| /* |
| * Copyright (C) 2019 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 <stddef.h> |
| #include <stdint.h> |
| #include <unistd.h> |
| |
| #include "perfetto/ext/base/file_utils.h" |
| #include "perfetto/ext/base/temp_file.h" |
| #include "src/profiling/memory/shared_ring_buffer.h" |
| |
| namespace perfetto { |
| namespace profiling { |
| namespace { |
| |
| struct FuzzingInputHeader { |
| size_t write_size; |
| SharedRingBuffer::MetadataPage metadata_page; |
| }; |
| |
| size_t RoundToPow2(size_t v) { |
| uint64_t x = static_cast<uint64_t>(v); |
| if (x < 2) |
| return 2; |
| |
| x--; |
| x |= x >> 1; |
| x |= x >> 2; |
| x |= x >> 4; |
| x |= x >> 8; |
| x |= x >> 16; |
| x |= x >> 32; |
| x++; |
| return static_cast<size_t>(x); |
| } |
| |
| int FuzzRingBufferWrite(const uint8_t* data, size_t size) { |
| if (size <= sizeof(FuzzingInputHeader)) |
| return 0; |
| |
| auto fd = base::TempFile::CreateUnlinked().ReleaseFD(); |
| PERFETTO_CHECK(fd); |
| |
| // Prefill shared buffer with fuzzer input, then attempt to write. |
| // TODO(fmayer): Do we actually need to fill the buffer with payload, or |
| // should we only fuzz the metadata? |
| size_t payload_size = size - sizeof(FuzzingInputHeader); |
| const uint8_t* payload = data + sizeof(FuzzingInputHeader); |
| size_t payload_size_pages = |
| (payload_size + base::kPageSize - 1) / base::kPageSize; |
| // Upsize test buffer to be 2^n data pages (precondition of the impl) + 1 page |
| // for the metadata. |
| size_t total_size_pages = 1 + RoundToPow2(payload_size_pages); |
| |
| // Clear spinlock field, as otherwise we will fail acquiring the lock below. |
| FuzzingInputHeader header = {}; |
| memcpy(&header, data, sizeof(header)); |
| SharedRingBuffer::MetadataPage& metadata_page = header.metadata_page; |
| metadata_page.spinlock.locked = false; |
| metadata_page.spinlock.poisoned = false; |
| |
| PERFETTO_CHECK(ftruncate(*fd, static_cast<off_t>(total_size_pages * |
| base::kPageSize)) == 0); |
| PERFETTO_CHECK(base::WriteAll(*fd, &metadata_page, sizeof(metadata_page)) != |
| -1); |
| PERFETTO_CHECK(lseek(*fd, base::kPageSize, SEEK_SET) != -1); |
| PERFETTO_CHECK(base::WriteAll(*fd, payload, payload_size) != -1); |
| |
| auto buf = SharedRingBuffer::Attach(std::move(fd)); |
| PERFETTO_CHECK(!!buf); |
| |
| SharedRingBuffer::Buffer write_buf; |
| { |
| auto lock = buf->AcquireLock(ScopedSpinlock::Mode::Try); |
| PERFETTO_CHECK(lock.locked()); |
| write_buf = buf->BeginWrite(lock, header.write_size); |
| } |
| if (!write_buf) |
| return 0; |
| |
| memset(write_buf.data, '\0', write_buf.size); |
| buf->EndWrite(std::move(write_buf)); |
| return 0; |
| } |
| |
| } // namespace |
| } // namespace profiling |
| } // namespace perfetto |
| |
| extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size); |
| |
| extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) { |
| return perfetto::profiling::FuzzRingBufferWrite(data, size); |
| } |