bpf, sockmap: Fix potential memory leak on unlikely error case

If skb_linearize is needed and fails we could leak a msg on the error
handling. To fix ensure we kfree the msg block before returning error.
Found during code review.

Fixes: 4363023d26 ("bpf, sockmap: Avoid failures from skb_to_sgvec when skb has frag_list")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Cong Wang <cong.wang@bytedance.com>
Link: https://lore.kernel.org/bpf/20210712195546.423990-2-john.fastabend@gmail.com
This commit is contained in:
John Fastabend 2021-07-12 12:55:45 -07:00 committed by Daniel Borkmann
parent 9109165625
commit 7e6b27a691

View file

@ -508,10 +508,8 @@ static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb,
if (skb_linearize(skb)) if (skb_linearize(skb))
return -EAGAIN; return -EAGAIN;
num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len); num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len);
if (unlikely(num_sge < 0)) { if (unlikely(num_sge < 0))
kfree(msg);
return num_sge; return num_sge;
}
copied = skb->len; copied = skb->len;
msg->sg.start = 0; msg->sg.start = 0;
@ -530,6 +528,7 @@ static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
{ {
struct sock *sk = psock->sk; struct sock *sk = psock->sk;
struct sk_msg *msg; struct sk_msg *msg;
int err;
/* If we are receiving on the same sock skb->sk is already assigned, /* If we are receiving on the same sock skb->sk is already assigned,
* skip memory accounting and owner transition seeing it already set * skip memory accounting and owner transition seeing it already set
@ -548,7 +547,10 @@ static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
* into user buffers. * into user buffers.
*/ */
skb_set_owner_r(skb, sk); skb_set_owner_r(skb, sk);
return sk_psock_skb_ingress_enqueue(skb, psock, sk, msg); err = sk_psock_skb_ingress_enqueue(skb, psock, sk, msg);
if (err < 0)
kfree(msg);
return err;
} }
/* Puts an skb on the ingress queue of the socket already assigned to the /* Puts an skb on the ingress queue of the socket already assigned to the
@ -559,12 +561,16 @@ static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb
{ {
struct sk_msg *msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC); struct sk_msg *msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC);
struct sock *sk = psock->sk; struct sock *sk = psock->sk;
int err;
if (unlikely(!msg)) if (unlikely(!msg))
return -EAGAIN; return -EAGAIN;
sk_msg_init(msg); sk_msg_init(msg);
skb_set_owner_r(skb, sk); skb_set_owner_r(skb, sk);
return sk_psock_skb_ingress_enqueue(skb, psock, sk, msg); err = sk_psock_skb_ingress_enqueue(skb, psock, sk, msg);
if (err < 0)
kfree(msg);
return err;
} }
static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb, static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb,