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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 /net/ipv4/route.c
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 'net/ipv4/route.c')
-rw-r--r--net/ipv4/route.c23
1 files changed, 18 insertions, 5 deletions
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 98c6f3429593..fe5d14ef5c4d 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1726,6 +1726,7 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
struct in_device *in_dev = __in_dev_get_rcu(dev);
unsigned int flags = RTCF_MULTICAST;
struct rtable *rth;
+ bool no_policy;
u32 itag = 0;
int err;
@@ -1736,8 +1737,12 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
if (our)
flags |= RTCF_LOCAL;
+ no_policy = IN_DEV_ORCONF(in_dev, NOPOLICY);
+ if (no_policy)
+ IPCB(skb)->flags |= IPSKB_NOPOLICY;
+
rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
- IN_DEV_ORCONF(in_dev, NOPOLICY), false);
+ no_policy, false);
if (!rth)
return -ENOBUFS;
@@ -1795,7 +1800,7 @@ static int __mkroute_input(struct sk_buff *skb,
struct rtable *rth;
int err;
struct in_device *out_dev;
- bool do_cache;
+ bool do_cache, no_policy;
u32 itag = 0;
/* get a working reference to the output device */
@@ -1840,6 +1845,10 @@ static int __mkroute_input(struct sk_buff *skb,
}
}
+ no_policy = IN_DEV_ORCONF(in_dev, NOPOLICY);
+ if (no_policy)
+ IPCB(skb)->flags |= IPSKB_NOPOLICY;
+
fnhe = find_exception(nhc, daddr);
if (do_cache) {
if (fnhe)
@@ -1852,8 +1861,7 @@ static int __mkroute_input(struct sk_buff *skb,
}
}
- rth = rt_dst_alloc(out_dev->dev, 0, res->type,
- IN_DEV_ORCONF(in_dev, NOPOLICY),
+ rth = rt_dst_alloc(out_dev->dev, 0, res->type, no_policy,
IN_DEV_ORCONF(out_dev, NOXFRM));
if (!rth) {
err = -ENOBUFS;
@@ -2228,6 +2236,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
struct rtable *rth;
struct flowi4 fl4;
bool do_cache = true;
+ bool no_policy;
/* IP on this device is disabled. */
@@ -2346,6 +2355,10 @@ brd_input:
RT_CACHE_STAT_INC(in_brd);
local_input:
+ no_policy = IN_DEV_ORCONF(in_dev, NOPOLICY);
+ if (no_policy)
+ IPCB(skb)->flags |= IPSKB_NOPOLICY;
+
do_cache &= res->fi && !itag;
if (do_cache) {
struct fib_nh_common *nhc = FIB_RES_NHC(*res);
@@ -2360,7 +2373,7 @@ local_input:
rth = rt_dst_alloc(ip_rt_get_dev(net, res),
flags | RTCF_LOCAL, res->type,
- IN_DEV_ORCONF(in_dev, NOPOLICY), false);
+ no_policy, false);
if (!rth)
goto e_nobufs;