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authorBenjamin Hesmans2021-09-03 15:23:35 +0200
committerPablo Neira Ayuso2021-09-03 18:25:31 +0200
commit730affed24bffcd1eebd5903171960f5ff9f1f22 (patch)
tree058c69fd129cb1588773c62a58a4d4e2e60f9974
parentd7e7747ac5c2496c98291944c6066adaa9f3b975 (diff)
netfilter: socket: icmp6: fix use-after-scope
Bug reported by KASAN: BUG: KASAN: use-after-scope in inet6_ehashfn (net/ipv6/inet6_hashtables.c:40) Call Trace: (...) inet6_ehashfn (net/ipv6/inet6_hashtables.c:40) (...) nf_sk_lookup_slow_v6 (net/ipv6/netfilter/nf_socket_ipv6.c:91 net/ipv6/netfilter/nf_socket_ipv6.c:146) It seems that this bug has already been fixed by Eric Dumazet in the past in: commit 78296c97ca1f ("netfilter: xt_socket: fix a stack corruption bug") But a variant of the same issue has been introduced in commit d64d80a2cde9 ("netfilter: x_tables: don't extract flow keys on early demuxed sks in socket match") `daddr` and `saddr` potentially hold a reference to ipv6_var that is no longer in scope when the call to `nf_socket_get_sock_v6` is made. Fixes: d64d80a2cde9 ("netfilter: x_tables: don't extract flow keys on early demuxed sks in socket match") Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Benjamin Hesmans <benjamin.hesmans@tessares.net> Reviewed-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
-rw-r--r--net/ipv6/netfilter/nf_socket_ipv6.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/net/ipv6/netfilter/nf_socket_ipv6.c b/net/ipv6/netfilter/nf_socket_ipv6.c
index 6fd54744cbc3..aa5bb8789ba0 100644
--- a/net/ipv6/netfilter/nf_socket_ipv6.c
+++ b/net/ipv6/netfilter/nf_socket_ipv6.c
@@ -99,7 +99,7 @@ struct sock *nf_sk_lookup_slow_v6(struct net *net, const struct sk_buff *skb,
{
__be16 dport, sport;
const struct in6_addr *daddr = NULL, *saddr = NULL;
- struct ipv6hdr *iph = ipv6_hdr(skb);
+ struct ipv6hdr *iph = ipv6_hdr(skb), ipv6_var;
struct sk_buff *data_skb = NULL;
int doff = 0;
int thoff = 0, tproto;
@@ -129,8 +129,6 @@ struct sock *nf_sk_lookup_slow_v6(struct net *net, const struct sk_buff *skb,
thoff + sizeof(*hp);
} else if (tproto == IPPROTO_ICMPV6) {
- struct ipv6hdr ipv6_var;
-
if (extract_icmp6_fields(skb, thoff, &tproto, &saddr, &daddr,
&sport, &dport, &ipv6_var))
return NULL;