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authorEric Dumazet <edumazet@google.com>2013-05-09 10:28:16 +0000
committerDavid S. Miller <davem@davemloft.net>2013-05-11 16:26:38 -0700
commitf77d602124d865c38705df7fa25c03de9c284ad2 (patch)
tree173c11c4c8bfe13a891dcee6bf546c2bc4c9ed76 /include/net
parent233c7df0821c4190e2d3f4be0f2ca0ab40a5ed8c (diff)
ipv6: do not clear pinet6 field
We have seen multiple NULL dereferences in __inet6_lookup_established() After analysis, I found that inet6_sk() could be NULL while the check for sk_family == AF_INET6 was true. Bug was added in linux-2.6.29 when RCU lookups were introduced in UDP and TCP stacks. Once an IPv6 socket, using SLAB_DESTROY_BY_RCU is inserted in a hash table, we no longer can clear pinet6 field. This patch extends logic used in commit fcbdf09d9652c891 ("net: fix nulls list corruptions in sk_prot_alloc") TCP/UDP/UDPLite IPv6 protocols provide their own .clear_sk() method to make sure we do not clear pinet6 field. At socket clone phase, we do not really care, as cloning the parent (non NULL) pinet6 is not adding a fatal race. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
-rw-r--r--include/net/sock.h12
1 files changed, 12 insertions, 0 deletions
diff --git a/include/net/sock.h b/include/net/sock.h
index 5c97b0fc562..66772cf8c3c 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -866,6 +866,18 @@ struct inet_hashinfo;
struct raw_hashinfo;
struct module;
+/*
+ * caches using SLAB_DESTROY_BY_RCU should let .next pointer from nulls nodes
+ * un-modified. Special care is taken when initializing object to zero.
+ */
+static inline void sk_prot_clear_nulls(struct sock *sk, int size)
+{
+ if (offsetof(struct sock, sk_node.next) != 0)
+ memset(sk, 0, offsetof(struct sock, sk_node.next));
+ memset(&sk->sk_node.pprev, 0,
+ size - offsetof(struct sock, sk_node.pprev));
+}
+
/* Networking protocol blocks we attach to sockets.
* socket layer -> transport layer interface
* transport -> network interface is defined by struct inet_proto