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Remember the initialized dynptr (i.e.,g !(arg_type |= MEM_UNINIT)) pass to a dynptr kfunc during process_dynptr_func() so that we can easily retrieve the information for verification later. By saving it in meta->dynptr, there is no need to call dynptr helpers such as dynptr_id(), dynptr_ref_obj_id() and dynptr_type() in check_func_arg(). Remove and open code the helpers in process_dynptr_func() when saving id, ref_obj_id, and type. It is okay to drop spi < 0 check as is_dynptr_reg_valid_init() has made sure the dynptr is valid. Besides, since dynptr ref_obj_id information is now pass around in meta->bpf_dynptr_desc, drop the check in helper_multiple_ref_obj_use. Acked-by: Eduard Zingerman Signed-off-by: Amery Hung --- include/linux/bpf_verifier.h | 12 ++- kernel/bpf/verifier.c | 178 +++++++---------------------------- 2 files changed, 41 insertions(+), 149 deletions(-) diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index b148f816f25b..dc0cff59246d 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -1319,6 +1319,12 @@ struct bpf_map_desc { int uid; }; +struct bpf_dynptr_desc { + enum bpf_dynptr_type type; + u32 id; + u32 ref_obj_id; +}; + struct bpf_kfunc_call_arg_meta { /* In parameters */ struct btf *btf; @@ -1359,16 +1365,12 @@ struct bpf_kfunc_call_arg_meta { struct { struct btf_field *field; } arg_rbtree_root; - struct { - enum bpf_dynptr_type type; - u32 id; - u32 ref_obj_id; - } initialized_dynptr; struct { u8 spi; u8 frameno; } iter; struct bpf_map_desc map; + struct bpf_dynptr_desc dynptr; u64 mem_size; }; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 185210b73385..41e4ea41c72e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -232,6 +232,7 @@ static void bpf_map_key_store(struct bpf_insn_aux_data *aux, u64 state) struct bpf_call_arg_meta { struct bpf_map_desc map; + struct bpf_dynptr_desc dynptr; bool raw_mode; bool pkt_access; u8 release_regno; @@ -240,7 +241,6 @@ struct bpf_call_arg_meta { int mem_size; u64 msize_max_value; int ref_obj_id; - int dynptr_id; int func_id; struct btf *btf; u32 btf_id; @@ -434,11 +434,6 @@ static bool is_ptr_cast_function(enum bpf_func_id func_id) func_id == BPF_FUNC_skc_to_tcp_request_sock; } -static bool is_dynptr_ref_function(enum bpf_func_id func_id) -{ - return func_id == BPF_FUNC_dynptr_data; -} - static bool is_sync_callback_calling_kfunc(u32 btf_id); static bool is_async_callback_calling_kfunc(u32 btf_id); static bool is_callback_calling_kfunc(u32 btf_id); @@ -507,8 +502,6 @@ static bool helper_multiple_ref_obj_use(enum bpf_func_id func_id, ref_obj_uses++; if (is_acquire_function(func_id, map)) ref_obj_uses++; - if (is_dynptr_ref_function(func_id)) - ref_obj_uses++; return ref_obj_uses > 1; } @@ -7433,7 +7426,8 @@ static int process_kptr_func(struct bpf_verifier_env *env, int regno, * and checked dynamically during runtime. */ static int process_dynptr_func(struct bpf_verifier_env *env, int regno, int insn_idx, - enum bpf_arg_type arg_type, int clone_ref_obj_id) + enum bpf_arg_type arg_type, int clone_ref_obj_id, + struct bpf_dynptr_desc *dynptr) { struct bpf_reg_state *reg = reg_state(env, regno); int err; @@ -7499,6 +7493,20 @@ static int process_dynptr_func(struct bpf_verifier_env *env, int regno, int insn } err = mark_dynptr_read(env, reg); + + if (dynptr) { + struct bpf_func_state *state = bpf_func(env, reg); + int spi; + + if (reg->type != CONST_PTR_TO_DYNPTR) { + spi = dynptr_get_spi(env, reg); + reg = &state->stack[spi].spilled_ptr; + } + + dynptr->id = reg->id; + dynptr->type = reg->dynptr.type; + dynptr->ref_obj_id = reg->ref_obj_id; + } } return err; } @@ -8263,72 +8271,6 @@ static int check_func_arg_reg_off(struct bpf_verifier_env *env, } } -static struct bpf_reg_state *get_dynptr_arg_reg(struct bpf_verifier_env *env, - const struct bpf_func_proto *fn, - struct bpf_reg_state *regs) -{ - struct bpf_reg_state *state = NULL; - int i; - - for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) - if (arg_type_is_dynptr(fn->arg_type[i])) { - if (state) { - verbose(env, "verifier internal error: multiple dynptr args\n"); - return NULL; - } - state = ®s[BPF_REG_1 + i]; - } - - if (!state) - verbose(env, "verifier internal error: no dynptr arg found\n"); - - return state; -} - -static int dynptr_id(struct bpf_verifier_env *env, struct bpf_reg_state *reg) -{ - struct bpf_func_state *state = bpf_func(env, reg); - int spi; - - if (reg->type == CONST_PTR_TO_DYNPTR) - return reg->id; - spi = dynptr_get_spi(env, reg); - if (spi < 0) - return spi; - return state->stack[spi].spilled_ptr.id; -} - -static int dynptr_ref_obj_id(struct bpf_verifier_env *env, struct bpf_reg_state *reg) -{ - struct bpf_func_state *state = bpf_func(env, reg); - int spi; - - if (reg->type == CONST_PTR_TO_DYNPTR) - return reg->ref_obj_id; - spi = dynptr_get_spi(env, reg); - if (spi < 0) - return spi; - return state->stack[spi].spilled_ptr.ref_obj_id; -} - -static enum bpf_dynptr_type dynptr_get_type(struct bpf_verifier_env *env, - struct bpf_reg_state *reg) -{ - struct bpf_func_state *state = bpf_func(env, reg); - int spi; - - if (reg->type == CONST_PTR_TO_DYNPTR) - return reg->dynptr.type; - - spi = bpf_get_spi(reg->var_off.value); - if (spi < 0) { - verbose(env, "verifier internal error: invalid spi when querying dynptr type\n"); - return BPF_DYNPTR_TYPE_INVALID; - } - - return state->stack[spi].spilled_ptr.dynptr.type; -} - static int check_reg_const_str(struct bpf_verifier_env *env, struct bpf_reg_state *reg, u32 regno) { @@ -8683,7 +8625,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, true, meta); break; case ARG_PTR_TO_DYNPTR: - err = process_dynptr_func(env, regno, insn_idx, arg_type, 0); + err = process_dynptr_func(env, regno, insn_idx, arg_type, 0, &meta->dynptr); if (err) return err; break; @@ -9342,7 +9284,7 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog, if (ret) return ret; - ret = process_dynptr_func(env, regno, -1, arg->arg_type, 0); + ret = process_dynptr_func(env, regno, -1, arg->arg_type, 0, NULL); if (ret) return ret; } else if (base_type(arg->arg_type) == ARG_PTR_TO_BTF_ID) { @@ -10429,52 +10371,10 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn } } break; - case BPF_FUNC_dynptr_data: - { - struct bpf_reg_state *reg; - int id, ref_obj_id; - - reg = get_dynptr_arg_reg(env, fn, regs); - if (!reg) - return -EFAULT; - - - if (meta.dynptr_id) { - verifier_bug(env, "meta.dynptr_id already set"); - return -EFAULT; - } - if (meta.ref_obj_id) { - verifier_bug(env, "meta.ref_obj_id already set"); - return -EFAULT; - } - - id = dynptr_id(env, reg); - if (id < 0) { - verifier_bug(env, "failed to obtain dynptr id"); - return id; - } - - ref_obj_id = dynptr_ref_obj_id(env, reg); - if (ref_obj_id < 0) { - verifier_bug(env, "failed to obtain dynptr ref_obj_id"); - return ref_obj_id; - } - - meta.dynptr_id = id; - meta.ref_obj_id = ref_obj_id; - - break; - } case BPF_FUNC_dynptr_write: { - enum bpf_dynptr_type dynptr_type; - struct bpf_reg_state *reg; + enum bpf_dynptr_type dynptr_type = meta.dynptr.type; - reg = get_dynptr_arg_reg(env, fn, regs); - if (!reg) - return -EFAULT; - - dynptr_type = dynptr_get_type(env, reg); if (dynptr_type == BPF_DYNPTR_TYPE_INVALID) return -EFAULT; @@ -10665,10 +10565,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn return -EFAULT; } - if (is_dynptr_ref_function(func_id)) - regs[BPF_REG_0].dynptr_id = meta.dynptr_id; - - if (is_ptr_cast_function(func_id) || is_dynptr_ref_function(func_id)) { + if (is_ptr_cast_function(func_id)) { /* For release_reference() */ regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id; } else if (is_acquire_function(func_id, meta.map.ptr)) { @@ -10682,6 +10579,11 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn regs[BPF_REG_0].ref_obj_id = id; } + if (func_id == BPF_FUNC_dynptr_data) { + regs[BPF_REG_0].dynptr_id = meta.dynptr.id; + regs[BPF_REG_0].ref_obj_id = meta.dynptr.ref_obj_id; + } + err = do_refine_retval_range(env, regs, fn->ret_type, func_id, &meta); if (err) return err; @@ -12260,7 +12162,7 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ meta->release_regno = regno; } else if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_clone] && (dynptr_arg_type & MEM_UNINIT)) { - enum bpf_dynptr_type parent_type = meta->initialized_dynptr.type; + enum bpf_dynptr_type parent_type = meta->dynptr.type; if (parent_type == BPF_DYNPTR_TYPE_INVALID) { verifier_bug(env, "no dynptr type for parent of clone"); @@ -12268,29 +12170,17 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ } dynptr_arg_type |= (unsigned int)get_dynptr_type_flag(parent_type); - clone_ref_obj_id = meta->initialized_dynptr.ref_obj_id; + clone_ref_obj_id = meta->dynptr.ref_obj_id; if (dynptr_type_refcounted(parent_type) && !clone_ref_obj_id) { verifier_bug(env, "missing ref obj id for parent of clone"); return -EFAULT; } } - ret = process_dynptr_func(env, regno, insn_idx, dynptr_arg_type, clone_ref_obj_id); + ret = process_dynptr_func(env, regno, insn_idx, dynptr_arg_type, clone_ref_obj_id, + &meta->dynptr); if (ret < 0) return ret; - - if (!(dynptr_arg_type & MEM_UNINIT)) { - int id = dynptr_id(env, reg); - - if (id < 0) { - verifier_bug(env, "failed to obtain dynptr id"); - return id; - } - meta->initialized_dynptr.id = id; - meta->initialized_dynptr.type = dynptr_get_type(env, reg); - meta->initialized_dynptr.ref_obj_id = dynptr_ref_obj_id(env, reg); - } - break; } case KF_ARG_PTR_TO_ITER: @@ -12894,7 +12784,7 @@ static int check_special_kfunc(struct bpf_verifier_env *env, struct bpf_kfunc_ca } } else if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_slice] || meta->func_id == special_kfunc_list[KF_bpf_dynptr_slice_rdwr]) { - enum bpf_type_flag type_flag = get_dynptr_type_flag(meta->initialized_dynptr.type); + enum bpf_type_flag type_flag = get_dynptr_type_flag(meta->dynptr.type); mark_reg_known_zero(env, regs, BPF_REG_0); @@ -12918,11 +12808,11 @@ static int check_special_kfunc(struct bpf_verifier_env *env, struct bpf_kfunc_ca } } - if (!meta->initialized_dynptr.id) { + if (!meta->dynptr.id) { verifier_bug(env, "no dynptr id"); return -EFAULT; } - regs[BPF_REG_0].dynptr_id = meta->initialized_dynptr.id; + regs[BPF_REG_0].dynptr_id = meta->dynptr.id; /* we don't need to set BPF_REG_0's ref obj id * because packet slices are not refcounted (see @@ -13110,7 +13000,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, if (meta.release_regno) { struct bpf_reg_state *reg = ®s[meta.release_regno]; - if (meta.initialized_dynptr.ref_obj_id) { + if (meta.dynptr.ref_obj_id) { err = unmark_stack_slots_dynptr(env, reg); } else { err = release_reference(env, reg->ref_obj_id); -- 2.52.0