[libvirt] [PATCH 2/2] virt-login-shell joins users into lxc container.
Daniel J Walsh
dwalsh at redhat.com
Thu Jan 2 15:18:16 UTC 2014
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On 12/23/2013 05:44 PM, Eric Blake wrote:
> On 12/23/2013 03:17 PM, Eric Blake wrote:
>>>> + if (!(conf = virConfReadFile(login_shell_path, 0))) + goto
>>> ...and non-root invariably fails here, since login_shell_path
>>> (/etc/libvirt/virt-login-shell.conf) is buried inside a directory that
>>> is not searchable by either root or virtlogin.
>> Ah, I see - non-root fails here if run unprivileged (such as under gdb),
>> but when run setuid it has the permissions of root and can read the file
>> just fine.
Maybe need to give it cap_dac_read_search?
/* Overrides all DAC restrictions regarding read and search on files
and directories, including ACL restrictions if [_POSIX_ACL] is
defined. Excluding DAC access covered by CAP_LINUX_IMMUTABLE. */
#define CAP_DAC_READ_SEARCH 2
> Then again, when run as setuid, it's not even getting past virInitialize().
> At least I managed to figure out how to debug things: I recompiled with a
> sleep() at the beginning, gave my just-compiled binary the same setuid
> permissions as the installed binary, and then attach gdb (as root, since
> non-root can't ptrace a running setuid binary for obvious reasons). So I
> suspect that the failure in virInitialize() is yet more fallout from the
> CVE-2013-4400 patches being untested.
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