[flang][runtime] Fix integer overflow check for FORMATs #79471
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@llvm/pr-subscribers-flang-runtime Author: Peter Klausler (klausler) ChangesThe code that parses repeat counts, field widths, &c. from FORMAT strings has an incorrect overflow check, so the maximum integer value is not accepted. Fix. Fixes #79255. Full diff: https://github.com/llvm/llvm-project/pull/79471.diff 1 Files Affected:
diff --git a/flang/runtime/format-implementation.h b/flang/runtime/format-implementation.h
index c54ac062c7beab..b0a4f6b9eb2f79 100644
--- a/flang/runtime/format-implementation.h
+++ b/flang/runtime/format-implementation.h
@@ -85,8 +85,8 @@ int FormatControl<CONTEXT>::GetIntField(
ch = PeekNext();
}
while (ch >= '0' && ch <= '9') {
- if (result >
- std::numeric_limits<int>::max() / 10 - (static_cast<int>(ch) - '0')) {
+ constexpr int tenth{std::numeric_limits<int>::max() / 10};
+ if (result > tenth || ch - '0' > std::numeric_limits<int>::max() - result) {
handler.SignalError(
IostatErrorInFormat, "FORMAT integer field out of range");
if (hadError) {
|
vzakhari
reviewed
Jan 25, 2024
| if (result > | ||
| std::numeric_limits<int>::max() / 10 - (static_cast<int>(ch) - '0')) { | ||
| constexpr int tenth{std::numeric_limits<int>::max() / 10}; | ||
| if (result > tenth || ch - '0' > std::numeric_limits<int>::max() - result) { |
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Not sure, but shouldn't it look like || ch - '0' > std::numeric_limits<int>::max() - result * 10?
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Right, sorry; will fix.
The code that parses repeat counts, field widths, &c. from FORMAT strings has an incorrect overflow check, so the maximum integer value is not accepted. Fix. Fixes llvm#79255.
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The code that parses repeat counts, field widths, &c. from FORMAT strings has an incorrect overflow check, so the maximum integer value is not accepted. Fix.
Fixes #79255.