| /* |
| * Copyright (C) 2013 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include <jni.h> |
| #include <sys/types.h> |
| #include <unistd.h> |
| #include <sys/syscall.h> |
| #include <sys/prctl.h> |
| #include <sys/ptrace.h> |
| #include <sys/wait.h> |
| #include <signal.h> |
| #include <stdlib.h> |
| #include <cutils/log.h> |
| |
| /* |
| * Returns true iff this device is vulnerable to CVE-2013-2094. |
| * A patch for CVE-2013-2094 can be found at |
| * http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=8176cced706b5e5d15887584150764894e94e02f |
| */ |
| static jboolean android_security_cts_NativeCodeTest_doPerfEventTest(JNIEnv* env, jobject thiz) |
| { |
| uint64_t attr[10] = { 0x4800000001, (uint32_t) -1, 0, 0, 0, 0x300 }; |
| |
| int fd = syscall(__NR_perf_event_open, attr, 0, -1, -1, 0); |
| jboolean result = (fd != -1); |
| |
| if (fd != -1) { |
| close(fd); |
| } |
| |
| return result; |
| } |
| |
| #define SEARCH_SIZE 0x4000 |
| |
| static int secret; |
| |
| static bool isValidChildAddress(pid_t child, uintptr_t addr) { |
| long word; |
| long ret = syscall(__NR_ptrace, PTRACE_PEEKDATA, child, addr, &word); |
| return (ret == 0); |
| } |
| |
| /* A lazy, do nothing child. GET A JOB. */ |
| static void child() { |
| int res; |
| ALOGE("in child"); |
| secret = 0xbaadadd4; |
| res = prctl(PR_SET_DUMPABLE, 1, 0, 0, 0); |
| if (res != 0) { |
| ALOGE("prctl failed"); |
| } |
| res = ptrace(PTRACE_TRACEME, 0, 0, 0); |
| if (res != 0) { |
| ALOGE("child ptrace failed"); |
| } |
| signal(SIGSTOP, SIG_IGN); |
| kill(getpid(), SIGSTOP); |
| } |
| |
| static jboolean parent(pid_t child) { |
| int status; |
| // Wait for the child to suspend itself so we can trace it. |
| waitpid(child, &status, 0); |
| jboolean result = true; |
| |
| uintptr_t addr; |
| for (addr = 0x00000000; addr < 0xFFFF1000; addr+=SEARCH_SIZE) { |
| if (isValidChildAddress(child, addr)) { |
| // Don't scribble on our memory. |
| // (which has the same mapping as our child) |
| // We don't want to corrupt ourself. |
| continue; |
| } |
| |
| errno = 0; |
| syscall(__NR_ptrace, PTRACE_PEEKDATA, child, &secret, addr); |
| if (errno == 0) { |
| result = false; |
| // We found an address which isn't in our our, or our child's, |
| // address space, but yet which is still writable. Scribble |
| // all over it. |
| ALOGE("parent: found writable at %x", addr); |
| uintptr_t addr2; |
| for (addr2 = addr; addr2 < addr + SEARCH_SIZE; addr2++) { |
| syscall(__NR_ptrace, PTRACE_PEEKDATA, child, &secret, addr2); |
| } |
| } |
| } |
| |
| ptrace(PTRACE_DETACH, child, 0, 0); |
| return result; |
| } |
| |
| /* |
| * Prior to https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/arch/arm/include/asm/uaccess.h?id=8404663f81d212918ff85f493649a7991209fa04 |
| * there was a flaw in the kernel's handling of get_user and put_user |
| * requests. Normally, get_user and put_user are supposed to guarantee |
| * that reads/writes outside the process's address space are not |
| * allowed. |
| * |
| * In this test, we use prctl(PTRACE_PEEKDATA) to force a write to |
| * an address outside of our address space. Without the patch applied, |
| * this write succeeds, because prctl(PTRACE_PEEKDATA) uses the |
| * vulnerable put_user call. |
| */ |
| static jboolean android_security_cts_NativeCodeTest_doVrootTest(JNIEnv*, jobject) |
| { |
| ALOGE("Starting doVrootTest"); |
| pid_t pid = fork(); |
| if (pid == -1) { |
| return false; |
| } |
| |
| if (pid == 0) { |
| child(); |
| exit(0); |
| } |
| |
| return parent(pid); |
| } |
| |
| static JNINativeMethod gMethods[] = { |
| { "doPerfEventTest", "()Z", |
| (void *) android_security_cts_NativeCodeTest_doPerfEventTest }, |
| { "doVrootTest", "()Z", |
| (void *) android_security_cts_NativeCodeTest_doVrootTest }, |
| }; |
| |
| int register_android_security_cts_NativeCodeTest(JNIEnv* env) |
| { |
| jclass clazz = env->FindClass("android/security/cts/NativeCodeTest"); |
| return env->RegisterNatives(clazz, gMethods, |
| sizeof(gMethods) / sizeof(JNINativeMethod)); |
| } |