From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xi Wang Subject: [PATCH v2] rps: fix insufficient bounds checking in store_rps_dev_flow_table_cnt() Date: Thu, 22 Dec 2011 18:35:22 -0500 Message-ID: <4EF3BEBA.4040402@gmail.com> References: <1324493459-19764-1-git-send-email-xi.wang@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Tom Herbert , "David S. Miller" , netdev@vger.kernel.org To: Eric Dumazet Return-path: Received: from mail-iy0-f174.google.com ([209.85.210.174]:58853 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751334Ab1LVXf1 (ORCPT ); Thu, 22 Dec 2011 18:35:27 -0500 Received: by iaeh11 with SMTP id h11so14171680iae.19 for ; Thu, 22 Dec 2011 15:35:26 -0800 (PST) In-Reply-To: <1324493459-19764-1-git-send-email-xi.wang@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: Setting a large rps_flow_cnt like (1 << 30) on 32-bit platform will cause a kernel oops due to insufficient bounds checking. if (count > 1<<30) { /* Enforce a limit to prevent overflow */ return -EINVAL; } count = roundup_pow_of_two(count); table = vmalloc(RPS_DEV_FLOW_TABLE_SIZE(count)); Note that the macro RPS_DEV_FLOW_TABLE_SIZE(count) is defined as: ... + (count * sizeof(struct rps_dev_flow)) where sizeof(struct rps_dev_flow) is 8. (1 << 30) * 8 will overflow 32 bits. This patch replaces the magic number (1 << 30) with a symbolic bound. Suggested-by: Eric Dumazet Signed-off-by: Xi Wang --- net/core/net-sysfs.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-) diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index c71c434..385aefe 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -665,11 +665,14 @@ static ssize_t store_rps_dev_flow_table_cnt(struct netdev_rx_queue *queue, if (count) { int i; - if (count > 1<<30) { + if (count > INT_MAX) + return -EINVAL; + count = roundup_pow_of_two(count); + if (count > (ULONG_MAX - sizeof(struct rps_dev_flow_table)) + / sizeof(struct rps_dev_flow)) { /* Enforce a limit to prevent overflow */ return -EINVAL; } - count = roundup_pow_of_two(count); table = vmalloc(RPS_DEV_FLOW_TABLE_SIZE(count)); if (!table) return -ENOMEM; -- 1.7.5.4