// SPDX-License-Identifier: ISC/* * Fuzz target: clm_tools_dispatch() * * Feeds arbitrary bytes as a JSON tool-calls array into the dispatch * engine. Tests how clm parses, validates, and handles adversarial * model responses with malformed or malicious tool calls. * * Build: CC=clang ninja -C build-fuzz fuzz/fuzz_tool_dispatch * Run:   ./build-fuzz/fuzz/fuzz_tool_dispatch */#include <errno.h>#include <stdbool.h>#include <stdint.h>#include <stdio.h>#include <stdlib.h>#include <string.h> #include <cjson/cJSON.h> #include "clm/clm.h"#include "clm/internal.h"#include "clm/cleanup.h" /* libFuzzer entry; declared here so -Wmissing-prototypes is satisfied. */int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size); /* ------------------------------------------------------------------ *//* Minimal stub host (no real I/O)                                     *//* ------------------------------------------------------------------ */ static intstub_http_post(void *ctx, const struct clm_http_req *req,               clm_http_success_cb success, clm_http_error_cb error,               clm_http_data_cb data, void *user,               struct clm_http_call **out){	(void)ctx; (void)req; (void)success; (void)error;	(void)data; (void)user;	if (out != NULL)		*out = NULL;	return -ENOSYS;} static intstub_timer_set(void *ctx, uint64_t ms, clm_timer_cb cb, void *arg,               struct clm_timer **out){	(void)ctx; (void)ms; (void)cb; (void)arg;	*out = NULL; /* no timer; dispatch runs immediately */	return 0;} static void stub_timer_cancel(struct clm_timer *t) { (void)t; }static void stub_http_cancel(struct clm_http_call *c) { (void)c; } static struct clm_host stub_host = {	.http_post    = stub_http_post,	.http_cancel  = stub_http_cancel,	.timer_set    = stub_timer_set,	.timer_cancel = stub_timer_cancel,}; /* ------------------------------------------------------------------ *//* Dummy tool: completes synchronously with fixed output               *//* ------------------------------------------------------------------ */ static voidnoop_invoke(struct clm_tool_invocation *inv, void *user){	(void)user;	clm_tool_complete(inv, "ok");} static voidregister_tool(struct clm_agent *agent, const char *name){	struct clm_tool_def def = {		.name          = name,		.description   = "dummy",		.params_schema = "{}",		.invoke        = noop_invoke,		.output_cap    = 4096,		.timeout_ms    = 5000,		.flags         = CLM_TOOL_NO_PROMPT, /* skip permission gate */	};	clm_tool_add(agent, &def);} /* ------------------------------------------------------------------ */ intLLVMFuzzerTestOneInput(const uint8_t *data, size_t size){	struct clm_agent *agent;	struct clm_cfg cfg;	json_cleanup cJSON *root = NULL;	cJSON *tool_calls = NULL; 	if (size == 0)		return 0; 	/* Parse fuzz input as JSON. Invalid input returns NULL, which is safe.	 * require_null_terminated=0: fuzz input is not guaranteed NUL-terminated	 * by the harness, but we pass an explicit length either way. */	root = cJSON_ParseWithLengthOpts((const char *)data, size, NULL, 0);	if (root == NULL)		return 0; 	/* Extract a JSON array (either top-level or nested under common keys). */	if (cJSON_IsArray(root)) {		tool_calls = root;	} else if (cJSON_IsObject(root)) {		cJSON *tc = cJSON_GetObjectItemCaseSensitive(root, "tool_calls");		if (tc == NULL)			tc = cJSON_GetObjectItemCaseSensitive(root, "choices");		if (tc == NULL)			tc = cJSON_GetObjectItemCaseSensitive(root, "arguments");		if (tc != NULL && cJSON_IsArray(tc))			tool_calls = tc;	} 	if (tool_calls == NULL || cJSON_GetArraySize(tool_calls) == 0)		return 0; 	/* Build a fresh agent per input. */	memset(&cfg, 0, sizeof(cfg));	cfg.api_key       = "fuzz";	cfg.base_url      = "http://localhost/v1/chat/completions";	cfg.provider      = CLM_PROVIDER_OPENAI;	cfg.model         = "fuzz-model";	cfg.system_prompt = "fuzz"; 	if (clm_agent_new(&cfg, &stub_host, NULL, NULL, &agent) < 0)		return 0; 	/* Register 512 dummy tools to stress the registry lookup. */	for (int i = 0; i < 512; i++) {		char name[32];		if (snprintf(name, sizeof(name), "tool_%d", i) > 0)			register_tool(agent, name);	} 	/* Dispatch the adversarial tool-calls array. */	clm_tools_dispatch(agent, tool_calls); 	clm_agent_free(agent);	return 0;}