Remove jl_getch() to fix race condition in getpass()
#45954
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This should fix the intermittent testing failures seen in the following buildkite logs:
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We accidentally introduced a race condition in `getpass()` by having `jl_getch()` toggle terminal modes for each keystroke. Not only is this slower and wasteful, it allows the kernel to receive keystrokes within a TTY in canonical mode (where it replaces certain characters [0]) and then reads from the kernel buffer in non-canonical mode. This results in us reading a `0x00` when we expected a `0x04` in certain cases on CI, which breaks some of our tests. The fix is to switch the TTY into raw mode once, before we ever print the password prompt, which closes the race condition. To do this, we moved more code from C to Julia, and removed the `jl_getch()` export, instead providing `jl_termios_size()`. [0] https://github.com/torvalds/linux/blob/e35e5b6f695d241ffb1d223207da58a1fbcdff4b/drivers/tty/n_tty.c#L1318
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vtjnash
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Jul 8, 2022
Co-authored-by: Jameson Nash <[email protected]>
vtjnash
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Jul 8, 2022
Co-authored-by: Jameson Nash <[email protected]>
vtjnash
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vtjnash
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Jul 8, 2022
Co-authored-by: Jameson Nash <[email protected]>
This was referenced Jul 10, 2022
ffucci
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Aug 11, 2022
…5954) * Remove `jl_getch()` to fix race condition in `getpass()` We accidentally introduced a race condition in `getpass()` by having `jl_getch()` toggle terminal modes for each keystroke. Not only is this slower and wasteful, it allows the kernel to receive keystrokes within a TTY in canonical mode (where it replaces certain characters [0]) and then reads from the kernel buffer in non-canonical mode. This results in us reading a `0x00` when we expected a `0x04` in certain cases on CI, which breaks some of our tests. The fix is to switch the TTY into raw mode once, before we ever print the password prompt, which closes the race condition. To do this, we moved more code from C to Julia, and removed the `jl_getch()` export, instead providing `jl_termios_size()`. [0] https://github.com/torvalds/linux/blob/e35e5b6f695d241ffb1d223207da58a1fbcdff4b/drivers/tty/n_tty.c#L1318 * Update base/util.jl Co-authored-by: Jameson Nash <[email protected]> * Apply suggestions from code review Co-authored-by: Jameson Nash <[email protected]> * Apply suggestions from code review Co-authored-by: Jameson Nash <[email protected]> Co-authored-by: Jameson Nash <[email protected]>
pcjentsch
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Aug 18, 2022
…5954) * Remove `jl_getch()` to fix race condition in `getpass()` We accidentally introduced a race condition in `getpass()` by having `jl_getch()` toggle terminal modes for each keystroke. Not only is this slower and wasteful, it allows the kernel to receive keystrokes within a TTY in canonical mode (where it replaces certain characters [0]) and then reads from the kernel buffer in non-canonical mode. This results in us reading a `0x00` when we expected a `0x04` in certain cases on CI, which breaks some of our tests. The fix is to switch the TTY into raw mode once, before we ever print the password prompt, which closes the race condition. To do this, we moved more code from C to Julia, and removed the `jl_getch()` export, instead providing `jl_termios_size()`. [0] https://github.com/torvalds/linux/blob/e35e5b6f695d241ffb1d223207da58a1fbcdff4b/drivers/tty/n_tty.c#L1318 * Update base/util.jl Co-authored-by: Jameson Nash <[email protected]> * Apply suggestions from code review Co-authored-by: Jameson Nash <[email protected]> * Apply suggestions from code review Co-authored-by: Jameson Nash <[email protected]> Co-authored-by: Jameson Nash <[email protected]>
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We accidentally introduced a race condition in
getpass()by havingjl_getch()toggle terminal modes for each keystroke. Not only is thisslower and wasteful, it allows the kernel to receive keystrokes within a
TTY in canonical mode (where it replaces certain characters [0]) and
then reads from the kernel buffer in non-canonical mode. This results
in us reading a
0x00when we expected a0x04in certain cases on CI,which breaks some of our tests.
The fix is to switch the TTY into raw mode once, before we ever print
the password prompt, which closes the race condition. To do this, we
moved more code from C to Julia, and removed the
jl_getch()export,instead providing
jl_termios_size().[0] https://github.com/torvalds/linux/blob/e35e5b6f695d241ffb1d223207da58a1fbcdff4b/drivers/tty/n_tty.c#L1318