[PATCH v7 23/42] selinux: introduce cred_has_extended_perms()

[Stephen Smalley <stephen.smalley.work@gmail.com>]

Introduce cred_has_extended_perms() to check extended permissions
against the current SELinux namespace and all ancestor namespaces.
Update the caller of avc_has_extended_perms() to use this function
instead.

Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
---
 security/selinux/avc.c         | 26 ++++++++++++++++++++++++++
 security/selinux/hooks.c       |  7 +++----
 security/selinux/include/avc.h |  4 ++++
 3 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index 44caaead16aa..03760f7e7cac 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -1290,6 +1290,32 @@ int cred_task_has_perm(const struct cred *cred, const struct task_struct *p,
 	return 0;
 }
 
+int cred_has_extended_perms(const struct cred *cred, u32 tsid, u16 tclass,
+			    u32 requested, u8 driver, u8 base_perm, u8 xperm,
+			    struct common_audit_data *ad)
+{
+	struct task_security_struct *tsec;
+	struct selinux_state *state;
+	u32 ssid;
+	int rc;
+
+	do {
+		tsec = selinux_cred(cred);
+		ssid = tsec->sid;
+		state = tsec->state;
+
+		rc = avc_has_extended_perms(state, ssid, tsid, tclass,
+					    requested, driver, base_perm,
+					    xperm, ad);
+		if (rc)
+			return rc;
+
+		cred = tsec->parent_cred;
+	} while (cred);
+
+	return 0;
+}
+
 u32 avc_policy_seqno(struct selinux_state *state)
 {
 	return state->avc->avc_cache.latest_notif;
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index d21b3d03cced..f22acce323b8 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3913,10 +3913,9 @@ static int ioctl_has_perm(const struct cred *cred, struct file *file,
 		return 0;
 
 	isec = inode_security(inode);
-	rc = avc_has_extended_perms(cred_selinux_state(cred),
-				    ssid, isec->sid, isec->sclass,
-				    requested, driver, AVC_EXT_IOCTL, xperm,
-				    &ad);
+	rc = cred_has_extended_perms(cred, isec->sid, isec->sclass,
+				     requested, driver, AVC_EXT_IOCTL,
+				     xperm, &ad);
 out:
 	return rc;
 }
diff --git a/security/selinux/include/avc.h b/security/selinux/include/avc.h
index 5d79bb7c610c..adbbecc681f2 100644
--- a/security/selinux/include/avc.h
+++ b/security/selinux/include/avc.h
@@ -154,6 +154,10 @@ int cred_task_has_perm(const struct cred *cred, const struct task_struct *p,
 		       u16 tclass, u32 requested,
 		       struct common_audit_data *auditdata);
 
+int cred_has_extended_perms(const struct cred *cred, u32 tsid, u16 tclass,
+			    u32 requested, u8 driver, u8 base_perm, u8 xperm,
+			    struct common_audit_data *ad);
+
 u32 avc_policy_seqno(struct selinux_state *state);
 
 #define AVC_CALLBACK_GRANT		1
-- 
2.50.1