fix: Avoid arithmetic overflow and panics #302
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m4b
reviewed
Feb 4, 2022
src/mach/exports.rs
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| @@ -274,10 +274,16 @@ impl<'a> ExportTrie<'a> { | |||
| /// Create a new, lazy, zero-copy export trie from the `DyldInfo` `command` | |||
| pub fn new(bytes: &'a [u8], command: &load_command::DyldInfoCommand) -> Self { | |||
| let start = command.export_off as usize; | |||
| let end = (command.export_size + command.export_off) as usize; | |||
| let end = start.saturating_add(command.export_size as usize); | |||
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Since this silently truncates maybe should do checked add and warn when it’s too large ? I assume this would only ever happen on a 32-bit system reading the 6GB binary ?
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I added some log::warn for this and the FatArch case.
This here I found via fuzzing, though the FatArch was indeed a valid file.
m4b
approved these changes
Feb 14, 2022
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| // check the length | ||
| if thread_state_bytes.len() < thread_state_byte_length { | ||
| if bytes.len() < 16 + thread_state_byte_length { |
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i know you didn't introduce 16 but it might be nice to turn this into a const since it's used again below and will be puzzling to future reviewers
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thank you for adding the tests! |
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The first comes from a real and valid fat file that is ~6G, the other overflow was found while fuzzing.