Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751274AbeAAOWh (ORCPT + 1 other); Mon, 1 Jan 2018 09:22:37 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:41250 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751088AbeAAOWg (ORCPT ); Mon, 1 Jan 2018 09:22:36 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jerry Tang , Takashi Iwai , Kees Cook , Borislav Petkov , "Rafael J. Wysocki" Subject: [PATCH 3.18 01/32] ACPI: APEI / ERST: Fix missing error handling in erst_reader() Date: Mon, 1 Jan 2018 15:22:08 +0100 Message-Id: <20180101140012.904254454@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20180101140012.582300879@linuxfoundation.org> References: <20180101140012.582300879@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit bb82e0b4a7e96494f0c1004ce50cec3d7b5fb3d1 upstream. The commit f6f828513290 ("pstore: pass allocated memory region back to caller") changed the check of the return value from erst_read() in erst_reader() in the following way: if (len == -ENOENT) goto skip; - else if (len < 0) { - rc = -1; + else if (len < sizeof(*rcd)) { + rc = -EIO; goto out; This introduced another bug: since the comparison with sizeof() is cast to unsigned, a negative len value doesn't hit any longer. As a result, when an error is returned from erst_read(), the code falls through, and it may eventually lead to some weird thing like memory corruption. This patch adds the negative error value check more explicitly for addressing the issue. Fixes: f6f828513290 (pstore: pass allocated memory region back to caller) Tested-by: Jerry Tang Signed-off-by: Takashi Iwai Acked-by: Kees Cook Reviewed-by: Borislav Petkov Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/acpi/apei/erst.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/acpi/apei/erst.c +++ b/drivers/acpi/apei/erst.c @@ -1023,7 +1023,7 @@ skip: /* The record may be cleared by others, try read next record */ if (len == -ENOENT) goto skip; - else if (len < sizeof(*rcd)) { + else if (len < 0 || len < sizeof(*rcd)) { rc = -EIO; goto out; }