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authorDust Li <dust.li@linux.alibaba.com>2019-04-01 16:04:53 +0800
committerDavid S. Miller <davem@davemloft.net>2019-04-01 10:11:41 -0700
commitb506bc975f60f06e13e74adb35e708a23dc4e87c (patch)
tree90a10d72c1a9e02ce8e5de0d7f23ae114b8f6ea7 /net/ipv4
parent7ff0b608984b9589b5374aaa26ffd1621d8601f5 (diff)
tcp: fix a potential NULL pointer dereference in tcp_sk_exit
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>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/tcp_ipv4.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 277d71239d75..2f8039a26b08 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));