diff options
Diffstat (limited to 'kernel/bpf/verifier.c')
| -rw-r--r-- | kernel/bpf/verifier.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 4938477912cd..df3ec6b05f05 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7322,6 +7322,18 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn reg_type_str(env, regs[BPF_REG_1].type)); return -EACCES; } + break; + case BPF_FUNC_set_retval: + if (env->prog->expected_attach_type == BPF_LSM_CGROUP) { + if (!env->prog->aux->attach_func_proto->type) { + /* Make sure programs that attach to void + * hooks don't try to modify return value. + */ + verbose(env, "BPF_LSM_CGROUP that attach to void LSM hooks can't modify return value!\n"); + return -EINVAL; + } + } + break; } if (err) @@ -10527,6 +10539,22 @@ static int check_return_code(struct bpf_verifier_env *env) case BPF_PROG_TYPE_SK_LOOKUP: range = tnum_range(SK_DROP, SK_PASS); break; + + case BPF_PROG_TYPE_LSM: + if (env->prog->expected_attach_type != BPF_LSM_CGROUP) { + /* Regular BPF_PROG_TYPE_LSM programs can return + * any value. + */ + return 0; + } + if (!env->prog->aux->attach_func_proto->type) { + /* Make sure programs that attach to void + * hooks don't try to modify return value. + */ + range = tnum_range(1, 1); + } + break; + case BPF_PROG_TYPE_EXT: /* freplace program can return anything as its return value * depends on the to-be-replaced kernel func or bpf program. @@ -10543,6 +10571,9 @@ static int check_return_code(struct bpf_verifier_env *env) if (!tnum_in(range, reg->var_off)) { verbose_invalid_scalar(env, reg, &range, "program exit", "R0"); + if (prog->expected_attach_type == BPF_LSM_CGROUP && + !prog->aux->attach_func_proto->type) + verbose(env, "Note, BPF_LSM_CGROUP that attach to void LSM hooks can't modify return value!\n"); return -EINVAL; } @@ -14902,6 +14933,7 @@ int bpf_check_attach_target(struct bpf_verifier_log *log, fallthrough; case BPF_MODIFY_RETURN: case BPF_LSM_MAC: + case BPF_LSM_CGROUP: case BPF_TRACE_FENTRY: case BPF_TRACE_FEXIT: if (!btf_type_is_func(t)) { |