diff options
| -rw-r--r-- | core/jni/com_android_internal_os_Zygote.cpp | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/core/jni/com_android_internal_os_Zygote.cpp b/core/jni/com_android_internal_os_Zygote.cpp index e7835db85793..6d40626c0a25 100644 --- a/core/jni/com_android_internal_os_Zygote.cpp +++ b/core/jni/com_android_internal_os_Zygote.cpp @@ -430,6 +430,20 @@ static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArra jstring instructionSet, jstring dataDir) { SetSigChldHandler(); + sigset_t sigchld; + sigemptyset(&sigchld); + sigaddset(&sigchld, SIGCHLD); + + // Temporarily block SIGCHLD during forks. The SIGCHLD handler might + // log, which would result in the logging FDs we close being reopened. + // This would cause failures because the FDs are not whitelisted. + // + // Note that the zygote process is single threaded at this point. + if (sigprocmask(SIG_BLOCK, &sigchld, NULL) == -1) { + ALOGE("sigprocmask(SIG_SETMASK, { SIGCHLD }) failed: %s", strerror(errno)); + RuntimeAbort(env, __LINE__, "Call to sigprocmask(SIG_BLOCK, { SIGCHLD }) failed."); + } + // Close any logging related FDs before we start evaluating the list of // file descriptors. __android_log_close(); @@ -461,6 +475,11 @@ static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArra RuntimeAbort(env, __LINE__, "Unable to reopen whitelisted descriptors."); } + if (sigprocmask(SIG_UNBLOCK, &sigchld, NULL) == -1) { + ALOGE("sigprocmask(SIG_SETMASK, { SIGCHLD }) failed: %s", strerror(errno)); + RuntimeAbort(env, __LINE__, "Call to sigprocmask(SIG_UNBLOCK, { SIGCHLD }) failed."); + } + // Keep capabilities across UID change, unless we're staying root. if (uid != 0) { EnableKeepCapabilities(env); @@ -592,6 +611,12 @@ static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArra } } else if (pid > 0) { // the parent process + + // We blocked SIGCHLD prior to a fork, we unblock it here. + if (sigprocmask(SIG_UNBLOCK, &sigchld, NULL) == -1) { + ALOGE("sigprocmask(SIG_SETMASK, { SIGCHLD }) failed: %s", strerror(errno)); + RuntimeAbort(env, __LINE__, "Call to sigprocmask(SIG_UNBLOCK, { SIGCHLD }) failed."); + } } return pid; } |