[PATCH 2/2] AppArmor: Fix masking of capabilities in complain mode

John Johansen
2011-06-29T01:45:06Z

AppArmor is masking the capabilities returned by capget against the
capabilities mask in the profile. This is wrong, in complain mode the
profile has effectively all capabilities, as the profile restrictions are
not being enforced, merely tested against to determine if an access is
known by the profile.

This can result in the wrong behavior of security conscience applications
like sshd which examine their capability set, and change their behavior
accordingly. In this case because of the masked capability set being
returned sshd fails due to DAC checks, even when the profile is in complain
mode.

Kernels affected: 2.6.36 - 3.0.

Signed-off-by: John Johansen <john.johansen@canonical.com>
---
security/apparmor/lsm.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 3d2fd14..3783202 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -127,7 +127,7 @@ static int apparmor_capget(struct task_struct *target, kernel_cap_t *effective,
*inheritable = cred->cap_inheritable;
*permitted = cred->cap_permitted;

- if (!unconfined(profile)) {
+ if (!unconfined(profile) && !COMPLAIN_MODE(profile)) {
*effective = cap_intersect(*effective, profile->caps.allow);
*permitted = cap_intersect(*permitted, profile->caps.allow);
}
--
1.7.4.1