From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ECBBB11C8D for ; Mon, 28 Aug 2023 10:17:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6512CC433CD; Mon, 28 Aug 2023 10:17:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1693217844; bh=Zkq6h8sbXIb0xBoXy99exjMW6bvySiuMbrvGyWsTlXA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MCFNJktWYgKvXssUWLhzKptK0gqaRxG7qxYyY0gjHsG9L6xTXUMGcoU/zB4AAWgLg aziARVwM95zkH5tGVo8IDictxhZEHb41hLpxTiFLqSdKqG5q+yhj7oRrd0xMdDxuCB 6+KTz+5ZqTKuKp3W3xwPGnaPLpPfm3rkMJAjrjm8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sishuai Gong , Simon Horman , Julian Anastasov , Florian Westphal Subject: [PATCH 4.14 45/57] ipvs: fix racy memcpy in proc_do_sync_threshold Date: Mon, 28 Aug 2023 12:13:05 +0200 Message-ID: <20230828101145.923612650@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230828101144.231099710@linuxfoundation.org> References: <20230828101144.231099710@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sishuai Gong commit 5310760af1d4fbea1452bfc77db5f9a680f7ae47 upstream. When two threads run proc_do_sync_threshold() in parallel, data races could happen between the two memcpy(): Thread-1 Thread-2 memcpy(val, valp, sizeof(val)); memcpy(valp, val, sizeof(val)); This race might mess up the (struct ctl_table *) table->data, so we add a mutex lock to serialize them. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Link: https://lore.kernel.org/netdev/B6988E90-0A1E-4B85-BF26-2DAF6D482433@gmail.com/ Signed-off-by: Sishuai Gong Acked-by: Simon Horman Acked-by: Julian Anastasov Signed-off-by: Florian Westphal Signed-off-by: Greg Kroah-Hartman --- net/netfilter/ipvs/ip_vs_ctl.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/net/netfilter/ipvs/ip_vs_ctl.c +++ b/net/netfilter/ipvs/ip_vs_ctl.c @@ -1682,6 +1682,7 @@ static int proc_do_sync_threshold(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { + struct netns_ipvs *ipvs = table->extra2; int *valp = table->data; int val[2]; int rc; @@ -1691,6 +1692,7 @@ proc_do_sync_threshold(struct ctl_table .mode = table->mode, }; + mutex_lock(&ipvs->sync_mutex); memcpy(val, valp, sizeof(val)); rc = proc_dointvec(&tmp, write, buffer, lenp, ppos); if (write) { @@ -1700,6 +1702,7 @@ proc_do_sync_threshold(struct ctl_table else memcpy(valp, val, sizeof(val)); } + mutex_unlock(&ipvs->sync_mutex); return rc; } @@ -3976,6 +3979,7 @@ static int __net_init ip_vs_control_net_ ipvs->sysctl_sync_threshold[0] = DEFAULT_SYNC_THRESHOLD; ipvs->sysctl_sync_threshold[1] = DEFAULT_SYNC_PERIOD; tbl[idx].data = &ipvs->sysctl_sync_threshold; + tbl[idx].extra2 = ipvs; tbl[idx++].maxlen = sizeof(ipvs->sysctl_sync_threshold); ipvs->sysctl_sync_refresh_period = DEFAULT_SYNC_REFRESH_PERIOD; tbl[idx++].data = &ipvs->sysctl_sync_refresh_period;