Re: [PATCH v8 05/19] ima: Move measurement list related variables into ima_namespace

[Stefan Berger]

On 1/13/22 15:27, Mimi Zohar wrote:
> Hi Stefan,
>
> On Tue, 2022-01-04 at 12:04 -0500, Stefan Berger wrote:
> > From: Stefan Berger <stefanb@xxxxxxxxxxxxx>
> >
> > Move measurement list related variables into the ima_namespace. This way a
> > front-end like SecurityFS can show the measurement list inside an IMA
> > namespace.
> >
> > Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
> > ---
> >   security/integrity/ima/ima.h             |  5 +++--
> >   security/integrity/ima/ima_fs.c          |  6 ++++--
> >   security/integrity/ima/ima_init_ima_ns.c |  5 +++++
> >   security/integrity/ima/ima_kexec.c       | 12 +++++++-----
> >   security/integrity/ima/ima_queue.c       | 24 ++++++++++--------------
> >   5 files changed, 29 insertions(+), 23 deletions(-)
> >
> > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> > index 68d8a8e6fd1d..ee16ce5050c8 100644
> > --- a/security/integrity/ima/ima.h
> > +++ b/security/integrity/ima/ima.h
> > @@ -106,7 +106,6 @@ struct ima_queue_entry {
> >   	struct list_head later;		/* place in ima_measurements list */
> >   	struct ima_template_entry *entry;
> >   };
> > -extern struct list_head ima_measurements;	/* list of all measurements */
> >   
> >   /* Some details preceding the binary serialized measurement list */
> >   struct ima_kexec_hdr {
> > @@ -134,6 +133,8 @@ struct ima_namespace {
> >   	int ima_policy_flag;
> >   
> >   	struct ima_h_table ima_htable;
> > +	struct list_head ima_measurements;
> > +	unsigned long binary_runtime_size;
> Please add a comment indicating binary_runtime_size is only applicable
> to ns_ima_init.

It looks like this now:

        struct list_head ima_measurements;
        /* binary_runtime_size is used only by init_ima_ns */
        unsigned long binary_runtime_size;


> >   } __randomize_layout;
> >   extern struct ima_namespace init_ima_ns;
>
> > @@ -124,12 +119,13 @@ static int ima_add_digest_entry(struct ima_namespace *ns,
> >    * entire binary_runtime_measurement list, including the ima_kexec_hdr
> >    * structure.
> >    */
> > -unsigned long ima_get_binary_runtime_size(void)
> > +unsigned long ima_get_binary_runtime_size(struct ima_namespace *ns)
> >   {
> > -	if (binary_runtime_size >= (ULONG_MAX - sizeof(struct ima_kexec_hdr)))
> > +	if (ns->binary_runtime_size >=
> > +				(ULONG_MAX - sizeof(struct ima_kexec_hdr)))
> >   		return ULONG_MAX;
> >   	else
> > -		return binary_runtime_size + sizeof(struct ima_kexec_hdr);
> > +		return ns->binary_runtime_size + sizeof(struct ima_kexec_hdr);
> >   }
> >   
> Please update the function description indicating that either carrying
> the measurement list across kexec is limited to ns_ima_init or not
> supported by namespaces.

This is the updated function description:


/*
 * Return the amount of memory required for serializing the
 * entire binary_runtime_measurement list, including the ima_kexec_hdr
 * structure. Carrying the measurement list across kexec is limited
 * to init_ima_ns.
 */
> thanks,
>
> Mimi