Messages in this thread | | | From | Eric Dumazet <> | Date | Mon, 1 Apr 2019 02:23:39 -0700 | Subject | Re: [PATCH] tcp: fix a potential NULL pointer dereference in tcp_sk_exit |
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On Mon, Apr 1, 2019 at 1:05 AM dust.li <dust.li@linux.alibaba.com> wrote: > > From: Dust Li <dust.li@linux.alibaba.com> > > 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. > > Signed-off-by: Dust Li <dust.li@linux.alibaba.com>
Fixes: 6670e1524477 ("tcp: Namespace-ify sysctl_tcp_default_congestion_control") Signed-off-by: Eric Dumazet <edumazet@google.com>
Thanks.
> --- > 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 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)); > -- > 2.14.4.44.g2045bb6 >
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