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android_system_core/toolbox/getevent.c
Michael Wright 344e929e6d Only allow system to write to existing input nodes. 
This prevents the shell user from injecting input as if it were coming
from an existing input device, which in turn makes it easier for malware
/ abuse analysis to detect when someone is injecting input via the
command line vs a real user using a device.

(cherrypick of 95637eb2a332b9a09914b1bf32c10fccfba4a175.)

Bug: 30861057
Test: ran getevent, saw correct output, played with device
Change-Id: Ib53eea1b7767f25510b5d36fe6109101a9fad8e0
2017-02-09 14:45:25 -08:00

689 lines
21 KiB
C
Raw Blame History

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <dirent.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/inotify.h>
#include <sys/limits.h>
#include <sys/poll.h>
#include <linux/input.h>
#include <err.h>
#include <errno.h>
#include <unistd.h>
struct label {
const char *name;
int value;
};
#define LABEL(constant) { #constant, constant }
#define LABEL_END { NULL, -1 }
static struct label key_value_labels[] = {
{ "UP", 0 },
{ "DOWN", 1 },
{ "REPEAT", 2 },
LABEL_END,
};
#include "input.h-labels.h"
#undef LABEL
#undef LABEL_END
static struct pollfd *ufds;
static char **device_names;
static int nfds;
enum {
PRINT_DEVICE_ERRORS = 1U << 0,
PRINT_DEVICE = 1U << 1,
PRINT_DEVICE_NAME = 1U << 2,
PRINT_DEVICE_INFO = 1U << 3,
PRINT_VERSION = 1U << 4,
PRINT_POSSIBLE_EVENTS = 1U << 5,
PRINT_INPUT_PROPS = 1U << 6,
PRINT_HID_DESCRIPTOR = 1U << 7,
PRINT_ALL_INFO = (1U << 8) - 1,
PRINT_LABELS = 1U << 16,
};
static const char *get_label(const struct label *labels, int value)
{
while(labels->name && value != labels->value) {
labels++;
}
return labels->name;
}
static int print_input_props(int fd)
{
uint8_t bits[INPUT_PROP_CNT / 8];
int i, j;
int res;
int count;
const char *bit_label;
printf(" input props:\n");
res = ioctl(fd, EVIOCGPROP(sizeof(bits)), bits);
if(res < 0) {
printf(" <not available\n");
return 1;
}
count = 0;
for(i = 0; i < res; i++) {
for(j = 0; j < 8; j++) {
if (bits[i] & 1 << j) {
bit_label = get_label(input_prop_labels, i * 8 + j);
if(bit_label)
printf(" %s\n", bit_label);
else
printf(" %04x\n", i * 8 + j);
count++;
}
}
}
if (!count)
printf(" <none>\n");
return 0;
}
static int print_possible_events(int fd, int print_flags)
{
uint8_t *bits = NULL;
ssize_t bits_size = 0;
const char* label;
int i, j, k;
int res, res2;
struct label* bit_labels;
const char *bit_label;
printf(" events:\n");
for(i = EV_KEY; i <= EV_MAX; i++) { // skip EV_SYN since we cannot query its available codes
int count = 0;
while(1) {
res = ioctl(fd, EVIOCGBIT(i, bits_size), bits);
if(res < bits_size)
break;
bits_size = res + 16;
bits = realloc(bits, bits_size * 2);
if(bits == NULL)
err(1, "failed to allocate buffer of size %d\n", (int)bits_size);
}
res2 = 0;
switch(i) {
case EV_KEY:
res2 = ioctl(fd, EVIOCGKEY(res), bits + bits_size);
label = "KEY";
bit_labels = key_labels;
break;
case EV_REL:
label = "REL";
bit_labels = rel_labels;
break;
case EV_ABS:
label = "ABS";
bit_labels = abs_labels;
break;
case EV_MSC:
label = "MSC";
bit_labels = msc_labels;
break;
case EV_LED:
res2 = ioctl(fd, EVIOCGLED(res), bits + bits_size);
label = "LED";
bit_labels = led_labels;
break;
case EV_SND:
res2 = ioctl(fd, EVIOCGSND(res), bits + bits_size);
label = "SND";
bit_labels = snd_labels;
break;
case EV_SW:
res2 = ioctl(fd, EVIOCGSW(bits_size), bits + bits_size);
label = "SW ";
bit_labels = sw_labels;
break;
case EV_REP:
label = "REP";
bit_labels = rep_labels;
break;
case EV_FF:
label = "FF ";
bit_labels = ff_labels;
break;
case EV_PWR:
label = "PWR";
bit_labels = NULL;
break;
case EV_FF_STATUS:
label = "FFS";
bit_labels = ff_status_labels;
break;
default:
res2 = 0;
label = "???";
bit_labels = NULL;
}
for(j = 0; j < res; j++) {
for(k = 0; k < 8; k++)
if(bits[j] & 1 << k) {
char down;
if(j < res2 && (bits[j + bits_size] & 1 << k))
down = '*';
else
down = ' ';
if(count == 0)
printf(" %s (%04x):", label, i);
else if((count & (print_flags & PRINT_LABELS ? 0x3 : 0x7)) == 0 || i == EV_ABS)
printf("\n ");
if(bit_labels && (print_flags & PRINT_LABELS)) {
bit_label = get_label(bit_labels, j * 8 + k);
if(bit_label)
printf(" %.20s%c%*s", bit_label, down, (int) (20 - strlen(bit_label)), "");
else
printf(" %04x%c ", j * 8 + k, down);
} else {
printf(" %04x%c", j * 8 + k, down);
}
if(i == EV_ABS) {
struct input_absinfo abs;
if(ioctl(fd, EVIOCGABS(j * 8 + k), &abs) == 0) {
printf(" : value %d, min %d, max %d, fuzz %d, flat %d, resolution %d",
abs.value, abs.minimum, abs.maximum, abs.fuzz, abs.flat,
abs.resolution);
}
}
count++;
}
}
if(count)
printf("\n");
}
free(bits);
return 0;
}
static void print_event(int type, int code, int value, int print_flags)
{
const char *type_label, *code_label, *value_label;
if (print_flags & PRINT_LABELS) {
type_label = get_label(ev_labels, type);
code_label = NULL;
value_label = NULL;
switch(type) {
case EV_SYN:
code_label = get_label(syn_labels, code);
break;
case EV_KEY:
code_label = get_label(key_labels, code);
value_label = get_label(key_value_labels, value);
break;
case EV_REL:
code_label = get_label(rel_labels, code);
break;
case EV_ABS:
code_label = get_label(abs_labels, code);
switch(code) {
case ABS_MT_TOOL_TYPE:
value_label = get_label(mt_tool_labels, value);
}
break;
case EV_MSC:
code_label = get_label(msc_labels, code);
break;
case EV_LED:
code_label = get_label(led_labels, code);
break;
case EV_SND:
code_label = get_label(snd_labels, code);
break;
case EV_SW:
code_label = get_label(sw_labels, code);
break;
case EV_REP:
code_label = get_label(rep_labels, code);
break;
case EV_FF:
code_label = get_label(ff_labels, code);
break;
case EV_FF_STATUS:
code_label = get_label(ff_status_labels, code);
break;
}
if (type_label)
printf("%-12.12s", type_label);
else
printf("%04x ", type);
if (code_label)
printf(" %-20.20s", code_label);
else
printf(" %04x ", code);
if (value_label)
printf(" %-20.20s", value_label);
else
printf(" %08x ", value);
} else {
printf("%04x %04x %08x", type, code, value);
}
}
static void print_hid_descriptor(int bus, int vendor, int product)
{
const char *dirname = "/sys/kernel/debug/hid";
char prefix[16];
DIR *dir;
struct dirent *de;
char filename[PATH_MAX];
FILE *file;
char line[2048];
snprintf(prefix, sizeof(prefix), "%04X:%04X:%04X.", bus, vendor, product);
dir = opendir(dirname);
if(dir == NULL)
return;
while((de = readdir(dir))) {
if (strstr(de->d_name, prefix) == de->d_name) {
snprintf(filename, sizeof(filename), "%s/%s/rdesc", dirname, de->d_name);
file = fopen(filename, "r");
if (file) {
printf(" HID descriptor: %s\n\n", de->d_name);
while (fgets(line, sizeof(line), file)) {
fputs(" ", stdout);
fputs(line, stdout);
}
fclose(file);
puts("");
}
}
}
closedir(dir);
}
static int open_device(const char *device, int print_flags)
{
int version;
int fd;
int clkid = CLOCK_MONOTONIC;
struct pollfd *new_ufds;
char **new_device_names;
char name[80];
char location[80];
char idstr[80];
struct input_id id;
fd = open(device, O_RDONLY);
if(fd < 0) {
if(print_flags & PRINT_DEVICE_ERRORS)
fprintf(stderr, "could not open %s, %s\n", device, strerror(errno));
return -1;
}
if(ioctl(fd, EVIOCGVERSION, &version)) {
if(print_flags & PRINT_DEVICE_ERRORS)
fprintf(stderr, "could not get driver version for %s, %s\n", device, strerror(errno));
return -1;
}
if(ioctl(fd, EVIOCGID, &id)) {
if(print_flags & PRINT_DEVICE_ERRORS)
fprintf(stderr, "could not get driver id for %s, %s\n", device, strerror(errno));
return -1;
}
name[sizeof(name) - 1] = '\0';
location[sizeof(location) - 1] = '\0';
idstr[sizeof(idstr) - 1] = '\0';
if(ioctl(fd, EVIOCGNAME(sizeof(name) - 1), &name) < 1) {
//fprintf(stderr, "could not get device name for %s, %s\n", device, strerror(errno));
name[0] = '\0';
}
if(ioctl(fd, EVIOCGPHYS(sizeof(location) - 1), &location) < 1) {
//fprintf(stderr, "could not get location for %s, %s\n", device, strerror(errno));
location[0] = '\0';
}
if(ioctl(fd, EVIOCGUNIQ(sizeof(idstr) - 1), &idstr) < 1) {
//fprintf(stderr, "could not get idstring for %s, %s\n", device, strerror(errno));
idstr[0] = '\0';
}
if (ioctl(fd, EVIOCSCLOCKID, &clkid) != 0) {
fprintf(stderr, "Can't enable monotonic clock reporting: %s\n", strerror(errno));
// a non-fatal error
}
new_ufds = realloc(ufds, sizeof(ufds[0]) * (nfds + 1));
if(new_ufds == NULL) {
fprintf(stderr, "out of memory\n");
return -1;
}
ufds = new_ufds;
new_device_names = realloc(device_names, sizeof(device_names[0]) * (nfds + 1));
if(new_device_names == NULL) {
fprintf(stderr, "out of memory\n");
return -1;
}
device_names = new_device_names;
if(print_flags & PRINT_DEVICE)
printf("add device %d: %s\n", nfds, device);
if(print_flags & PRINT_DEVICE_INFO)
printf(" bus: %04x\n"
" vendor %04x\n"
" product %04x\n"
" version %04x\n",
id.bustype, id.vendor, id.product, id.version);
if(print_flags & PRINT_DEVICE_NAME)
printf(" name: \"%s\"\n", name);
if(print_flags & PRINT_DEVICE_INFO)
printf(" location: \"%s\"\n"
" id: \"%s\"\n", location, idstr);
if(print_flags & PRINT_VERSION)
printf(" version: %d.%d.%d\n",
version >> 16, (version >> 8) & 0xff, version & 0xff);
if(print_flags & PRINT_POSSIBLE_EVENTS) {
print_possible_events(fd, print_flags);
}
if(print_flags & PRINT_INPUT_PROPS) {
print_input_props(fd);
}
if(print_flags & PRINT_HID_DESCRIPTOR) {
print_hid_descriptor(id.bustype, id.vendor, id.product);
}
ufds[nfds].fd = fd;
ufds[nfds].events = POLLIN;
device_names[nfds] = strdup(device);
nfds++;
return 0;
}
int close_device(const char *device, int print_flags)
{
int i;
for(i = 1; i < nfds; i++) {
if(strcmp(device_names[i], device) == 0) {
int count = nfds - i - 1;
if(print_flags & PRINT_DEVICE)
printf("remove device %d: %s\n", i, device);
free(device_names[i]);
memmove(device_names + i, device_names + i + 1, sizeof(device_names[0]) * count);
memmove(ufds + i, ufds + i + 1, sizeof(ufds[0]) * count);
nfds--;
return 0;
}
}
if(print_flags & PRINT_DEVICE_ERRORS)
fprintf(stderr, "remote device: %s not found\n", device);
return -1;
}
static int read_notify(const char *dirname, int nfd, int print_flags)
{
int res;
char devname[PATH_MAX];
char *filename;
char event_buf[512];
int event_size;
int event_pos = 0;
struct inotify_event *event;
res = read(nfd, event_buf, sizeof(event_buf));
if(res < (int)sizeof(*event)) {
if(errno == EINTR)
return 0;
fprintf(stderr, "could not get event, %s\n", strerror(errno));
return 1;
}
//printf("got %d bytes of event information\n", res);
strcpy(devname, dirname);
filename = devname + strlen(devname);
*filename++ = '/';
while(res >= (int)sizeof(*event)) {
event = (struct inotify_event *)(event_buf + event_pos);
//printf("%d: %08x \"%s\"\n", event->wd, event->mask, event->len ? event->name : "");
if(event->len) {
strcpy(filename, event->name);
if(event->mask & IN_CREATE) {
open_device(devname, print_flags);
}
else {
close_device(devname, print_flags);
}
}
event_size = sizeof(*event) + event->len;
res -= event_size;
event_pos += event_size;
}
return 0;
}
static int scan_dir(const char *dirname, int print_flags)
{
char devname[PATH_MAX];
char *filename;
DIR *dir;
struct dirent *de;
dir = opendir(dirname);
if(dir == NULL)
return -1;
strcpy(devname, dirname);
filename = devname + strlen(devname);
*filename++ = '/';
while((de = readdir(dir))) {
if(de->d_name[0] == '.' &&
(de->d_name[1] == '\0' ||
(de->d_name[1] == '.' && de->d_name[2] == '\0')))
continue;
strcpy(filename, de->d_name);
open_device(devname, print_flags);
}
closedir(dir);
return 0;
}
static void usage(char *name)
{
fprintf(stderr, "Usage: %s [-t] [-n] [-s switchmask] [-S] [-v [mask]] [-d] [-p] [-i] [-l] [-q] [-c count] [-r] [device]\n", name);
fprintf(stderr, " -t: show time stamps\n");
fprintf(stderr, " -n: don't print newlines\n");
fprintf(stderr, " -s: print switch states for given bits\n");
fprintf(stderr, " -S: print all switch states\n");
fprintf(stderr, " -v: verbosity mask (errs=1, dev=2, name=4, info=8, vers=16, pos. events=32, props=64)\n");
fprintf(stderr, " -d: show HID descriptor, if available\n");
fprintf(stderr, " -p: show possible events (errs, dev, name, pos. events)\n");
fprintf(stderr, " -i: show all device info and possible events\n");
fprintf(stderr, " -l: label event types and names in plain text\n");
fprintf(stderr, " -q: quiet (clear verbosity mask)\n");
fprintf(stderr, " -c: print given number of events then exit\n");
fprintf(stderr, " -r: print rate events are received\n");
}
int getevent_main(int argc, char *argv[])
{
int c;
int i;
int res;
int get_time = 0;
int print_device = 0;
char *newline = "\n";
uint16_t get_switch = 0;
struct input_event event;
int print_flags = 0;
int print_flags_set = 0;
int dont_block = -1;
int event_count = 0;
int sync_rate = 0;
int64_t last_sync_time = 0;
const char *device = NULL;
const char *device_path = "/dev/input";
opterr = 0;
do {
c = getopt(argc, argv, "tns:Sv::dpilqc:rh");
if (c == EOF)
break;
switch (c) {
case 't':
get_time = 1;
break;
case 'n':
newline = "";
break;
case 's':
get_switch = strtoul(optarg, NULL, 0);
if(dont_block == -1)
dont_block = 1;
break;
case 'S':
get_switch = ~0;
if(dont_block == -1)
dont_block = 1;
break;
case 'v':
if(optarg)
print_flags |= strtoul(optarg, NULL, 0);
else
print_flags |= PRINT_DEVICE | PRINT_DEVICE_NAME | PRINT_DEVICE_INFO | PRINT_VERSION;
print_flags_set = 1;
break;
case 'd':
print_flags |= PRINT_HID_DESCRIPTOR;
break;
case 'p':
print_flags |= PRINT_DEVICE_ERRORS | PRINT_DEVICE
| PRINT_DEVICE_NAME | PRINT_POSSIBLE_EVENTS | PRINT_INPUT_PROPS;
print_flags_set = 1;
if(dont_block == -1)
dont_block = 1;
break;
case 'i':
print_flags |= PRINT_ALL_INFO;
print_flags_set = 1;
if(dont_block == -1)
dont_block = 1;
break;
case 'l':
print_flags |= PRINT_LABELS;
break;
case 'q':
print_flags_set = 1;
break;
case 'c':
event_count = atoi(optarg);
dont_block = 0;
break;
case 'r':
sync_rate = 1;
break;
case '?':
fprintf(stderr, "%s: invalid option -%c\n",
argv[0], optopt);
case 'h':
usage(argv[0]);
exit(1);
}
} while (1);
if(dont_block == -1)
dont_block = 0;
if (optind + 1 == argc) {
device = argv[optind];
optind++;
}
if (optind != argc) {
usage(argv[0]);
exit(1);
}
nfds = 1;
ufds = calloc(1, sizeof(ufds[0]));
ufds[0].fd = inotify_init();
ufds[0].events = POLLIN;
if(device) {
if(!print_flags_set)
print_flags |= PRINT_DEVICE_ERRORS;
res = open_device(device, print_flags);
if(res < 0) {
return 1;
}
} else {
if(!print_flags_set)
print_flags |= PRINT_DEVICE_ERRORS | PRINT_DEVICE | PRINT_DEVICE_NAME;
print_device = 1;
res = inotify_add_watch(ufds[0].fd, device_path, IN_DELETE | IN_CREATE);
if(res < 0) {
fprintf(stderr, "could not add watch for %s, %s\n", device_path, strerror(errno));
return 1;
}
res = scan_dir(device_path, print_flags);
if(res < 0) {
fprintf(stderr, "scan dir failed for %s\n", device_path);
return 1;
}
}
if(get_switch) {
for(i = 1; i < nfds; i++) {
uint16_t sw;
res = ioctl(ufds[i].fd, EVIOCGSW(1), &sw);
if(res < 0) {
fprintf(stderr, "could not get switch state, %s\n", strerror(errno));
return 1;
}
sw &= get_switch;
printf("%04x%s", sw, newline);
}
}
if(dont_block)
return 0;
while(1) {
//int pollres =
poll(ufds, nfds, -1);
//printf("poll %d, returned %d\n", nfds, pollres);
if(ufds[0].revents & POLLIN) {
read_notify(device_path, ufds[0].fd, print_flags);
}
for(i = 1; i < nfds; i++) {
if(ufds[i].revents) {
if(ufds[i].revents & POLLIN) {
res = read(ufds[i].fd, &event, sizeof(event));
if(res < (int)sizeof(event)) {
fprintf(stderr, "could not get event\n");
return 1;
}
if(get_time) {
printf("[%8ld.%06ld] ", event.time.tv_sec, event.time.tv_usec);
}
if(print_device)
printf("%s: ", device_names[i]);
print_event(event.type, event.code, event.value, print_flags);
if(sync_rate && event.type == 0 && event.code == 0) {
int64_t now = event.time.tv_sec * 1000000LL + event.time.tv_usec;
if(last_sync_time)
printf(" rate %lld", 1000000LL / (now - last_sync_time));
last_sync_time = now;
}
printf("%s", newline);
if(event_count && --event_count == 0)
return 0;
}
}
}
}
return 0;
}
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