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/*
* 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;
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);
}
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