vmm/builder: correctly handle invalid fd for serial console#570
Merged
jakecorrenti merged 1 commit intocontainers:mainfrom Mar 11, 2026
Merged
vmm/builder: correctly handle invalid fd for serial console#570jakecorrenti merged 1 commit intocontainers:mainfrom
jakecorrenti merged 1 commit intocontainers:mainfrom
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This pull request correctly moves the serial console TTY setup logic inside the check for a valid file descriptor, preventing a panic when an invalid fd is provided. However, the implementation introduces a soundness issue by creating both a BorrowedFd and an owning File from the same raw file descriptor. This can lead to use-after-free bugs if not handled carefully. I've suggested a change to make the code safer by creating the File first and then borrowing from it, although this still relies on unsafe due to lifetime complexities.
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Commit bf3f2bf ("builder: set raw mode for ttys on serial devices") added support for raw for TTYs on serial devices, but didn't seem to take into account that the provided 'input_fd' may be invalid -- a condition supported by code below that checks for positive values. As a result, we may run into a panic as part of BorrowedFd::borrow_raw()'s sanity checks. Fix this issue by massaging the code slightly. Signed-off-by: Daniel Müller <deso@posteo.net>
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dorindabassey
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Mar 10, 2026
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Commit bf3f2bf ("builder: set raw mode for ttys on serial devices") added support for raw for TTYs on serial devices, but didn't seem to take into account that the provided 'input_fd' may be invalid -- a condition supported by code below that checks for positive values. As a result, we may run into a panic as part of BorrowedFd::borrow_raw()'s sanity checks.
Fix this issue by moving code around slightly.