Delivered-To: patch@linaro.org Received: by 2002:a92:4782:0:0:0:0:0 with SMTP id e2csp3930847ilk; Tue, 2 Jul 2019 01:04:33 -0700 (PDT) X-Google-Smtp-Source: APXvYqzZOfFcKLLY79nA6Ny1LLYfxNcY8Ep1Hjk/dPkTto56VZfhnyFkvIqushyspkXEqA0j9D8i X-Received: by 2002:a63:5c1c:: with SMTP id q28mr28737047pgb.288.1562054672847; Tue, 02 Jul 2019 01:04:32 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1562054672; cv=none; d=google.com; s=arc-20160816; b=z8Yv1+ss5AkqshqARnverSMDMlvQmKLiRYJQlCmB9hboDkbeC0WgCwmd7hEea/7rwk QOhGONc8kxIjv1L75YxQ37nDuS9dl2uFFaf75S7Rm2CnoitacrIguLEdWGnQSC9en/tj Y/G33mY+A38r0PYXKmCXgrZcw3aW0Dpfcc9qPvS92oOrEErVkLlaZynA9piLneJUaojB GDiviANdyWPZxRCSIkS6gqGzI0NfKtUGvFPzTKWEKsGthnlLhvYhktgIUDDffv+nYEMT ppVmuit5GfVMib20ejF+Ffs8gK1GvIfpPTw9EQYxf9kZgLC0jsOf7UqQD3ngGcfiKYrK bmPA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :user-agent:references:in-reply-to:message-id:date:subject:cc:to :from:dkim-signature; bh=smwADwmnPQHrDMAIex54M14jdc9d+yYb03vjNtzVKkE=; b=sYLK7w/Atr+6cR5q+GVDnVsMnHGZik8xUAK5XsWV7vBVIF5j9kwEKE1fVXJjdVokka srYdHIIls+xkDHkxyKOB+vQLzMO0KKXsC+lpt6QkBt9FhGXqBAWheat/rDy2n1xN4A5w wJJtnVPb/VG8qVtn9vL0mcIraR/2x9e7MGpQ4tA83JghLzBst9EoUtkkoCf3FP9Tfzm1 EqSGVGwbg5j8aUWnRHmOJeObLFXh1uA5Io8S4EYWk8oQY1W6TgFgcDvZ7Dr21g1woYJq FCSh9cI7zhRMtx02mzuXSHwLrbi+lqUdU4v0b/MoGSIaCSX9sngFrH+IPLxwyat7CVLw g2ug== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=eQNgn5Ie; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id x1si1655199pju.84.2019.07.02.01.04.32; Tue, 02 Jul 2019 01:04:32 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=eQNgn5Ie; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727743AbfGBIEb (ORCPT + 30 others); Tue, 2 Jul 2019 04:04:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:49938 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727726AbfGBIE2 (ORCPT ); Tue, 2 Jul 2019 04:04:28 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B7C6A20659; Tue, 2 Jul 2019 08:04:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562054668; bh=emvwUdVW0+nZbV6MltQoEQlRpt9QAeRJY2O4pV29Klw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eQNgn5IeUXjFIM/aUxnKj4cU4jMlZtGVUB+NTxtdC9RS8NOj7z23+wmJBAOb8771R 1/IwbOHoz0EaNmF86cNFfwkrDLx2twgajJqa4Thr24NWdUYGciwTri29xuGoXp3znJ O2wYJBzcCcxNOuRLtqpBRVLHqOHlgHF6kO8SlWrg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Will Deacon Subject: [PATCH 5.1 50/55] arm64: futex: Avoid copying out uninitialised stack in failed cmpxchg() Date: Tue, 2 Jul 2019 10:01:58 +0200 Message-Id: <20190702080126.687857009@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190702080124.103022729@linuxfoundation.org> References: <20190702080124.103022729@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Will Deacon commit 8e4e0ac02b449297b86498ac24db5786ddd9f647 upstream. Returning an error code from futex_atomic_cmpxchg_inatomic() indicates that the caller should not make any use of *uval, and should instead act upon on the value of the error code. Although this is implemented correctly in our futex code, we needlessly copy uninitialised stack to *uval in the error case, which can easily be avoided. Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/asm/futex.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/arch/arm64/include/asm/futex.h +++ b/arch/arm64/include/asm/futex.h @@ -134,7 +134,9 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, : "memory"); uaccess_disable(); - *uval = val; + if (!ret) + *uval = val; + return ret; }