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winebus.sys: Add code path to bypass udevd and use inotify. 

In a container with a non-trivial user namespace, we cannot rely on
libudev communicating with udevd as a way to monitor device nodes,
for the following reasons:

* If uid 0 from the host is not mapped to uid 0 in the container, libudev
  cannot authenticate netlink messages from the host, because their sender
  uid appears to be the overflowuid. Resolving this by mapping uid 0 into
  the container is not allowed when creating user namespaces as an
  unprivileged user, and even when running as a privileged user, it might
  be desirable for the real uid 0 to not be mapped as a way to harden the
  security boundary between container and host.

* Depending on the container configuration, initial enumeration might
  not be able to read /run/udev from the host system. If it can't, sysfs
  attributes will still work because those are read directly from the
  kernel via sysfs, but udev properties coming from user-space rules
  (in particular ID_INPUT_JOYSTICK and friends) will appear to be missing.

* The protocols between udevd and libudev (netlink messages for monitoring,
  and /run/udev for initial enumeration) are considered to be private to
  a particular version of udev, and are not a stable API; but in a
  container, we cannot expect that our copy of libudev is at exactly the
  same version as udevd on the host system.

Sidestep this by adding a code path that continues to use libudev for
the parts that work regardless of whether udevd is running or can be
communicated with.

Signed-off-by: Rémi Bernon <rbernon@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>
This commit is contained in:
Simon McVittie 2021-10-20 11:07:27 +02:00 committed by Alexandre Julliard
parent 22dae167d3
commit ab3416c61f
3 changed files with 268 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

276
dlls/winebus.sys/bus_udev.c
View File

@ -29,6 +29,8 @@
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <sys/types.h>
#include <dirent.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
@ -47,6 +49,9 @@
#ifdef HAVE_SYS_IOCTL_H
# include <sys/ioctl.h>
#endif
#ifdef HAVE_SYS_INOTIFY_H
# include <sys/inotify.h>
#endif
#ifdef HAVE_LINUX_INPUT_H
# include <linux/input.h>
@ -112,6 +117,7 @@ struct base_device
void (*read_report)(struct unix_device *iface);
struct udev_device *udev_device;
char devnode[MAX_PATH];
int device_fd;
};
@ -1177,7 +1183,7 @@ static void hidraw_set_quirks(struct hidraw_device *impl, DWORD bus_type, WORD v
impl->quirks |= QUIRK_DS4_BT;
}
static void udev_add_device(struct udev_device *dev)
static void udev_add_device(struct udev_device *dev, int fd)
{
struct device_desc desc =
{
@ -1186,12 +1192,15 @@ static void udev_add_device(struct udev_device *dev)
struct base_device *impl;
const char *subsystem;
const char *devnode;
int fd, bus = 0;
int bus = 0;
if (!(devnode = udev_device_get_devnode(dev)))
{
if (fd >= 0) close(fd);
return;
}
if ((fd = open(devnode, O_RDWR)) == -1)
if (fd < 0 && (fd = open(devnode, O_RDWR)) == -1)
{
WARN("Unable to open udev device %s: %s\n", debugstr_a(devnode), strerror(errno));
return;
@ -1277,6 +1286,7 @@ static void udev_add_device(struct udev_device *dev)
list_add_tail(&device_list, &impl->unix_device.entry);
impl->read_report = hidraw_device_read_report;
impl->udev_device = udev_device_ref(dev);
strcpy(impl->devnode, devnode);
impl->device_fd = fd;
hidraw_set_quirks((struct hidraw_device *)impl, bus, desc.vid, desc.pid);
@ -1289,6 +1299,7 @@ static void udev_add_device(struct udev_device *dev)
list_add_tail(&device_list, &impl->unix_device.entry);
impl->read_report = lnxev_device_read_report;
impl->udev_device = udev_device_ref(dev);
strcpy(impl->devnode, devnode);
impl->device_fd = fd;
bus_event_queue_device_created(&event_queue, &impl->unix_device, &desc);
@ -1296,7 +1307,229 @@ static void udev_add_device(struct udev_device *dev)
#endif
}
static void build_initial_deviceset(void)
#ifdef HAVE_SYS_INOTIFY_H
static int dev_watch = -1;
#ifdef HAS_PROPER_INPUT_HEADER
static int devinput_watch = -1;
#endif
static void maybe_add_devnode(const char *base, const char *dir, const char *subsystem)
{
char *syspath = NULL, devnode[MAX_PATH], syslink[MAX_PATH];
struct udev_device *dev = NULL;
const char *udev_devnode;
int fd = -1;
TRACE("Considering %s/%s...\n", dir, base);
snprintf(devnode, sizeof(devnode), "%s/%s", dir, base);
if ((fd = open(devnode, O_RDWR)) < 0)
{
/* When using inotify monitoring, quietly ignore device nodes that we cannot read,
* without emitting a warning.
*
* We can expect that a significant number of device nodes will be permanently
* unreadable, such as the device nodes for keyboards and mice. We can also expect
* that joysticks and game controllers will be temporarily unreadable until udevd
* chmods them; we'll get another chance to open them when their attributes change. */
TRACE("Unable to open %s, ignoring: %s\n", debugstr_a(devnode), strerror(errno));
return;
}
snprintf(syslink, sizeof(syslink), "/sys/class/%s/%s", subsystem, base);
TRACE("Resolving real path to %s\n", debugstr_a(syslink));
if (!(syspath = realpath(syslink, NULL)))
{
WARN("Unable to resolve path \"%s\" for \"%s/%s\": %s\n",
debugstr_a(syslink), dir, base, strerror(errno));
goto error;
}
TRACE("Creating udev_device for %s\n", syspath);
if (!(dev = udev_device_new_from_syspath(udev_context, syspath)))
{
WARN("failed to create udev device from syspath %s\n", syspath);
goto error;
}
if (!(udev_devnode = udev_device_get_devnode(dev)) || strcmp(devnode, udev_devnode) != 0)
{
WARN("Tried to get udev device for \"%s\" but device node of \"%s\" -> \"%s\" is \"%s\"\n",
debugstr_a(devnode), debugstr_a(syslink), debugstr_a(syspath), debugstr_a(udev_devnode));
goto error;
}
TRACE("Adding device for %s\n", syspath);
udev_add_device(dev, fd);
udev_device_unref(dev);
return;
error:
if (dev) udev_device_unref(dev);
free(syspath);
close(fd);
}
static void build_initial_deviceset_direct(void)
{
struct dirent *dent;
int n, len;
DIR *dir;
if (!options.disable_hidraw)
{
TRACE("Initial enumeration of /dev/hidraw*\n");
if (!(dir = opendir("/dev"))) WARN("Unable to open /dev: %s\n", strerror(errno));
else
{
for (dent = readdir(dir); dent; dent = readdir(dir))
{
if (sscanf(dent->d_name, "hidraw%u%n", &n, &len) != 1 || len != strlen(dent->d_name))
WARN("ignoring %s, name doesn't match hidraw%%u\n", debugstr_a(dent->d_name));
else
maybe_add_devnode(dent->d_name, "/dev", "hidraw");
}
closedir(dir);
}
}
#ifdef HAS_PROPER_INPUT_HEADER
if (!options.disable_input)
{
TRACE("Initial enumeration of /dev/input/event*\n");
if (!(dir = opendir("/dev/input"))) WARN("Unable to open /dev/input: %s\n", strerror(errno));
else
{
for (dent = readdir(dir); dent; dent = readdir(dir))
{
if (sscanf(dent->d_name, "event%u%n", &n, &len) != 1 || len != strlen(dent->d_name))
WARN("ignoring %s, name doesn't match event%%u\n", debugstr_a(dent->d_name));
else
maybe_add_devnode(dent->d_name, "/dev/input", "input");
}
closedir(dir);
}
}
#endif
}
static int create_inotify(void)
{
int systems = 0, fd, flags = IN_CREATE | IN_DELETE | IN_MOVE | IN_ATTRIB;
if ((fd = inotify_init1(IN_NONBLOCK | IN_CLOEXEC)) < 0)
{
WARN("Unable to get inotify fd\n");
return fd;
}
if (!options.disable_hidraw)
{
/* We need to watch for attribute changes in addition to
* creation, because when a device is first created, it has
* permissions that we can't read. When udev chmods it to
* something that we maybe *can* read, we'll get an
* IN_ATTRIB event to tell us. */
dev_watch = inotify_add_watch(fd, "/dev", flags);
if (dev_watch < 0) WARN("Unable to initialize inotify for /dev: %s\n", strerror(errno));
else systems++;
}
#ifdef HAS_PROPER_INPUT_HEADER
if (!options.disable_input)
{
devinput_watch = inotify_add_watch(fd, "/dev/input", flags);
if (devinput_watch < 0) WARN("Unable to initialize inotify for /dev/input: %s\n", strerror(errno));
else systems++;
}
#endif
if (systems == 0)
{
WARN("No subsystems added to monitor\n");
close(fd);
return -1;
}
return fd;
}
static struct base_device *find_device_from_devnode(const char *path)
{
struct base_device *impl;
LIST_FOR_EACH_ENTRY(impl, &device_list, struct base_device, unix_device.entry)
if (!strcmp(impl->devnode, path)) return impl;
return NULL;
}
static void maybe_remove_devnode(const char *base, const char *dir)
{
struct base_device *impl;
char devnode[MAX_PATH];
snprintf(devnode, sizeof(devnode), "%s/%s", dir, base);
impl = find_device_from_devnode(devnode);
if (impl) bus_event_queue_device_removed(&event_queue, &impl->unix_device);
else WARN("failed to find device for path %s\n", devnode);
}
static void process_inotify_event(int fd)
{
union
{
struct inotify_event event;
char storage[4096];
char enough_for_inotify[sizeof(struct inotify_event) + NAME_MAX + 1];
} buf;
ssize_t bytes;
int n, len;
if ((bytes = read(fd, &buf, sizeof(buf))) < 0)
WARN("read failed: %u %s\n", errno, strerror(errno));
else while (bytes > 0)
{
if (buf.event.len > 0)
{
if (buf.event.wd == dev_watch)
{
if (sscanf(buf.event.name, "hidraw%u%n", &n, &len) != 1 || len != strlen(buf.event.name))
WARN("ignoring %s, name doesn't match hidraw%%u\n", debugstr_a(buf.event.name));
else if (buf.event.mask & (IN_DELETE | IN_MOVED_FROM))
maybe_remove_devnode(buf.event.name, "/dev");
else if (buf.event.mask & (IN_CREATE | IN_MOVED_TO))
maybe_add_devnode(buf.event.name, "/dev", "hidraw");
else if (buf.event.mask & IN_ATTRIB)
{
maybe_remove_devnode(buf.event.name, "/dev");
maybe_add_devnode(buf.event.name, "/dev", "hidraw");
}
}
#ifdef HAS_PROPER_INPUT_HEADER
else if (buf.event.wd == devinput_watch)
{
if (sscanf(buf.event.name, "event%u%n", &n, &len) != 1 || len != strlen(buf.event.name))
WARN("ignoring %s, name doesn't match event%%u\n", debugstr_a(buf.event.name));
else if (buf.event.mask & (IN_DELETE | IN_MOVED_FROM))
maybe_remove_devnode(buf.event.name, "/dev/input");
else if (buf.event.mask & (IN_CREATE | IN_MOVED_TO))
maybe_add_devnode(buf.event.name, "/dev/input", "input");
else if (buf.event.mask & IN_ATTRIB)
{
maybe_remove_devnode(buf.event.name, "/dev/input");
maybe_add_devnode(buf.event.name, "/dev/input", "input");
}
}
#endif
}
len = sizeof(struct inotify_event) + buf.event.len;
bytes -= len;
if (bytes > 0) memmove(&buf.storage[0], &buf.storage[len], bytes);
}
}
#endif /* HAVE_SYS_INOTIFY_H */
static void build_initial_deviceset_udevd(void)
{
struct udev_enumerate *enumerate;
struct udev_list_entry *devices, *dev_list_entry;
@ -1331,7 +1564,7 @@ static void build_initial_deviceset(void)
path = udev_list_entry_get_name(dev_list_entry);
if ((dev = udev_device_new_from_syspath(udev_context, path)))
{
udev_add_device(dev);
udev_add_device(dev, -1);
udev_device_unref(dev);
}
}
@ -1405,7 +1638,7 @@ static void process_monitor_event(struct udev_monitor *monitor)
if (!action)
WARN("No action received\n");
else if (strcmp(action, "remove"))
udev_add_device(dev);
udev_add_device(dev, -1);
else
{
impl = find_device_from_udev(dev);
@ -1418,7 +1651,7 @@ static void process_monitor_event(struct udev_monitor *monitor)
NTSTATUS udev_bus_init(void *args)
{
int monitor_fd;
int monitor_fd = -1;
TRACE("args %p\n", args);
@ -1436,12 +1669,22 @@ NTSTATUS udev_bus_init(void *args)
goto error;
}
if (!(udev_monitor = create_monitor(&monitor_fd)))
#if HAVE_SYS_INOTIFY_H
if (options.disable_udevd) monitor_fd = create_inotify();
if (monitor_fd < 0) options.disable_udevd = FALSE;
#else
if (options.disable_udevd) ERR("inotify support not compiled in!\n");
options.disable_udevd = FALSE;
#endif
if (monitor_fd < 0 && !(udev_monitor = create_monitor(&monitor_fd)))
{
ERR("UDEV monitor creation failed\n");
goto error;
}
if (monitor_fd < 0) goto error;
poll_fds[0].fd = monitor_fd;
poll_fds[0].events = POLLIN;
poll_fds[0].revents = 0;
@ -1450,10 +1693,15 @@ NTSTATUS udev_bus_init(void *args)
poll_fds[1].revents = 0;
poll_count = 2;
build_initial_deviceset();
if (!options.disable_udevd) build_initial_deviceset_udevd();
#if HAVE_SYS_INOTIFY_H
else build_initial_deviceset_direct();
#endif
return STATUS_SUCCESS;
error:
if (udev_monitor) udev_monitor_unref(udev_monitor);
if (udev_context) udev_unref(udev_context);
udev_context = NULL;
close(deviceloop_control[0]);
@ -1486,7 +1734,13 @@ NTSTATUS udev_bus_wait(void *args)
while (poll(pfd, count, -1) <= 0) {}
pthread_mutex_lock(&udev_cs);
if (pfd[0].revents) process_monitor_event(udev_monitor);
if (pfd[0].revents)
{
if (udev_monitor) process_monitor_event(udev_monitor);
#if HAVE_SYS_INOTIFY_H
else process_inotify_event(pfd[0].fd);
#endif
}
if (pfd[1].revents) read(deviceloop_control[0], &ctrl, 1);
for (i = 2; i < count; ++i)
{
@ -1499,7 +1753,7 @@ NTSTATUS udev_bus_wait(void *args)
TRACE("UDEV main loop exiting\n");
bus_event_queue_destroy(&event_queue);
udev_monitor_unref(udev_monitor);
if (udev_monitor) udev_monitor_unref(udev_monitor);
udev_unref(udev_context);
udev_context = NULL;
close(deviceloop_control[0]);

2
dlls/winebus.sys/main.c
View File

@ -730,6 +730,8 @@ static NTSTATUS udev_driver_init(void)
if (bus_options.disable_hidraw) TRACE("UDEV hidraw devices disabled in registry\n");
bus_options.disable_input = check_bus_option(L"DisableInput", 0);
if (bus_options.disable_input) TRACE("UDEV input devices disabled in registry\n");
bus_options.disable_udevd = check_bus_option(L"DisableUdevd", 0);
if (bus_options.disable_udevd) TRACE("UDEV udevd use disabled in registry\n");
return bus_main_thread_start(&bus);
}

1
dlls/winebus.sys/unixlib.h
View File

@ -56,6 +56,7 @@ struct udev_bus_options
{
BOOL disable_hidraw;
BOOL disable_input;
BOOL disable_udevd;
};
struct iohid_bus_options