Re: [Fwd: Re: [PATCH 2/2] ima: add policy support for file systemuuid]

[Randy Dunlap]

On 02/22/13 10:43, Mimi Zohar wrote:
> -------- Forwarded Message --------
> From: David Rientjes <rientjes@xxxxxxxxxx>
> To: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
> Cc: linux-security-module@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx,
> Dmitry Kasatkin <dmitry.kasatkin@xxxxxxxxx>
> Subject: Re: [PATCH 2/2] ima: add policy support for file system uuid
> Date: Fri, 22 Feb 2013 02:39:43 -0800 (PST)
> 
> On Thu, 21 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?

It's fine with me to ifdef that entire case and just return something like
ENOTBLK or EINVAL.  ENOTSUPP says that it is for NFSv3.


>> 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.
>>
> 
> Who's pushing this to linux-next?
> --

I had cc-ed Jens Axboe on it since it is block-related, but he seems
to have missed it.

-- 
~Randy
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