[apparmor] [PATCH -next] apparmor: fix invalid reference on profile->disconnected

[John Johansen]

On 8/22/23 11:01, Georgia Garcia wrote:
> On Tue, 2023-08-22 at 10:13 -0700, John Johansen wrote:
>> On 8/21/23 11:37, Georgia Garcia wrote:
>>> profile->disconnected was storing an invalid reference to the
>>> disconnected path. Fix it by duplicating the string using
>>> aa_unpack_strdup and freeing accordingly.
>>>
>> This is going to need the Fixes tag
>>
>> Fixes: 72c8a768641d ("apparmor: allow profiles to provide info to disconnected paths")
> 
> Thanks!
> 
>>
>>> Signed-off-by: Georgia Garcia <georgia.garcia at canonical.com>
>>
>> the patch certainly addresses the issue, and I can add the Fixes tag, but unless
>> there is something I am missing I think we should avoid the intermediate variable
>> as noted below
>>
>>> ---
>>>    security/apparmor/policy.c        | 1 +
>>>    security/apparmor/policy_unpack.c | 5 +++--
>>>    2 files changed, 4 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/security/apparmor/policy.c b/security/apparmor/policy.c
>>> index 4817c1b30105..d7525f228c43 100644
>>> --- a/security/apparmor/policy.c
>>> +++ b/security/apparmor/policy.c
>>> @@ -255,6 +255,7 @@ void aa_free_profile(struct aa_profile *profile)
>>>    
>>>    	aa_put_ns(profile->ns);
>>>    	kfree_sensitive(profile->rename);
>>> +	kfree_sensitive(profile->disconnected);
>>>    
>>>    	free_attachment(&profile->attach);
>>>    
>>> diff --git a/security/apparmor/policy_unpack.c b/security/apparmor/policy_unpack.c
>>> index d2d740bb5618..8b2ad42c80ba 100644
>>> --- a/security/apparmor/policy_unpack.c
>>> +++ b/security/apparmor/policy_unpack.c
>>> @@ -804,7 +804,7 @@ static struct aa_profile *unpack_profile(struct aa_ext *e, char **ns_name)
>>>    	const char *info = "failed to unpack profile";
>>>    	size_t ns_len;
>>>    	struct rhashtable_params params = { 0 };
>>> -	char *key = NULL;
>>> +	char *key = NULL, *disconnected = NULL;
>>>    	struct aa_data *data;
>>>    	int error = -EPROTO;
>>>    	kernel_cap_t tmpcap;
>>> @@ -870,7 +870,8 @@ static struct aa_profile *unpack_profile(struct aa_ext *e, char **ns_name)
>>>    	}
>>>    
>>>    	/* disconnected attachment string is optional */
>>> -	(void) aa_unpack_str(e, &profile->disconnected, "disconnected");
>>> +	(void) aa_unpack_strdup(e, &disconnected, "disconnected");
>>> +	profile->disconnected = disconnected;
>>
>> is there any reason you added the intermediate step of unpacking to &disconnected instead of just directly to the value as before?
> 
> profile->disconnected is const and but the second argument of
> aa_unpack_strdup is not, so the compiler throws an error saying
> "incompatible pointer type".
>
ah right, I guess its worth keeping the const, thanks.
  
>>>    
>>>    	/* per profile debug flags (complain, audit) */
>>>    	if (!aa_unpack_nameX(e, AA_STRUCT, "flags")) {
>>
>