Messages in this thread | | | Date | Tue, 02 Sep 2014 12:53:14 -0700 | From | Andy Lutomirski <> | Subject | Re: How is pivot_root intended to be used? |
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On 09/01/2014 02:19 PM, Steven Stewart-Gallus wrote: > Hello, > > I am not confused about how I can currently use pivot_root for > containers on my kernel (version 3.13). Currently a sequence like: > > if (-1 == syscall(__NR_pivot_root, ".", ".")) { > perror("pivot_root"); > return EXIT_FAILURE; > } > > if (-1 == umount2(".", MNT_DETACH)) { > perror("umount"); > return EXIT_FAILURE;
Given the comment, you don't know what '.' refers to in the umount2 call above. In fact, I think you're actually detaching the wrong thing, leaving possible security issues.
See:
https://github.com/sandstorm-io/sandstorm/blob/master/src/sandstorm/supervisor-main.c%2B%2B#L922
for a program that does this more carefully.
--Andy
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