tequilaOS/platform_system_core
2
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

logd: handle uidToName() directly

Browse source 
uidToName() originally used a separate worker thread with additional
group permissions.  Threads are not security boundaries however, so
these group permissions are removed in a previous change.

This change handles the lookup for uidToName() directly without using
a separate thread.

Test: boot CF, logd unit tests
Change-Id: If245388bc221bc77102a0bbcee82c8f42b140760
This commit is contained in:
Tom Cherry 2017-09-06 10:07:37 -07:00
parent acf19e8031
commit 36f5399341
1 changed files with 21 additions and 48 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

69
logd/main.cpp
View file

@ -150,43 +150,14 @@ void android::prdebug(const char* fmt, ...) {
}
}
static sem_t uidName;
static uid_t uid;
static char* name;
static sem_t reinit;
static bool reinit_running = false;
static LogBuffer* logBuf = nullptr;
static bool package_list_parser_cb(pkg_info* info, void* /* userdata */) {
bool rc = true;
if (info->uid == uid) {
name = strdup(info->name);
// false to stop processing
rc = false;
}
packagelist_free(info);
return rc;
}
static void* reinit_thread_start(void* /*obj*/) {
prctl(PR_SET_NAME, "logd.daemon");
while (reinit_running && !sem_wait(&reinit) && reinit_running) {
// uidToName Privileged Worker
if (uid) {
name = nullptr;
// if we got the perms wrong above, this would spam if we reported
// problems with acquisition of an uid name from the packages.
(void)packagelist_parse(package_list_parser_cb, nullptr);
uid = 0;
sem_post(&uidName);
continue;
}
if (fdDmesg >= 0) {
static const char reinit_message[] = { KMSG_PRIORITY(LOG_INFO),
'l',
@ -223,26 +194,30 @@ static void* reinit_thread_start(void* /*obj*/) {
return nullptr;
}
static sem_t sem_name;
char* android::uidToName(uid_t u) {
if (!u || !reinit_running) {
return nullptr;
}
struct Userdata {
uid_t uid;
char* name;
} userdata = {
.uid = u,
.name = nullptr,
};
sem_wait(&sem_name);
packagelist_parse(
[](pkg_info* info, void* callback_parameter) {
auto userdata = reinterpret_cast<Userdata*>(callback_parameter);
bool result = true;
if (info->uid == userdata->uid) {
userdata->name = strdup(info->name);
// false to stop processing
result = false;
}
packagelist_free(info);
return result;
},
&userdata);
// Not multi-thread safe, we use sem_name to protect
uid = u;
name = nullptr;
sem_post(&reinit);
sem_wait(&uidName);
char* ret = name;
sem_post(&sem_name);
return ret;
return userdata.name;
}
// Serves as a global method to trigger reinitialization
@ -363,8 +338,6 @@ int main(int argc, char* argv[]) {
// Reinit Thread
sem_init(&reinit, 0, 0);
sem_init(&uidName, 0, 0);
sem_init(&sem_name, 0, 1);
pthread_attr_t attr;
if (!pthread_attr_init(&attr)) {
struct sched_param param;