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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 28DFBCA90AF for ; Tue, 12 May 2020 17:19:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 09F3F205ED for ; Tue, 12 May 2020 17:19:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729871AbgELRTj (ORCPT ); Tue, 12 May 2020 13:19:39 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:43977 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726287AbgELRTj (ORCPT ); Tue, 12 May 2020 13:19:39 -0400 Received: from 1.general.cking.uk.vpn ([10.172.193.212] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1jYYZ2-0002Sf-8n; Tue, 12 May 2020 17:19:32 +0000 From: Colin King To: Kees Cook , Anton Vorontsov , Colin Cross , Tony Luck , WeiXiong Liao Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH][next] pstore/zone: fix dereference of pointer before it has been null checked Date: Tue, 12 May 2020 18:19:32 +0100 Message-Id: <20200512171932.222102-1-colin.king@canonical.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Ian King Currently the assignment of cnt dereferences pointer 'record' before the pointer has been null checked. Fix this by only making this dereference after it has been null checked close to the point cnt is to be used. Addresses-Coverity: ("Dereference before null check") Fixes: 637ce64e7f57 ("pstore/zone,blk: Add support for pmsg frontend") Signed-off-by: Colin Ian King --- fs/pstore/zone.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/pstore/zone.c b/fs/pstore/zone.c index c5bf3b9f644f..3cf7d6762c76 100644 --- a/fs/pstore/zone.c +++ b/fs/pstore/zone.c @@ -825,7 +825,7 @@ static int notrace psz_record_write(struct pstore_zone *zone, struct pstore_record *record) { size_t start, rem; - int cnt = record->size; + int cnt; bool is_full_data = false; char *buf = record->buf; @@ -835,6 +835,7 @@ static int notrace psz_record_write(struct pstore_zone *zone, if (atomic_read(&zone->buffer->datalen) >= zone->buffer_size) is_full_data = true; + cnt = record->size; if (unlikely(cnt > zone->buffer_size)) { buf += cnt - zone->buffer_size; cnt = zone->buffer_size; -- 2.25.1