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Fix integer overflow in tensor dimensions and PPM parser #896

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Merged
copybara-service merged 2 commits into from
Apr 17, 2026
Merged

Fix integer overflow in tensor dimensions and PPM parser #896

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e260706
Fix integer overflow in tensor dimensions and PPM parser
sharadboni Apr 15, 2026
c4d14db
Use HWY_ABORT instead of std::cerr for overflow checks in ReadPPM
sharadboni Apr 16, 2026
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15 changes: 13 additions & 2 deletions paligemma/image.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -83,8 +83,11 @@ const char* ParseUnsigned(const char* pos, const char* end, size_t& num) {
}
num = 0;
for (; pos < end && std::isdigit(*pos); ++pos) {
num *= 10;
num += *pos - '0';
const size_t digit = *pos - '0';
if (num > (SIZE_MAX - digit) / 10) {
return nullptr; // overflow
}
num = num * 10 + digit;
}
return pos;
}
Expand Down Expand Up @@ -136,6 +139,14 @@ bool Image::ReadPPM(const hwy::Span<const char>& buf) {
return false;
}
++pos;
if (width == 0 || height == 0) {
HWY_ABORT("Invalid zero dimension\n");
return false;
}
if (width > SIZE_MAX / 3 || width * 3 > SIZE_MAX / height) {
HWY_ABORT("Image dimensions overflow\n");
return false;
}
const size_t data_size = width * height * 3;
if (buf.cend() - pos < static_cast<ptrdiff_t>(data_size)) {
std::cerr << "Insufficient data remaining\n";
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7 changes: 6 additions & 1 deletion util/basics.h
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Original file line number Diff line number Diff line change
Expand Up @@ -97,7 +97,12 @@ struct Extents2D {
constexpr Extents2D() : rows(0), cols(0) {}
constexpr Extents2D(size_t rows, size_t cols) : rows(rows), cols(cols) {}

size_t Area() const { return rows * cols; }
size_t Area() const {
if (rows != 0 && cols > SIZE_MAX / rows) {
HWY_ABORT("Tensor dimension overflow: rows=%zu cols=%zu", rows, cols);
}
return rows * cols;
}

size_t rows;
size_t cols;
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