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| author | Eric Dumazet <edumazet@google.com> | 2013-05-09 10:28:16 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-05-19 10:04:46 -0700 |
| commit | 1e74f2ea952f201c5ee5edce74daab21aea89b31 (patch) | |
| tree | aa499b1a35551e34fa1f169bb75ef375428ae2cb /include | |
| parent | d5bf240fa193989d605a715bda7cb3283b1abc89 (diff) | |
| download | lwn-1e74f2ea952f201c5ee5edce74daab21aea89b31.tar.gz lwn-1e74f2ea952f201c5ee5edce74daab21aea89b31.zip | |
ipv6: do not clear pinet6 field
[ Upstream commit f77d602124d865c38705df7fa25c03de9c284ad2 ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/net/sock.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index b2deeab84c9b..b6abd4ff6b1e 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -721,6 +721,18 @@ struct timewait_sock_ops; struct inet_hashinfo; struct raw_hashinfo; +/* + * 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 |