[LTP] [PATCH] fs/proc01.c:add known issues

[Jan Stancek]

----- Original Message -----

> thanks for good question.

> i check the source linux-source-5.8.0,in filesecurity/smack/smack_lsm.c:
> smack_getprocattr
> directly return -EINVAL.

> static int smack_getprocattr(struct task_struct *p, char *name, char **value)
> {
> struct smack_known *skp = smk_of_task_struct(p);
> char *cp;
> int slen;

> if (strcmp(name, "current") != 0 && strcmp(name, "context") != 0)
> return -EINVAL;

That doesn't look correct, strcmp when reading "current" returns 0, so you condition above 
shouldn't be hit. 

I'm guessing you don't have smack enabled, and EINVAL is the default LSM ret value 
in such case: 

LSM_HOOK(int, -EINVAL, getprocattr, struct task_struct *p, char *name, 
char **value) 

int security_getprocattr(struct task_struct *p, const char *lsm, char *name, 
char **value) 
{ 
struct security_hook_list *hp; 

hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) { 
if (lsm != NULL && strcmp(lsm, hp->lsm)) 
continue; 
return hp->hook.getprocattr(p, name, value); 
} 
return LSM_RET_DEFAULT(getprocattr); 
} 

> cp = kstrdup(skp->smk_known, GFP_KERNEL);
> if (cp == NULL)
> return -ENOMEM;

> slen = strlen(cp);
> *value = cp;
> return slen;
> }

> > From: Jan Stancek
> 
> > Date: 2021-01-15 22:54
> 
> > To: Xinpeng Liu
> 
> > CC: ltp
> 
> > Subject: Re: [LTP] [PATCH] fs/proc01.c:add known issues
> 
> > ----- Original Message -----
> 
> > > Test in ubuntu20.10,there are several failure tests.
> 
> > >
> 
> > > proc01 1 TFAIL : proc01.c:396: read failed:
> 
> > > /proc/self/task/61595/attr/smack/current: errno=EINVAL(22): Invalid
> > > argument
> 
> > > proc01 2 TFAIL : proc01.c:396: read failed:
> 
> > > /proc/self/task/61595/attr/apparmor/prev: errno=EINVAL(22): Invalid
> > > argument
> 
> > > proc01 3 TFAIL : proc01.c:396: read failed:
> 
> > > /proc/self/task/61595/attr/apparmor/exec: errno=EINVAL(22): Invalid
> > > argument
> 
> > > proc01 4 TFAIL : proc01.c:396: read failed:
> 
> > > /proc/self/attr/smack/current: errno=EINVAL(22): Invalid argument
> 
> > > proc01 5 TFAIL : proc01.c:396: read failed:
> 
> > > /proc/self/attr/apparmor/prev: errno=EINVAL(22): Invalid argument
> 
> > > proc01 6 TFAIL : proc01.c:396: read failed:
> 
> > > /proc/self/attr/apparmor/exec: errno=EINVAL(22): Invalid argument
> 
> > I'm OK with ignoring it, but commit log could explain more why we get
> > EINVAL
> 
> > on read here.
> 
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