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authorEyal Birger <eyal.birger@gmail.com>2022-05-13 23:34:02 +0300
committerSteffen Klassert <steffen.klassert@secunet.com>2022-05-16 10:31:26 +0300
commite6175a2ed1f18bf2f649625bf725e07adcfa6a28 (patch)
tree6b1e9cc11f5c66e9f71fcb9db966352317eff62c /include
parent79396934e289dbc501316c1d1f975bb4c88ae460 (diff)
downloadlinux-e6175a2ed1f18bf2f649625bf725e07adcfa6a28.tar.xz
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 <shmulik.ladkani@gmail.com> Signed-off-by: Eyal Birger <eyal.birger@gmail.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Diffstat (limited to 'include')
-rw-r--r--include/net/ip.h1
-rw-r--r--include/net/xfrm.h14
2 files changed, 14 insertions, 1 deletions
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);
}