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xfrm: policy: match with both mark and mask on user interfaces
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In commit ed17b8d ("xfrm: fix a warning in xfrm_policy_insert_list"),
it would take 'priority' to make a policy unique, and allow duplicated
policies with different 'priority' to be added, which is not expected
by userland, as Tobias reported in strongswan.

To fix this duplicated policies issue, and also fix the issue in
commit ed17b8d ("xfrm: fix a warning in xfrm_policy_insert_list"),
when doing add/del/get/update on user interfaces, this patch is to change
to look up a policy with both mark and mask by doing:

  mark.v == pol->mark.v && mark.m == pol->mark.m

and leave the check:

  (mark & pol->mark.m) == pol->mark.v

for tx/rx path only.

As the userland expects an exact mark and mask match to manage policies.

v1->v2:
  - make xfrm_policy_mark_match inline and fix the changelog as
    Tobias suggested.

Fixes: 295fae5 ("xfrm: Allow user space manipulation of SPD mark")
Fixes: ed17b8d ("xfrm: fix a warning in xfrm_policy_insert_list")
Reported-by: Tobias Brunner <[email protected]>
Tested-by: Tobias Brunner <[email protected]>
Signed-off-by: Xin Long <[email protected]>
Signed-off-by: Steffen Klassert <[email protected]>
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@lxin @klassert
lxin authored and klassert committed Jun 24, 2020
1 parent 0275875 commit 4f47e8a
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Showing 4 changed files with 36 additions and 36 deletions.
11 changes: 7 additions & 4 deletions include/net/xfrm.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1630,13 +1630,16 @@ int xfrm_policy_walk(struct net *net, struct xfrm_policy_walk *walk,
void *);
void xfrm_policy_walk_done(struct xfrm_policy_walk *walk, struct net *net);
int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl);
struct xfrm_policy *xfrm_policy_bysel_ctx(struct net *net, u32 mark, u32 if_id,
u8 type, int dir,
struct xfrm_policy *xfrm_policy_bysel_ctx(struct net *net,
const struct xfrm_mark *mark,
u32 if_id, u8 type, int dir,
struct xfrm_selector *sel,
struct xfrm_sec_ctx *ctx, int delete,
int *err);
struct xfrm_policy *xfrm_policy_byid(struct net *net, u32 mark, u32 if_id, u8,
int dir, u32 id, int delete, int *err);
struct xfrm_policy *xfrm_policy_byid(struct net *net,
const struct xfrm_mark *mark, u32 if_id,
u8 type, int dir, u32 id, int delete,
int *err);
int xfrm_policy_flush(struct net *net, u8 type, bool task_valid);
void xfrm_policy_hash_rebuild(struct net *net);
u32 xfrm_get_acqseq(void);
Expand Down
4 changes: 2 additions & 2 deletions net/key/af_key.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2400,7 +2400,7 @@ static int pfkey_spddelete(struct sock *sk, struct sk_buff *skb, const struct sa
return err;
}

xp = xfrm_policy_bysel_ctx(net, DUMMY_MARK, 0, XFRM_POLICY_TYPE_MAIN,
xp = xfrm_policy_bysel_ctx(net, &dummy_mark, 0, XFRM_POLICY_TYPE_MAIN,
pol->sadb_x_policy_dir - 1, &sel, pol_ctx,
1, &err);
security_xfrm_policy_free(pol_ctx);
Expand Down Expand Up @@ -2651,7 +2651,7 @@ static int pfkey_spdget(struct sock *sk, struct sk_buff *skb, const struct sadb_
return -EINVAL;

delete = (hdr->sadb_msg_type == SADB_X_SPDDELETE2);
xp = xfrm_policy_byid(net, DUMMY_MARK, 0, XFRM_POLICY_TYPE_MAIN,
xp = xfrm_policy_byid(net, &dummy_mark, 0, XFRM_POLICY_TYPE_MAIN,
dir, pol->sadb_x_policy_id, delete, &err);
if (xp == NULL)
return -ENOENT;
Expand Down
39 changes: 16 additions & 23 deletions net/xfrm/xfrm_policy.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1433,14 +1433,10 @@ static void xfrm_policy_requeue(struct xfrm_policy *old,
spin_unlock_bh(&pq->hold_queue.lock);
}

static bool xfrm_policy_mark_match(struct xfrm_policy *policy,
struct xfrm_policy *pol)
static inline bool xfrm_policy_mark_match(const struct xfrm_mark *mark,
struct xfrm_policy *pol)
{
if (policy->mark.v == pol->mark.v &&
policy->priority == pol->priority)
return true;

return false;
return mark->v == pol->mark.v && mark->m == pol->mark.m;
}

static u32 xfrm_pol_bin_key(const void *data, u32 len, u32 seed)
Expand Down Expand Up @@ -1503,7 +1499,7 @@ static void xfrm_policy_insert_inexact_list(struct hlist_head *chain,
if (pol->type == policy->type &&
pol->if_id == policy->if_id &&
!selector_cmp(&pol->selector, &policy->selector) &&
xfrm_policy_mark_match(policy, pol) &&
xfrm_policy_mark_match(&policy->mark, pol) &&
xfrm_sec_ctx_match(pol->security, policy->security) &&
!WARN_ON(delpol)) {
delpol = pol;
Expand Down Expand Up @@ -1538,7 +1534,7 @@ static struct xfrm_policy *xfrm_policy_insert_list(struct hlist_head *chain,
if (pol->type == policy->type &&
pol->if_id == policy->if_id &&
!selector_cmp(&pol->selector, &policy->selector) &&
xfrm_policy_mark_match(policy, pol) &&
xfrm_policy_mark_match(&policy->mark, pol) &&
xfrm_sec_ctx_match(pol->security, policy->security) &&
!WARN_ON(delpol)) {
if (excl)
Expand Down Expand Up @@ -1610,9 +1606,8 @@ int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
EXPORT_SYMBOL(xfrm_policy_insert);

static struct xfrm_policy *
__xfrm_policy_bysel_ctx(struct hlist_head *chain, u32 mark, u32 if_id,
u8 type, int dir,
struct xfrm_selector *sel,
__xfrm_policy_bysel_ctx(struct hlist_head *chain, const struct xfrm_mark *mark,
u32 if_id, u8 type, int dir, struct xfrm_selector *sel,
struct xfrm_sec_ctx *ctx)
{
struct xfrm_policy *pol;
Expand All @@ -1623,7 +1618,7 @@ __xfrm_policy_bysel_ctx(struct hlist_head *chain, u32 mark, u32 if_id,
hlist_for_each_entry(pol, chain, bydst) {
if (pol->type == type &&
pol->if_id == if_id &&
(mark & pol->mark.m) == pol->mark.v &&
xfrm_policy_mark_match(mark, pol) &&
!selector_cmp(sel, &pol->selector) &&
xfrm_sec_ctx_match(ctx, pol->security))
return pol;
Expand All @@ -1632,11 +1627,10 @@ __xfrm_policy_bysel_ctx(struct hlist_head *chain, u32 mark, u32 if_id,
return NULL;
}

struct xfrm_policy *xfrm_policy_bysel_ctx(struct net *net, u32 mark, u32 if_id,
u8 type, int dir,
struct xfrm_selector *sel,
struct xfrm_sec_ctx *ctx, int delete,
int *err)
struct xfrm_policy *
xfrm_policy_bysel_ctx(struct net *net, const struct xfrm_mark *mark, u32 if_id,
u8 type, int dir, struct xfrm_selector *sel,
struct xfrm_sec_ctx *ctx, int delete, int *err)
{
struct xfrm_pol_inexact_bin *bin = NULL;
struct xfrm_policy *pol, *ret = NULL;
Expand Down Expand Up @@ -1703,9 +1697,9 @@ struct xfrm_policy *xfrm_policy_bysel_ctx(struct net *net, u32 mark, u32 if_id,
}
EXPORT_SYMBOL(xfrm_policy_bysel_ctx);

struct xfrm_policy *xfrm_policy_byid(struct net *net, u32 mark, u32 if_id,
u8 type, int dir, u32 id, int delete,
int *err)
struct xfrm_policy *
xfrm_policy_byid(struct net *net, const struct xfrm_mark *mark, u32 if_id,
u8 type, int dir, u32 id, int delete, int *err)
{
struct xfrm_policy *pol, *ret;
struct hlist_head *chain;
Expand All @@ -1720,8 +1714,7 @@ struct xfrm_policy *xfrm_policy_byid(struct net *net, u32 mark, u32 if_id,
ret = NULL;
hlist_for_each_entry(pol, chain, byidx) {
if (pol->type == type && pol->index == id &&
pol->if_id == if_id &&
(mark & pol->mark.m) == pol->mark.v) {
pol->if_id == if_id && xfrm_policy_mark_match(mark, pol)) {
xfrm_pol_hold(pol);
if (delete) {
*err = security_xfrm_policy_delete(
Expand Down
18 changes: 11 additions & 7 deletions net/xfrm/xfrm_user.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1863,7 +1863,6 @@ static int xfrm_get_policy(struct sk_buff *skb, struct nlmsghdr *nlh,
struct km_event c;
int delete;
struct xfrm_mark m;
u32 mark = xfrm_mark_get(attrs, &m);
u32 if_id = 0;

p = nlmsg_data(nlh);
Expand All @@ -1880,8 +1879,11 @@ static int xfrm_get_policy(struct sk_buff *skb, struct nlmsghdr *nlh,
if (attrs[XFRMA_IF_ID])
if_id = nla_get_u32(attrs[XFRMA_IF_ID]);

xfrm_mark_get(attrs, &m);

if (p->index)
xp = xfrm_policy_byid(net, mark, if_id, type, p->dir, p->index, delete, &err);
xp = xfrm_policy_byid(net, &m, if_id, type, p->dir,
p->index, delete, &err);
else {
struct nlattr *rt = attrs[XFRMA_SEC_CTX];
struct xfrm_sec_ctx *ctx;
Expand All @@ -1898,8 +1900,8 @@ static int xfrm_get_policy(struct sk_buff *skb, struct nlmsghdr *nlh,
if (err)
return err;
}
xp = xfrm_policy_bysel_ctx(net, mark, if_id, type, p->dir, &p->sel,
ctx, delete, &err);
xp = xfrm_policy_bysel_ctx(net, &m, if_id, type, p->dir,
&p->sel, ctx, delete, &err);
security_xfrm_policy_free(ctx);
}
if (xp == NULL)
Expand Down Expand Up @@ -2166,7 +2168,6 @@ static int xfrm_add_pol_expire(struct sk_buff *skb, struct nlmsghdr *nlh,
u8 type = XFRM_POLICY_TYPE_MAIN;
int err = -ENOENT;
struct xfrm_mark m;
u32 mark = xfrm_mark_get(attrs, &m);
u32 if_id = 0;

err = copy_from_user_policy_type(&type, attrs);
Expand All @@ -2180,8 +2181,11 @@ static int xfrm_add_pol_expire(struct sk_buff *skb, struct nlmsghdr *nlh,
if (attrs[XFRMA_IF_ID])
if_id = nla_get_u32(attrs[XFRMA_IF_ID]);

xfrm_mark_get(attrs, &m);

if (p->index)
xp = xfrm_policy_byid(net, mark, if_id, type, p->dir, p->index, 0, &err);
xp = xfrm_policy_byid(net, &m, if_id, type, p->dir, p->index,
0, &err);
else {
struct nlattr *rt = attrs[XFRMA_SEC_CTX];
struct xfrm_sec_ctx *ctx;
Expand All @@ -2198,7 +2202,7 @@ static int xfrm_add_pol_expire(struct sk_buff *skb, struct nlmsghdr *nlh,
if (err)
return err;
}
xp = xfrm_policy_bysel_ctx(net, mark, if_id, type, p->dir,
xp = xfrm_policy_bysel_ctx(net, &m, if_id, type, p->dir,
&p->sel, ctx, 0, &err);
security_xfrm_policy_free(ctx);
}
Expand Down

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