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authorSteffen Klassert <steffen.klassert@secunet.com>2021-07-18 09:11:06 +0200
committerSteffen Klassert <steffen.klassert@secunet.com>2021-07-21 09:49:19 +0200
commit2d151d39073aff498358543801fca0f670fea981 (patch)
tree76abb9648c571bb6fc5ccb5d7c25f000e22c1273 /net
parentf8fdadef92b7a39e9a9a83bc2df68731ac6c298b (diff)
xfrm: Add possibility to set the default to block if we have no policy
As the default we assume the traffic to pass, if we have no matching IPsec policy. With this patch, we have a possibility to change this default from allow to block. It can be configured via netlink. Each direction (input/output/forward) can be configured separately. With the default to block configuered, we need allow policies for all packet flows we accept. We do not use default policy lookup for the loopback device. v1->v2 - fix compiling when XFRM is disabled - Reported-by: kernel test robot <lkp@intel.com> Co-developed-by: Christian Langrock <christian.langrock@secunet.com> Signed-off-by: Christian Langrock <christian.langrock@secunet.com> Co-developed-by: Antony Antony <antony.antony@secunet.com> Signed-off-by: Antony Antony <antony.antony@secunet.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Diffstat (limited to 'net')
-rw-r--r--net/xfrm/xfrm_policy.c16
-rw-r--r--net/xfrm/xfrm_user.c52
2 files changed, 68 insertions, 0 deletions
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 827d84255021..d5cb082e11fc 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -3165,6 +3165,11 @@ ok:
return dst;
nopol:
+ if (!(dst_orig->dev->flags & IFF_LOOPBACK) &&
+ !xfrm_default_allow(net, dir)) {
+ err = -EPERM;
+ goto error;
+ }
if (!(flags & XFRM_LOOKUP_ICMP)) {
dst = dst_orig;
goto ok;
@@ -3553,6 +3558,11 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
}
if (!pol) {
+ if (!xfrm_default_allow(net, dir)) {
+ XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOPOLS);
+ return 0;
+ }
+
if (sp && secpath_has_nontransport(sp, 0, &xerr_idx)) {
xfrm_secpath_reject(xerr_idx, skb, &fl);
XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOPOLS);
@@ -3607,6 +3617,12 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
tpp[ti++] = &pols[pi]->xfrm_vec[i];
}
xfrm_nr = ti;
+
+ if (!xfrm_default_allow(net, dir) && !xfrm_nr) {
+ XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
+ goto reject;
+ }
+
if (npols > 1) {
xfrm_tmpl_sort(stp, tpp, xfrm_nr, family);
tpp = stp;
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index b47d613409b7..4eafd1130c3e 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1961,6 +1961,54 @@ static struct sk_buff *xfrm_policy_netlink(struct sk_buff *in_skb,
return skb;
}
+static int xfrm_set_default(struct sk_buff *skb, struct nlmsghdr *nlh,
+ struct nlattr **attrs)
+{
+ struct net *net = sock_net(skb->sk);
+ struct xfrm_userpolicy_default *up = nlmsg_data(nlh);
+ u8 dirmask = (1 << up->dirmask) & XFRM_POL_DEFAULT_MASK;
+ u8 old_default = net->xfrm.policy_default;
+
+ net->xfrm.policy_default = (old_default & (0xff ^ dirmask))
+ | (up->action << up->dirmask);
+
+ rt_genid_bump_all(net);
+
+ return 0;
+}
+
+static int xfrm_get_default(struct sk_buff *skb, struct nlmsghdr *nlh,
+ struct nlattr **attrs)
+{
+ struct sk_buff *r_skb;
+ struct nlmsghdr *r_nlh;
+ struct net *net = sock_net(skb->sk);
+ struct xfrm_userpolicy_default *r_up, *up;
+ int len = NLMSG_ALIGN(sizeof(struct xfrm_userpolicy_default));
+ u32 portid = NETLINK_CB(skb).portid;
+ u32 seq = nlh->nlmsg_seq;
+
+ up = nlmsg_data(nlh);
+
+ r_skb = nlmsg_new(len, GFP_ATOMIC);
+ if (!r_skb)
+ return -ENOMEM;
+
+ r_nlh = nlmsg_put(r_skb, portid, seq, XFRM_MSG_GETDEFAULT, sizeof(*r_up), 0);
+ if (!r_nlh) {
+ kfree_skb(r_skb);
+ return -EMSGSIZE;
+ }
+
+ r_up = nlmsg_data(r_nlh);
+
+ r_up->action = ((net->xfrm.policy_default & (1 << up->dirmask)) >> up->dirmask);
+ r_up->dirmask = up->dirmask;
+ nlmsg_end(r_skb, r_nlh);
+
+ return nlmsg_unicast(net->xfrm.nlsk, r_skb, portid);
+}
+
static int xfrm_get_policy(struct sk_buff *skb, struct nlmsghdr *nlh,
struct nlattr **attrs)
{
@@ -2664,6 +2712,8 @@ const int xfrm_msg_min[XFRM_NR_MSGTYPES] = {
[XFRM_MSG_GETSADINFO - XFRM_MSG_BASE] = sizeof(u32),
[XFRM_MSG_NEWSPDINFO - XFRM_MSG_BASE] = sizeof(u32),
[XFRM_MSG_GETSPDINFO - XFRM_MSG_BASE] = sizeof(u32),
+ [XFRM_MSG_SETDEFAULT - XFRM_MSG_BASE] = XMSGSIZE(xfrm_userpolicy_default),
+ [XFRM_MSG_GETDEFAULT - XFRM_MSG_BASE] = XMSGSIZE(xfrm_userpolicy_default),
};
EXPORT_SYMBOL_GPL(xfrm_msg_min);
@@ -2743,6 +2793,8 @@ static const struct xfrm_link {
.nla_pol = xfrma_spd_policy,
.nla_max = XFRMA_SPD_MAX },
[XFRM_MSG_GETSPDINFO - XFRM_MSG_BASE] = { .doit = xfrm_get_spdinfo },
+ [XFRM_MSG_SETDEFAULT - XFRM_MSG_BASE] = { .doit = xfrm_set_default },
+ [XFRM_MSG_GETDEFAULT - XFRM_MSG_BASE] = { .doit = xfrm_get_default },
};
static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,