Guard against usize overflows/underflows and raw pointer undefined behavior #50
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PSeitz
reviewed
May 17, 2022
| @@ -177,7 +177,7 @@ fn count_same_bytes(input: &[u8], cur: &mut usize, source: &[u8], candidate: usi | |||
| // compare 4 bytes block | |||
| #[cfg(target_pointer_width = "64")] | |||
| { | |||
| if *cur + 4 <= input_end { | |||
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cur and input_end are usize, they are unaffected by the issue
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Right, but since we're dealing with under/overflow style problems I thought it would be best to fix all of them. Theoretically an allocation at the end of the address space could lead to *cur + 4 to overflow.
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hehe when compressing 2^32-1 on 32 bit systems
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Awesome, thanks for the PR! |
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The main change is to change patterns like
current_position + something > max_positiontomax_position - current_position < something, which is overflow safe. Closes #49