diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/btf.c | 50 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 35 |
2 files changed, 60 insertions, 25 deletions
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index b12db397303e..c9338fb397fc 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -8047,15 +8047,44 @@ BTF_ID_LIST_GLOBAL(btf_tracing_ids, MAX_BTF_TRACING_TYPE) BTF_TRACING_TYPE_xxx #undef BTF_TRACING_TYPE +/* Validate well-formedness of iter argument type. + * On success, return positive BTF ID of iter state's STRUCT type. + * On error, negative error is returned. + */ +int btf_check_iter_arg(struct btf *btf, const struct btf_type *func, int arg_idx) +{ + const struct btf_param *arg; + const struct btf_type *t; + const char *name; + int btf_id; + + if (btf_type_vlen(func) <= arg_idx) + return -EINVAL; + + arg = &btf_params(func)[arg_idx]; + t = btf_type_skip_modifiers(btf, arg->type, NULL); + if (!t || !btf_type_is_ptr(t)) + return -EINVAL; + t = btf_type_skip_modifiers(btf, t->type, &btf_id); + if (!t || !__btf_type_is_struct(t)) + return -EINVAL; + + name = btf_name_by_offset(btf, t->name_off); + if (!name || strncmp(name, ITER_PREFIX, sizeof(ITER_PREFIX) - 1)) + return -EINVAL; + + return btf_id; +} + static int btf_check_iter_kfuncs(struct btf *btf, const char *func_name, const struct btf_type *func, u32 func_flags) { u32 flags = func_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY); - const char *name, *sfx, *iter_name; - const struct btf_param *arg; + const char *sfx, *iter_name; const struct btf_type *t; char exp_name[128]; u32 nr_args; + int btf_id; /* exactly one of KF_ITER_{NEW,NEXT,DESTROY} can be set */ if (!flags || (flags & (flags - 1))) @@ -8066,28 +8095,21 @@ static int btf_check_iter_kfuncs(struct btf *btf, const char *func_name, if (nr_args < 1) return -EINVAL; - arg = &btf_params(func)[0]; - t = btf_type_skip_modifiers(btf, arg->type, NULL); - if (!t || !btf_type_is_ptr(t)) - return -EINVAL; - t = btf_type_skip_modifiers(btf, t->type, NULL); - if (!t || !__btf_type_is_struct(t)) - return -EINVAL; - - name = btf_name_by_offset(btf, t->name_off); - if (!name || strncmp(name, ITER_PREFIX, sizeof(ITER_PREFIX) - 1)) - return -EINVAL; + btf_id = btf_check_iter_arg(btf, func, 0); + if (btf_id < 0) + return btf_id; /* sizeof(struct bpf_iter_<type>) should be a multiple of 8 to * fit nicely in stack slots */ + t = btf_type_by_id(btf, btf_id); if (t->size == 0 || (t->size % 8)) return -EINVAL; /* validate bpf_iter_<type>_{new,next,destroy}(struct bpf_iter_<type> *) * naming pattern */ - iter_name = name + sizeof(ITER_PREFIX) - 1; + iter_name = btf_name_by_offset(btf, t->name_off) + sizeof(ITER_PREFIX) - 1; if (flags & KF_ITER_NEW) sfx = "new"; else if (flags & KF_ITER_NEXT) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index df3be12096cf..920d7c5fe944 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7970,12 +7970,17 @@ static bool is_iter_destroy_kfunc(struct bpf_kfunc_call_arg_meta *meta) return meta->kfunc_flags & KF_ITER_DESTROY; } -static bool is_kfunc_arg_iter(struct bpf_kfunc_call_arg_meta *meta, int arg) +static bool is_kfunc_arg_iter(struct bpf_kfunc_call_arg_meta *meta, int arg_idx, + const struct btf_param *arg) { /* btf_check_iter_kfuncs() guarantees that first argument of any iter * kfunc is iter state pointer */ - return arg == 0 && is_iter_kfunc(meta); + if (is_iter_kfunc(meta)) + return arg_idx == 0; + + /* iter passed as an argument to a generic kfunc */ + return btf_param_match_suffix(meta->btf, arg, "__iter"); } static int process_iter_arg(struct bpf_verifier_env *env, int regno, int insn_idx, @@ -7983,14 +7988,20 @@ static int process_iter_arg(struct bpf_verifier_env *env, int regno, int insn_id { struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; const struct btf_type *t; - const struct btf_param *arg; - int spi, err, i, nr_slots; - u32 btf_id; + int spi, err, i, nr_slots, btf_id; - /* btf_check_iter_kfuncs() ensures we don't need to validate anything here */ - arg = &btf_params(meta->func_proto)[0]; - t = btf_type_skip_modifiers(meta->btf, arg->type, NULL); /* PTR */ - t = btf_type_skip_modifiers(meta->btf, t->type, &btf_id); /* STRUCT */ + /* For iter_{new,next,destroy} functions, btf_check_iter_kfuncs() + * ensures struct convention, so we wouldn't need to do any BTF + * validation here. But given iter state can be passed as a parameter + * to any kfunc, if arg has "__iter" suffix, we need to be a bit more + * conservative here. + */ + btf_id = btf_check_iter_arg(meta->btf, meta->func_proto, regno - 1); + if (btf_id < 0) { + verbose(env, "expected valid iter pointer as arg #%d\n", regno); + return -EINVAL; + } + t = btf_type_by_id(meta->btf, btf_id); nr_slots = t->size / BPF_REG_SIZE; if (is_iter_new_kfunc(meta)) { @@ -8012,7 +8023,9 @@ static int process_iter_arg(struct bpf_verifier_env *env, int regno, int insn_id if (err) return err; } else { - /* iter_next() or iter_destroy() expect initialized iter state*/ + /* iter_next() or iter_destroy(), as well as any kfunc + * accepting iter argument, expect initialized iter state + */ err = is_iter_reg_valid_init(env, reg, meta->btf, btf_id, nr_slots); switch (err) { case 0: @@ -11382,7 +11395,7 @@ get_kfunc_ptr_arg_type(struct bpf_verifier_env *env, if (is_kfunc_arg_dynptr(meta->btf, &args[argno])) return KF_ARG_PTR_TO_DYNPTR; - if (is_kfunc_arg_iter(meta, argno)) + if (is_kfunc_arg_iter(meta, argno, &args[argno])) return KF_ARG_PTR_TO_ITER; if (is_kfunc_arg_list_head(meta->btf, &args[argno])) |