Fix unsoundness in msys_tty_on
#183
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The `name_info_bytes` Vec is only guaranteed to have an alignment of 1 (`std::mem::align_of::<u8>()`), however a raw pointer to it gets turned into a `&FILE_NAME_INFO`, which has an alignment requirement of 4. Creating unaligned references is immediate undefined behavior. This bug was copied from `atty` and is tracked there as RUSTSEC-2021-0145 [1]. The fix in this commit is taken from `atty`'s fork `is-terminal` [2], which was created since `atty` is unmaintained. Note that this code only gets compiled in on Windows and Windows' system allocator guarantees a large enough alignment. Thus, in practice the pointer could only be unaligned if a custom global allocator is used. [1] https://rustsec.org/advisories/RUSTSEC-2021-0145.html [2] sunfishcode/is-terminal@0c8d91d
In some situations involving long paths it is possible that `GetFileInformationByHandleEx` produces a `FILE_NAME_INFO` with `FileNameLength` exceeding the provided buffer [1]. Return `false` from `msys_tty_on` if that happens, instead of reading beyond the end of the allocation. [1] sunfishcode/is-terminal#18
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Two distinct problems here:
See the commit messages for details. Both fixes are ported from
is-terminal.