net: convert sock.sk_refcnt from atomic_t to refcount_t
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
This patch uses refcount_inc_not_zero() instead of
atomic_inc_not_zero_hint() due to absense of a _hint()
version of refcount API. If the hint() version must
be used, we might need to revisit API.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 86fad2a..25294d4 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -577,7 +577,7 @@ struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
sk = __udp4_lib_lookup(net, saddr, sport, daddr, dport,
dif, &udp_table, NULL);
- if (sk && !atomic_inc_not_zero(&sk->sk_refcnt))
+ if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
sk = NULL;
return sk;
}
@@ -2242,7 +2242,7 @@ void udp_v4_early_demux(struct sk_buff *skb)
uh->source, iph->saddr, dif);
}
- if (!sk || !atomic_inc_not_zero_hint(&sk->sk_refcnt, 2))
+ if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt))
return;
skb->sk = sk;
@@ -2691,7 +2691,7 @@ static void udp4_format_sock(struct sock *sp, struct seq_file *f,
0, 0L, 0,
from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
0, sock_i_ino(sp),
- atomic_read(&sp->sk_refcnt), sp,
+ refcount_read(&sp->sk_refcnt), sp,
atomic_read(&sp->sk_drops));
}