[ 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));