Refactor kprobe handler for usb_submit_urb to improve data copying and logging on ARM64;
目前可以阻断，但是会返回用户空间错误码，并且只在libusb模式下测试过了，键盘设备会卡建
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kylin_bg
parent
4bba36cdb9
commit
6c40865f39
99
libusbMod.c
99
libusbMod.c
@ -1,63 +1,96 @@
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/usbdevice_fs.h>
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#include <linux/kprobes.h>
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#include <linux/sched.h>
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#include <linux/uaccess.h> // for copy_from_user
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#include <linux/sched.h> // for current->comm, current->pid
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#include <linux/uaccess.h> // for copy_from_user, copy_to_user (如果需要访问用户空间内存)
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#include <linux/usb.h> // 包含 USB 核心数据结构，如 struct urb
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Leo");
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MODULE_DESCRIPTION("Hook USBDEVFS_SUBMITURB ioctl on arm64");
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MODULE_DESCRIPTION("Hook usb_submit_urb ioctl on arm64"); // 这里的注释可能不完全准确，usb_submit_urb不是ioctl，是内核函数
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static struct kprobe kp;
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// 针对 ARM64 (AArch64) 架构，函数参数通常在 x0, x1, x2... 寄存器中。
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// pt_regs 中的 regs 数组索引通常对应这些寄存器。
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// 对于 AArch64，x0 是 regs[0]，x1 是 regs[1]，以此类推。
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// usb_submit_urb 函数原型通常是：int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
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// 所以第一个参数 struct urb *urb 应该在 x0 寄存器中，对应 regs[0]。
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static int handler_pre(struct kprobe *p, struct pt_regs *regs)
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{
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unsigned int cmd = 0;
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struct usbdevfs_urb urb_kern;
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struct usbdevfs_urb __user *urb_user;
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// !!! 核心修改点：在 ARM64 上，函数第一个参数通常在 x0 (regs[0]) !!!
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struct urb *urb_kern = (struct urb *)regs->regs[0];
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cmd = (unsigned int)regs->regs[1]; // ioctl 的第二个参数
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// 严谨的空指针检查
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if (!urb_kern) {
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pr_err("[usbFilter] handler_pre: urb_kern is NULL. Skipping.\n");
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return 0; // KPROBE_OK, 让原始函数继续执行，避免崩溃
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}
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if (cmd == USBDEVFS_SUBMITURB) {
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urb_user = (struct usbdevfs_urb __user *)regs->regs[2]; // 第三个参数
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if (urb_user) {
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if (copy_from_user(&urb_kern, urb_user, sizeof(struct usbdevfs_urb)) == 0) {
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pr_info("[usbFilter] process: %s, pid: %d, ep: 0x%x, len: %d\n",
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current->comm, current->pid,
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urb_kern.endpoint, urb_kern.buffer_length);
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// 打印进程信息、PID
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pr_info("[usbFilter] process: %s, pid: %d\n",
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current->comm, current->pid);
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if (urb_kern.buffer && urb_kern.buffer_length > 0) {
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unsigned char data[16] = {0};
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unsigned int to_copy = urb_kern.buffer_length > 16 ? 16 : urb_kern.buffer_length;
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if (copy_from_user(data, urb_kern.buffer, to_copy) == 0) {
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char hex[3 * 16 + 1] = {0};
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int i;
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for (i = 0; i < to_copy; ++i)
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snprintf(hex + i * 3, 4, "%02X ", data[i]);
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pr_info("[usbFilter] first %u bytes (hex): %s\n", to_copy, hex);
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} else {
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pr_warn("[usbFilter] copy_from_user buffer failed\n");
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}
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}
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} else {
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pr_warn("[usbFilter] copy_from_user failed\n");
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// 获取端点地址、传输长度和 pipe 信息
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pr_info("[usbFilter] urb_kern: %p, pipe: 0x%08x, ep: 0x%x, len: %d\n",
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urb_kern,
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urb_kern->pipe, // 新增打印 pipe 信息
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urb_kern->ep ? urb_kern->ep->desc.bEndpointAddress : 0, // 检查 urb_kern->ep
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urb_kern->transfer_buffer_length);
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if (urb_kern->transfer_buffer && urb_kern->transfer_buffer_length > 0) {
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unsigned char data[16] = {0}; // 局部缓冲区，用于存放拷贝的数据
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unsigned int to_copy = min((unsigned int)16, urb_kern->transfer_buffer_length);
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bool data_copied_successfully = false;
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// 尝试从用户空间拷贝
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if (copy_from_user(data, urb_kern->transfer_buffer, to_copy) == 0) { // 0 表示成功
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pr_info("[usbFilter] Successfully copied %u bytes using copy_from_user from user buffer at %p.\n", to_copy, urb_kern->transfer_buffer);
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data_copied_successfully = true;
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} else {
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// copy_from_user 失败
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pr_warn("[usbFilter] copy_from_user failed for buffer at %p. Attempting memcpy (assuming buffer is in kernel space).\n", urb_kern->transfer_buffer);
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// 警告：如果 transfer_buffer 不是有效的内核地址，memcpy 可能会导致内核崩溃。
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// 这仅作为调试时的后备尝试。
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memcpy(data, urb_kern->transfer_buffer, to_copy);
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// 如果 memcpy 没有导致崩溃，我们假设数据为了打印目的是成功拷贝的。
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pr_info("[usbFilter] memcpy attempted for %u bytes from buffer at %p (assumed kernel space).\n", to_copy, urb_kern->transfer_buffer);
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data_copied_successfully = true; // 标记为成功，以便后续打印
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}
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if (data_copied_successfully) {
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char hex[3 * 16 + 1] = {0}; // 用于存放十六进制字符串
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int i;
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for (i = 0; i < to_copy; ++i) {
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// 确保 snprintf 不会溢出 hex 缓冲区
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snprintf(hex + i * 3, sizeof(hex) - (i * 3), "%02X ", data[i]);
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}
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pr_info("[usbFilter] first %u bytes (hex): %s\n", to_copy, hex);
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}
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}
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return 0;
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regs->regs[0] = 0; // 设置 x0 寄存器（返回值）为 0 (成功)
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// return 0; // KPROBE_OK，默认让原始函数继续执行
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// 如果要阻断，这里返回 1 (KPROBE_HANDLED)x
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return 1;
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}
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static int __init usb_hook_init(void)
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{
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kp.symbol_name = "usbdev_do_ioctl";
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// usb_submit_urb 是一个导出的符号，Kprobe 可以 Hook
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kp.symbol_name = "usb_submit_urb";
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kp.pre_handler = handler_pre;
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if (register_kprobe(&kp) < 0) {
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pr_err("[usbFilter] register_kprobe failed\n");
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return -1;
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}
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pr_info("[usbFilter] kprobe registered for %s\n", kp.symbol_name);
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pr_info("[usbFilter] kprobe registered for %s at %p\n", kp.symbol_name, kp.addr);
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return 0;
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}
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