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vsock: fix recursive ->recvmsg calls

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After a vsock socket has been added to a BPF sockmap, its prot->recvmsg
has been replaced with vsock_bpf_recvmsg(). Thus the following
recursiion could happen:

vsock_bpf_recvmsg()
 -> __vsock_recvmsg()
  -> vsock_connectible_recvmsg()
   -> prot->recvmsg()
    -> vsock_bpf_recvmsg() again

We need to fix it by calling the original ->recvmsg() without any BPF
sockmap logic in __vsock_recvmsg().

Fixes: 634f1a7110 ("vsock: support sockmap")
Reported-by: syzbot+bdb4bd87b5e22058e2a4@syzkaller.appspotmail.com
Tested-by: syzbot+bdb4bd87b5e22058e2a4@syzkaller.appspotmail.com
Cc: Bobby Eshleman <bobby.eshleman@bytedance.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://patch.msgid.link/20240812022153.86512-1-xiyou.wangcong@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Cong Wang 2024-08-11 19:21:53 -07:00 committed by Paolo Abeni
parent b2ca1661c7
commit 69139d2919
3 changed files with 35 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/net/af_vsock.h
View File

@ -230,8 +230,12 @@ struct vsock_tap {
int vsock_add_tap(struct vsock_tap *vt);
int vsock_remove_tap(struct vsock_tap *vt);
void vsock_deliver_tap(struct sk_buff *build_skb(void *opaque), void *opaque);
int __vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
int flags);
int vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
int flags);
int __vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
size_t len, int flags);
int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
size_t len, int flags);

50
net/vmw_vsock/af_vsock.c
View File

@ -1270,25 +1270,28 @@ out:
return err;
}
int __vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
size_t len, int flags)
{
struct sock *sk = sock->sk;
struct vsock_sock *vsk = vsock_sk(sk);
return vsk->transport->dgram_dequeue(vsk, msg, len, flags);
}
int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
size_t len, int flags)
{
#ifdef CONFIG_BPF_SYSCALL
struct sock *sk = sock->sk;
const struct proto *prot;
#endif
struct vsock_sock *vsk;
struct sock *sk;
sk = sock->sk;
vsk = vsock_sk(sk);
#ifdef CONFIG_BPF_SYSCALL
prot = READ_ONCE(sk->sk_prot);
if (prot != &vsock_proto)
return prot->recvmsg(sk, msg, len, flags, NULL);
#endif
return vsk->transport->dgram_dequeue(vsk, msg, len, flags);
return __vsock_dgram_recvmsg(sock, msg, len, flags);
}
EXPORT_SYMBOL_GPL(vsock_dgram_recvmsg);
@ -2174,15 +2177,12 @@ out:
}
int
vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
int flags)
__vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
int flags)
{
struct sock *sk;
struct vsock_sock *vsk;
const struct vsock_transport *transport;
#ifdef CONFIG_BPF_SYSCALL
const struct proto *prot;
#endif
int err;
sk = sock->sk;
@ -2233,14 +2233,6 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
goto out;
}
#ifdef CONFIG_BPF_SYSCALL
prot = READ_ONCE(sk->sk_prot);
if (prot != &vsock_proto) {
release_sock(sk);
return prot->recvmsg(sk, msg, len, flags, NULL);
}
#endif
if (sk->sk_type == SOCK_STREAM)
err = __vsock_stream_recvmsg(sk, msg, len, flags);
else
@ -2250,6 +2242,22 @@ out:
release_sock(sk);
return err;
}
int
vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
int flags)
{
#ifdef CONFIG_BPF_SYSCALL
struct sock *sk = sock->sk;
const struct proto *prot;
prot = READ_ONCE(sk->sk_prot);
if (prot != &vsock_proto)
return prot->recvmsg(sk, msg, len, flags, NULL);
#endif
return __vsock_connectible_recvmsg(sock, msg, len, flags);
}
EXPORT_SYMBOL_GPL(vsock_connectible_recvmsg);
static int vsock_set_rcvlowat(struct sock *sk, int val)

4
net/vmw_vsock/vsock_bpf.c
View File

@ -64,9 +64,9 @@ static int __vsock_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int
int err;
if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)
err = vsock_connectible_recvmsg(sock, msg, len, flags);
err = __vsock_connectible_recvmsg(sock, msg, len, flags);
else if (sk->sk_type == SOCK_DGRAM)
err = vsock_dgram_recvmsg(sock, msg, len, flags);
err = __vsock_dgram_recvmsg(sock, msg, len, flags);
else
err = -EPROTOTYPE;