anbox-modules/binder/deps.c

208 lines
6.8 KiB
C

#include <linux/task_work.h>
#include <linux/sched.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/atomic.h>
#include <linux/ipc_namespace.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/kallsyms.h>
#include <linux/kprobes.h>
#include <linux/version.h>
#include <linux/task_work.h>
#include "deps.h"
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,7,0))
#ifndef CONFIG_KPROBES
# error "Your kernel does not support KProbes, but this is required to compile binder as a kernel module on kernel 5.7 and later"
#endif
typedef unsigned long (*kallsyms_lookup_name_t)(const char *name);
static int dummy_kprobe_handler(struct kprobe *p, struct pt_regs *regs)
{
return 0;
}
static kallsyms_lookup_name_t get_kallsyms_lookup_name_ptr(void)
{
struct kprobe probe;
int ret;
kallsyms_lookup_name_t addr;
memset(&probe, 0, sizeof(probe));
probe.pre_handler = dummy_kprobe_handler;
probe.symbol_name = "kallsyms_lookup_name";
ret = register_kprobe(&probe);
if (ret)
return NULL;
addr = (kallsyms_lookup_name_t) probe.addr;
unregister_kprobe(&probe);
return addr;
}
#endif
/*
* On kernel 5.7 and later, kallsyms_lookup_name() can no longer be called from a kernel
* module for reasons described here: https://lwn.net/Articles/813350/
* As binder really needs to use kallsysms_lookup_name() to access some kernel
* functions that otherwise wouldn't be accessible, KProbes are used on later
* kernels to get the address of kallsysms_lookup_name(). The function is
* afterwards used just as before. This is a very dirty hack though and the much
* better solution would be if all the functions that are currently resolved
* with kallsysms_lookup_name() would get an EXPORT_SYMBOL() annotation to
* make them directly accessible to kernel modules.
*/
static unsigned long kallsyms_lookup_name_wrapper(const char *name)
{
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,7,0))
static kallsyms_lookup_name_t func_ptr = NULL;
if (!func_ptr)
func_ptr = get_kallsyms_lookup_name_ptr();
return func_ptr(name);
#else
return kallsyms_lookup_name(name);
#endif
}
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,19,0))
static struct file *(*close_fd_get_file_ptr)(unsigned int fd)
#else
static int (*close_fd_get_file_ptr)(unsigned int fd, struct file **res)
#endif
= NULL;
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(6,8,0))
struct file *file_close_fd(unsigned int fd)
#elif (LINUX_VERSION_CODE >= KERNEL_VERSION(5,19,0))
struct file *close_fd_get_file(unsigned int fd)
#elif (LINUX_VERSION_CODE >= KERNEL_VERSION(5,11,0))
int close_fd_get_file(unsigned int fd, struct file **res)
#else
int __close_fd_get_file(unsigned int fd, struct file **res)
#endif
{
if (!close_fd_get_file_ptr)
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(6,8,0))
close_fd_get_file_ptr = kallsyms_lookup_name_wrapper("file_close_fd");
#elif (LINUX_VERSION_CODE >= KERNEL_VERSION(5,11,0))
close_fd_get_file_ptr = kallsyms_lookup_name_wrapper("close_fd_get_file");
#else
close_fd_get_file_ptr = kallsyms_lookup_name_wrapper("__close_fd_get_file");
#endif
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,19,0))
return close_fd_get_file_ptr(fd);
#else
return close_fd_get_file_ptr(fd, res);
#endif
}
static int (*can_nice_ptr)(const struct task_struct *, const int) = NULL;
int can_nice(const struct task_struct *p, const int nice)
{
if (!can_nice_ptr)
can_nice_ptr = kallsyms_lookup_name_wrapper("can_nice");
return can_nice_ptr(p, nice);
}
static void (*mmput_async_ptr)(struct mm_struct *mm) = NULL;
void mmput_async(struct mm_struct *mm)
{
if (!mmput_async_ptr)
mmput_async_ptr = kallsyms_lookup_name_wrapper("mmput_async");
return mmput_async_ptr(mm);
}
static int (*security_binder_set_context_mgr_ptr)(struct task_struct *mgr) = NULL;
int security_binder_set_context_mgr(struct task_struct *mgr)
{
if (!security_binder_set_context_mgr_ptr)
security_binder_set_context_mgr_ptr = kallsyms_lookup_name_wrapper("security_binder_set_context_mgr");
return security_binder_set_context_mgr_ptr(mgr);
}
static int (*security_binder_transaction_ptr)(struct task_struct *from, struct task_struct *to) = NULL;
int security_binder_transaction(struct task_struct *from, struct task_struct *to)
{
if (!security_binder_transaction_ptr)
security_binder_transaction_ptr = kallsyms_lookup_name_wrapper("security_binder_transaction");
return security_binder_transaction_ptr(from, to);
}
static int (*security_binder_transfer_binder_ptr)(struct task_struct *from, struct task_struct *to) = NULL;
int security_binder_transfer_binder(struct task_struct *from, struct task_struct *to)
{
if (!security_binder_transfer_binder_ptr)
security_binder_transfer_binder_ptr = kallsyms_lookup_name_wrapper("security_binder_transfer_binder");
return security_binder_transfer_binder_ptr(from, to);
}
static int (*security_binder_transfer_file_ptr)(struct task_struct *from, struct task_struct *to, struct file *file) = NULL;
int security_binder_transfer_file(struct task_struct *from, struct task_struct *to, struct file *file)
{
if (!security_binder_transfer_file_ptr)
security_binder_transfer_file_ptr = kallsyms_lookup_name_wrapper("security_binder_transfer_file");
return security_binder_transfer_file_ptr(from, to, file);
}
static int (*task_work_add_ptr)(struct task_struct *task, struct callback_head *work,
enum task_work_notify_mode notify) = NULL;
int task_work_add(struct task_struct *task, struct callback_head *work,
enum task_work_notify_mode notify)
{
if (!task_work_add_ptr)
task_work_add_ptr = kallsyms_lookup_name_wrapper("task_work_add");
return task_work_add_ptr(task, work, notify);
}
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(6,3,0))
static void (*zap_page_range_single_ptr)(struct vm_area_struct *, unsigned long, unsigned long, struct zap_details *) = NULL;
void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, unsigned long size, struct zap_details *details)
{
if (!zap_page_range_single_ptr)
zap_page_range_single_ptr = kallsyms_lookup_name_wrapper("zap_page_range_single");
zap_page_range_single_ptr(vma, address, size, details);
}
#else
static void (*zap_page_range_ptr)(struct vm_area_struct *, unsigned long, unsigned long) = NULL;
void zap_page_range(struct vm_area_struct *vma, unsigned long address, unsigned long size)
{
if (!zap_page_range_ptr)
zap_page_range_ptr = kallsyms_lookup_name_wrapper("zap_page_range");
zap_page_range_ptr(vma, address, size);
}
#endif
static void (*put_ipc_ns_ptr)(struct ipc_namespace *ns) = NULL;
void put_ipc_ns(struct ipc_namespace *ns)
{
if (!put_ipc_ns_ptr)
put_ipc_ns_ptr = kallsyms_lookup_name_wrapper("put_ipc_ns");
put_ipc_ns_ptr(ns);
}
static struct ipc_namespace *init_ipc_ns_ptr = NULL;
struct ipc_namespace *get_init_ipc_ns_ptr(void)
{
if (!init_ipc_ns_ptr)
init_ipc_ns_ptr = kallsyms_lookup_name_wrapper("init_ipc_ns");
return init_ipc_ns_ptr;
}