405 lines
13 KiB
C
405 lines
13 KiB
C
#define _GNU_SOURCE
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#include <dlfcn.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <json-c/json.h>
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#include <stdbool.h> // 引入 bool 类型
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/ipc.h>
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#include <sys/shm.h>
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#include <sys/stat.h>
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#include <time.h>
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#include <unistd.h>
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#ifdef DEBUG
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#define DEBUG_LOG(fmt, ...) \
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fprintf(stderr, "[DEBUG] %s:%d:%s(): " fmt "\n", __FILE__, __LINE__, \
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__func__, ##__VA_ARGS__)
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#else
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#define DEBUG_LOG(fmt, ...) ((void)0)
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#endif
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#define CONFIG_FILE "/tmp/exec_hook/config/execve_rules.json"
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#define LOG_FILE "/tmp/exec_hook/logs/execve.log"
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#define LOG_OUT_FILE "/tmp/exec_hook/logs/execve_out.log"
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#define COMMAND_NOT_FOUND "/usr/lib/command-not-found"
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#define ANSI_COLOR_RED "\033[31m"
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#define ANSI_COLOR_YELLOW "\033[33m"
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#define ANSI_COLOR_RESET "\033[0m"
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#define SHM_KEY 12345 // 用于标识共享内存的键值，需要确保唯一性
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#define MAX_RULES 100 // 假设最大规则数量
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#define MAX_ARGS 10 // 支持最多 10 个参数
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typedef struct {
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char cmd[256];
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char type[32];
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char msg[1024];
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char args[MAX_ARGS][256]; // 支持最多 MAX_ARGS 个参数
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int arg_count;
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} Rule;
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typedef struct {
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bool enabled;
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Rule rules[MAX_RULES];
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int rule_count;
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} ConfigData;
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// 全局变量，指向共享内存中的配置数据
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static ConfigData *shared_config = NULL;
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static int shm_id = -1;
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static time_t last_modified_time = 0;
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// 加载配置到共享内存
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int load_config_to_shm() {
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DEBUG_LOG("Loading configuration from %s to shared memory", CONFIG_FILE);
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json_object *root = json_object_from_file(CONFIG_FILE);
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if (!root) {
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DEBUG_LOG("Failed to parse config file from %s", CONFIG_FILE);
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return -1;
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}
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ConfigData temp_config;
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temp_config.enabled = false;
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temp_config.rule_count = 0;
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json_object *enabled_obj;
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if (json_object_object_get_ex(root, "enabled", &enabled_obj)) {
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temp_config.enabled = json_object_get_boolean(enabled_obj);
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}
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if (!temp_config.enabled) {
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json_object_put(root);
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return 0; // 功能未启用，不加载规则
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}
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json_object *rules_array_obj;
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if (json_object_object_get_ex(root, "rules", &rules_array_obj) &&
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json_object_get_type(rules_array_obj) == json_type_array) {
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int rules_len = json_object_array_length(rules_array_obj);
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temp_config.rule_count = rules_len < MAX_RULES ? rules_len : MAX_RULES;
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for (int i = 0; i < temp_config.rule_count; i++) {
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json_object *rule_obj =
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json_object_array_get_idx(rules_array_obj, i);
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json_object *cmd, *type, *msg, *args;
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json_object_object_get_ex(rule_obj, "cmd", &cmd);
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json_object_object_get_ex(rule_obj, "type", &type);
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json_object_object_get_ex(rule_obj, "msg", &msg);
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if (cmd)
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strncpy(temp_config.rules[i].cmd, json_object_get_string(cmd),
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sizeof(temp_config.rules[i].cmd) - 1);
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if (type)
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strncpy(temp_config.rules[i].type, json_object_get_string(type),
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sizeof(temp_config.rules[i].type) - 1);
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if (msg)
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strncpy(temp_config.rules[i].msg, json_object_get_string(msg),
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sizeof(temp_config.rules[i].msg) - 1);
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// 解析 args 参数
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temp_config.rules[i].arg_count = 0;
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if (json_object_object_get_ex(rule_obj, "args", &args) &&
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json_object_get_type(args) == json_type_array) {
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int args_len = json_object_array_length(args);
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temp_config.rules[i].arg_count =
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args_len < MAX_ARGS ? args_len
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: MAX_ARGS; // 限制最多 MAX_ARGS 个参数
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for (int j = 0; j < temp_config.rules[i].arg_count; j++) {
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json_object *arg_item = json_object_array_get_idx(args, j);
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if (arg_item) {
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strncpy(temp_config.rules[i].args[j],
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json_object_get_string(arg_item),
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sizeof(temp_config.rules[i].args[j]) - 1);
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}
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}
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}
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}
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}
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json_object_put(root);
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// 将临时配置复制到共享内存
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memcpy(shared_config, &temp_config, sizeof(ConfigData));
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DEBUG_LOG("Loaded %d rules to shared memory", shared_config->rule_count);
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return 0;
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}
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// 检查 args 是否匹配
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int args_match(char *const argv[], Rule *rule) {
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DEBUG_LOG("Matching args for rule with cmd: %s", rule->cmd);
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if (rule->arg_count == 0) {
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return 1; // 没有 args 约束，则直接匹配
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}
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for (int i = 0; i < rule->arg_count; i++) {
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int found = 0;
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for (int j = 1; argv[j] != NULL; j++) { // 跳过 argv[0] (命令本身)
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if (strcmp(argv[j], rule->args[i]) == 0) {
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found = 1;
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break;
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}
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}
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if (!found) return 0; // 只要有一个参数没有匹配，则不符合规则
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}
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return 1;
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}
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// 写入日志
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void write_log(const char *filename, char *const argv[]) {
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DEBUG_LOG("Writing exec log for command: %s", filename);
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time_t now;
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time(&now);
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FILE *log = fopen(LOG_FILE, "a");
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if (!log) return;
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fprintf(log, "[%s] Command: %s\n", ctime(&now), filename);
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for (int i = 0; argv[i]; i++) {
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fprintf(log, "arg[%d]: %s\n", i, argv[i]);
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}
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fclose(log);
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}
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// 判断字符是否为 ANSI 转义序列
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int is_ansi_escape_sequence(const char *str) {
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// ANSI 转义序列的常见格式是以 ESC 开头，后跟 '[', 'm' 等
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return str[0] == '\033' && str[1] == '[';
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}
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// 保存原始的 write 函数指针
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static ssize_t (*original_write)(int fd, const void *buf, size_t count) = NULL;
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// 保存日志文件描述符
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static int log_fd = -1;
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// 我们自己的 write 函数
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ssize_t write(int fd, const void *buf, size_t count) {
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ssize_t result = -1;
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result = original_write(fd, buf, count);
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// 如果原始 write 成功，则将相同的内容写入日志文件
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if (result > 0 && log_fd != -1) {
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ssize_t log_result = original_write(log_fd, buf, count);
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if (log_result == -1) {
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fprintf(stderr, "Error writing to log file: %s\n", strerror(errno));
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// 注意：这里不应该影响原始 write 的返回值
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}
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}
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return result;
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}
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typedef int (*orig_execve_type)(const char *filename, char *const argv[],
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char *const envp[]);
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// 原始指针
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static orig_execve_type orig_execve = NULL;
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// 判断父进程是否为终端 shell (bash, zsh, fish 等)
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int is_terminal_shell() {
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pid_t ppid = getppid();
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char path[64], proc_name[256];
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FILE *file;
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snprintf(path, sizeof(path), "/proc/%d/comm", ppid);
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file = fopen(path, "r");
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if (!file) return 0;
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if (fgets(proc_name, sizeof(proc_name), file)) {
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proc_name[strcspn(proc_name, "\n")] = 0; // 去除换行符
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if (strcmp(proc_name, "bash") == 0 || strcmp(proc_name, "zsh") == 0 ||
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strcmp(proc_name, "fish") == 0 || strcmp(proc_name, "sh") == 0) {
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fclose(file);
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return 1;
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}
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}
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fclose(file);
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return 0;
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}
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// 检查配置文件是否已修改
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int config_file_modified() {
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struct stat file_stat;
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if (stat(CONFIG_FILE, &file_stat) != 0) {
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DEBUG_LOG("Cannot get stat for FILE: %s", CONFIG_FILE);
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return 0;
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}
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int isChanged = file_stat.st_mtime != last_modified_time;
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if (isChanged != 0) {
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DEBUG_LOG("Updating last_modified_time to: %ld", file_stat.st_mtime);
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last_modified_time = file_stat.st_mtime;
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return 1;
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}
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return 0;
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}
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// 加载或重新加载配置到共享内存
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void load_config_if_needed() {
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if (shared_config == NULL) {
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// 首次加载，创建共享内存
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shm_id = shmget(SHM_KEY, sizeof(ConfigData), IPC_CREAT | 0644);
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if (shm_id == -1) {
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perror("shmget failed");
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return;
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}
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shared_config = (ConfigData *)shmat(shm_id, NULL, 0);
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if (shared_config == (void *)-1) {
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perror("shmat failed");
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shared_config = NULL;
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return;
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}
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// 首次加载时读取配置文件
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struct stat file_stat;
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if (stat(CONFIG_FILE, &file_stat) == 0) {
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last_modified_time = file_stat.st_mtime;
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load_config_to_shm();
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} else {
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DEBUG_LOG("Cannot get stat for FILE: %s", CONFIG_FILE);
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// 初始化一个空的配置
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shared_config->enabled = false;
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shared_config->rule_count = 0;
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}
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} else if (config_file_modified()) {
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DEBUG_LOG("Config file has been modified.");
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load_config_to_shm();
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} else {
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DEBUG_LOG("Config file has not been modified, skipping reload.");
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}
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}
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int execve(const char *filename, char *const argv[], char *const envp[]) {
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DEBUG_LOG("Intercepted execve for: %s", filename);
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DEBUG_LOG("argv[0] = %s", argv[0]);
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// 仅在 shell 终端调用 execve 时拦截
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if (!is_terminal_shell()) {
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DEBUG_LOG("Not a terminal shell, bypassing interception.");
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return orig_execve(filename, argv, envp);
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}
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// 加载配置（仅在需要时）
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load_config_if_needed();
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// 当前配置信息
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DEBUG_LOG("Current Config rule count : %d", shared_config->rule_count);
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// 如果共享内存未成功加载，则直接执行
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if (shared_config == NULL) {
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DEBUG_LOG("Shared memory not initialized, bypassing interception.");
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return orig_execve(filename, argv, envp);
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}
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// 如果功能被禁用，则直接执行
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if (!shared_config->enabled) {
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DEBUG_LOG("Not enabled.");
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return orig_execve(filename, argv, envp);
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}
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write_log(filename, argv);
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const char *basename = argv[0];
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if (strcmp(filename, COMMAND_NOT_FOUND) == 0 && argv[2]) {
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basename = argv[2];
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}
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// 特殊处理以 shell.posix
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// 方式执行的命令，直接执行，不进行规则匹配和输出重定向
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if (argv[1] != NULL && strcmp(argv[1], "shell.posix") == 0) {
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return orig_execve(filename, argv, envp);
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}
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for (int i = 0; i < shared_config->rule_count; i++) {
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if (strcmp(basename, shared_config->rules[i].cmd) == 0 &&
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args_match(argv, &shared_config->rules[i])) {
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DEBUG_LOG("Rule matched: %s (type: %s)",
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shared_config->rules[i].cmd,
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shared_config->rules[i].type);
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if (strcmp(shared_config->rules[i].type, "warn") == 0) {
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printf(ANSI_COLOR_YELLOW "[Warning] %s\n" ANSI_COLOR_RESET,
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shared_config->rules[i].msg);
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printf("按下 'Y' 继续执行, 或按任意键取消: ");
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char input = getchar();
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if (input != 'Y' && input != 'y') {
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printf("\nExecution cancelled.\n");
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return -1;
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}
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printf("\nContinuing execution...\n");
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} else if (strcmp(shared_config->rules[i].type, "error") == 0) {
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printf(ANSI_COLOR_RED "[Error] %s" ANSI_COLOR_RESET "\n",
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shared_config->rules[i].msg);
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return -1;
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}
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break;
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}
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}
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// 复制 stdout 和 stderr 到日志文件
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// duplicate_output_to_log();
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return orig_execve(filename, argv, envp);
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}
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// 构造函数，在库被加载时执行
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__attribute__((constructor)) static void initialize() {
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DEBUG_LOG("Initializing execve_intercept library.");
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// 获取原始的 write 函数
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original_write = dlsym(RTLD_NEXT, "write");
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if (original_write == NULL) {
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fprintf(stderr, "Error in dlsym(\"write\"): %s\n", dlerror());
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exit(EXIT_FAILURE);
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}
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// 打开日志文件，以追加模式打开，如果不存在则创建
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log_fd = open(LOG_OUT_FILE, O_WRONLY | O_CREAT | O_APPEND, 0644);
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if (log_fd == -1) {
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fprintf(stderr, "Error opening log file \"%s\": %s\n", LOG_OUT_FILE,
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strerror(errno));
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exit(EXIT_FAILURE);
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}
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load_config_if_needed();
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orig_execve = (orig_execve_type)dlsym(RTLD_NEXT, "execve");
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if (orig_execve == NULL) {
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fprintf(stderr, "Error in dlsym(\"execve\"): %s\n", dlerror());
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exit(EXIT_FAILURE);
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}
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}
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// 在库卸载时分离和删除共享内存
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__attribute__((destructor)) static void cleanup_shared_memory() {
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DEBUG_LOG("Cleaning up shared memory.");
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if (shared_config != NULL) {
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if (shmdt(shared_config) == -1) {
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perror("shmdt failed");
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}
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shared_config = NULL;
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}
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if (log_fd != -1) {
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DEBUG_LOG("Closing log file descriptor.");
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close(log_fd);
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}
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// 注意：这里不删除共享内存段，因为可能被其他进程使用。
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// 如果需要删除，需要一个明确的机制来判断是否是最后一个使用者。
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// 例如，可以创建一个单独的工具来管理共享内存的生命周期。
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}
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__attribute__((destructor)) static void debug_log() {
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DEBUG_LOG("execve_intercept library unloaded.");
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// log输出路径
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DEBUG_LOG("Log file: %s", LOG_FILE);
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DEBUG_LOG("Log out file: %s", LOG_OUT_FILE);
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DEBUG_LOG("Config file: %s", CONFIG_FILE);
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DEBUG_LOG("Shared memory ID: %d", shm_id);
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}
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