diff options
| -rw-r--r-- | runtime/native/dalvik_system_Zygote.cc | 50 |
1 files changed, 47 insertions, 3 deletions
diff --git a/runtime/native/dalvik_system_Zygote.cc b/runtime/native/dalvik_system_Zygote.cc index 22c5430..7e6432e 100644 --- a/runtime/native/dalvik_system_Zygote.cc +++ b/runtime/native/dalvik_system_Zygote.cc @@ -23,8 +23,10 @@ #include <signal.h> #include <stdlib.h> #include <sys/types.h> +#include <sys/stat.h> #include <sys/wait.h> #include <unistd.h> +#include <fcntl.h> #include "cutils/fs.h" #include "cutils/multiuser.h" @@ -406,13 +408,43 @@ static bool NeedsNoRandomizeWorkaround() { } #endif +// Utility to close down the Zygote socket file descriptors while +// the child is still running as root with Zygote's privileges. Each +// descriptor (if any) is closed via dup2(), replacing it with a valid +// (open) descriptor to /dev/null. + +static void DetachDescriptors(JNIEnv* env, jintArray fdsToClose) { + if (!fdsToClose) { + return; + } + jsize count = env->GetArrayLength(fdsToClose); + jint *ar = env->GetIntArrayElements(fdsToClose, 0); + if (!ar) { + PLOG(FATAL) << "Bad fd array"; + } + jsize i; + int devnull; + for (i = 0; i < count; i++) { + devnull = open("/dev/null", O_RDWR); + if (devnull < 0) { + PLOG(FATAL) << "Failed to open /dev/null"; + continue; + } + PLOG(VERBOSE) << "Switching descriptor " << ar[i] << " to /dev/null"; + if (dup2(devnull, ar[i]) < 0) { + PLOG(FATAL) << "Failed dup2() on descriptor " << ar[i]; + } + close(devnull); + } +} + // Utility routine to fork zygote and specialize the child process. static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArray javaGids, jint debug_flags, jobjectArray javaRlimits, jlong permittedCapabilities, jlong effectiveCapabilities, jint mount_external, jstring java_se_info, jstring java_se_name, - bool is_system_server) { + bool is_system_server, jintArray fdsToClose) { Runtime* runtime = Runtime::Current(); CHECK(runtime->IsZygote()) << "runtime instance not started with -Xzygote"; if (!runtime->PreZygoteFork()) { @@ -431,6 +463,9 @@ static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArra // The child process. gMallocLeakZygoteChild = 1; + // Clean up any descriptors which must be closed immediately + DetachDescriptors(env, fdsToClose); + // Keep capabilities across UID change, unless we're staying root. if (uid != 0) { EnableKeepCapabilities(); @@ -531,11 +566,19 @@ static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArra return pid; } +static jint Zygote_nativeForkAndSpecialize_new(JNIEnv* env, jclass, jint uid, jint gid, jintArray gids, + jint debug_flags, jobjectArray rlimits, + jint mount_external, jstring se_info, jstring se_name, + jintArray fdsToClose) { + return ForkAndSpecializeCommon(env, uid, gid, gids, debug_flags, rlimits, 0, 0, mount_external, + se_info, se_name, false, fdsToClose); +} + static jint Zygote_nativeForkAndSpecialize(JNIEnv* env, jclass, jint uid, jint gid, jintArray gids, jint debug_flags, jobjectArray rlimits, jint mount_external, jstring se_info, jstring se_name) { return ForkAndSpecializeCommon(env, uid, gid, gids, debug_flags, rlimits, 0, 0, mount_external, - se_info, se_name, false); + se_info, se_name, false, NULL); } static jint Zygote_nativeForkSystemServer(JNIEnv* env, jclass, uid_t uid, gid_t gid, jintArray gids, @@ -545,7 +588,7 @@ static jint Zygote_nativeForkSystemServer(JNIEnv* env, jclass, uid_t uid, gid_t pid_t pid = ForkAndSpecializeCommon(env, uid, gid, gids, debug_flags, rlimits, permittedCapabilities, effectiveCapabilities, - MOUNT_EXTERNAL_NONE, NULL, NULL, true); + MOUNT_EXTERNAL_NONE, NULL, NULL, true, NULL); if (pid > 0) { // The zygote process checks whether the child process has died or not. LOG(INFO) << "System server process " << pid << " has been created"; @@ -562,6 +605,7 @@ static jint Zygote_nativeForkSystemServer(JNIEnv* env, jclass, uid_t uid, gid_t } static JNINativeMethod gMethods[] = { + NATIVE_METHOD(Zygote, nativeForkAndSpecialize_new, "(II[II[[IILjava/lang/String;Ljava/lang/String;[I)I"), NATIVE_METHOD(Zygote, nativeForkAndSpecialize, "(II[II[[IILjava/lang/String;Ljava/lang/String;)I"), NATIVE_METHOD(Zygote, nativeForkSystemServer, "(II[II[[IJJ)I"), }; |