fix: don't pass all environment variables through sshd #1186
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dzhu
approved these changes
Aug 27, 2020
| # After openssh 8+ is the only version of openssh supported (that is, after we | ||
| # only support ubuntu >= 20.04), we can use the more obvious SetEnv option and | ||
| # skip this awkwardness. | ||
| vars="$(env | sed -e 's/=.*//')" | ||
| blacklist="(_|HOME|TERM|LANG|LC_[^=]*)" | ||
| vars="$(env | sed -E -e '/^('"$blacklist"')=/d; s/=.*//')" |
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non-blocking: Looks like there's an unnecessary set of parentheses around the blacklist here, and things can be simplified a bit if you switch the two statements. I think this does the same thing:
blacklist="^(_|HOME|TERM|LANG|LC_.*)\$"
vars="$(env | sed -E -e "s/=.*//; /$blacklist/d")"
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Ah, yes good call on both accounts.
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Description
The HOME variable was always set to / for non-root shells, when sshd should be setting it.
While we are at it, we might as well filter out several other environment variables which I think ought not to be passed in this way at all.