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Verifier Refinements (#7490)

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This commit is contained in:
Derek Bailey
2022-08-29 19:21:42 -07:00
committed by GitHub
parent bf5d23230a
commit b190ce11b0
1 changed files with 20 additions and 35 deletions
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55
include/flatbuffers/verifier.h
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@@ -34,39 +34,25 @@ class Verifier FLATBUFFERS_FINAL_CLASS {
bool check_alignment = true;
// If true, run verifier on nested flatbuffers
bool check_nested_flatbuffers = true;
// Manually implemented constructors for compilers that can't figure it out.
Options() = default;
Options(uoffset_t d, uoffset_t t, bool a, bool n)
: max_depth(d),
max_tables(t),
check_alignment(a),
check_nested_flatbuffers(n) {}
};
Verifier(const uint8_t *const buf, const size_t buf_len, const Options opts)
: buf_(buf),
size_(buf_len),
opts_(opts),
upper_bound_(0),
depth_(0),
num_tables_(0),
flex_reuse_tracker_(nullptr) {
explicit Verifier(const uint8_t *const buf, const size_t buf_len,
const Options &opts)
: buf_(buf), size_(buf_len), opts_(opts) {
FLATBUFFERS_ASSERT(size_ < FLATBUFFERS_MAX_BUFFER_SIZE);
}
// Deprecated API, please construct with Verifier::Options.
Verifier(const uint8_t *const buf, const size_t buf_len,
const uoffset_t _max_depth = 64,
const uoffset_t _max_tables = 1000000,
const bool _check_alignment = true)
: Verifier(buf, buf_len,
{
_max_depth,
_max_tables,
_check_alignment,
true,
}) {}
const uoffset_t max_depth = 64, const uoffset_t max_tables = 1000000,
const bool check_alignment = true)
: Verifier(buf, buf_len, [&] {
Options opts;
opts.max_depth = max_depth;
opts.max_tables = max_tables;
opts.check_alignment = check_alignment;
return opts;
}()) {}
// Central location where any verification failures register.
bool Check(const bool ok) const {
@@ -153,8 +139,8 @@ class Verifier FLATBUFFERS_FINAL_CLASS {
const auto veco = static_cast<size_t>(vec - buf_);
// Check we can read the size field.
if (!Verify<uoffset_t>(veco)) return false;
// Check the whole array. If this is a string, the byte past the array
// must be 0.
// Check the whole array. If this is a string, the byte past the array must
// be 0.
const auto size = ReadScalar<uoffset_t>(vec);
const auto max_elems = FLATBUFFERS_MAX_BUFFER_SIZE / elem_size;
if (!Check(size < max_elems))
@@ -277,9 +263,8 @@ class Verifier FLATBUFFERS_FINAL_CLASS {
}
// Called at the start of a table to increase counters measuring data
// structure depth and amount, and possibly bails out with false if
// limits set by the constructor have been hit. Needs to be balanced
// with EndTable().
// structure depth and amount, and possibly bails out with false if limits set
// by the constructor have been hit. Needs to be balanced with EndTable().
bool VerifyComplexity() {
depth_++;
num_tables_++;
@@ -320,11 +305,11 @@ class Verifier FLATBUFFERS_FINAL_CLASS {
const size_t size_;
const Options opts_;
mutable size_t upper_bound_;
mutable size_t upper_bound_ = 0;
uoffset_t depth_;
uoffset_t num_tables_;
std::vector<uint8_t> *flex_reuse_tracker_;
uoffset_t depth_ = 0;
uoffset_t num_tables_ = 0;
std::vector<uint8_t> *flex_reuse_tracker_ = nullptr;
};
} // namespace flatbuffers