From: Hangyu Hua <hbh25y@xxxxxxxxx>
[ Upstream commit f85daf0e725358be78dfd208dea5fd665d8cb901 ]
xfrm_policy_lookup() will call xfrm_pol_hold_rcu() to get a refcount of
pols[0]. This refcount can be dropped in xfrm_expand_policies() when
xfrm_expand_policies() return error. pols[0]'s refcount is balanced in
here. But xfrm_bundle_lookup() will also call xfrm_pols_put() with
num_pols == 1 to drop this refcount when xfrm_expand_policies() return
error.
This patch also fix an illegal address access. pols[0] will save a error
point when xfrm_policy_lookup fails. This lead to xfrm_pols_put to resolve
an illegal address in xfrm_bundle_lookup's error path.
Fix these by setting num_pols = 0 in xfrm_expand_policies()'s error path.
Fixes: 80c802f3073e ("xfrm: cache bundles instead of policies for outgoing flows")
Signed-off-by: Hangyu Hua <hbh25y@xxxxxxxxx>
Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/xfrm/xfrm_policy.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index d87121d61a2b..e1840f70c0ff 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1673,8 +1673,10 @@ static int xfrm_expand_policies(const struct flowi *fl, u16 family,
*num_xfrms = 0;
return 0;
}
- if (IS_ERR(pols[0]))
+ if (IS_ERR(pols[0])) {
+ *num_pols = 0;
return PTR_ERR(pols[0]);
+ }
*num_xfrms = pols[0]->xfrm_nr;
@@ -1688,6 +1690,7 @@ static int xfrm_expand_policies(const struct flowi *fl, u16 family,
if (pols[1]) {
if (IS_ERR(pols[1])) {
xfrm_pols_put(pols, *num_pols);
+ *num_pols = 0;
return PTR_ERR(pols[1]);
}
(*num_pols)++;
--
2.35.1
