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On Mon, Feb 4, 2019 at 9:35 AM Alexis Ballier <aballier@g.o> wrote: |
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> |
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> On Mon, 04 Feb 2019 15:13:36 +0100 |
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> Michał Górny <mgorny@g.o> wrote: |
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> |
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> > 2. By design, postinst is run with full privileges. It is meant to |
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> > allow ebuilds to run stuff, as root. |
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> |
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> And that is precisely that kind of design that makes it hard or |
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> unrealistic to have unreviewed global repositories. |
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> |
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Unless you're doing something like per-app sandboxes at runtime fixing |
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this is just shifting the problem elsewhere. |
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Ok, so the package can't run stuff at root at time of install. But, |
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it can drop whatever shell script it wants into /etc/cron.hourly, or |
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enable some service by default. Or it can stick something in the |
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default shell profile. Or it can install /sbin/bash which is ahead of |
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/bin/bash in PATH, or whatever. |
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If malware is recognized as a legitimate package by your package |
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manager, you've basically already lost, at least in the typical |
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linux/unix-like access control model. Now, if you're doing |
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unconventional things like android does with uids or putting 3 layers |
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of SELinux on top of everything then you can have more defense in |
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depth. But, that also requires sandboxing your package manager so |
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that it can't tamper with ALL of your security. |
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As mgorny has already pointed out, you can't just sandbox package |
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phases to fix the problem. I think sandboxing your build system is a |
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great way to improve build system QA in general, but it doesn't solve |
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intrusion. |
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-- |
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Rich |
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