From: John Fastabend <john.fastabend@xxxxxxxxx>
commit 8163999db445021f2651a8a47b5632483e8722ea upstream.
Report from Dan Carpenter,
net/core/skmsg.c:792 sk_psock_write_space()
error: we previously assumed 'psock' could be null (see line 790)
net/core/skmsg.c
789 psock = sk_psock(sk);
790 if (likely(psock && sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)))
Check for NULL
791 schedule_work(&psock->work);
792 write_space = psock->saved_write_space;
^^^^^^^^^^^^^^^^^^^^^^^^
793 rcu_read_unlock();
794 write_space(sk);
Ensure psock dereference on line 792 only occurs if psock is not null.
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: John Fastabend <john.fastabend@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/core/skmsg.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -793,15 +793,18 @@ static void sk_psock_strp_data_ready(str
static void sk_psock_write_space(struct sock *sk)
{
struct sk_psock *psock;
- void (*write_space)(struct sock *sk);
+ void (*write_space)(struct sock *sk) = NULL;
rcu_read_lock();
psock = sk_psock(sk);
- if (likely(psock && sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)))
- schedule_work(&psock->work);
- write_space = psock->saved_write_space;
+ if (likely(psock)) {
+ if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
+ schedule_work(&psock->work);
+ write_space = psock->saved_write_space;
+ }
rcu_read_unlock();
- write_space(sk);
+ if (write_space)
+ write_space(sk);
}
int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
