Messages in this thread | | | Subject | Re: [PATCH 2/2] SELinux: Measure state and hash of policy using IMA | From | Lakshmi Ramasubramanian <> | Date | Thu, 13 Aug 2020 11:03:04 -0700 |
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On 8/13/20 10:58 AM, Stephen Smalley wrote: > On Thu, Aug 13, 2020 at 1:52 PM Lakshmi Ramasubramanian > <nramas@linux.microsoft.com> wrote: >> >> On 8/13/20 10:42 AM, Stephen Smalley wrote: >> >>>> diff --git a/security/selinux/measure.c b/security/selinux/measure.c >>>> new file mode 100644 >>>> index 000000000000..f21b7de4e2ae >>>> --- /dev/null >>>> +++ b/security/selinux/measure.c >>>> @@ -0,0 +1,204 @@ >>>> +static int selinux_hash_buffer(void *buf, size_t buf_len, >>>> + void **buf_hash, int *buf_hash_len) >>>> +{ >>>> + struct crypto_shash *tfm; >>>> + struct shash_desc *desc = NULL; >>>> + void *digest = NULL; >>>> + int desc_size; >>>> + int digest_size; >>>> + int ret = 0; >>>> + >>>> + tfm = crypto_alloc_shash("sha256", 0, 0); >>>> + if (IS_ERR(tfm)) >>>> + return PTR_ERR(tfm); >>> Can we make the algorithm selectable via kernel parameter and/or writing >>> to a new selinuxfs node? >> >> I can add a kernel parameter to select this hash algorithm. > > Also can we provide a Kconfig option for the default value like IMA does? >
Would we need both - Kconfig and kernel param?
The other option is to provide an IMA function to return the current hash algorithm used for measurement. That way a consistent hash algorithm can be employed by both IMA and the callers. Would that be better?
-lakshmi
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