diff options
| -rw-r--r-- | include/linux/btf.h | 5 | ||||
| -rw-r--r-- | kernel/bpf/btf.c | 50 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 35 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c | 16 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/iters_testmod_seq.c | 50 |
5 files changed, 127 insertions, 29 deletions
diff --git a/include/linux/btf.h b/include/linux/btf.h index cffb43133c68..b8a583194c4a 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -580,6 +580,7 @@ bool btf_is_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf, int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type prog_type); bool btf_types_are_same(const struct btf *btf1, u32 id1, const struct btf *btf2, u32 id2); +int btf_check_iter_arg(struct btf *btf, const struct btf_type *func, int arg_idx); #else static inline const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id) @@ -654,6 +655,10 @@ static inline bool btf_types_are_same(const struct btf *btf1, u32 id1, { return false; } +static inline int btf_check_iter_arg(struct btf *btf, const struct btf_type *func, int arg_idx) +{ + return -EOPNOTSUPP; +} #endif static inline bool btf_type_is_struct_ptr(struct btf *btf, const struct btf_type *t) 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])) diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c index 3687a40b61c6..c04b7dec2ab9 100644 --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c @@ -141,13 +141,12 @@ bpf_testmod_test_mod_kfunc(int i) __bpf_kfunc int bpf_iter_testmod_seq_new(struct bpf_iter_testmod_seq *it, s64 value, int cnt) { - if (cnt < 0) { - it->cnt = 0; + it->cnt = cnt; + + if (cnt < 0) return -EINVAL; - } it->value = value; - it->cnt = cnt; return 0; } @@ -162,6 +161,14 @@ __bpf_kfunc s64 *bpf_iter_testmod_seq_next(struct bpf_iter_testmod_seq* it) return &it->value; } +__bpf_kfunc s64 bpf_iter_testmod_seq_value(int val, struct bpf_iter_testmod_seq* it__iter) +{ + if (it__iter->cnt < 0) + return 0; + + return val + it__iter->value; +} + __bpf_kfunc void bpf_iter_testmod_seq_destroy(struct bpf_iter_testmod_seq *it) { it->cnt = 0; @@ -531,6 +538,7 @@ BTF_KFUNCS_START(bpf_testmod_common_kfunc_ids) BTF_ID_FLAGS(func, bpf_iter_testmod_seq_new, KF_ITER_NEW) BTF_ID_FLAGS(func, bpf_iter_testmod_seq_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_testmod_seq_destroy, KF_ITER_DESTROY) +BTF_ID_FLAGS(func, bpf_iter_testmod_seq_value) BTF_ID_FLAGS(func, bpf_kfunc_common_test) BTF_ID_FLAGS(func, bpf_kfunc_dynptr_test) BTF_ID_FLAGS(func, bpf_testmod_ctx_create, KF_ACQUIRE | KF_RET_NULL) diff --git a/tools/testing/selftests/bpf/progs/iters_testmod_seq.c b/tools/testing/selftests/bpf/progs/iters_testmod_seq.c index 3873fb6c292a..4a176e6aede8 100644 --- a/tools/testing/selftests/bpf/progs/iters_testmod_seq.c +++ b/tools/testing/selftests/bpf/progs/iters_testmod_seq.c @@ -12,6 +12,7 @@ struct bpf_iter_testmod_seq { extern int bpf_iter_testmod_seq_new(struct bpf_iter_testmod_seq *it, s64 value, int cnt) __ksym; extern s64 *bpf_iter_testmod_seq_next(struct bpf_iter_testmod_seq *it) __ksym; +extern s64 bpf_iter_testmod_seq_value(int blah, struct bpf_iter_testmod_seq *it) __ksym; extern void bpf_iter_testmod_seq_destroy(struct bpf_iter_testmod_seq *it) __ksym; const volatile __s64 exp_empty = 0 + 1; @@ -76,4 +77,53 @@ int testmod_seq_truncated(const void *ctx) return 0; } +SEC("?raw_tp") +__failure +__msg("expected an initialized iter_testmod_seq as arg #2") +int testmod_seq_getter_before_bad(const void *ctx) +{ + struct bpf_iter_testmod_seq it; + + return bpf_iter_testmod_seq_value(0, &it); +} + +SEC("?raw_tp") +__failure +__msg("expected an initialized iter_testmod_seq as arg #2") +int testmod_seq_getter_after_bad(const void *ctx) +{ + struct bpf_iter_testmod_seq it; + s64 sum = 0, *v; + + bpf_iter_testmod_seq_new(&it, 100, 100); + + while ((v = bpf_iter_testmod_seq_next(&it))) { + sum += *v; + } + + bpf_iter_testmod_seq_destroy(&it); + + return sum + bpf_iter_testmod_seq_value(0, &it); +} + +SEC("?socket") +__success __retval(1000000) +int testmod_seq_getter_good(const void *ctx) +{ + struct bpf_iter_testmod_seq it; + s64 sum = 0, *v; + + bpf_iter_testmod_seq_new(&it, 100, 100); + + while ((v = bpf_iter_testmod_seq_next(&it))) { + sum += *v; + } + + sum *= bpf_iter_testmod_seq_value(0, &it); + + bpf_iter_testmod_seq_destroy(&it); + + return sum; +} + char _license[] SEC("license") = "GPL"; |