Eric Van Hensbergen wrote:
> Somewhat related question for Viro/the group:
>
> Why is CLONE_NEWNS considered a priveledged operation? Would placing
> limits on the number of private namespaces a user can own solve any
> resource concerns or is there something more nefarious I'm missing?
> -
> To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
Likely because its a chroot vulnerability.
It allows a process to obtain a reference to the root vfsmount that
doesn't have chroot checks performed on it.
Consider the following pseudo example:
main():
chdir("/");
fd = open(".", O_RDONLY);
clone(cloned_func, cloned_stack, CLONE_NEWNS, NULL);
cloned_func:
fchdir(fd);
chdir("..");
if main is run within a chroot where it's "/" is on the same vfsmount as
it's "..", then the application can step out of the chroot using clone(2).
Note: using chdir in a vfsmount outside of your namespace works, however
you won't be able to walk off that vfsmount (to its parent or children).
Mike Waychison
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]