Do accounting for skb's real sk.
In some case skb->sk != asoc->base.sk.
Reported-and-tested-by: [email protected]
Signed-off-by: Qiujun Huang <[email protected]>
---
net/sctp/socket.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 1b56fc4..5f5c28b 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -9080,7 +9080,7 @@ static void sctp_wfree(struct sk_buff *skb)
{
struct sctp_chunk *chunk = skb_shinfo(skb)->destructor_arg;
struct sctp_association *asoc = chunk->asoc;
- struct sock *sk = asoc->base.sk;
+ struct sock *sk = skb->sk;
sk_mem_uncharge(sk, skb->truesize);
sk->sk_wmem_queued -= skb->truesize + sizeof(struct sctp_chunk);
@@ -9109,7 +9109,7 @@ static void sctp_wfree(struct sk_buff *skb)
}
sock_wfree(skb);
- sctp_wake_up_waiters(sk, asoc);
+ sctp_wake_up_waiters(asoc->base.sk, asoc);
sctp_association_put(asoc);
}
--
1.8.3.1
From: Qiujun Huang <[email protected]>
Date: Mon, 16 Mar 2020 11:53:24 +0800
> Do accounting for skb's real sk.
> In some case skb->sk != asoc->base.sk.
>
> Reported-and-tested-by: [email protected]
> Signed-off-by: Qiujun Huang <[email protected]>
SCTP folks, please review.
On Mon, Mar 16, 2020 at 11:53:24AM +0800, Qiujun Huang wrote:
> Do accounting for skb's real sk.
> In some case skb->sk != asoc->base.sk.
This is a too simple description. Please elaborate how this can
happen in sctp_wfree. Especially considering the construct for
migrating the tx queue on sctp_sock_migrate(), as both sockets are
locked while moving the chunks around and the asoc itself is only
moved in between decrementing and incrementing the refcount:
lock_sock_nested(newsk, SINGLE_DEPTH_NESTING);
sctp_for_each_tx_datachunk(assoc, sctp_clear_owner_w);
sctp_assoc_migrate(assoc, newsk);
sctp_for_each_tx_datachunk(assoc, sctp_set_owner_w);
...
>
> Reported-and-tested-by: [email protected]
I can't see a positive test result, though. If I didn't loose any
email, your last test with a patch similar to this one actually
failed.
I'm talking about syzbot test result at Message-ID: <[email protected]>
> Signed-off-by: Qiujun Huang <[email protected]>
> ---
> net/sctp/socket.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 1b56fc4..5f5c28b 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -9080,7 +9080,7 @@ static void sctp_wfree(struct sk_buff *skb)
> {
> struct sctp_chunk *chunk = skb_shinfo(skb)->destructor_arg;
> struct sctp_association *asoc = chunk->asoc;
> - struct sock *sk = asoc->base.sk;
> + struct sock *sk = skb->sk;
>
> sk_mem_uncharge(sk, skb->truesize);
> sk->sk_wmem_queued -= skb->truesize + sizeof(struct sctp_chunk);
> @@ -9109,7 +9109,7 @@ static void sctp_wfree(struct sk_buff *skb)
> }
>
> sock_wfree(skb);
> - sctp_wake_up_waiters(sk, asoc);
> + sctp_wake_up_waiters(asoc->base.sk, asoc);
>
> sctp_association_put(asoc);
> }
> --
> 1.8.3.1
>
On Tue, Mar 17, 2020 at 12:15 PM Marcelo Ricardo Leitner
<[email protected]> wrote:
>
> On Mon, Mar 16, 2020 at 11:53:24AM +0800, Qiujun Huang wrote:
> > Do accounting for skb's real sk.
> > In some case skb->sk != asoc->base.sk.
>
> This is a too simple description. Please elaborate how this can
> happen in sctp_wfree. Especially considering the construct for
> migrating the tx queue on sctp_sock_migrate(), as both sockets are
> locked while moving the chunks around and the asoc itself is only
> moved in between decrementing and incrementing the refcount:
>
> lock_sock_nested(newsk, SINGLE_DEPTH_NESTING);
> sctp_for_each_tx_datachunk(assoc, sctp_clear_owner_w);
> sctp_assoc_migrate(assoc, newsk);
> sctp_for_each_tx_datachunk(assoc, sctp_set_owner_w);
> ...
Yeah, the description is too simple. I'll send v2.
>
> >
> > Reported-and-tested-by: [email protected]
>
> I can't see a positive test result, though. If I didn't loose any
> email, your last test with a patch similar to this one actually
> failed.
> I'm talking about syzbot test result at Message-ID: <[email protected]>
I told with syzbot privately avoiding noise :p
Thanks!