From: Pablo Neira Ayuso <pablo@netfilter.org> stable inclusion from stable-v6.6.134 commit e7ccaa0a62a8ff2be5d521299ce79390c318d306 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14147 CVE: CVE-2026-31414 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit f01794106042ee27e54af6fdf5b319a2fe3df94d ] Use expect->helper in ctnetlink and /proc to dump the helper name. Using nfct_help() without holding a reference to the master conntrack is unsafe. Use exp->master->helper in ctnetlink path if userspace does not provide an explicit helper when creating an expectation to retain the existing behaviour. The ctnetlink expectation path holds the reference on the master conntrack and nf_conntrack_expect lock and the nfnetlink glue path refers to the master ct that is attached to the skb. Reported-by: Hyunwoo Kim <imv4bel@gmail.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Stable-dep-of: 917b61fa2042 ("netfilter: ctnetlink: ignore explicit helper on new expectations") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Li Xiasong <lixiasong1@huawei.com> --- net/netfilter/nf_conntrack_expect.c | 2 +- net/netfilter/nf_conntrack_helper.c | 6 +----- net/netfilter/nf_conntrack_netlink.c | 24 ++++++++++-------------- net/netfilter/nf_conntrack_sip.c | 2 +- 4 files changed, 13 insertions(+), 21 deletions(-) diff --git a/net/netfilter/nf_conntrack_expect.c b/net/netfilter/nf_conntrack_expect.c index 2fbd1fb1b92f..d94123a88b1b 100644 --- a/net/netfilter/nf_conntrack_expect.c +++ b/net/netfilter/nf_conntrack_expect.c @@ -666,7 +666,7 @@ static int exp_seq_show(struct seq_file *s, void *v) if (expect->flags & NF_CT_EXPECT_USERSPACE) seq_printf(s, "%sUSERSPACE", delim); - helper = rcu_dereference(nfct_help(expect->master)->helper); + helper = rcu_dereference(expect->helper); if (helper) { seq_printf(s, "%s%s", expect->flags ? " " : "", helper->name); if (helper->expect_policy[expect->class].name[0]) diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c index e4ac1abc7cbf..366d8be51783 100644 --- a/net/netfilter/nf_conntrack_helper.c +++ b/net/netfilter/nf_conntrack_helper.c @@ -400,14 +400,10 @@ EXPORT_SYMBOL_GPL(nf_conntrack_helper_register); static bool expect_iter_me(struct nf_conntrack_expect *exp, void *data) { - struct nf_conn_help *help = nfct_help(exp->master); const struct nf_conntrack_helper *me = data; const struct nf_conntrack_helper *this; - if (rcu_access_pointer(exp->helper) == me) - return true; - - this = rcu_dereference_protected(help->helper, + this = rcu_dereference_protected(exp->helper, lockdep_is_held(&nf_conntrack_expect_lock)); return this == me; } diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 566f9834325e..98f8812a3b21 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -3000,7 +3000,7 @@ ctnetlink_exp_dump_expect(struct sk_buff *skb, { struct nf_conn *master = exp->master; long timeout = ((long)exp->timeout.expires - (long)jiffies) / HZ; - struct nf_conn_help *help; + struct nf_conntrack_helper *helper; #if IS_ENABLED(CONFIG_NF_NAT) struct nlattr *nest_parms; struct nf_conntrack_tuple nat_tuple = {}; @@ -3045,15 +3045,12 @@ ctnetlink_exp_dump_expect(struct sk_buff *skb, nla_put_be32(skb, CTA_EXPECT_FLAGS, htonl(exp->flags)) || nla_put_be32(skb, CTA_EXPECT_CLASS, htonl(exp->class))) goto nla_put_failure; - help = nfct_help(master); - if (help) { - struct nf_conntrack_helper *helper; - helper = rcu_dereference(help->helper); - if (helper && - nla_put_string(skb, CTA_EXPECT_HELP_NAME, helper->name)) - goto nla_put_failure; - } + helper = rcu_dereference(exp->helper); + if (helper && + nla_put_string(skb, CTA_EXPECT_HELP_NAME, helper->name)) + goto nla_put_failure; + expfn = nf_ct_helper_expectfn_find_by_symbol(exp->expectfn); if (expfn != NULL && nla_put_string(skb, CTA_EXPECT_FN, expfn->name)) @@ -3382,12 +3379,9 @@ static int ctnetlink_get_expect(struct sk_buff *skb, static bool expect_iter_name(struct nf_conntrack_expect *exp, void *data) { struct nf_conntrack_helper *helper; - const struct nf_conn_help *m_help; const char *name = data; - m_help = nfct_help(exp->master); - - helper = rcu_dereference(m_help->helper); + helper = rcu_dereference(exp->helper); if (!helper) return false; @@ -3522,9 +3516,9 @@ ctnetlink_alloc_expect(const struct nlattr * const cda[], struct nf_conn *ct, struct nf_conntrack_tuple *tuple, struct nf_conntrack_tuple *mask) { - u_int32_t class = 0; struct nf_conntrack_expect *exp; struct nf_conn_help *help; + u32 class = 0; int err; help = nfct_help(ct); @@ -3561,6 +3555,8 @@ ctnetlink_alloc_expect(const struct nlattr * const cda[], struct nf_conn *ct, exp->class = class; exp->master = ct; + if (!helper) + helper = rcu_dereference(help->helper); rcu_assign_pointer(exp->helper, helper); exp->tuple = *tuple; exp->mask.src.u3 = mask->src.u3; diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c index faf2e82f9d74..48f9d2e45e60 100644 --- a/net/netfilter/nf_conntrack_sip.c +++ b/net/netfilter/nf_conntrack_sip.c @@ -924,7 +924,7 @@ static int set_expected_rtp_rtcp(struct sk_buff *skb, unsigned int protoff, exp = __nf_ct_expect_find(net, nf_ct_zone(ct), &tuple); if (!exp || exp->master == ct || - nfct_help(exp->master)->helper != nfct_help(ct)->helper || + exp->helper != nfct_help(ct)->helper || exp->class != class) break; #if IS_ENABLED(CONFIG_NF_NAT) -- 2.34.1