bpf: Don't refcount LISTEN sockets in sk_assign()
[ upstream commit 7ae215d23c12a939005f35d1848ca55b6109b9c0 ]
Avoid taking a reference on listen sockets by checking the socket type
in the sk_assign and in the corresponding skb_steal_sock() code in the
the transport layer, and by ensuring that the prefetch free (sock_pfree)
function uses the same logic to check whether the socket is refcounted.
BUG=b/171890773,b/177547417
TEST=compile
SOURCE=UPSTREAM(7ae215d23c12a939005f35d1848ca55b6109b9c0)
RELEASE_NOTE=Added support for the bpf_get_netns_cookie eBPF helper.
cos-patch: lts-refresh
Suggested-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200329225342.16317-4-joe@wand.net.nz
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Change-Id: Ifdd4581c618d137c6895833cbc11d923dd573a88
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/8211
Reviewed-by: Roy Yang <royyang@google.com>
Tested-by: Roy Yang <royyang@google.com>
(cherry picked from commit 7cd0bb51c646d420133435f1d8cc092c55ed002c)
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/10635
Main-Branch-Verified: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
diff --git a/include/net/sock.h b/include/net/sock.h
index 8e4096b..91179f6 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2495,6 +2495,21 @@
#endif /* CONFIG_INET */
}
+/* This helper checks if a socket is a full socket,
+ * ie _not_ a timewait or request socket.
+ */
+static inline bool sk_fullsock(const struct sock *sk)
+{
+ return (1 << sk->sk_state) & ~(TCPF_TIME_WAIT | TCPF_NEW_SYN_RECV);
+}
+
+static inline bool
+sk_is_refcounted(struct sock *sk)
+{
+ /* Only full sockets have sk->sk_flags. */
+ return !sk_fullsock(sk) || !sock_flag(sk, SOCK_RCU_FREE);
+}
+
/**
* skb_steal_sock
* @skb to steal the socket from
@@ -2507,6 +2522,8 @@
struct sock *sk = skb->sk;
*refcounted = true;
+ if (skb_sk_is_prefetched(skb))
+ *refcounted = sk_is_refcounted(sk);
skb->destructor = NULL;
skb->sk = NULL;
return sk;
@@ -2515,14 +2532,6 @@
return NULL;
}
-/* This helper checks if a socket is a full socket,
- * ie _not_ a timewait or request socket.
- */
-static inline bool sk_fullsock(const struct sock *sk)
-{
- return (1 << sk->sk_state) & ~(TCPF_TIME_WAIT | TCPF_NEW_SYN_RECV);
-}
-
/* Checks if this SKB belongs to an HW offloaded socket
* and whether any SW fallbacks are required based on dev.
* Check decrypted mark in case skb_orphan() cleared socket.
diff --git a/net/core/filter.c b/net/core/filter.c
index 5de9440..4435ba3 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5472,8 +5472,7 @@
BPF_CALL_1(bpf_sk_release, struct sock *, sk)
{
- /* Only full sockets have sk->sk_flags. */
- if (!sk_fullsock(sk) || !sock_flag(sk, SOCK_RCU_FREE))
+ if (sk_is_refcounted(sk))
sock_gen_put(sk);
return 0;
}
@@ -6003,7 +6002,8 @@
return -ENETUNREACH;
if (unlikely(sk_fullsock(sk) && sk->sk_reuseport))
return -ESOCKTNOSUPPORT;
- if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
+ if (sk_is_refcounted(sk) &&
+ unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
return -ENOENT;
skb_orphan(skb);
diff --git a/net/core/sock.c b/net/core/sock.c
index 11b96b3..9df7db3 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2068,7 +2068,8 @@
#ifdef CONFIG_INET
void sock_pfree(struct sk_buff *skb)
{
- sock_gen_put(skb->sk);
+ if (sk_is_refcounted(skb->sk))
+ sock_gen_put(skb->sk);
}
EXPORT_SYMBOL(sock_pfree);
#endif /* CONFIG_INET */
