I think that is what he was suggesting. It reuses the integrity code but it loses the integrity flexibility. I don't think it is a good solution :-(
On Mon, Mar 4, 2013 at 1:59 PM, Mimi Zohar <zo...@linux.vnet.ibm.com> wrote: > On Mon, 2013-03-04 at 10:29 -0500, Vivek Goyal wrote: > [...] > >> Hi Mimi, >> >> If we decide to merge flags, then practically we modified the >> ima_appraise_tcb policy. ima_appraise_tcb policy expects to cache the >> results and we will not do that. And this conflict just grows if we >> are forced to add more options in future. >> >> Also as you mentioned that in some cases flag merging is OR operation >> and in another cases it might be AND operation. And we will most likely >> end up hardcoding all this. I think slowly this is getting complicated >> and as people add more complex rules things can quickly get out of hand. >> >> I am wondering that why are we trying to make multiple policies work >> together. Can we try to keep it simple and say that at one point of >> time only one policy can be effective. It could either be a built in >> policy or user defined one. In fact that's how things are working right now. >> User defined policy replaces built-in policy. >> >> For the sake of backward compatibility "ima_tcb" and "ima_appraise_tcb" >> can co-exist together (like today). But ima_secureboot_policy will not >> be compatible with other policies. I understand that there might be a >> desire to use multiple policies together down the line, but I guess in >> that case policies need to specified using "policy" interface. And >> ima_secureboot will be odd man out here as it can not trust the root >> to specify policy. So practically ima_secureboot will be disabled. >> >> We just have to provide an IMA interface so that caller can query what's >> the effective policy currently. Say, IMA_POLICY_SECUREBOOT, >> IMA_POLICY_TCB, or IMA_POLICY_USER. Caller of the bprm_check() or >> bprm_post_load() can also check for current policy in force and give >> CAP_SIGNED only if desired policy is in effect. >> >> This reduces our options but trying to make multiple policies co-exist >> together is just making it complicated. We can take it up again when >> somebody has a strong use case of using secureboot policy along with >> other policies. In fact a user can still define a custom policy which >> is mix of multiple policies. Just that it is not compatible with >> "secureboot" policy because for that we can't trust "root" to define >> policy. > > Let me get this straight. You're suggesting that distros/users will > need to make a Kconfig build decision of enabling secureboot, including > the secureboot built-in policy, or be allowed to enable other integrity > policies. If RH enables secureboot, then no other integrity policy will > be permitted. Is that what you're saying, and if so, why would I agree > to this? > > thanks, > > Mimi > > -- > To unsubscribe from this list: send the line "unsubscribe > linux-security-module" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
