check_func_arg() derives every argument from BPF_REG_1 + arg. That works for helpers, which have at most five arguments, but kfunc arguments beyond the fifth are passed on the stack. Switch to the argno_t addressing used by check_kfunc_args(): obtain argument state with get_func_arg_reg(), use argno for diagnostics, and call check_reg_arg() only when the argument is held in a register. This prepares check_func_arg() to be shared with kfunc verification. There is no functional change for helpers. reg_arg_name() renders their register arguments as R%d, so the updated diagnostics remain unchanged. Signed-off-by: Amery Hung --- kernel/bpf/verifier.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index f49c90beefc5..30e1f7a7553e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -8769,10 +8769,12 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, int insn_idx) { const struct bpf_func_proto *fn = meta->fn; - u32 regno = BPF_REG_1 + arg; - struct bpf_reg_state *reg = reg_state(env, regno); + struct bpf_func_state *caller = cur_func(env); + struct bpf_reg_state *regs = cur_regs(env); + argno_t argno = argno_from_arg(arg + 1); + struct bpf_reg_state *reg = get_func_arg_reg(caller, regs, arg); enum bpf_arg_type arg_type = fn->arg_type[arg]; - argno_t argno = argno_from_reg(regno); + int regno = reg_from_argno(argno); enum bpf_reg_type type = reg->type; u32 *arg_btf_id = NULL; u32 key_size; @@ -8786,9 +8788,9 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, return err; if (arg_type == ARG_ANYTHING) { - if (is_pointer_value(env, regno)) { - verbose(env, "R%d leaks addr into helper function\n", - regno); + if (__is_pointer_value(env->allow_ptr_leaks, reg)) { + verbose(env, "%s leaks addr into helper function\n", + reg_arg_name(env, argno)); return -EACCES; } return 0; @@ -8904,7 +8906,8 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, break; case ARG_PTR_TO_PERCPU_BTF_ID: if (!reg->btf_id) { - verbose(env, "Helper has invalid btf_id in R%d\n", regno); + verbose(env, "Helper has invalid btf_id in %s\n", + reg_arg_name(env, argno)); return -EACCES; } meta->ret_btf = reg->btf; @@ -8941,7 +8944,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, * next is_mem_size argument below. */ if (arg_type & MEM_FIXED_SIZE) { - err = check_mem_reg(env, reg, argno_from_reg(regno), fn->arg_size[arg], + err = check_mem_reg(env, reg, argno, fn->arg_size[arg], arg_type & MEM_WRITE ? BPF_WRITE : BPF_READ, meta, NULL); if (err) return err; @@ -8950,14 +8953,14 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, } break; case ARG_MEM_SIZE: - err = check_mem_size_reg(env, reg_state(env, regno - 1), reg, - argno_from_reg(regno - 1), argno, + err = check_mem_size_reg(env, get_func_arg_reg(caller, regs, arg - 1), reg, + argno_from_arg(arg), argno, fn->arg_type[arg - 1] & MEM_WRITE ? BPF_WRITE : BPF_READ, false, meta, NULL); break; case ARG_MEM_SIZE_OR_ZERO: - err = check_mem_size_reg(env, reg_state(env, regno - 1), reg, - argno_from_reg(regno - 1), argno, + err = check_mem_size_reg(env, get_func_arg_reg(caller, regs, arg - 1), reg, + argno_from_arg(arg), argno, fn->arg_type[arg - 1] & MEM_WRITE ? BPF_WRITE : BPF_READ, true, meta, NULL); break; -- 2.52.0