From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id 5A709A0577; Tue, 7 Apr 2020 12:46:17 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id BE73A2BE9; Tue, 7 Apr 2020 12:46:16 +0200 (CEST) Received: from git-send-mailer.rdmz.labs.mlnx (unknown [37.142.13.130]) by dpdk.org (Postfix) with ESMTP id 7ABB52B96; Tue, 7 Apr 2020 12:46:15 +0200 (CEST) From: Bing Zhao To: anatoly.burakov@intel.com Cc: dev@dpdk.org, sergio.gonzalez.monroy@intel.com, stable@dpdk.org Date: Tue, 7 Apr 2020 18:46:04 +0800 Message-Id: <1586256364-185699-1-git-send-email-bingz@mellanox.com> X-Mailer: git-send-email 1.8.3.1 Subject: [dpdk-dev] [PATCH] mem: fix the alloc size roundup overflow X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" The size checking is done in the caller. The size parameter is an unsigned (64b wide) right now, so the comparison with zero should be enough in most cases. But it won't help in the following case. If the allocating request input a huge number by mistake, e.g., some overflow after the calculation (especially subtraction), the checking in the caller will succeed since it is not zero. Indeed, there is not enough space in the system to support such huge memory allocation. Usually it will return failure in the following code. But if the input size is just a little smaller than the UINT64_MAX, like -2 in signed type. The roundup will cause an overflow and then "reset" the size to 0, and then only a header (128B now) with zero length will be returned. The following will be the previous allocation header. It should be OK in most cases if the application won't access the memory body. Or else, some critical issue will be caused and not easy to debug. So this issue should be prevented at the beginning, like other big size failure, NULL pointer should be returned also. Fixes: fdf20fa7bee9 ("add prefix to cache line macros") Cc: sergio.gonzalez.monroy@intel.com Cc: stable@dpdk.org Signed-off-by: Bing Zhao --- lib/librte_eal/common/malloc_heap.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/lib/librte_eal/common/malloc_heap.c b/lib/librte_eal/common/malloc_heap.c index 842eb9d..bd50656 100644 --- a/lib/librte_eal/common/malloc_heap.c +++ b/lib/librte_eal/common/malloc_heap.c @@ -241,6 +241,9 @@ size = RTE_CACHE_LINE_ROUNDUP(size); align = RTE_CACHE_LINE_ROUNDUP(align); + /* roundup might cause an overflow */ + if (size == 0) + return NULL; elem = find_suitable_element(heap, size, flags, align, bound, contig); if (elem != NULL) { elem = malloc_elem_alloc(elem, size, align, bound, contig); -- 1.8.3.1