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| author | Eric Dumazet <edumazet@google.com> | 2013-05-09 14:28:16 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-05-12 03:26:38 +0400 |
| commit | f77d602124d865c38705df7fa25c03de9c284ad2 (patch) | |
| tree | 173c11c4c8bfe13a891dcee6bf546c2bc4c9ed76 /net/ipv6/udp.c | |
| parent | 233c7df0821c4190e2d3f4be0f2ca0ab40a5ed8c (diff) | |
| download | linux-f77d602124d865c38705df7fa25c03de9c284ad2.tar.xz | |
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 'net/ipv6/udp.c')
| -rw-r--r-- | net/ipv6/udp.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index d4defdd44937..42923b14dfa6 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -1432,6 +1432,17 @@ void udp6_proc_exit(struct net *net) { } #endif /* CONFIG_PROC_FS */ +void udp_v6_clear_sk(struct sock *sk, int size) +{ + struct inet_sock *inet = inet_sk(sk); + + /* we do not want to clear pinet6 field, because of RCU lookups */ + sk_prot_clear_portaddr_nulls(sk, offsetof(struct inet_sock, pinet6)); + + size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6); + memset(&inet->pinet6 + 1, 0, size); +} + /* ------------------------------------------------------------------------ */ struct proto udpv6_prot = { @@ -1462,7 +1473,7 @@ struct proto udpv6_prot = { .compat_setsockopt = compat_udpv6_setsockopt, .compat_getsockopt = compat_udpv6_getsockopt, #endif - .clear_sk = sk_prot_clear_portaddr_nulls, + .clear_sk = udp_v6_clear_sk, }; static struct inet_protosw udpv6_protosw = { |