diff options
| author | Eric Dumazet <edumazet@google.com> | 2015-11-05 13:39:24 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-11-05 16:45:51 -0500 |
| commit | 212cd0895330b775f2db49451f046a5ca4e5704b (patch) | |
| tree | c4f9be4c046587df4fad72299a5888096153f4c9 /security | |
| parent | 432599d7a7062ad7e37e72601607dc35596afe40 (diff) | |
| download | lwn-212cd0895330b775f2db49451f046a5ca4e5704b.tar.gz lwn-212cd0895330b775f2db49451f046a5ca4e5704b.zip | |
selinux: fix random read in selinux_ip_postroute_compat()
In commit e446f9dfe17b ("net: synack packets can be attached to request
sockets"), I missed one remaining case of invalid skb->sk->sk_security
access.
Dmitry Vyukov got a KASan report pointing to it.
Add selinux_skb_sk() helper that is responsible to get back to the
listener if skb is attached to a request socket, instead of
duplicating the logic.
Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'security')
| -rw-r--r-- | security/selinux/hooks.c | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 26f4039d54b8..c9b2d5467477 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -4931,11 +4931,23 @@ static unsigned int selinux_ipv4_output(void *priv, return selinux_ip_output(skb, PF_INET); } +/* SYNACK messages might be attached to request sockets. + * To get back to sk_security, we need to look at the listener. + */ +static struct sock *selinux_skb_sk(const struct sk_buff *skb) +{ + struct sock *sk = skb->sk; + + if (sk && sk->sk_state == TCP_NEW_SYN_RECV) + sk = inet_reqsk(sk)->rsk_listener; + return sk; +} + static unsigned int selinux_ip_postroute_compat(struct sk_buff *skb, int ifindex, u16 family) { - struct sock *sk = skb->sk; + struct sock *sk = selinux_skb_sk(skb); struct sk_security_struct *sksec; struct common_audit_data ad; struct lsm_network_audit net = {0,}; @@ -4990,7 +5002,7 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb, if (!secmark_active && !peerlbl_active) return NF_ACCEPT; - sk = skb->sk; + sk = selinux_skb_sk(skb); #ifdef CONFIG_XFRM /* If skb->dst->xfrm is non-NULL then the packet is undergoing an IPsec @@ -5035,8 +5047,6 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb, u32 skb_sid; struct sk_security_struct *sksec; - if (sk->sk_state == TCP_NEW_SYN_RECV) - sk = inet_reqsk(sk)->rsk_listener; sksec = sk->sk_security; if (selinux_skb_peerlbl_sid(skb, family, &skb_sid)) return NF_DROP; |