NACK: [PATCH][SRU][xenial] UBUNTU: SAUCE: apparmor: fix nnp subset test for unconfined

[Tyler Hicks]

On 2019-10-03 16:26:42, John Johansen wrote:
> On 10/3/19 2:14 PM, Tyler Hicks wrote:
> > On 2019-10-03 12:15:03, John Johansen wrote:
> >> The subset test is not taking into account the unconfined exception
> >> which will cause profile transitions in the stacked confinement
> >> case to fail when no_new_privs is applied.
> >>
> >> This fixes a regression introduced in the fix for
> >> https://bugs.launchpad.net/bugs/1839037
> >>
> >> Fixes: 0924738c7386d ("UBUNTU: SAUCE: apparmor: fix nnp subset check failure when, stacking")
> >> BugLink: https://bugs.launchpad.net/bugs/1844186
> >> Signed-off-by: John Johansen <john.johansen at canonical.com>
> >> ---
> >>  security/apparmor/domain.c        |  4 ++--
> >>  security/apparmor/include/label.h |  1 +
> >>  security/apparmor/label.c         | 33 +++++++++++++++++++++++++++++++
> >>  3 files changed, 36 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c
> >> index 38595ca7e642e..231535930f09c 100644
> >> --- a/security/apparmor/domain.c
> >> +++ b/security/apparmor/domain.c
> >> @@ -765,7 +765,7 @@ int apparmor_bprm_set_creds(struct linux_binprm *bprm)
> >>  	 * aways results in a further reduction of permissions.
> >>  	 */
> >>  	if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
> >> -	    !unconfined(label) && !aa_label_is_subset(new, label)) {
> >> +	    !unconfined(label) && !aa_label_is_unconfined_subset(new, label)) {
> >>  		error = -EPERM;
> >>  		info = "no new privs";
> >>  		goto audit;
> >> @@ -1117,7 +1117,7 @@ static int change_profile_perms_wrapper(const char *op, const char *name,
> >>  	 */
> >>  	if (task_no_new_privs(current) && !stack &&
> >>  	    !profile_unconfined(profile) &&
> >> -	    !aa_label_is_subset(target, &profile->label)) {
> >> +	    !aa_label_is_unconfined_subset(target, &profile->label)) {
> >>  		info = "no new privs";
> >>  		error = -EPERM;
> >>  	}
> > 
> > Same question in Xenial as Bionic in regards to fixing aa_change_hat().
> > 
> yep, I send a v2 with both fixes

Thanks!

Tyler

> 
> > Tyler
> > 
> >> diff --git a/security/apparmor/include/label.h b/security/apparmor/include/label.h
> >> index 829d6e452cb86..10830078ba890 100644
> >> --- a/security/apparmor/include/label.h
> >> +++ b/security/apparmor/include/label.h
> >> @@ -356,6 +356,7 @@ bool aa_label_init(struct aa_label *label, int size);
> >>  struct aa_label *aa_label_alloc(int size, struct aa_proxy *proxy, gfp_t gfp);
> >>  
> >>  bool aa_label_is_subset(struct aa_label *set, struct aa_label *sub);
> >> +bool aa_label_is_unconfined_subset(struct aa_label *set, struct aa_label *sub);
> >>  struct aa_profile *__aa_label_next_not_in_set(struct label_it *I,
> >>  					     struct aa_label *set,
> >>  					     struct aa_label *sub);
> >> diff --git a/security/apparmor/label.c b/security/apparmor/label.c
> >> index 69a600b4c1a15..a942c14505ce2 100644
> >> --- a/security/apparmor/label.c
> >> +++ b/security/apparmor/label.c
> >> @@ -551,6 +551,39 @@ bool aa_label_is_subset(struct aa_label *set, struct aa_label *sub)
> >>  	return __aa_label_next_not_in_set(&i, set, sub) == NULL;
> >>  }
> >>  
> >> +/**
> >> + * aa_label_is_unconfined_subset - test if @sub is a subset of @set
> >> + * @set: label to test against
> >> + * @sub: label to test if is subset of @set
> >> + *
> >> + * This checks for subset but taking into account unconfined. IF
> >> + * @sub contains an unconfined profile that does not have a matching
> >> + * unconfined in @set then this will not cause the test to fail.
> >> + * Conversely we don't care about an unconfined in @set that is not in
> >> + * @sub
> >> + *
> >> + * Returns: true if @sub is special_subset of @set
> >> + *     else false
> >> + */
> >> +bool aa_label_is_unconfined_subset(struct aa_label *set, struct aa_label *sub)
> >> +{
> >> +	struct label_it i = { };
> >> +	struct aa_profile *p;
> >> +
> >> +	AA_BUG(!set);
> >> +	AA_BUG(!sub);
> >> +
> >> +	if (sub == set)
> >> +		return true;
> >> +
> >> +	do {
> >> +		p = __aa_label_next_not_in_set(&i, set, sub);
> >> +		if (p && !profile_unconfined(p))
> >> +			break;
> >> +	} while (p);
> >> +
> >> +	return p == NULL;
> >> +}
> >>  
> >>  
> >>  /**
> >> -- 
> >> 2.17.1
> >>
> >>
> >> -- 
> >> kernel-team mailing list
> >> kernel-team at lists.ubuntu.com
> >> https://lists.ubuntu.com/mailman/listinfo/kernel-team
>