Merge "ueventd: create classes for dev and sys permissions"

am: ffa38cfc1e

Change-Id: Idc3ecf436d5750564de4ba16f0811c1d76cc609d
This commit is contained in:
Tom Cherry 2017-04-17 21:42:11 +00:00 committed by android-build-merger
commit e29fa61725
4 changed files with 186 additions and 146 deletions

View file

@ -14,6 +14,8 @@
* limitations under the License.
*/
#include "devices.h"
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
@ -27,23 +29,19 @@
#include <sys/sendfile.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <unistd.h>
#include <algorithm>
#include <memory>
#include <string>
#include <thread>
#include <vector>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <cutils/list.h>
#include <cutils/uevent.h>
#include <private/android_filesystem_config.h>
#include <selinux/android.h>
@ -51,119 +49,67 @@
#include <selinux/label.h>
#include <selinux/selinux.h>
#include "devices.h"
#include "ueventd_parser.h"
#include "util.h"
#define SYSFS_PREFIX "/sys"
extern struct selabel_handle *sehandle;
static android::base::unique_fd device_fd;
struct perms_ {
char *name;
char *attr;
mode_t perm;
unsigned int uid;
unsigned int gid;
unsigned short prefix;
unsigned short wildcard;
};
struct perm_node {
struct perms_ dp;
struct listnode plist;
};
static list_declare(sys_perms);
static list_declare(dev_perms);
int add_dev_perms(const char *name, const char *attr,
mode_t perm, unsigned int uid, unsigned int gid,
unsigned short prefix,
unsigned short wildcard) {
struct perm_node *node = (perm_node*) calloc(1, sizeof(*node));
if (!node)
return -ENOMEM;
node->dp.name = strdup(name);
if (!node->dp.name) {
free(node);
return -ENOMEM;
Permissions::Permissions(const std::string& name, mode_t perm, uid_t uid, gid_t gid)
: name_(name), perm_(perm), uid_(uid), gid_(gid), prefix_(false), wildcard_(false) {
// If the first * is the last character, then we'll treat name_ as a prefix
// Otherwise, if a * is present, then we do a full fnmatch().
auto wildcard_position = name_.find('*');
if (wildcard_position == name_.length() - 1) {
prefix_ = true;
name_.pop_back();
} else if (wildcard_position != std::string::npos) {
wildcard_ = true;
}
if (attr) {
node->dp.attr = strdup(attr);
if (!node->dp.attr) {
free(node->dp.name);
free(node);
return -ENOMEM;
}
}
node->dp.perm = perm;
node->dp.uid = uid;
node->dp.gid = gid;
node->dp.prefix = prefix;
node->dp.wildcard = wildcard;
if (attr)
list_add_tail(&sys_perms, &node->plist);
else
list_add_tail(&dev_perms, &node->plist);
return 0;
}
static bool perm_path_matches(const char *path, struct perms_ *dp)
{
if (dp->prefix) {
if (strncmp(path, dp->name, strlen(dp->name)) == 0)
return true;
} else if (dp->wildcard) {
if (fnmatch(dp->name, path, FNM_PATHNAME) == 0)
return true;
bool Permissions::Match(const std::string& path) const {
if (prefix_) {
return android::base::StartsWith(path, name_.c_str());
} else if (wildcard_) {
return fnmatch(name_.c_str(), path.c_str(), FNM_PATHNAME) == 0;
} else {
if (strcmp(path, dp->name) == 0)
return true;
return path == name_;
}
return false;
}
static bool match_subsystem(perms_* dp, const char* pattern,
const char* path, const char* subsystem) {
if (!pattern || !subsystem || strstr(dp->name, subsystem) == NULL) {
return false;
bool SysfsPermissions::MatchWithSubsystem(const std::string& path,
const std::string& subsystem) const {
std::string path_basename = android::base::Basename(path);
if (name().find(subsystem) != std::string::npos) {
if (Match("/sys/class/" + subsystem + "/" + path_basename)) return true;
if (Match("/sys/bus/" + subsystem + "/devices/" + path_basename)) return true;
}
std::string subsys_path = android::base::StringPrintf(pattern, subsystem, basename(path));
return perm_path_matches(subsys_path.c_str(), dp);
return Match(path);
}
static void fixup_sys_perms(const std::string& upath, const std::string& subsystem) {
void SysfsPermissions::SetPermissions(const std::string& path) const {
std::string attribute_file = path + "/" + attribute_;
LOG(INFO) << "fixup " << attribute_file << " " << uid() << " " << gid() << " " << std::oct
<< perm();
chown(attribute_file.c_str(), uid(), gid());
chmod(attribute_file.c_str(), perm());
}
// TODO: Move these to be member variables of a future devices class.
std::vector<Permissions> dev_permissions;
std::vector<SysfsPermissions> sysfs_permissions;
static void fixup_sys_permissions(const std::string& upath, const std::string& subsystem) {
// upaths omit the "/sys" that paths in this list
// contain, so we prepend it...
std::string path = SYSFS_PREFIX + upath;
std::string path = "/sys" + upath;
listnode* node;
list_for_each(node, &sys_perms) {
perms_* dp = &(node_to_item(node, perm_node, plist))->dp;
if (match_subsystem(dp, SYSFS_PREFIX "/class/%s/%s", path.c_str(), subsystem.c_str())) {
; // matched
} else if (match_subsystem(dp, SYSFS_PREFIX "/bus/%s/devices/%s", path.c_str(),
subsystem.c_str())) {
; // matched
} else if (!perm_path_matches(path.c_str(), dp)) {
continue;
}
std::string attr_file = path + "/" + dp->attr;
LOG(INFO) << "fixup " << attr_file
<< " " << dp->uid << " " << dp->gid << " " << std::oct << dp->perm;
chown(attr_file.c_str(), dp->uid, dp->gid);
chmod(attr_file.c_str(), dp->perm);
for (const auto& s : sysfs_permissions) {
if (s.MatchWithSubsystem(path, subsystem)) s.SetPermissions(path);
}
if (access(path.c_str(), F_OK) == 0) {
@ -172,42 +118,26 @@ static void fixup_sys_perms(const std::string& upath, const std::string& subsyst
}
}
static mode_t get_device_perm(const char* path, const std::vector<std::string>& links,
unsigned* uid, unsigned* gid) {
struct listnode *node;
struct perm_node *perm_node;
struct perms_ *dp;
/* search the perms list in reverse so that ueventd.$hardware can
* override ueventd.rc
*/
list_for_each_reverse(node, &dev_perms) {
perm_node = node_to_item(node, struct perm_node, plist);
dp = &perm_node->dp;
if (perm_path_matches(path, dp) ||
std::any_of(links.begin(), links.end(),
[dp](const auto& link) { return perm_path_matches(link.c_str(), dp); })) {
*uid = dp->uid;
*gid = dp->gid;
return dp->perm;
static std::tuple<mode_t, uid_t, gid_t> get_device_permissions(
const std::string& path, const std::vector<std::string>& links) {
// Search the perms list in reverse so that ueventd.$hardware can override ueventd.rc.
for (auto it = dev_permissions.rbegin(); it != dev_permissions.rend(); ++it) {
if (it->Match(path) || std::any_of(links.begin(), links.end(),
[it](const auto& link) { return it->Match(link); })) {
return {it->perm(), it->uid(), it->gid()};
}
}
/* Default if nothing found. */
*uid = 0;
*gid = 0;
return 0600;
return {0600, 0, 0};
}
static void make_device(const std::string& path, int block, int major, int minor,
const std::vector<std::string>& links) {
unsigned uid;
unsigned gid;
mode_t mode;
dev_t dev;
char *secontext = NULL;
mode = get_device_perm(path.c_str(), links, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
auto [mode, uid, gid] = get_device_permissions(path, links);
mode |= (block ? S_IFBLK : S_IFCHR);
if (sehandle) {
std::vector<const char*> c_links;
@ -607,7 +537,7 @@ static void handle_generic_device_event(uevent* uevent) {
static void handle_device_event(struct uevent *uevent)
{
if (uevent->action == "add" || uevent->action == "change" || uevent->action == "online") {
fixup_sys_perms(uevent->path, uevent->subsystem);
fixup_sys_permissions(uevent->path, uevent->subsystem);
}
if (uevent->subsystem == "block") {

View file

@ -18,6 +18,7 @@
#define _INIT_DEVICES_H
#include <sys/stat.h>
#include <sys/types.h>
#include <functional>
#include <string>
@ -47,15 +48,48 @@ struct uevent {
int minor;
};
class Permissions {
public:
Permissions(const std::string& name, mode_t perm, uid_t uid, gid_t gid);
bool Match(const std::string& path) const;
mode_t perm() const { return perm_; }
uid_t uid() const { return uid_; }
gid_t gid() const { return gid_; }
protected:
const std::string& name() const { return name_; }
private:
std::string name_;
mode_t perm_;
uid_t uid_;
gid_t gid_;
bool prefix_;
bool wildcard_;
};
class SysfsPermissions : public Permissions {
public:
SysfsPermissions(const std::string& name, const std::string& attribute, mode_t perm, uid_t uid,
gid_t gid)
: Permissions(name, perm, uid, gid), attribute_(attribute) {}
bool MatchWithSubsystem(const std::string& path, const std::string& subsystem) const;
void SetPermissions(const std::string& path) const;
private:
const std::string attribute_;
};
extern std::vector<Permissions> dev_permissions;
extern std::vector<SysfsPermissions> sysfs_permissions;
typedef std::function<coldboot_action_t(struct uevent* uevent)> coldboot_callback;
extern coldboot_action_t handle_device_fd(coldboot_callback fn = nullptr);
extern void device_init(const char* path = nullptr, coldboot_callback fn = nullptr);
extern void device_close();
extern int add_dev_perms(const char *name, const char *attr,
mode_t perm, unsigned int uid,
unsigned int gid, unsigned short prefix,
unsigned short wildcard);
int get_device_fd();
// Exposed for testing

View file

@ -316,3 +316,94 @@ TEST(devices, sanitize_onebad) {
sanitize_partition_name(&string);
EXPECT_EQ("_", string);
}
TEST(devices, DevPermissionsMatchNormal) {
// Basic from ueventd.rc
// /dev/null 0666 root root
Permissions permissions("/dev/null", 0666, 0, 0);
EXPECT_TRUE(permissions.Match("/dev/null"));
EXPECT_FALSE(permissions.Match("/dev/nullsuffix"));
EXPECT_FALSE(permissions.Match("/dev/nul"));
EXPECT_EQ(0666U, permissions.perm());
EXPECT_EQ(0U, permissions.uid());
EXPECT_EQ(0U, permissions.gid());
}
TEST(devices, DevPermissionsMatchPrefix) {
// Prefix from ueventd.rc
// /dev/dri/* 0666 root graphics
Permissions permissions("/dev/dri/*", 0666, 0, 1000);
EXPECT_TRUE(permissions.Match("/dev/dri/some_dri_device"));
EXPECT_TRUE(permissions.Match("/dev/dri/some_other_dri_device"));
EXPECT_TRUE(permissions.Match("/dev/dri/"));
EXPECT_FALSE(permissions.Match("/dev/dr/non_match"));
EXPECT_EQ(0666U, permissions.perm());
EXPECT_EQ(0U, permissions.uid());
EXPECT_EQ(1000U, permissions.gid());
}
TEST(devices, DevPermissionsMatchWildcard) {
// Wildcard example
// /dev/device*name 0666 root graphics
Permissions permissions("/dev/device*name", 0666, 0, 1000);
EXPECT_TRUE(permissions.Match("/dev/devicename"));
EXPECT_TRUE(permissions.Match("/dev/device123name"));
EXPECT_TRUE(permissions.Match("/dev/deviceabcname"));
EXPECT_FALSE(permissions.Match("/dev/device123name/subdevice"));
EXPECT_FALSE(permissions.Match("/dev/deviceame"));
EXPECT_EQ(0666U, permissions.perm());
EXPECT_EQ(0U, permissions.uid());
EXPECT_EQ(1000U, permissions.gid());
}
TEST(devices, DevPermissionsMatchWildcardPrefix) {
// Wildcard+Prefix example
// /dev/device*name* 0666 root graphics
Permissions permissions("/dev/device*name*", 0666, 0, 1000);
EXPECT_TRUE(permissions.Match("/dev/devicename"));
EXPECT_TRUE(permissions.Match("/dev/device123name"));
EXPECT_TRUE(permissions.Match("/dev/deviceabcname"));
EXPECT_TRUE(permissions.Match("/dev/device123namesomething"));
// FNM_PATHNAME doesn't match '/' with *
EXPECT_FALSE(permissions.Match("/dev/device123name/something"));
EXPECT_FALSE(permissions.Match("/dev/deviceame"));
EXPECT_EQ(0666U, permissions.perm());
EXPECT_EQ(0U, permissions.uid());
EXPECT_EQ(1000U, permissions.gid());
}
TEST(devices, SysfsPermissionsMatchWithSubsystemNormal) {
// /sys/devices/virtual/input/input* enable 0660 root input
SysfsPermissions permissions("/sys/devices/virtual/input/input*", "enable", 0660, 0, 1001);
EXPECT_TRUE(permissions.MatchWithSubsystem("/sys/devices/virtual/input/input0", "input"));
EXPECT_FALSE(permissions.MatchWithSubsystem("/sys/devices/virtual/input/not_input0", "input"));
EXPECT_EQ(0660U, permissions.perm());
EXPECT_EQ(0U, permissions.uid());
EXPECT_EQ(1001U, permissions.gid());
}
TEST(devices, SysfsPermissionsMatchWithSubsystemClass) {
// /sys/class/input/event* enable 0660 root input
SysfsPermissions permissions("/sys/class/input/event*", "enable", 0660, 0, 1001);
EXPECT_TRUE(permissions.MatchWithSubsystem(
"/sys/devices/soc.0/f9924000.i2c/i2c-2/2-0020/input/input0/event0", "input"));
EXPECT_FALSE(permissions.MatchWithSubsystem(
"/sys/devices/soc.0/f9924000.i2c/i2c-2/2-0020/input/input0/not_event0", "input"));
EXPECT_FALSE(permissions.MatchWithSubsystem(
"/sys/devices/soc.0/f9924000.i2c/i2c-2/2-0020/input/input0/event0", "not_input"));
EXPECT_EQ(0660U, permissions.perm());
EXPECT_EQ(0U, permissions.uid());
EXPECT_EQ(1001U, permissions.gid());
}
TEST(devices, SysfsPermissionsMatchWithSubsystemBus) {
// /sys/bus/i2c/devices/i2c-* enable 0660 root input
SysfsPermissions permissions("/sys/bus/i2c/devices/i2c-*", "enable", 0660, 0, 1001);
EXPECT_TRUE(permissions.MatchWithSubsystem("/sys/devices/soc.0/f9967000.i2c/i2c-5", "i2c"));
EXPECT_FALSE(permissions.MatchWithSubsystem("/sys/devices/soc.0/f9967000.i2c/not-i2c", "i2c"));
EXPECT_FALSE(
permissions.MatchWithSubsystem("/sys/devices/soc.0/f9967000.i2c/i2c-5", "not_i2c"));
EXPECT_EQ(0660U, permissions.perm());
EXPECT_EQ(0U, permissions.uid());
EXPECT_EQ(1001U, permissions.gid());
}

View file

@ -101,8 +101,6 @@ void set_device_permission(const char* fn, int line, int nargs, char **args)
mode_t perm;
uid_t uid;
gid_t gid;
int prefix = 0;
int wildcard = 0;
char *endptr;
if (nargs == 0)
@ -125,15 +123,6 @@ void set_device_permission(const char* fn, int line, int nargs, char **args)
return;
}
int len = strlen(name);
char *wildcard_chr = strchr(name, '*');
if ((name[len - 1] == '*') && (wildcard_chr == (name + len - 1))) {
prefix = 1;
name[len - 1] = '\0';
} else if (wildcard_chr) {
wildcard = 1;
}
perm = strtol(args[1], &endptr, 8);
if (!endptr || *endptr != '\0') {
LOG(ERROR) << "invalid mode (" << fn << ":" << line << ") '" << args[1] << "'";
@ -154,13 +143,9 @@ void set_device_permission(const char* fn, int line, int nargs, char **args)
}
gid = grp->gr_gid;
if (add_dev_perms(name, attr, perm, uid, gid, prefix, wildcard) != 0) {
PLOG(ERROR) << "add_dev_perms(name=" << name <<
", attr=" << attr <<
", perm=" << std::oct << perm << std::dec <<
", uid=" << uid << ", gid=" << gid <<
", prefix=" << prefix << ", wildcard=" << wildcard <<
")";
return;
if (attr) {
sysfs_permissions.emplace_back(name, attr, perm, uid, gid);
} else {
dev_permissions.emplace_back(name, perm, uid, gid);
}
}