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Implement overflow check in MaxCompressedLength function #242

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Implement overflow check in MaxCompressedLength function #242

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a9d2c4a
Implement overflow check in MaxCompressedLength function
yusmer96-maker Jun 4, 2026
5639685
Refactor MaxCompressedLength to use std::numeric_limits
yusmer96-maker Jun 4, 2026
9d0af7c
Add limits header to snappy.cc
yusmer96-maker Jun 4, 2026
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5 changes: 5 additions & 0 deletions snappy.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -194,6 +194,11 @@ inline uint16_t* TableEntry8ByteMatch(uint16_t* table, uint64_t bytes,
} // namespace

size_t MaxCompressedLength(size_t source_bytes) {
// Avoid integer overflow that could cause undersized buffer allocations.
// Return SIZE_MAX to force a controlled allocation failure.
if (source_bytes > (SIZE_MAX - 32) / 7 * 6) {
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@danilak-G danilak-G Jun 4, 2026

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LGTM. Can you use std::numeric_limits<size_t>::max() ?

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@yusmer96-maker yusmer96-maker Jun 4, 2026

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Sure! I initially used SIZE_MAX because I didn't notice was included transitively through snappy-stubs-internal.h. Now that I see it's available, I'll update to std::numeric_limits<size_t>::max(). Thanks for the suggestion.

return SIZE_MAX;
}
// Compressed data can be defined as:
// compressed := item* literal*
// item := literal* copy
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