From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C39C6C48BD1 for ; Tue, 8 Jun 2021 19:13:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A3467613AC for ; Tue, 8 Jun 2021 19:13:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238258AbhFHTO3 (ORCPT ); Tue, 8 Jun 2021 15:14:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:40100 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236933AbhFHTDg (ORCPT ); Tue, 8 Jun 2021 15:03:36 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 68BB061926; Tue, 8 Jun 2021 18:45:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1623177940; bh=oUJDRI9PvMCWPWvYm722dhyXrB9pkcvy4+YoyhsR/M8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q1MJwTD1S/uNGAIgWGLhC5I5MKILWl006GFOGIHs0nyN/5Z6HXgecFBnkCLBSuvOI olHzMQWHMBLvQzjeuaU6Re2xO+cuFRLX14W9+FeGVc+FcdrV2IYmmp33ImqFpNyPlz xUsGsVRm/j8cyFUCtLfs1RBRXNRC8WV18f17cHmo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Rasmus Villemoes , Ard Biesheuvel , Sasha Levin Subject: [PATCH 5.12 010/161] efi: cper: fix snprintf() use in cper_dimm_err_location() Date: Tue, 8 Jun 2021 20:25:40 +0200 Message-Id: <20210608175945.821402865@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210608175945.476074951@linuxfoundation.org> References: <20210608175945.476074951@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rasmus Villemoes [ Upstream commit 942859d969de7f6f7f2659a79237a758b42782da ] snprintf() should be given the full buffer size, not one less. And it guarantees nul-termination, so doing it manually afterwards is pointless. It's even potentially harmful (though probably not in practice because CPER_REC_LEN is 256), due to the "return how much would have been written had the buffer been big enough" semantics. I.e., if the bank and/or device strings are long enough that the "DIMM location ..." output gets truncated, writing to msg[n] is a buffer overflow. Signed-off-by: Rasmus Villemoes Fixes: 3760cd20402d4 ("CPER: Adjust code flow of some functions") Signed-off-by: Ard Biesheuvel Signed-off-by: Sasha Levin --- drivers/firmware/efi/cper.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c index e15d484b6a5a..ea7ca74fc173 100644 --- a/drivers/firmware/efi/cper.c +++ b/drivers/firmware/efi/cper.c @@ -276,8 +276,7 @@ static int cper_dimm_err_location(struct cper_mem_err_compact *mem, char *msg) if (!msg || !(mem->validation_bits & CPER_MEM_VALID_MODULE_HANDLE)) return 0; - n = 0; - len = CPER_REC_LEN - 1; + len = CPER_REC_LEN; dmi_memdev_name(mem->mem_dev_handle, &bank, &device); if (bank && device) n = snprintf(msg, len, "DIMM location: %s %s ", bank, device); @@ -286,7 +285,6 @@ static int cper_dimm_err_location(struct cper_mem_err_compact *mem, char *msg) "DIMM location: not present. DMI handle: 0x%.4x ", mem->mem_dev_handle); - msg[n] = '\0'; return n; } -- 2.30.2