netdev - [PATCH bpf-next v2 1/9] bpf, lsm: Add disabled BPF LSM hook list

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Message-Id: <20240719110059.797546-2-xukuohai@huaweicloud.com>
Date: Fri, 19 Jul 2024 19:00:51 +0800
From: Xu Kuohai <xukuohai@...weicloud.com>
To: bpf@...r.kernel.org,
	netdev@...r.kernel.org,
	linux-security-module@...r.kernel.org
Cc: Alexei Starovoitov <ast@...nel.org>,
	Andrii Nakryiko <andrii@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Eduard Zingerman <eddyz87@...il.com>,
	Shung-Hsi Yu <shung-hsi.yu@...e.com>,
	Yonghong Song <yonghong.song@...ux.dev>,
	KP Singh <kpsingh@...nel.org>,
	Roberto Sassu <roberto.sassu@...wei.com>,
	Matt Bobrowski <mattbobrowski@...gle.com>,
	Yafang Shao <laoar.shao@...il.com>,
	Ilya Leoshkevich <iii@...ux.ibm.com>,
	"Jose E . Marchesi" <jose.marchesi@...cle.com>,
	James Morris <jamorris@...ux.microsoft.com>,
	Kees Cook <kees@...nel.org>,
	Brendan Jackman <jackmanb@...gle.com>,
	Florent Revest <revest@...gle.com>
Subject: [PATCH bpf-next v2 1/9] bpf, lsm: Add disabled BPF LSM hook list

From: Xu Kuohai <xukuohai@...wei.com>

Add a disabled hooks list for BPF LSM. progs being attached to the
listed hooks will be rejected by the verifier.

Suggested-by: KP Singh <kpsingh@...nel.org>
Signed-off-by: Xu Kuohai <xukuohai@...wei.com>
---
 kernel/bpf/bpf_lsm.c | 31 +++++++++++++++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c
index 08a338e1f231..1f596ad6257c 100644
--- a/kernel/bpf/bpf_lsm.c
+++ b/kernel/bpf/bpf_lsm.c
@@ -36,6 +36,24 @@ BTF_SET_START(bpf_lsm_hooks)
 #undef LSM_HOOK
 BTF_SET_END(bpf_lsm_hooks)
 
+BTF_SET_START(bpf_lsm_disabled_hooks)
+BTF_ID(func, bpf_lsm_vm_enough_memory)
+BTF_ID(func, bpf_lsm_inode_need_killpriv)
+BTF_ID(func, bpf_lsm_inode_getsecurity)
+BTF_ID(func, bpf_lsm_inode_listsecurity)
+BTF_ID(func, bpf_lsm_inode_copy_up_xattr)
+BTF_ID(func, bpf_lsm_getselfattr)
+BTF_ID(func, bpf_lsm_getprocattr)
+BTF_ID(func, bpf_lsm_setprocattr)
+#ifdef CONFIG_KEYS
+BTF_ID(func, bpf_lsm_key_getsecurity)
+#endif
+#ifdef CONFIG_AUDIT
+BTF_ID(func, bpf_lsm_audit_rule_match)
+#endif
+BTF_ID(func, bpf_lsm_ismaclabel)
+BTF_SET_END(bpf_lsm_disabled_hooks)
+
 /* List of LSM hooks that should operate on 'current' cgroup regardless
  * of function signature.
  */
@@ -97,15 +115,24 @@ void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog,
 int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
 			const struct bpf_prog *prog)
 {
+	u32 btf_id = prog->aux->attach_btf_id;
+	const char *func_name = prog->aux->attach_func_name;
+
 	if (!prog->gpl_compatible) {
 		bpf_log(vlog,
 			"LSM programs must have a GPL compatible license\n");
 		return -EINVAL;
 	}
 
-	if (!btf_id_set_contains(&bpf_lsm_hooks, prog->aux->attach_btf_id)) {
+	if (btf_id_set_contains(&bpf_lsm_disabled_hooks, btf_id)) {
+		bpf_log(vlog, "attach_btf_id %u points to disabled hook %s\n",
+			btf_id, func_name);
+		return -EINVAL;
+	}
+
+	if (!btf_id_set_contains(&bpf_lsm_hooks, btf_id)) {
 		bpf_log(vlog, "attach_btf_id %u points to wrong type name %s\n",
-			prog->aux->attach_btf_id, prog->aux->attach_func_name);
+			btf_id, func_name);
 		return -EINVAL;
 	}
 
-- 
2.30.2