From: Xu Kuohai xukuohai@huawei.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@kernel.org Signed-off-by: Xu Kuohai xukuohai@huawei.com --- kernel/bpf/bpf_lsm.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c index 4e1a4a333000..7f5648b404f2 100644 --- a/kernel/bpf/bpf_lsm.c +++ b/kernel/bpf/bpf_lsm.c @@ -68,6 +68,12 @@ 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_getprocattr) +BTF_ID(func, bpf_lsm_setprocattr) +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. */ @@ -129,15 +135,25 @@ 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 bpf lsm 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; }