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authorJoe Stringer <joe@wand.net.nz>2020-03-29 15:53:40 -0700
committerAlexei Starovoitov <ast@kernel.org>2020-03-30 13:45:05 -0700
commit7ae215d23c12a939005f35d1848ca55b6109b9c0 (patch)
treebc88bf441433f5bf7a3d66610adb5d1ad1707390 /net
parent71489e21d720a09388b565d60ef87ae993c10528 (diff)
downloadlinux-7ae215d23c12a939005f35d1848ca55b6109b9c0.tar.bz2
bpf: Don't refcount LISTEN sockets in sk_assign()
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. 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
Diffstat (limited to 'net')
-rw-r--r--net/core/filter.c6
-rw-r--r--net/core/sock.c3
2 files changed, 5 insertions, 4 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index ac5c1633f8d2..7628b947dbc3 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5401,8 +5401,7 @@ static const struct bpf_func_proto bpf_sk_lookup_udp_proto = {
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;
}
@@ -5928,7 +5927,8 @@ BPF_CALL_3(bpf_sk_assign, struct sk_buff *, skb, struct sock *, sk, u64, flags)
return -ENETUNREACH;
if (unlikely(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 87e3a03c9056..da32d9b6d09f 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2077,7 +2077,8 @@ EXPORT_SYMBOL(sock_efree);
#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 */