From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anatoly Burakov Subject: [PATCH 4/5] malloc: fix potential dereferencing of NULL pointer Date: Tue, 17 Apr 2018 16:48:16 +0100 Message-ID: References: Cc: thomas@monjalon.net, anatoly.burakov@intel.com To: dev@dpdk.org Return-path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by dpdk.org (Postfix) with ESMTP id BA961CF9E for ; Tue, 17 Apr 2018 17:48:21 +0200 (CEST) In-Reply-To: In-Reply-To: References: List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Previous code checked for both first/last elements being NULL, but if they weren't, the expectation was that they're both non-NULL, which will be the case under normal conditions, but may not be the case due to heap structure corruption. Coverity issue: 272566 Fixes: bb372060dad4 ("malloc: make heap a doubly-linked list") Cc: anatoly.burakov@intel.com Signed-off-by: Anatoly Burakov --- lib/librte_eal/common/malloc_elem.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/lib/librte_eal/common/malloc_elem.c b/lib/librte_eal/common/malloc_elem.c index ee79dcd..af81961 100644 --- a/lib/librte_eal/common/malloc_elem.c +++ b/lib/librte_eal/common/malloc_elem.c @@ -49,6 +49,12 @@ malloc_elem_insert(struct malloc_elem *elem) struct malloc_elem *prev_elem, *next_elem; struct malloc_heap *heap = elem->heap; + /* first and last elements must be both NULL or both non-NULL */ + if ((heap->first == NULL) != (heap->last == NULL)) { + RTE_LOG(ERR, EAL, "Heap is probably corrupt\n"); + return; + } + if (heap->first == NULL && heap->last == NULL) { /* if empty heap */ heap->first = elem; -- 2.7.4