ueventd: Run external handler as non-root group
The external firmware handler always has root group privileges because
it is forked/executed without setgid() by ueventd which has root
privileges. This patch calls setgid() with group ID specified in
ueventd.rc before execv().
Test: atest CtsInitTestCases
Signed-off-by: Suchang Woo <suchang.woo@samsung.com>
Change-Id: Id1430e783b0e409d55ac80fe213e81ba099729e2
diff --git a/init/firmware_handler.cpp b/init/firmware_handler.cpp
index bdc2922..30e808d 100644
--- a/init/firmware_handler.cpp
+++ b/init/firmware_handler.cpp
@@ -19,6 +19,7 @@
#include <fcntl.h>
#include <fnmatch.h>
#include <glob.h>
+#include <grp.h>
#include <pwd.h>
#include <signal.h>
#include <stdlib.h>
@@ -81,9 +82,9 @@
return access("/dev/.booting", F_OK) == 0;
}
-ExternalFirmwareHandler::ExternalFirmwareHandler(std::string devpath, uid_t uid,
+ExternalFirmwareHandler::ExternalFirmwareHandler(std::string devpath, uid_t uid, gid_t gid,
std::string handler_path)
- : devpath(std::move(devpath)), uid(uid), handler_path(std::move(handler_path)) {
+ : devpath(std::move(devpath)), uid(uid), gid(gid), handler_path(std::move(handler_path)) {
auto wildcard_position = this->devpath.find('*');
if (wildcard_position != std::string::npos) {
if (wildcard_position == this->devpath.length() - 1) {
@@ -97,13 +98,17 @@
}
}
+ExternalFirmwareHandler::ExternalFirmwareHandler(std::string devpath, uid_t uid,
+ std::string handler_path)
+ : ExternalFirmwareHandler(devpath, uid, 0, handler_path) {}
+
FirmwareHandler::FirmwareHandler(std::vector<std::string> firmware_directories,
std::vector<ExternalFirmwareHandler> external_firmware_handlers)
: firmware_directories_(std::move(firmware_directories)),
external_firmware_handlers_(std::move(external_firmware_handlers)) {}
Result<std::string> FirmwareHandler::RunExternalHandler(const std::string& handler, uid_t uid,
- const Uevent& uevent) const {
+ gid_t gid, const Uevent& uevent) const {
unique_fd child_stdout;
unique_fd parent_stdout;
if (!Socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, &child_stdout, &parent_stdout)) {
@@ -140,6 +145,13 @@
}
c_args.emplace_back(nullptr);
+ if (gid != 0) {
+ if (setgid(gid) != 0) {
+ fprintf(stderr, "setgid() failed: %s", strerror(errno));
+ _exit(EXIT_FAILURE);
+ }
+ }
+
if (setuid(uid) != 0) {
fprintf(stderr, "setuid() failed: %s", strerror(errno));
_exit(EXIT_FAILURE);
@@ -196,8 +208,8 @@
<< "' for devpath: '" << uevent.path << "' firmware: '" << uevent.firmware
<< "'";
- auto result =
- RunExternalHandler(external_handler.handler_path, external_handler.uid, uevent);
+ auto result = RunExternalHandler(external_handler.handler_path, external_handler.uid,
+ external_handler.gid, uevent);
if (!result.ok()) {
LOG(ERROR) << "Using default firmware; External firmware handler failed: "
<< result.error();