| From 09a44f6ff0c65aa9b78ec861d31f679e700f1abe Mon Sep 17 00:00:00 2001 |
| From: Dust Li <dust.li@linux.alibaba.com> |
| Date: Mon, 1 Apr 2019 16:04:53 +0800 |
| Subject: tcp: fix a potential NULL pointer dereference in tcp_sk_exit |
| |
| [ Upstream commit b506bc975f60f06e13e74adb35e708a23dc4e87c ] |
| |
| When tcp_sk_init() failed in inet_ctl_sock_create(), |
| 'net->ipv4.tcp_congestion_control' will be left |
| uninitialized, but tcp_sk_exit() hasn't check for |
| that. |
| |
| This patch add checking on 'net->ipv4.tcp_congestion_control' |
| in tcp_sk_exit() to prevent NULL-ptr dereference. |
| |
| Fixes: 6670e1524477 ("tcp: Namespace-ify sysctl_tcp_default_congestion_control") |
| Signed-off-by: Dust Li <dust.li@linux.alibaba.com> |
| Signed-off-by: Eric Dumazet <edumazet@google.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| net/ipv4/tcp_ipv4.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c |
| index 1aae9ab57fe9..00852f47a73d 100644 |
| --- a/net/ipv4/tcp_ipv4.c |
| +++ b/net/ipv4/tcp_ipv4.c |
| @@ -2578,7 +2578,8 @@ static void __net_exit tcp_sk_exit(struct net *net) |
| { |
| int cpu; |
| |
| - module_put(net->ipv4.tcp_congestion_control->owner); |
| + if (net->ipv4.tcp_congestion_control) |
| + module_put(net->ipv4.tcp_congestion_control->owner); |
| |
| for_each_possible_cpu(cpu) |
| inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu)); |
| -- |
| 2.19.1 |
| |
