xfrm: Check if_id in xfrm_migrate

[ Upstream commit c1aca3080e382886e2e58e809787441984a2f89b ]

This patch enables distinguishing SAs and SPs based on if_id during
the xfrm_migrate flow. This ensures support for xfrm interfaces
throughout the SA/SP lifecycle.

When there are multiple existing SPs with the same direction,
the same xfrm_selector and different endpoint addresses,
xfrm_migrate might fail with ENODATA.

Specifically, the code path for performing xfrm_migrate is:
  Stage 1: find policy to migrate with
    xfrm_migrate_policy_find(sel, dir, type, net)
  Stage 2: find and update state(s) with
    xfrm_migrate_state_find(mp, net)
  Stage 3: update endpoint address(es) of template(s) with
    xfrm_policy_migrate(pol, m, num_migrate)

Currently "Stage 1" always returns the first xfrm_policy that
matches, and "Stage 3" looks for the xfrm_tmpl that matches the
old endpoint address. Thus if there are multiple xfrm_policy
with same selector, direction, type and net, "Stage 1" might
rertun a wrong xfrm_policy and "Stage 3" will fail with ENODATA
because it cannot find a xfrm_tmpl with the matching endpoint
address.

The fix is to allow userspace to pass an if_id and add if_id
to the matching rule in Stage 1 and Stage 2 since if_id is a
unique ID for xfrm_policy and xfrm_state. For compatibility,
if_id will only be checked if the attribute is set.

Tested with additions to Android's kernel unit test suite:
https://android-review.googlesource.com/c/kernel/tests/+/1668886

Signed-off-by: Yan Yan <evitayan@google.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Yan Yan
2022-01-18 16:00:13 -08:00
committed by Greg Kroah-Hartman
parent 6056abc99b
commit d8889a445b
5 changed files with 23 additions and 11 deletions

View File

@@ -1668,14 +1668,15 @@ int km_migrate(const struct xfrm_selector *sel, u8 dir, u8 type,
const struct xfrm_migrate *m, int num_bundles,
const struct xfrm_kmaddress *k,
const struct xfrm_encap_tmpl *encap);
struct xfrm_state *xfrm_migrate_state_find(struct xfrm_migrate *m, struct net *net);
struct xfrm_state *xfrm_migrate_state_find(struct xfrm_migrate *m, struct net *net,
u32 if_id);
struct xfrm_state *xfrm_state_migrate(struct xfrm_state *x,
struct xfrm_migrate *m,
struct xfrm_encap_tmpl *encap);
int xfrm_migrate(const struct xfrm_selector *sel, u8 dir, u8 type,
struct xfrm_migrate *m, int num_bundles,
struct xfrm_kmaddress *k, struct net *net,
struct xfrm_encap_tmpl *encap);
struct xfrm_encap_tmpl *encap, u32 if_id);
#endif
int km_new_mapping(struct xfrm_state *x, xfrm_address_t *ipaddr, __be16 sport);