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| author | Paolo Abeni <pabeni@redhat.com> | 2019-02-21 17:43:59 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-02-22 16:05:11 -0800 |
| commit | 424a7cd078401591fc45587ffb2c012d7f402fb7 (patch) | |
| tree | 346f6616db687c22ad228fb260b4e6e47053e9e3 | |
| parent | 5de362df44d71fc8f6b153ae4eaa2a1284c84490 (diff) | |
| download | linux-424a7cd078401591fc45587ffb2c012d7f402fb7.tar.gz linux-424a7cd078401591fc45587ffb2c012d7f402fb7.tar.bz2 linux-424a7cd078401591fc45587ffb2c012d7f402fb7.zip | |
udpv6: fix possible user after free in error handler
Before derefencing the encap pointer, commit e7cc082455cb ("udp: Support
for error handlers of tunnels with arbitrary destination port") checks
for a NULL value, but the two fetch operation can race with removal.
Fix the above using a single access.
Also fix a couple of type annotations, to make sparse happy.
Fixes: e7cc082455cb ("udp: Support for error handlers of tunnels with arbitrary destination port")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv6/udp.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index e6c52c27f354..b444483cdb2b 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -420,17 +420,19 @@ EXPORT_SYMBOL(udpv6_encap_enable); */ static int __udp6_lib_err_encap_no_sk(struct sk_buff *skb, struct inet6_skb_parm *opt, - u8 type, u8 code, int offset, u32 info) + u8 type, u8 code, int offset, __be32 info) { int i; for (i = 0; i < MAX_IPTUN_ENCAP_OPS; i++) { int (*handler)(struct sk_buff *skb, struct inet6_skb_parm *opt, - u8 type, u8 code, int offset, u32 info); + u8 type, u8 code, int offset, __be32 info); + const struct ip6_tnl_encap_ops *encap; - if (!ip6tun_encaps[i]) + encap = rcu_dereference(ip6tun_encaps[i]); + if (!encap) continue; - handler = rcu_dereference(ip6tun_encaps[i]->err_handler); + handler = encap->err_handler; if (handler && !handler(skb, opt, type, code, offset, info)) return 0; } |