oss-fuzz/infra/experimental/SystemSan/inspect_utils.cpp

74 lines
2.1 KiB
C++

/*
* Copyright 2022 Google LLC
* 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.
*/
/* A detector that uses ptrace to identify DNS arbitrary resolutions. */
/* C standard library */
#include <signal.h>
/* POSIX */
#include <unistd.h>
/* Linux */
#include <sys/ptrace.h>
#include <iostream>
#include <string>
#include <vector>
#include <map>
#include "inspect_utils.h"
extern pid_t g_root_pid;
extern std::map<pid_t, ThreadParent> root_pids;
std::vector<std::byte> read_memory(pid_t pid, unsigned long long address,
size_t size) {
std::vector<std::byte> memory;
for (size_t i = 0; i < size; i += sizeof(long)) {
long word = ptrace(PTRACE_PEEKTEXT, pid, address + i, 0);
if (word == -1) {
return memory;
}
std::byte *word_bytes = reinterpret_cast<std::byte *>(&word);
memory.insert(memory.end(), word_bytes, word_bytes + sizeof(long));
}
return memory;
}
void report_bug(std::string bug_type, pid_t tid) {
// Report the bug found based on the bug code.
std::cerr << "===BUG DETECTED: " << bug_type.c_str() << "===\n";
// Rely on sanitizers/libFuzzer to produce a stacktrace by sending SIGABRT
// to the root process.
// Note: this may not be reliable or consistent if shell injection happens
// in an async way.
// Find the thread group id, that is the pid.
pid_t pid = tid;
auto parent = root_pids[tid];
while (!parent.ran_exec) {
// Find the first parent which ran exec syscall.
if (parent.parent_tid == g_root_pid) {
break;
}
pid = parent.parent_tid;
parent = root_pids[parent.parent_tid];
}
tgkill(pid, tid, SIGABRT);
}