Fix buffer overflow in TIOCGWINSZ ioctl for Python 3.14+#20
Merged
Snaipe merged 1 commit intoSnaipe:masterfrom Jan 7, 2026
Merged
Fix buffer overflow in TIOCGWINSZ ioctl for Python 3.14+#20Snaipe merged 1 commit intoSnaipe:masterfrom
Snaipe merged 1 commit intoSnaipe:masterfrom
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TIOCGWINSZ ioctl expects struct winsize which contains 4 unsigned shorts (8 bytes total), not 2. Python 3.14 introduced stricter buffer validation that detects this mismatch and raises SystemError. Changes: - Increase buffer size from 4 to 8 bytes (b"\x00" * 4 -> b"\x00" * 8) - Update struct format from "hh" to "hhhh" to unpack all 4 shorts - Unpack all values but only use first two (rows, columns) Fixes #18
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Sorry for the delay; thanks for the fix! |
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Fixes #18
Problem
Python 3.14 introduced stricter buffer validation for ioctl calls. The current code passes a 4-byte buffer to TIOCGWINSZ, but it expects struct winsize (4 unsigned shorts = 8 bytes). This causes SystemError on Python 3.14+.
Solution
This matches the fix used by PyInvoke: pyinvoke/invoke#1040
Testing
Tested on Python 3.14 with B2 CLI which depends on rst2ansi.