Fix correctness issues for detectors #66
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This commit fixes incorrect bounds checking for the `is_cr2` detector, which would previously check for data bufffers of `len() > 9`, but would access `buf[10]`, which is invalid for buffers of `len() == 10`.
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I'm running fuzz tests against |
is_cr2Detection for MS-OOXML files will attempt to load a 32-bit address from the user-provided payload, adding a static offset that may lead to overflow if the original address is already near the max value for the type used. This commit has starting offset calculation be safe via use of `checked_add`, returning `None` if the user-provided address is beyond the bounds allowed.
deuill
commented
Jun 7, 2022
| @@ -67,7 +67,12 @@ fn msooxml(buf: &[u8]) -> Option<DocType> { | |||
| // skip to the second local file header | |||
| // since some documents include a 520-byte extra field following the file | |||
| // header, we need to scan for the next header | |||
| let mut start_offset = (u32::from_le_bytes(buf[18..22].try_into().unwrap()) + 49) as usize; | |||
| let mut start_offset = match u32::from_le_bytes(buf[18..22].try_into().unwrap()).checked_add(49) | |||
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Here's a file (generated by fuzz tests) that replicates this: overflow.docx
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Hello, thanks for the PR. Published in 0.8.1. |
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Thanks so much for the quick turnaround! |
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This PR includes commits that fix correctness issues for various detectors -- I'll include test cases for the more esoteric issues, but these have been replicated via
cargo-fuzzin any case.