chmod the /build subdir to 750
#11807
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Due to unknown reasons, some packages (notably yarn and npm) will stall during a build process. This causes a major problem, because the process cannot be killed and a cold-reset is needed to restart the system (a shutdown or reboot will hang trying to umount the partition where the build is happening). By letting the `/build` subdirectory be group-readable by the nixbld group, the problem is fixed. Also we do not sacrifice build privacy, because the parrent directory is owned by `root` and set to `700`. So even if we have a malicious setguid binary in one build and another tries to run it, it cannot access it because the parent folder is owned by `root`. fixes NixOS#11806 fixes NixOS/nixpkgs#353709 Signed-off-by: Florian Brandes <[email protected]>
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This does not in itself fix the issue. I've found that this patch works when on an older release of |
edolstra
approved these changes
Nov 5, 2024
| @@ -555,7 +555,7 @@ void LocalDerivationGoal::startBuilder() | |||
| possible. Any mitigation along these lines would have to be | |||
| done directly in the sandbox profile. */ | |||
| tmpDir = topTmpDir + "/build"; | |||
| createDir(tmpDir, 0700); | |||
| createDir(tmpDir, 0750); | |||
There was a problem hiding this comment.
Maybe add a comment here why we're doing 0750 instead of 0700.
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This is not needed. Bug is in the kernel, not in nix. See related issues |
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Due to unknown reasons, some packages (notably yarn and npm) will stall during a build process. This causes a major problem, because the process cannot be killed and a cold-reset is needed to restart the system (a shutdown or reboot will hang trying to umount the partition where the build is happening).
By letting the
/buildsubdirectory be group-readable by the nixbld group, the problem is fixed.Also we do not sacrifice build privacy, because the parrent directory is owned by
rootand set to700.So even if we have a malicious setguid binary in one build and another tries to run it, it cannot access it because the parent folder is owned by
root.fixes #11806
fixes NixOS/nixpkgs#353709
Motivation
See linked issues above
Context
See linked issues above
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