From 7b34ca2ac7063f4ebf07f85fd75253ed84d5c648 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Mon, 11 Jun 2012 04:13:57 -0700 Subject: [PATCH] inet: Avoid potential NULL peer dereference. We handle NULL in rt{,6}_set_peer but then our caller will try to pass that NULL pointer into inet_putpeer() which isn't ready for it. Fix this by moving the NULL check one level up, and then remove the now unnecessary NULL check from inetpeer_ptr_set_peer(). Reported-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/inetpeer.h | 2 +- net/ipv4/route.c | 11 ++++++----- net/ipv6/route.c | 10 ++++++---- 3 files changed, 13 insertions(+), 10 deletions(-) diff --git a/include/net/inetpeer.h b/include/net/inetpeer.h index e15c0862a686..c27c8f10ebdc 100644 --- a/include/net/inetpeer.h +++ b/include/net/inetpeer.h @@ -104,7 +104,7 @@ static inline bool inetpeer_ptr_set_peer(unsigned long *ptr, struct inet_peer *p unsigned long val = (unsigned long) peer; unsigned long orig = *ptr; - if (!(orig & INETPEER_BASE_BIT) || !val || + if (!(orig & INETPEER_BASE_BIT) || cmpxchg(ptr, orig, val) != orig) return false; return true; diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 4c33ce3000ed..842510d50453 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1333,11 +1333,12 @@ void rt_bind_peer(struct rtable *rt, __be32 daddr, int create) return; peer = inet_getpeer_v4(base, daddr, create); - - if (!rt_set_peer(rt, peer)) - inet_putpeer(peer); - else - rt->rt_peer_genid = rt_peer_genid(); + if (peer) { + if (!rt_set_peer(rt, peer)) + inet_putpeer(peer); + else + rt->rt_peer_genid = rt_peer_genid(); + } } /* diff --git a/net/ipv6/route.c b/net/ipv6/route.c index d9ba4808f26a..58a3ec23da2f 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -313,10 +313,12 @@ void rt6_bind_peer(struct rt6_info *rt, int create) return; peer = inet_getpeer_v6(base, &rt->rt6i_dst.addr, create); - if (!rt6_set_peer(rt, peer)) - inet_putpeer(peer); - else - rt->rt6i_peer_genid = rt6_peer_genid(); + if (peer) { + if (!rt6_set_peer(rt, peer)) + inet_putpeer(peer); + else + rt->rt6i_peer_genid = rt6_peer_genid(); + } } static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev, -- 2.20.1