Re: [PATCH 2/3] binfmt_elf: Verify signature of signed elf binary

[Eric W. Biederman]

Vivek Goyal <vgoyal@xxxxxxxxxx> writes:

> On Wed, Jan 16, 2013 at 05:35:23PM -0500, Mimi Zohar wrote:
>> On Tue, 2013-01-15 at 16:34 -0500, Vivek Goyal wrote:
>> > If a binary is signed, verify its signature. If signature is not valid, do
>> > not allow execution. If binary is not signed, execution is allowed
>> > unconditionally.
>> 
>> Basically you're building the policy into the executable.  Anyone can
>> rebuild the executable and, without signing it, install/replace an
>> existing one.  How is this safe?  The signature verification policy
>> needs to be defined independently of the executable.
>
> Upon signature verification this executable will also acquire a new
> capability(say CAP_SIGNED). And some of the services can be allowed only
> if process has that new capability. (TODO item)

Just a quick segway.  The ptrace problem is solved by existing
mechanisms if you have a capability that other binaries don't have.

Eric
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/