[PATCH 5.17 082/158] xfrm: rework default policy structure

Greg Kroah-Hartman
2022-05-23T18:03:09Z

From: Nicolas Dichtel <nicolas.dichtel@6wind.com>

[ Upstream commit b58b1f563ab78955d37e9e43e02790a85c66ac05 ]

This is a follow up of commit f8d858e607b2 ("xfrm: make user policy API
complete"). The goal is to align userland API to the internal structures.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/net/netns/xfrm.h | 6 +----
include/net/xfrm.h | 48 +++++++++++++++-------------------------
net/xfrm/xfrm_policy.c | 10 ++++++---
net/xfrm/xfrm_user.c | 43 +++++++++++++++--------------------
4 files changed, 44 insertions(+), 63 deletions(-)

diff --git a/include/net/netns/xfrm.h b/include/net/netns/xfrm.h
index 947733a639a6..bd7c3be4af5d 100644
--- a/include/net/netns/xfrm.h
+++ b/include/net/netns/xfrm.h
@@ -66,11 +66,7 @@ struct netns_xfrm {
int sysctl_larval_drop;
u32 sysctl_acq_expires;

- u8 policy_default;
-#define XFRM_POL_DEFAULT_IN 1
-#define XFRM_POL_DEFAULT_OUT 2
-#define XFRM_POL_DEFAULT_FWD 4
-#define XFRM_POL_DEFAULT_MASK 7
+ u8 policy_default[XFRM_POLICY_MAX];

#ifdef CONFIG_SYSCTL
struct ctl_table_header *sysctl_hdr;
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 76aa6f11a540..6fb899ff5afc 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1081,25 +1081,18 @@ xfrm_state_addr_cmp(const struct xfrm_tmpl *tmpl, const struct xfrm_state *x, un
}

#ifdef CONFIG_XFRM
-static inline bool
-xfrm_default_allow(struct net *net, int dir)
-{
- u8 def = net->xfrm.policy_default;
-
- switch (dir) {
- case XFRM_POLICY_IN:
- return def & XFRM_POL_DEFAULT_IN ? false : true;
- case XFRM_POLICY_OUT:
- return def & XFRM_POL_DEFAULT_OUT ? false : true;
- case XFRM_POLICY_FWD:
- return def & XFRM_POL_DEFAULT_FWD ? false : true;
- }
- return false;
-}
-
int __xfrm_policy_check(struct sock *, int dir, struct sk_buff *skb,
unsigned short family);

+static inline bool __xfrm_check_nopolicy(struct net *net, struct sk_buff *skb,
+ int dir)
+{
+ if (!net->xfrm.policy_count[dir] && !secpath_exists(skb))
+ return net->xfrm.policy_default[dir] == XFRM_USERPOLICY_ACCEPT;
+
+ return false;
+}
+
static inline int __xfrm_policy_check2(struct sock *sk, int dir,
struct sk_buff *skb,
unsigned int family, int reverse)
@@ -1110,13 +1103,9 @@ static inline int __xfrm_policy_check2(struct sock *sk, int dir,
if (sk && sk->sk_policy[XFRM_POLICY_IN])
return __xfrm_policy_check(sk, ndir, skb, family);

- if (xfrm_default_allow(net, dir))
- return (!net->xfrm.policy_count[dir] && !secpath_exists(skb)) ||
- (skb_dst(skb) && (skb_dst(skb)->flags & DST_NOPOLICY)) ||
- __xfrm_policy_check(sk, ndir, skb, family);
- else
- return (skb_dst(skb) && (skb_dst(skb)->flags & DST_NOPOLICY)) ||
- __xfrm_policy_check(sk, ndir, skb, family);
+ return __xfrm_check_nopolicy(net, skb, dir) ||
+ (skb_dst(skb) && (skb_dst(skb)->flags & DST_NOPOLICY)) ||
+ __xfrm_policy_check(sk, ndir, skb, family);
}

static inline int xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb, unsigned short family)
@@ -1168,13 +1157,12 @@ static inline int xfrm_route_forward(struct sk_buff *skb, unsigned short family)
{
struct net *net = dev_net(skb->dev);

- if (xfrm_default_allow(net, XFRM_POLICY_OUT))
- return !net->xfrm.policy_count[XFRM_POLICY_OUT] ||
- (skb_dst(skb)->flags & DST_NOXFRM) ||
- __xfrm_route_forward(skb, family);
- else
- return (skb_dst(skb)->flags & DST_NOXFRM) ||
- __xfrm_route_forward(skb, family);
+ if (!net->xfrm.policy_count[XFRM_POLICY_OUT] &&
+ net->xfrm.policy_default[XFRM_POLICY_OUT] == XFRM_USERPOLICY_ACCEPT)
+ return true;
+
+ return (skb_dst(skb)->flags & DST_NOXFRM) ||
+ __xfrm_route_forward(skb, family);
}

static inline int xfrm4_route_forward(struct sk_buff *skb)
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 882526159d3a..19aa994f5d2c 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -3158,7 +3158,7 @@ struct dst_entry *xfrm_lookup_with_ifid(struct net *net,

nopol:
if (!(dst_orig->dev->flags & IFF_LOOPBACK) &&
- !xfrm_default_allow(net, dir)) {
+ net->xfrm.policy_default[dir] == XFRM_USERPOLICY_BLOCK) {
err = -EPERM;
goto error;
}
@@ -3569,7 +3569,7 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
}

if (!pol) {
- if (!xfrm_default_allow(net, dir)) {
+ if (net->xfrm.policy_default[dir] == XFRM_USERPOLICY_BLOCK) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOPOLS);
return 0;
}
@@ -3629,7 +3629,8 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
}
xfrm_nr = ti;

- if (!xfrm_default_allow(net, dir) && !xfrm_nr) {
+ if (net->xfrm.policy_default[dir] == XFRM_USERPOLICY_BLOCK &&
+ !xfrm_nr) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
goto reject;
}
@@ -4118,6 +4119,9 @@ static int __net_init xfrm_net_init(struct net *net)
spin_lock_init(&net->xfrm.xfrm_policy_lock);
seqcount_spinlock_init(&net->xfrm.xfrm_policy_hash_generation, &net->xfrm.xfrm_policy_lock);
mutex_init(&net->xfrm.xfrm_cfg_mutex);
+ net->xfrm.policy_default[XFRM_POLICY_IN] = XFRM_USERPOLICY_ACCEPT;
+ net->xfrm.policy_default[XFRM_POLICY_FWD] = XFRM_USERPOLICY_ACCEPT;
+ net->xfrm.policy_default[XFRM_POLICY_OUT] = XFRM_USERPOLICY_ACCEPT;

rv = xfrm_statistics_init(net);
if (rv < 0)
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 72b2f173aac8..64fa8fdd6bbd 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1994,12 +1994,9 @@ static int xfrm_notify_userpolicy(struct net *net)
}

up = nlmsg_data(nlh);
- up->in = net->xfrm.policy_default & XFRM_POL_DEFAULT_IN ?
- XFRM_USERPOLICY_BLOCK : XFRM_USERPOLICY_ACCEPT;
- up->fwd = net->xfrm.policy_default & XFRM_POL_DEFAULT_FWD ?
- XFRM_USERPOLICY_BLOCK : XFRM_USERPOLICY_ACCEPT;
- up->out = net->xfrm.policy_default & XFRM_POL_DEFAULT_OUT ?
- XFRM_USERPOLICY_BLOCK : XFRM_USERPOLICY_ACCEPT;
+ up->in = net->xfrm.policy_default[XFRM_POLICY_IN];
+ up->fwd = net->xfrm.policy_default[XFRM_POLICY_FWD];
+ up->out = net->xfrm.policy_default[XFRM_POLICY_OUT];

nlmsg_end(skb, nlh);

@@ -2010,26 +2007,26 @@ static int xfrm_notify_userpolicy(struct net *net)
return err;
}

+static bool xfrm_userpolicy_is_valid(__u8 policy)
+{
+ return policy == XFRM_USERPOLICY_BLOCK ||
+ policy == XFRM_USERPOLICY_ACCEPT;
+}
+
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);

- if (up->in == XFRM_USERPOLICY_BLOCK)
- net->xfrm.policy_default |= XFRM_POL_DEFAULT_IN;
- else if (up->in == XFRM_USERPOLICY_ACCEPT)
- net->xfrm.policy_default &= ~XFRM_POL_DEFAULT_IN;
+ if (xfrm_userpolicy_is_valid(up->in))
+ net->xfrm.policy_default[XFRM_POLICY_IN] = up->in;

- if (up->fwd == XFRM_USERPOLICY_BLOCK)
- net->xfrm.policy_default |= XFRM_POL_DEFAULT_FWD;
- else if (up->fwd == XFRM_USERPOLICY_ACCEPT)
- net->xfrm.policy_default &= ~XFRM_POL_DEFAULT_FWD;
+ if (xfrm_userpolicy_is_valid(up->fwd))
+ net->xfrm.policy_default[XFRM_POLICY_FWD] = up->fwd;

- if (up->out == XFRM_USERPOLICY_BLOCK)
- net->xfrm.policy_default |= XFRM_POL_DEFAULT_OUT;
- else if (up->out == XFRM_USERPOLICY_ACCEPT)
- net->xfrm.policy_default &= ~XFRM_POL_DEFAULT_OUT;
+ if (xfrm_userpolicy_is_valid(up->out))
+ net->xfrm.policy_default[XFRM_POLICY_OUT] = up->out;

rt_genid_bump_all(net);

@@ -2059,13 +2056,9 @@ static int xfrm_get_default(struct sk_buff *skb, struct nlmsghdr *nlh,
}

r_up = nlmsg_data(r_nlh);
-
- r_up->in = net->xfrm.policy_default & XFRM_POL_DEFAULT_IN ?
- XFRM_USERPOLICY_BLOCK : XFRM_USERPOLICY_ACCEPT;
- r_up->fwd = net->xfrm.policy_default & XFRM_POL_DEFAULT_FWD ?
- XFRM_USERPOLICY_BLOCK : XFRM_USERPOLICY_ACCEPT;
- r_up->out = net->xfrm.policy_default & XFRM_POL_DEFAULT_OUT ?
- XFRM_USERPOLICY_BLOCK : XFRM_USERPOLICY_ACCEPT;
+ r_up->in = net->xfrm.policy_default[XFRM_POLICY_IN];
+ r_up->fwd = net->xfrm.policy_default[XFRM_POLICY_FWD];
+ r_up->out = net->xfrm.policy_default[XFRM_POLICY_OUT];
nlmsg_end(r_skb, r_nlh);

return nlmsg_unicast(net->xfrm.nlsk, r_skb, portid);
--
2.35.1