simpleperf: fix ReadCmdlineFeature for fuzzer.

Also remove other uses of MoveFromBinaryFormat() in
record_file_reader.cpp.

Bug: 258284687
Test: run simpleperf_unit_test
Change-Id: I12804355afd3f39c1d2ff8dd63391219bd9424a8

2 files changed, 37 insertions, 23 deletions

diff --git a/simpleperf/record_file_reader.cpp b/simpleperf/record_file_reader.cpp
index c70c0dcb..2dbc378a 100644
--- a/simpleperf/record_file_reader.cpp
+++ b/simpleperf/record_file_reader.cpp
@@ -454,22 +454,25 @@ bool RecordFileReader::ReadFeatureSection(int feature, std::string* data) {
 std::vector<std::string> RecordFileReader::ReadCmdlineFeature() {
   std::vector<char> buf;
   if (!ReadFeatureSection(FEAT_CMDLINE, &buf)) {
-    return std::vector<std::string>();
+    return {};
   }
-  const char* p = buf.data();
-  const char* end = buf.data() + buf.size();
+  BinaryReader reader(buf.data(), buf.size());
   std::vector<std::string> cmdline;
-  uint32_t arg_count;
-  MoveFromBinaryFormat(arg_count, p);
-  CHECK_LE(p, end);
-  for (size_t i = 0; i < arg_count; ++i) {
-    uint32_t len;
-    MoveFromBinaryFormat(len, p);
-    CHECK_LE(p + len, end);
-    cmdline.push_back(p);
-    p += len;
+
+  uint32_t arg_count = 0;
+  reader.Read(arg_count);
+  for (size_t i = 0; i < arg_count && !reader.error; ++i) {
+    uint32_t aligned_len;
+    reader.Read(aligned_len);
+    cmdline.emplace_back(reader.ReadString());
+    uint32_t len = cmdline.back().size() + 1;
+    if (aligned_len != Align(len, 64)) {
+      reader.error = true;
+      break;
+    }
+    reader.Move(aligned_len - len);
   }
-  return cmdline;
+  return reader.error ? std::vector<std::string>() : cmdline;
 }
 
 std::vector<BuildIdRecord> RecordFileReader::ReadBuildIdFeature() {
@@ -518,22 +521,27 @@ std::vector<uint64_t> RecordFileReader::ReadAuxTraceFeature() {
   if (!ReadFeatureSection(FEAT_AUXTRACE, &buf)) {
     return {};
   }
-  std::vector<uint64_t> auxtrace_offset;
-  const char* p = buf.data();
-  const char* end = buf.data() + buf.size();
-  if (buf.size() / sizeof(uint64_t) % 2 == 1) {
+  BinaryReader reader(buf.data(), buf.size());
+  if (reader.LeftSize() % sizeof(uint64_t) != 0) {
+    return {};
+  }
+  if (reader.LeftSize() / sizeof(uint64_t) % 2 == 1) {
     // Recording files generated by linux perf contain an extra uint64 field. Skip it here.
-    p += sizeof(uint64_t);
+    reader.Move(sizeof(uint64_t));
   }
-  while (p < end) {
+
+  std::vector<uint64_t> auxtrace_offset;
+  while (!reader.error && reader.LeftSize() > 0u) {
     uint64_t offset;
     uint64_t size;
-    MoveFromBinaryFormat(offset, p);
+    reader.Read(offset);
+    reader.Read(size);
     auxtrace_offset.push_back(offset);
-    MoveFromBinaryFormat(size, p);
-    CHECK_EQ(size, AuxTraceRecord::Size());
+    if (size != AuxTraceRecord::Size()) {
+      reader.error = true;
+    }
   }
-  return auxtrace_offset;
+  return reader.error ? std::vector<uint64_t>() : auxtrace_offset;
 }
 
 bool RecordFileReader::ReadFileFeature(size_t& read_pos, FileFeature* file) {
diff --git a/simpleperf/utils.h b/simpleperf/utils.h
index a9f8aa6d..ebc96068 100644
--- a/simpleperf/utils.h
+++ b/simpleperf/utils.h
@@ -166,6 +166,12 @@ struct BinaryReader {
     return true;
   }
 
+  void Move(size_t size) {
+    if (CheckLeftSize(size)) {
+      head += size;
+    }
+  }
+
   template <class T>
   void Read(T& data) {
     static_assert(std::is_standard_layout<T>::value, "not standard layout");