Re: [PATCH 2/2] ima: add policy support for file system uuid

[Mimi Zohar <zohar@linux.vnet.ibm.com>]

On Thu, 2013-02-21 at 13:54 -0800, David Rientjes wrote:
> On Tue, 5 Feb 2013, Mimi Zohar wrote:
> 
> > diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> > index 4adcd0f..23f49e3 100644
> > --- a/security/integrity/ima/ima_policy.c
> > +++ b/security/integrity/ima/ima_policy.c
> > @@ -16,6 +16,7 @@
> >  #include <linux/magic.h>
> >  #include <linux/parser.h>
> >  #include <linux/slab.h>
> > +#include <linux/genhd.h>
> >  
> >  #include "ima.h"
> >  
> > @@ -25,6 +26,7 @@
> >  #define IMA_FSMAGIC	0x0004
> >  #define IMA_UID		0x0008
> >  #define IMA_FOWNER	0x0010
> > +#define IMA_FSUUID	0x0020
> >  
> >  #define UNKNOWN		0
> >  #define MEASURE		0x0001	/* same as IMA_MEASURE */
> > @@ -45,6 +47,7 @@ struct ima_rule_entry {
> >  	enum ima_hooks func;
> >  	int mask;
> >  	unsigned long fsmagic;
> > +	u8 fsuuid[16];
> >  	kuid_t uid;
> >  	kuid_t fowner;
> >  	struct {
> > @@ -172,6 +175,9 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
> >  	if ((rule->flags & IMA_FSMAGIC)
> >  	    && rule->fsmagic != inode->i_sb->s_magic)
> >  		return false;
> > +	if ((rule->flags & IMA_FSUUID) &&
> > +		memcmp(rule->fsuuid, inode->i_sb->s_uuid, sizeof(rule->fsuuid)))
> > +		return false;
> >  	if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid))
> >  		return false;
> >  	if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid))
> > @@ -346,7 +352,7 @@ enum {
> >  	Opt_obj_user, Opt_obj_role, Opt_obj_type,
> >  	Opt_subj_user, Opt_subj_role, Opt_subj_type,
> >  	Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner,
> > -	Opt_appraise_type
> > +	Opt_appraise_type, Opt_fsuuid
> >  };
> >  
> >  static match_table_t policy_tokens = {
> > @@ -364,6 +370,7 @@ static match_table_t policy_tokens = {
> >  	{Opt_func, "func=%s"},
> >  	{Opt_mask, "mask=%s"},
> >  	{Opt_fsmagic, "fsmagic=%s"},
> > +	{Opt_fsuuid, "fsuuid=%s"},
> >  	{Opt_uid, "uid=%s"},
> >  	{Opt_fowner, "fowner=%s"},
> >  	{Opt_appraise_type, "appraise_type=%s"},
> > @@ -519,6 +526,19 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
> >  			if (!result)
> >  				entry->flags |= IMA_FSMAGIC;
> >  			break;
> > +		case Opt_fsuuid:
> > +			ima_log_string(ab, "fsuuid", args[0].from);
> > +
> > +			if (memchr_inv(entry->fsuuid, 0x00,
> > +			    sizeof(entry->fsuuid))) {
> > +				result = -EINVAL;
> > +				break;
> > +			}
> > +
> > +			part_pack_uuid(args[0].from, entry->fsuuid);
> > +			entry->flags |= IMA_FSUUID;
> > +			result = 0;
> > +			break;
> >  		case Opt_uid:
> >  			ima_log_string(ab, "uid", args[0].from);
> >  
> 
> We don't have part_pack_uuid() without CONFIG_BLOCK, so should this return 
> -ENOTSUPP if that option is not enabled?

Yes, this problem showed up in Randy's randconfig.  He suggested moving
part_pack_uuid() outside of the "ifdef CONFIG_BLOCK" to always make it
visible - http://marc.info/?l=linux-next&m=136139276002173&w=2.

thanks,

Mimi