Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756759Ab3I3Kbe (ORCPT ); Mon, 30 Sep 2013 06:31:34 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:43526 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755394Ab3I3KMX (ORCPT ); Mon, 30 Sep 2013 06:12:23 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Roman Gushchin , "David S. Miller" , Luis Henriques Subject: [PATCH 039/104] net: check net.core.somaxconn sysctl values Date: Mon, 30 Sep 2013 11:10:16 +0100 Message-Id: <1380535881-9239-40-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1380535881-9239-1-git-send-email-luis.henriques@canonical.com> References: <1380535881-9239-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2607 Lines: 80 3.5.7.22 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Roman Gushchin commit 5f671d6b4ec3e6d66c2a868738af2cdea09e7509 upstream. It's possible to assign an invalid value to the net.core.somaxconn sysctl variable, because there is no checks at all. The sk_max_ack_backlog field of the sock structure is defined as unsigned short. Therefore, the backlog argument in inet_listen() shouldn't exceed USHRT_MAX. The backlog argument in the listen() syscall is truncated to the somaxconn value. So, the somaxconn value shouldn't exceed 65535 (USHRT_MAX). Also, negative values of somaxconn are meaningless. before: $ sysctl -w net.core.somaxconn=256 net.core.somaxconn = 256 $ sysctl -w net.core.somaxconn=65536 net.core.somaxconn = 65536 $ sysctl -w net.core.somaxconn=-100 net.core.somaxconn = -100 after: $ sysctl -w net.core.somaxconn=256 net.core.somaxconn = 256 $ sysctl -w net.core.somaxconn=65536 error: "Invalid argument" setting key "net.core.somaxconn" $ sysctl -w net.core.somaxconn=-100 error: "Invalid argument" setting key "net.core.somaxconn" Based on a prior patch from Changli Gao. Signed-off-by: Roman Gushchin Reported-by: Changli Gao Suggested-by: Eric Dumazet Acked-by: Eric Dumazet Signed-off-by: David S. Miller [ luis: backported to 3.5: adjusted context ] Signed-off-by: Luis Henriques --- net/core/sysctl_net_core.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index a7c3684..df0dafe 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -20,6 +20,9 @@ #include #include +static int zero = 0; +static int ushort_max = USHRT_MAX; + #ifdef CONFIG_RPS static int rps_sock_flow_sysctl(ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) @@ -198,7 +201,9 @@ static struct ctl_table netns_core_table[] = { .data = &init_net.core.sysctl_somaxconn, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec + .extra1 = &zero, + .extra2 = &ushort_max, + .proc_handler = proc_dointvec_minmax }, { } }; -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/