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Added verifier alignment checking to table fields (#7018)

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This commit is contained in:
Wouter van Oortmerssen
2022-01-14 14:39:15 -08:00
committed by GitHub
parent 96cc2f3ee3
commit a42e898979
18 changed files with 273 additions and 248 deletions
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20
include/flatbuffers/verifier.h
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@@ -66,13 +66,13 @@ class Verifier FLATBUFFERS_FINAL_CLASS {
return Check(elem_len < size_ && elem <= size_ - elem_len);
}
template<typename T> bool VerifyAlignment(size_t elem) const {
return Check((elem & (sizeof(T) - 1)) == 0 || !check_alignment_);
bool VerifyAlignment(size_t elem, size_t align) const {
return Check((elem & (align - 1)) == 0 || !check_alignment_);
}
// Verify a range indicated by sizeof(T).
template<typename T> bool Verify(size_t elem) const {
return VerifyAlignment<T>(elem) && Verify(elem, sizeof(T));
return VerifyAlignment(elem, sizeof(T)) && Verify(elem, sizeof(T));
}
bool VerifyFromPointer(const uint8_t *p, size_t len) {
@@ -81,13 +81,16 @@ class Verifier FLATBUFFERS_FINAL_CLASS {
}
// Verify relative to a known-good base pointer.
bool Verify(const uint8_t *base, voffset_t elem_off, size_t elem_len) const {
return Verify(static_cast<size_t>(base - buf_) + elem_off, elem_len);
bool VerifyFieldStruct(const uint8_t *base, voffset_t elem_off, size_t elem_len,
size_t align) const {
auto f = static_cast<size_t>(base - buf_) + elem_off;
return VerifyAlignment(f, align) && Verify(f, elem_len);
}
template<typename T>
bool Verify(const uint8_t *base, voffset_t elem_off) const {
return Verify(static_cast<size_t>(base - buf_) + elem_off, sizeof(T));
bool VerifyField(const uint8_t *base, voffset_t elem_off, size_t align) const {
auto f = static_cast<size_t>(base - buf_) + elem_off;
return VerifyAlignment(f, align) && Verify(f, sizeof(T));
}
// Verify a pointer (may be NULL) of a table type.
@@ -162,7 +165,8 @@ class Verifier FLATBUFFERS_FINAL_CLASS {
auto vtableo = tableo - static_cast<size_t>(ReadScalar<soffset_t>(table));
// Check the vtable size field, then check vtable fits in its entirety.
return VerifyComplexity() && Verify<voffset_t>(vtableo) &&
VerifyAlignment<voffset_t>(ReadScalar<voffset_t>(buf_ + vtableo)) &&
VerifyAlignment(ReadScalar<voffset_t>(buf_ + vtableo),
sizeof(voffset_t)) &&
Verify(vtableo, ReadScalar<voffset_t>(buf_ + vtableo));
}