BigfootDev/flatbuffers
1
0
Fork 1
mirror of https://github.com/google/flatbuffers.git synced 2026-06-05 13:08:58 +00:00
Code Issues Packages Projects Releases Wiki Activity

Change SizedPrefixed verifier to be <= provided size (#7957)

Browse Source 
* Change SizedPrefixed verifier to be <= provided size

* add GetSizePrefixedBufferLength()
This commit is contained in:
Derek Bailey
2023-05-11 12:21:50 -07:00
committed by GitHub
parent 66e9d9823a
commit 33212657ae
3 changed files with 43 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
include/flatbuffers/flatbuffers.h
View File

@@ -81,6 +81,18 @@ inline SizeT GetPrefixedSize(const uint8_t *buf) {
return ReadScalar<SizeT>(buf);
}
// Gets the total length of the buffer given a sized prefixed FlatBuffer.
//
// This includes the size of the prefix as well as the buffer:
//
// [size prefix][flatbuffer]
// |---------length--------|
template<typename SizeT = uoffset_t>
inline SizeT GetSizePrefixedBufferLength(const uint8_t * const buf) {
return ReadScalar<SizeT>(buf) + sizeof(SizeT);
}
// Base class for native objects (FlatBuffer data de-serialized into native
// C++ data structures).
// Contains no functionality, purely documentative.

8
include/flatbuffers/verifier.h
View File

@@ -177,8 +177,8 @@ class Verifier FLATBUFFERS_FINAL_CLASS {
return true;
}
FLATBUFFERS_SUPPRESS_UBSAN("unsigned-integer-overflow") bool VerifyTableStart(
const uint8_t *const table) {
FLATBUFFERS_SUPPRESS_UBSAN("unsigned-integer-overflow")
bool VerifyTableStart(const uint8_t *const table) {
// Check the vtable offset.
const auto tableo = static_cast<size_t>(table - buf_);
if (!Verify<soffset_t>(tableo)) return false;
@@ -246,7 +246,9 @@ class Verifier FLATBUFFERS_FINAL_CLASS {
template<typename T, typename SizeT = uoffset_t>
bool VerifySizePrefixedBuffer(const char *const identifier) {
return Verify<SizeT>(0U) &&
Check(ReadScalar<SizeT>(buf_) == size_ - sizeof(SizeT)) &&
// Ensure the prefixed size is within the bounds of the provided
// length.
Check(ReadScalar<SizeT>(buf_) + sizeof(SizeT) <= size_) &&
VerifyBufferFromStart<T>(identifier, sizeof(SizeT));
}