Fix panic in parsing UnwindInfo #218
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jan-auer
changed the title
3 tasks
m4b
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May 8, 2020
| @@ -587,13 +587,13 @@ impl<'a> UnwindInfo<'a> { | |||
| // whenever flags UNW_FLAG_EHANDLER or UNW_FLAG_UHANDLER are set. The language-specific | |||
| // handler is called as part of the search for an exception handler or as part of an unwind. | |||
| } else if flags & (UNW_FLAG_EHANDLER | UNW_FLAG_UHANDLER) != 0 { | |||
| let offset = bytes.gread_with::<u32>(&mut offset, scroll::LE)? as usize; | |||
| let address = bytes.gread_with::<u32>(&mut offset, scroll::LE)?; | |||
| let data = &bytes[offset..]; | |||
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should data use offset or address here?
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Thanks for asking, data should in fact use offset.
For posterity: This is documented here. With the handler flags set, struct UNWIND_INFO contains a u32 address of the exception handler, followed immediately by variable length data.
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thanks for the PR @jan-auer |
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The exception handler address incorrectly shadowed the
offsetfor reading exception handler data. This could lead to out-of-bounds access which and results in a panic.Instead, the address should be treated as an opaque pointer (relative, probably RVA), while the data follows the pointer. See https://docs.microsoft.com/en-us/cpp/build/exception-handling-x64