From e6175a2ed1f18bf2f649625bf725e07adcfa6a28 Mon Sep 17 00:00:00 2001 From: Eyal Birger Date: Fri, 13 May 2022 23:34:02 +0300 Subject: xfrm: fix "disable_policy" flag use when arriving from different devices In IPv4 setting the "disable_policy" flag on a device means no policy should be enforced for traffic originating from the device. This was implemented by seting the DST_NOPOLICY flag in the dst based on the originating device. However, dsts are cached in nexthops regardless of the originating devices, in which case, the DST_NOPOLICY flag value may be incorrect. Consider the following setup: +------------------------------+ | ROUTER | +-------------+ | +-----------------+ | | ipsec src |----|-|ipsec0 | | +-------------+ | |disable_policy=0 | +----+ | | +-----------------+ |eth1|-|----- +-------------+ | +-----------------+ +----+ | | noipsec src |----|-|eth0 | | +-------------+ | |disable_policy=1 | | | +-----------------+ | +------------------------------+ Where ROUTER has a default route towards eth1. dst entries for traffic arriving from eth0 would have DST_NOPOLICY and would be cached and therefore can be reused by traffic originating from ipsec0, skipping policy check. Fix by setting a IPSKB_NOPOLICY flag in IPCB and observing it instead of the DST in IN/FWD IPv4 policy checks. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Shmulik Ladkani Signed-off-by: Eyal Birger Signed-off-by: Steffen Klassert --- include/net/ip.h | 1 + include/net/xfrm.h | 14 +++++++++++++- 2 files changed, 14 insertions(+), 1 deletion(-) (limited to 'include/net') diff --git a/include/net/ip.h b/include/net/ip.h index 3984f2c39c4b..0161137914cf 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -56,6 +56,7 @@ struct inet_skb_parm { #define IPSKB_DOREDIRECT BIT(5) #define IPSKB_FRAG_PMTU BIT(6) #define IPSKB_L3SLAVE BIT(7) +#define IPSKB_NOPOLICY BIT(8) u16 frag_max_size; }; diff --git a/include/net/xfrm.h b/include/net/xfrm.h index 6fb899ff5afc..d2efddce65d4 100644 --- a/include/net/xfrm.h +++ b/include/net/xfrm.h @@ -1093,6 +1093,18 @@ static inline bool __xfrm_check_nopolicy(struct net *net, struct sk_buff *skb, return false; } +static inline bool __xfrm_check_dev_nopolicy(struct sk_buff *skb, + int dir, unsigned short family) +{ + if (dir != XFRM_POLICY_OUT && family == AF_INET) { + /* same dst may be used for traffic originating from + * devices with different policy settings. + */ + return IPCB(skb)->flags & IPSKB_NOPOLICY; + } + return skb_dst(skb) && (skb_dst(skb)->flags & DST_NOPOLICY); +} + static inline int __xfrm_policy_check2(struct sock *sk, int dir, struct sk_buff *skb, unsigned int family, int reverse) @@ -1104,7 +1116,7 @@ static inline int __xfrm_policy_check2(struct sock *sk, int dir, return __xfrm_policy_check(sk, ndir, skb, family); return __xfrm_check_nopolicy(net, skb, dir) || - (skb_dst(skb) && (skb_dst(skb)->flags & DST_NOPOLICY)) || + __xfrm_check_dev_nopolicy(skb, dir, family) || __xfrm_policy_check(sk, ndir, skb, family); } -- cgit v1.2.3