[kbuild-all] Re: [PATCH bpf-next 1/5] bpf: Add a ARG_PTR_TO_CONST_STR argument type

Hi Florent, I love your patch! Perhaps something to improve: [auto build test WARNING on bpf-next/master] url: https://github.com/0day-ci/linux/commits/Florent-Revest/bpf-Add-a-ARG_PTR... base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master config: openrisc-randconfig-r023-20210308 (attached as .config) compiler: or1k-linux-gcc (GCC) 9.3.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/0day-ci/linux/commit/cbb95ec99fafe0955aeada270c9be3d14... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Florent-Revest/bpf-Add-a-ARG_PTR_TO_CONST_STR-argument-type/20210311-070306 git checkout cbb95ec99fafe0955aeada270c9be3d1477c3866 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=openrisc If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): kernel/bpf/verifier.c: In function 'check_func_arg': 4918 | map_ptr = (char *)(map_addr); | ^ In file included from include/linux/bpf_verifier.h:9, from kernel/bpf/verifier.c:12: kernel/bpf/verifier.c: In function 'jit_subprogs': include/linux/filter.h:363:4: warning: cast between incompatible function types from 'unsigned int (*)(const void *, const struct bpf_insn *)' to 'u64 (*)(u64, u64, u64, u64, u64)' {aka 'long long unsigned int (*)(long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int)'} [-Wcast-function-type] 363 | ((u64 (*)(u64, u64, u64, u64, u64))(x)) | ^ kernel/bpf/verifier.c:11728:16: note: in expansion of macro 'BPF_CAST_CALL' 11728 | insn->imm = BPF_CAST_CALL(func[subprog]->bpf_func) - | ^~~~~~~~~~~~~ kernel/bpf/verifier.c: In function 'do_misc_fixups': include/linux/filter.h:363:4: warning: cast between incompatible function types from 'void * (* const)(struct bpf_map *, void *)' to 'u64 (*)(u64, u64, u64, u64, u64)' {aka 'long long unsigned int (*)(long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int)'} [-Wcast-function-type] 363 | ((u64 (*)(u64, u64, u64, u64, u64))(x)) | ^ kernel/bpf/verifier.c:12136:17: note: in expansion of macro 'BPF_CAST_CALL' 12136 | insn->imm = BPF_CAST_CALL(ops->map_lookup_elem) - | ^~~~~~~~~~~~~ include/linux/filter.h:363:4: warning: cast between incompatible function types from 'int (* const)(struct bpf_map *, void *, void *, u64)' {aka 'int (* const)(struct bpf_map *, void *, void *, long long unsigned int)'} to 'u64 (*)(u64, u64, u64, u64, u64)' {aka 'long long unsigned int (*)(long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int)'} [-Wcast-function-type] 363 | ((u64 (*)(u64, u64, u64, u64, u64))(x)) | ^ kernel/bpf/verifier.c:12140:17: note: in expansion of macro 'BPF_CAST_CALL' 12140 | insn->imm = BPF_CAST_CALL(ops->map_update_elem) - | ^~~~~~~~~~~~~ include/linux/filter.h:363:4: warning: cast between incompatible function types from 'int (* const)(struct bpf_map *, void *)' to 'u64 (*)(u64, u64, u64, u64, u64)' {aka 'long long unsigned int (*)(long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int)'} [-Wcast-function-type] 363 | ((u64 (*)(u64, u64, u64, u64, u64))(x)) | ^ kernel/bpf/verifier.c:12144:17: note: in expansion of macro 'BPF_CAST_CALL' 12144 | insn->imm = BPF_CAST_CALL(ops->map_delete_elem) - | ^~~~~~~~~~~~~ include/linux/filter.h:363:4: warning: cast between incompatible function types from 'int (* const)(struct bpf_map *, void *, u64)' {aka 'int (* const)(struct bpf_map *, void *, long long unsigned int)'} to 'u64 (*)(u64, u64, u64, u64, u64)' {aka 'long long unsigned int (*)(long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int)'} [-Wcast-function-type] 363 | ((u64 (*)(u64, u64, u64, u64, u64))(x)) | ^ kernel/bpf/verifier.c:12148:17: note: in expansion of macro 'BPF_CAST_CALL' 12148 | insn->imm = BPF_CAST_CALL(ops->map_push_elem) - | ^~~~~~~~~~~~~ include/linux/filter.h:363:4: warning: cast between incompatible function types from 'int (* const)(struct bpf_map *, void *)' to 'u64 (*)(u64, u64, u64, u64, u64)' {aka 'long long unsigned int (*)(long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int)'} [-Wcast-function-type] 363 | ((u64 (*)(u64, u64, u64, u64, u64))(x)) | ^ kernel/bpf/verifier.c:12152:17: note: in expansion of macro 'BPF_CAST_CALL' 12152 | insn->imm = BPF_CAST_CALL(ops->map_pop_elem) - | ^~~~~~~~~~~~~ include/linux/filter.h:363:4: warning: cast between incompatible function types from 'int (* const)(struct bpf_map *, void *)' to 'u64 (*)(u64, u64, u64, u64, u64)' {aka 'long long unsigned int (*)(long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int)'} [-Wcast-function-type] 363 | ((u64 (*)(u64, u64, u64, u64, u64))(x)) | ^ kernel/bpf/verifier.c:12156:17: note: in expansion of macro 'BPF_CAST_CALL' 12156 | insn->imm = BPF_CAST_CALL(ops->map_peek_elem) - | ^~~~~~~~~~~~~ include/linux/filter.h:363:4: warning: cast between incompatible function types from 'int (* const)(struct bpf_map *, u32, u64)' {aka 'int (* const)(struct bpf_map *, unsigned int, long long unsigned int)'} to 'u64 (*)(u64, u64, u64, u64, u64)' {aka 'long long unsigned int (*)(long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int, long long unsigned int)'} [-Wcast-function-type] 363 | ((u64 (*)(u64, u64, u64, u64, u64))(x)) | ^ kernel/bpf/verifier.c:12160:17: note: in expansion of macro 'BPF_CAST_CALL' 12160 | insn->imm = BPF_CAST_CALL(ops->map_redirect) - | ^~~~~~~~~~~~~ vim +4918 kernel/bpf/verifier.c 4695 4696 static int check_func_arg(struct bpf_verifier_env *env, u32 arg, 4697 struct bpf_call_arg_meta *meta, 4698 const struct bpf_func_proto *fn) 4699 { 4700 u32 regno = BPF_REG_1 + arg; 4701 struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno]; 4702 enum bpf_arg_type arg_type = fn->arg_type[arg]; 4703 enum bpf_reg_type type = reg->type; 4704 int err = 0; 4705 4706 if (arg_type == ARG_DONTCARE) 4707 return 0; 4708 4709 err = check_reg_arg(env, regno, SRC_OP); 4710 if (err) 4711 return err; 4712 4713 if (arg_type == ARG_ANYTHING) { 4714 if (is_pointer_value(env, regno)) { 4715 verbose(env, "R%d leaks addr into helper function\n", 4716 regno); 4717 return -EACCES; 4718 } 4719 return 0; 4720 } 4721 4722 if (type_is_pkt_pointer(type) && 4723 !may_access_direct_pkt_data(env, meta, BPF_READ)) { 4724 verbose(env, "helper access to the packet is not allowed\n"); 4725 return -EACCES; 4726 } 4727 4728 if (arg_type == ARG_PTR_TO_MAP_VALUE || 4729 arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE || 4730 arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL) { 4731 err = resolve_map_arg_type(env, meta, &arg_type); 4732 if (err) 4733 return err; 4734 } 4735 4736 if (register_is_null(reg) && arg_type_may_be_null(arg_type)) 4737 /* A NULL register has a SCALAR_VALUE type, so skip 4738 * type checking. 4739 */ 4740 goto skip_type_check; 4741 4742 err = check_reg_type(env, regno, arg_type, fn->arg_btf_id[arg]); 4743 if (err) 4744 return err; 4745 4746 if (type == PTR_TO_CTX) { 4747 err = check_ctx_reg(env, reg, regno); 4748 if (err < 0) 4749 return err; 4750 } 4751 4752 skip_type_check: 4753 if (reg->ref_obj_id) { 4754 if (meta->ref_obj_id) { 4755 verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n", 4756 regno, reg->ref_obj_id, 4757 meta->ref_obj_id); 4758 return -EFAULT; 4759 } 4760 meta->ref_obj_id = reg->ref_obj_id; 4761 } 4762 4763 if (arg_type == ARG_CONST_MAP_PTR) { 4764 /* bpf_map_xxx(map_ptr) call: remember that map_ptr */ 4765 meta->map_ptr = reg->map_ptr; 4766 } else if (arg_type == ARG_PTR_TO_MAP_KEY) { 4767 /* bpf_map_xxx(..., map_ptr, ..., key) call: 4768 * check that [key, key + map->key_size) are within 4769 * stack limits and initialized 4770 */ 4771 if (!meta->map_ptr) { 4772 /* in function declaration map_ptr must come before 4773 * map_key, so that it's verified and known before 4774 * we have to check map_key here. Otherwise it means 4775 * that kernel subsystem misconfigured verifier 4776 */ 4777 verbose(env, "invalid map_ptr to access map->key\n"); 4778 return -EACCES; 4779 } 4780 err = check_helper_mem_access(env, regno, 4781 meta->map_ptr->key_size, false, 4782 NULL); 4783 } else if (arg_type == ARG_PTR_TO_MAP_VALUE || 4784 (arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL && 4785 !register_is_null(reg)) || 4786 arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE) { 4787 /* bpf_map_xxx(..., map_ptr, ..., value) call: 4788 * check [value, value + map->value_size) validity 4789 */ 4790 if (!meta->map_ptr) { 4791 /* kernel subsystem misconfigured verifier */ 4792 verbose(env, "invalid map_ptr to access map->value\n"); 4793 return -EACCES; 4794 } 4795 meta->raw_mode = (arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE); 4796 err = check_helper_mem_access(env, regno, 4797 meta->map_ptr->value_size, false, 4798 meta); 4799 } else if (arg_type == ARG_PTR_TO_PERCPU_BTF_ID) { 4800 if (!reg->btf_id) { 4801 verbose(env, "Helper has invalid btf_id in R%d\n", regno); 4802 return -EACCES; 4803 } 4804 meta->ret_btf = reg->btf; 4805 meta->ret_btf_id = reg->btf_id; 4806 } else if (arg_type == ARG_PTR_TO_SPIN_LOCK) { 4807 if (meta->func_id == BPF_FUNC_spin_lock) { 4808 if (process_spin_lock(env, regno, true)) 4809 return -EACCES; 4810 } else if (meta->func_id == BPF_FUNC_spin_unlock) { 4811 if (process_spin_lock(env, regno, false)) 4812 return -EACCES; 4813 } else { 4814 verbose(env, "verifier internal error\n"); 4815 return -EFAULT; 4816 } 4817 } else if (arg_type == ARG_PTR_TO_FUNC) { 4818 meta->subprogno = reg->subprogno; 4819 } else if (arg_type_is_mem_ptr(arg_type)) { 4820 /* The access to this pointer is only checked when we hit the 4821 * next is_mem_size argument below. 4822 */ 4823 meta->raw_mode = (arg_type == ARG_PTR_TO_UNINIT_MEM); 4824 } else if (arg_type_is_mem_size(arg_type)) { 4825 bool zero_size_allowed = (arg_type == ARG_CONST_SIZE_OR_ZERO); 4826 4827 /* This is used to refine r0 return value bounds for helpers 4828 * that enforce this value as an upper bound on return values. 4829 * See do_refine_retval_range() for helpers that can refine 4830 * the return value. C type of helper is u32 so we pull register 4831 * bound from umax_value however, if negative verifier errors 4832 * out. Only upper bounds can be learned because retval is an 4833 * int type and negative retvals are allowed. 4834 */ 4835 meta->msize_max_value = reg->umax_value; 4836 4837 /* The register is SCALAR_VALUE; the access check 4838 * happens using its boundaries. 4839 */ 4840 if (!tnum_is_const(reg->var_off)) 4841 /* For unprivileged variable accesses, disable raw 4842 * mode so that the program is required to 4843 * initialize all the memory that the helper could 4844 * just partially fill up. 4845 */ 4846 meta = NULL; 4847 4848 if (reg->smin_value < 0) { 4849 verbose(env, "R%d min value is negative, either use unsigned or 'var &= const'\n", 4850 regno); 4851 return -EACCES; 4852 } 4853 4854 if (reg->umin_value == 0) { 4855 err = check_helper_mem_access(env, regno - 1, 0, 4856 zero_size_allowed, 4857 meta); 4858 if (err) 4859 return err; 4860 } 4861 4862 if (reg->umax_value >= BPF_MAX_VAR_SIZ) { 4863 verbose(env, "R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n", 4864 regno); 4865 return -EACCES; 4866 } 4867 err = check_helper_mem_access(env, regno - 1, 4868 reg->umax_value, 4869 zero_size_allowed, meta); 4870 if (!err) 4871 err = mark_chain_precision(env, regno); 4872 } else if (arg_type_is_alloc_size(arg_type)) { 4873 if (!tnum_is_const(reg->var_off)) { 4874 verbose(env, "R%d is not a known constant'\n", 4875 regno); 4876 return -EACCES; 4877 } 4878 meta->mem_size = reg->var_off.value; 4879 } else if (arg_type_is_int_ptr(arg_type)) { 4880 int size = int_ptr_type_to_size(arg_type); 4881 4882 err = check_helper_mem_access(env, regno, size, false, meta); 4883 if (err) 4884 return err; 4885 err = check_ptr_alignment(env, reg, 0, size, true); 4886 } else if (arg_type == ARG_PTR_TO_CONST_STR) { 4887 struct bpf_map *map = reg->map_ptr; 4888 int map_off, i; 4889 u64 map_addr; 4890 char *map_ptr; 4891 4892 if (!map || !bpf_map_is_rdonly(map)) { 4893 verbose(env, "R%d does not point to a readonly map'\n", regno); 4894 return -EACCES; 4895 } 4896 4897 if (!tnum_is_const(reg->var_off)) { 4898 verbose(env, "R%d is not a constant address'\n", regno); 4899 return -EACCES; 4900 } 4901 4902 if (!map->ops->map_direct_value_addr) { 4903 verbose(env, "no direct value access support for this map type\n"); 4904 return -EACCES; 4905 } 4906 4907 err = check_helper_mem_access(env, regno, 4908 map->value_size - reg->off, 4909 false, meta); 4910 if (err) 4911 return err; 4912 4913 map_off = reg->off + reg->var_off.value; 4914 err = map->ops->map_direct_value_addr(map, &map_addr, map_off); 4915 if (err) 4916 return err; 4917 4919 for (i = map_off; map_ptr[i] != '\0'; i++) { 4920 if (i == map->value_size - 1) { 4921 verbose(env, "map does not contain a NULL-terminated string\n"); 4922 return -EACCES; 4923 } 4924 } 4925 } 4926 4927 return err; 4928 } 4929 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org