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…t/klassert/ipsec

Steffen Klassert says:

====================
pull request (net): ipsec 2014-09-22

We generate a blackhole or queueing route if a packet
matches an IPsec policy but a state can't be resolved.
Here we assume that dst_output() is called to kill
these packets. Unfortunately this assumption is not
true in all cases, so it is possible that these packets
leave the system without the necessary transformations.

This pull request contains two patches to fix this issue:

1) Fix for blackhole routed packets.

2) Fix for queue routed packets.

Both patches are serious stable candidates.

Please pull or let me know if there are problems.
====================

Signed-off-by: David S. Miller <[email protected]>
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@davem330
davem330 committed Sep 22, 2014
2 parents 09f3756 + b8c203b commit 84de67b
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Showing 4 changed files with 60 additions and 14 deletions.
16 changes: 15 additions & 1 deletion include/net/dst.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -480,6 +480,7 @@ void dst_init(void);
/* Flags for xfrm_lookup flags argument. */
enum {
XFRM_LOOKUP_ICMP = 1 << 0,
XFRM_LOOKUP_QUEUE = 1 << 1,
};

struct flowi;
Expand All @@ -490,7 +491,16 @@ static inline struct dst_entry *xfrm_lookup(struct net *net,
int flags)
{
return dst_orig;
}
}

static inline struct dst_entry *xfrm_lookup_route(struct net *net,
struct dst_entry *dst_orig,
const struct flowi *fl,
struct sock *sk,
int flags)
{
return dst_orig;
}

static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
{
Expand All @@ -502,6 +512,10 @@ struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
const struct flowi *fl, struct sock *sk,
int flags);

struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig,
const struct flowi *fl, struct sock *sk,
int flags);

/* skb attached with this dst needs transformation if dst->xfrm is valid */
static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
{
Expand Down
6 changes: 3 additions & 3 deletions net/ipv4/route.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2265,9 +2265,9 @@ struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
return rt;

if (flp4->flowi4_proto)
rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
flowi4_to_flowi(flp4),
sk, 0);
rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
flowi4_to_flowi(flp4),
sk, 0);

return rt;
}
Expand Down
4 changes: 2 additions & 2 deletions net/ipv6/ip6_output.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1009,7 +1009,7 @@ struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
if (final_dst)
fl6->daddr = *final_dst;

return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
}
EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);

Expand Down Expand Up @@ -1041,7 +1041,7 @@ struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
if (final_dst)
fl6->daddr = *final_dst;

return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
}
EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);

Expand Down
48 changes: 40 additions & 8 deletions net/xfrm/xfrm_policy.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,11 @@
#define XFRM_QUEUE_TMO_MAX ((unsigned)(60*HZ))
#define XFRM_MAX_QUEUE_LEN 100

struct xfrm_flo {
struct dst_entry *dst_orig;
u8 flags;
};

static DEFINE_SPINLOCK(xfrm_policy_afinfo_lock);
static struct xfrm_policy_afinfo __rcu *xfrm_policy_afinfo[NPROTO]
__read_mostly;
Expand Down Expand Up @@ -1877,23 +1882,27 @@ static int xdst_queue_output(struct sock *sk, struct sk_buff *skb)
}

static struct xfrm_dst *xfrm_create_dummy_bundle(struct net *net,
struct dst_entry *dst,
struct xfrm_flo *xflo,
const struct flowi *fl,
int num_xfrms,
u16 family)
{
int err;
struct net_device *dev;
struct dst_entry *dst;
struct dst_entry *dst1;
struct xfrm_dst *xdst;

xdst = xfrm_alloc_dst(net, family);
if (IS_ERR(xdst))
return xdst;

if (net->xfrm.sysctl_larval_drop || num_xfrms <= 0)
if (!(xflo->flags & XFRM_LOOKUP_QUEUE) ||
net->xfrm.sysctl_larval_drop ||
num_xfrms <= 0)
return xdst;

dst = xflo->dst_orig;
dst1 = &xdst->u.dst;
dst_hold(dst);
xdst->route = dst;
Expand Down Expand Up @@ -1935,7 +1944,7 @@ static struct flow_cache_object *
xfrm_bundle_lookup(struct net *net, const struct flowi *fl, u16 family, u8 dir,
struct flow_cache_object *oldflo, void *ctx)
{
struct dst_entry *dst_orig = (struct dst_entry *)ctx;
struct xfrm_flo *xflo = (struct xfrm_flo *)ctx;
struct xfrm_policy *pols[XFRM_POLICY_TYPE_MAX];
struct xfrm_dst *xdst, *new_xdst;
int num_pols = 0, num_xfrms = 0, i, err, pol_dead;
Expand Down Expand Up @@ -1976,7 +1985,8 @@ xfrm_bundle_lookup(struct net *net, const struct flowi *fl, u16 family, u8 dir,
goto make_dummy_bundle;
}

new_xdst = xfrm_resolve_and_create_bundle(pols, num_pols, fl, family, dst_orig);
new_xdst = xfrm_resolve_and_create_bundle(pols, num_pols, fl, family,
xflo->dst_orig);
if (IS_ERR(new_xdst)) {
err = PTR_ERR(new_xdst);
if (err != -EAGAIN)
Expand Down Expand Up @@ -2010,7 +2020,7 @@ xfrm_bundle_lookup(struct net *net, const struct flowi *fl, u16 family, u8 dir,
/* We found policies, but there's no bundles to instantiate:
* either because the policy blocks, has no transformations or
* we could not build template (no xfrm_states).*/
xdst = xfrm_create_dummy_bundle(net, dst_orig, fl, num_xfrms, family);
xdst = xfrm_create_dummy_bundle(net, xflo, fl, num_xfrms, family);
if (IS_ERR(xdst)) {
xfrm_pols_put(pols, num_pols);
return ERR_CAST(xdst);
Expand Down Expand Up @@ -2104,13 +2114,18 @@ struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
}

if (xdst == NULL) {
struct xfrm_flo xflo;

xflo.dst_orig = dst_orig;
xflo.flags = flags;

/* To accelerate a bit... */
if ((dst_orig->flags & DST_NOXFRM) ||
!net->xfrm.policy_count[XFRM_POLICY_OUT])
goto nopol;

flo = flow_cache_lookup(net, fl, family, dir,
xfrm_bundle_lookup, dst_orig);
xfrm_bundle_lookup, &xflo);
if (flo == NULL)
goto nopol;
if (IS_ERR(flo)) {
Expand Down Expand Up @@ -2138,7 +2153,7 @@ struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
xfrm_pols_put(pols, drop_pols);
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTNOSTATES);

return make_blackhole(net, family, dst_orig);
return ERR_PTR(-EREMOTE);
}

err = -EAGAIN;
Expand Down Expand Up @@ -2195,6 +2210,23 @@ struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
}
EXPORT_SYMBOL(xfrm_lookup);

/* Callers of xfrm_lookup_route() must ensure a call to dst_output().
* Otherwise we may send out blackholed packets.
*/
struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig,
const struct flowi *fl,
struct sock *sk, int flags)
{
struct dst_entry *dst = xfrm_lookup(net, dst_orig, fl, sk,
flags | XFRM_LOOKUP_QUEUE);

if (IS_ERR(dst) && PTR_ERR(dst) == -EREMOTE)
return make_blackhole(net, dst_orig->ops->family, dst_orig);

return dst;
}
EXPORT_SYMBOL(xfrm_lookup_route);

static inline int
xfrm_secpath_reject(int idx, struct sk_buff *skb, const struct flowi *fl)
{
Expand Down Expand Up @@ -2460,7 +2492,7 @@ int __xfrm_route_forward(struct sk_buff *skb, unsigned short family)

skb_dst_force(skb);

dst = xfrm_lookup(net, skb_dst(skb), &fl, NULL, 0);
dst = xfrm_lookup(net, skb_dst(skb), &fl, NULL, XFRM_LOOKUP_QUEUE);
if (IS_ERR(dst)) {
res = 0;
dst = NULL;
Expand Down

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