From: Hangyu Hua <hbh25y@gmail.com> stable inclusion from stable-v4.19.254 commit fdb4fba1ba8512fa579a9d091dcb6c410f82f96a category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5JMHA CVE: CVE-2022-36879 -------------------------------- [ 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@gmail.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com> Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com> Reviewed-by: Wei Yongjun <weiyongjun1@huawei.com> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> --- 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 e9aea82f370d..408e3f34d16c 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -1703,8 +1703,10 @@ 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; @@ -1719,6 +1721,7 @@ 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)++; -- 2.25.1