Re: [RFC] [PATCH] file posix capabilities

From: Eric W. Biederman
Date: Mon Aug 14 2006 - 20:17:55 EST

"Serge E. Hallyn" <serue@xxxxxxxxxx> writes:

> Quoting Serge E. Hallyn (serue@xxxxxxxxxx):
>> This patch implements file (posix) capabilities. This allows
>> a binary to gain a subset of root's capabilities without having
>> the file actually be setuid root.
>> There are some other implementations out there taking various
>> approaches. This patch keeps all the changes within the
>> capability LSM, and stores the file capabilities in xattrs
>> named "security.capability". First question is, do we want
>> this in the kernel? Second is, is this sort of implementation
>> we'd want?
>> Some userspace tools to manipulate the fscaps are at
>> For instance,
>> setcap writeroot "cap_dac_read_search,cap_dac_override+eip"
>> allows the 'writeroot' testcase to write to /root/ab when
>> run as a normal user.
>> This patch doesn't address the need to update
>> cap_bprm_secureexec().

Looking at your ondisk format it doesn't look like you include a
version. There is no reason to believe the current set of kernel
capabilities is fixed for all time. So we need some for of
forward/backward compatibility. Maybe in the cap name?

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