Add an assertion to unix_term::read_bytes to prevent reading past the end of a buffer
#225
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tamird
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Dec 16, 2024
| @@ -183,6 +183,7 @@ fn read_single_char(fd: i32) -> io::Result<Option<char>> { | |||
| // If successful, return the number of bytes read. | |||
| // Will return an error if nothing was read, i.e when called at end of file. | |||
| fn read_bytes(fd: i32, buf: &mut [u8], count: u8) -> io::Result<u8> { | |||
| assert!((count as usize) <= buf.len()); // Safety precondition - prevent reading past end of buffer. | |||
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the signature of this function is cursed. I've done a more thorough refactor in #223.
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Dec 17, 2024
Slices already encode their lengths; use that instead. Remove the unused return value while I'm here. Closes console-rs#225.
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The (marked safe)
read_bytesfunction makes a call to the unsafe functionlibc::read. Ifread_byteswere to be called with acountvalue larger than the length ofbuf, the call tolibc::readwould be undefined behaviour and unsafe. All current callsites ofread_bytesappear OK, but adding an assertion would ensure that all possible calls toread_byteswill be safe. If you would prefer to avoid a runtime assertion, I would suggest markingread_bytesas unsafe instead.