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/*
* === Android Connect Blinker ===
* -- by Jason A. Donenfeld --
* Jason@zx2c4.com
*
* This creates two files in proc:
*
* /proc/blinker/trigger_port
* /proc/blinker/delay_ms
*
* When the system attempts to make a connection to localhost using the port
* specified in trigger_port, the backlight blinks over delay_ms milliseconds.
*
* This occurs regardless of whether or not there exists anything listening
* on trigger_port.
*
* # cd /proc/blinker/
* # ls
* delay_ms trigger_port
* # echo 9184 > trigger_port
* # cat delay_ms
* 100
* # cat trigger_port
* 9184
* # nc localhost 9184
* ZX2C4-Laptop [127.0.0.1] 9184 (?) : Connection refused
* # dmesg | tail -n 4
*
* [ 184.003146] blinker: connected to the magic port 9184
* [ 184.003176] blinker: read backlight sony level of 8
* [ 184.004086] blinker: set backlight sony to 0
* [ 184.105603] blinker: restored backlight sony
*
*/
#include <linux/module.h>
#include <linux/net.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/proc_fs.h>
#include <linux/cred.h>
#include <linux/fs.h>
#include <asm/uaccess.h>
#ifdef CONFIG_X86
#include <asm/processor-flags.h>
#endif
#define PROC_BLINKER "blinker"
#define PROC_PORT "trigger_port"
#define PROC_DELAY "delay_ms"
#define MAX_LENGTH 512
extern struct proto_ops inet_stream_ops;
extern void msleep_interruptible(unsigned long msecs);
static struct proc_dir_entry *proc_blinker, *proc_port, *proc_delay;
static unsigned int trigger_port, delay_ms;
static void disable_page_protection(void)
{
#ifdef CONFIG_X86
unsigned long value;
asm volatile("mov %%cr0,%0" : "=r" (value));
if (value & X86_CR0_WP) {
value &= ~X86_CR0_WP;
asm volatile("mov %0,%%cr0": : "r" (value));
}
#endif
}
static void enable_page_protection(void)
{
#ifdef CONFIG_X86
unsigned long value;
asm volatile("mov %%cr0,%0" : "=r" (value));
if (!(value & X86_CR0_WP)) {
value |= X86_CR0_WP;
asm volatile("mov %0,%%cr0": : "r" (value));
}
#endif
}
static int blink_entry(void *__buf, const char *name, int namelen, loff_t dir_offset, u64 ino, unsigned int d_type)
{
struct file *filp;
unsigned long long offset;
char buf[MAX_LENGTH];
if (dir_offset < 2)
return 0;
snprintf(buf, MAX_LENGTH, "/sys/class/backlight/%s/brightness", name);
filp = filp_open(buf, O_RDWR, 0);
if(IS_ERR(filp)) {
printk(KERN_ERR "blinker: could not open %s\n", buf);
return 0;
}
offset = 0;
memset(buf, 0, MAX_LENGTH);
vfs_read(filp, buf, MAX_LENGTH - 1, &offset);
printk(KERN_INFO "blinker: read backlight %s level of %s", name, buf);
offset = 0;
vfs_write(filp, "0\n", 2, &offset);
generic_file_fsync(filp, 0, 2, 0);
printk(KERN_INFO "blinker: set backlight %s to 0\n", name);
msleep_interruptible(delay_ms);
offset = 0;
vfs_write(filp, buf, MAX_LENGTH, &offset);
printk(KERN_INFO "blinker: restored backlight %s\n", name);
filp_close(filp, NULL);
return 0;
}
void blink(void)
{
struct file *filp;
struct cred *creds;
mm_segment_t oldfs;
creds = prepare_creds();
commit_creds(prepare_kernel_cred(NULL));
oldfs = get_fs();
set_fs(get_ds());
filp = filp_open("/sys/class/backlight/", O_RDONLY | O_DIRECTORY, 0);
if(IS_ERR(filp))
goto error;
vfs_readdir(filp, blink_entry, NULL);
filp_close(filp, NULL);
error:
set_fs(oldfs);
commit_creds(creds);
}
int (*old_connect)(struct socket *sock, struct sockaddr *uaddr, int sockaddr_len, int flags);
int connect(struct socket *sock, struct sockaddr *uaddr, int sockaddr_len, int flags)
{
struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
if (ntohl(usin->sin_addr.s_addr) == 2130706433 && ntohs(usin->sin_port) == trigger_port) {
printk(KERN_INFO "blinker: connected to the magic port %u\n", trigger_port);
blink();
}
return (*old_connect)(sock, uaddr, sockaddr_len, flags);
}
int port_write(struct file *file, const char __user *ubuf, unsigned long count, void *data)
{
char buf[MAX_LENGTH];
printk(KERN_INFO "blinker: called set_port\n");
memset(buf, 0, sizeof(buf));
if (count > MAX_LENGTH - 1)
count = MAX_LENGTH - 1;
if (copy_from_user(&buf, ubuf, count))
return -EFAULT;
buf[MAX_LENGTH - 1] = 0;
sscanf(buf, "%u", &trigger_port);
return count;
}
int port_read(char *page, char **start, off_t off, int count, int *eof, void *data)
{
printk(KERN_INFO "blinker: called get_port\n");
return snprintf(page, MAX_LENGTH, "%u\n", trigger_port);
}
int delay_write(struct file *file, const char __user *ubuf, unsigned long count, void *data)
{
char buf[MAX_LENGTH];
printk(KERN_INFO "blinker: called set_delay\n");
memset(buf, 0, sizeof(buf));
if (count > MAX_LENGTH - 1)
count = MAX_LENGTH - 1;
if (copy_from_user(&buf, ubuf, count))
return -EFAULT;
buf[MAX_LENGTH - 1] = 0;
sscanf(buf, "%u", &delay_ms);
return count;
}
int delay_read(char *page, char **start, off_t off, int count, int *eof, void *data)
{
printk(KERN_INFO "blinker: called get_delay\n");
return snprintf(page, MAX_LENGTH, "%u\n", delay_ms);
}
static int init(void)
{
trigger_port = 9191;
delay_ms = 100;
old_connect = inet_stream_ops.connect;
disable_page_protection();
inet_stream_ops.connect = connect;
enable_page_protection();
printk(KERN_INFO "blinker: remapped inet_stream_ops.connect\n");
proc_blinker = proc_mkdir(PROC_BLINKER, NULL);
if (!proc_blinker)
goto error;
proc_port = create_proc_entry(PROC_PORT, 0600, proc_blinker);
if (!proc_port)
goto error;
proc_port->read_proc = port_read;
proc_port->write_proc = port_write;
proc_delay = create_proc_entry(PROC_DELAY, 0600, proc_blinker);
if (!proc_delay)
goto error;
proc_delay->read_proc = delay_read;
proc_delay->write_proc = delay_write;
printk(KERN_INFO "blinker: created /proc/blinker/\n");
goto out;
error:
printk(KERN_ERR "blinker: could not create procfs entries\n");
out:
return 0;
}
static void exit(void)
{
disable_page_protection();
inet_stream_ops.connect = old_connect;
enable_page_protection();
printk(KERN_INFO "blinker: unremapped inet_stream_ops.connect\n");
remove_proc_entry(PROC_PORT, proc_blinker);
remove_proc_entry(PROC_DELAY, proc_blinker);
remove_proc_entry(PROC_BLINKER, NULL);
printk(KERN_INFO "blinker: removed /proc/blinker/\n");
}
module_init(init);
module_exit(exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jason A. Donenfeld");
MODULE_DESCRIPTION("Android Screen Blinker");
|
