Messages in this thread | | | Date | Wed, 27 Apr 2011 16:22:34 -0700 | From | Casey Schaufler <> | Subject | Re: [RFC][PATCH 4/7] smack: fix label check in smack_kernel_act_as() |
| |
On 4/27/2011 5:34 AM, Roberto Sassu wrote: > The function smack_kernel_act_as() must return -EINVAL if the label > returned by smack_from_secid() is equal to 'smack_known_invalid.smk_known', > which means that no entries in the 'smack_known_list' list matching the > security identifier given are found.
I'll admit that the code here is wrong, but I disagree with the fix.
smack_from_secid() will never return NULL, so the check for NULL is pointless. Checking for known_invalid is not right either, as the Smack philosophy is to return a label in all cases, as is evident by the behavior of smack_from_secid(). Thus, the correct change would be to remove the error check completely and set the new task value to the value obtained from smack_from_secid in all cases.
Besides, where did the caller of this function get a secid that isn't going to map to a Smack label?
> Signed-off-by: Roberto Sassu <roberto.sassu@polito.it> > --- > security/smack/smack_lsm.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c > index e3c9e54..0e7ed31 100644 > --- a/security/smack/smack_lsm.c > +++ b/security/smack/smack_lsm.c > @@ -1415,7 +1415,7 @@ static int smack_kernel_act_as(struct cred *new, u32 secid) > struct task_smack *new_tsp = new->security; > char *smack = smack_from_secid(secid); > > - if (smack == NULL) > + if (smack == smack_known_invalid.smk_known) > return -EINVAL; > > new_tsp->smk_task = smack;
| |