From: Qi Tang <tpluszz77@gmail.com> stable inclusion from stable-v6.6.134 commit 2898080c054ea4d6ddfaaf21bbedbc229a9a8376 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14558 CVE: CVE-2026-43026 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 35177c6877134a21315f37d57a5577846225623e ] ctnetlink_alloc_expect() allocates expectations from a non-zeroing slab cache via nf_ct_expect_alloc(). When CTA_EXPECT_NAT is not present in the netlink message, saved_addr and saved_proto are never initialized. Stale data from a previous slab occupant can then be dumped to userspace by ctnetlink_exp_dump_expect(), which checks these fields to decide whether to emit CTA_EXPECT_NAT. The safe sibling nf_ct_expect_init(), used by the packet path, explicitly zeroes these fields. Zero saved_addr, saved_proto and dir in the else branch, guarded by IS_ENABLED(CONFIG_NF_NAT) since these fields only exist when NAT is enabled. Confirmed by priming the expect slab with NAT-bearing expectations, freeing them, creating a new expectation without CTA_EXPECT_NAT, and observing that the ctnetlink dump emits a spurious CTA_EXPECT_NAT containing stale data from the prior allocation. Fixes: 076a0ca02644 ("netfilter: ctnetlink: add NAT support for expectations") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Qi Tang <tpluszz77@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> --- net/netfilter/nf_conntrack_netlink.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 67a0762915e3..90c32031bcf1 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -3571,6 +3571,12 @@ ctnetlink_alloc_expect(const struct nlattr * const cda[], struct nf_conn *ct, exp, nf_ct_l3num(ct)); if (err < 0) goto err_out; +#if IS_ENABLED(CONFIG_NF_NAT) + } else { + memset(&exp->saved_addr, 0, sizeof(exp->saved_addr)); + memset(&exp->saved_proto, 0, sizeof(exp->saved_proto)); + exp->dir = 0; +#endif } return exp; err_out: -- 2.43.0