基于PAM自定义ssh登陆认证

本文主要是介绍基于PAM自定义ssh登陆认证，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

以下是一个基于Linux PAM认证SSH登录的动态链接库（.so）模块的示例代码，使用C语言编写，其中包括对用户名、密码以及约定的口令的认证：

```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <security/pam_appl.h>
#include <security/pam_modules.h>

PAM_EXTERN int pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc, const char **argv) {
const char *username = NULL;
const char *password = NULL;
const char *secret = "mypassword"; // 替换为约定的口令
const void *conv_ptr = NULL;
struct pam_conv *conv = NULL;
struct pam_message msg;
const struct pam_message *pmsg = &msg;
struct pam_response *resp = NULL;
int retval;

// 获取用户名
retval = pam_get_user(pamh, &username, "Username: ");
if (retval != PAM_SUCCESS) {
return retval;
}

// 获取密码
retval = pam_get_authtok(pamh, PAM_AUTHTOK, &password, "Password: ");
if (retval != PAM_SUCCESS) {
return retval;
}

// 获取对话函数指针
retval = pam_get_item(pamh, PAM_CONV, &conv_ptr);
if (retval != PAM_SUCCESS || conv_ptr == NULL) {
return retval;
}

conv = (struct pam_conv *)conv_ptr;

// 提示用户输入约定的口令
msg.msg = "Secret: ";
msg.msg_style = PAM_PROMPT_ECHO_OFF;
retval = conv->conv(1, &pmsg, &resp, conv->appdata_ptr);
if (retval != PAM_SUCCESS) {
return retval;
}

// 验证约定的口令
if (strcmp(resp->resp, secret) == 0) {
retval = PAM_SUCCESS;
} else {
retval = PAM_AUTH_ERR;
}

// 清理内存
if (resp != NULL) {
memset(resp->resp, 0, strlen(resp->resp));
free(resp->resp);
free(resp);
}

return retval;
}
```