capabilities: move audit log decision to function

Move the audit log decision logic to its own function to isolate the
complexity in one place.

Suggested-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Acked-by: Kees Cook <keescook@chromium.org>
Okay-ished-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>

diff --git a/security/commoncap.c b/security/commoncap.c
index 421f743..d7f0cbd 100644 (file)
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -765,6 +765,32 @@ static inline bool __is_setuid(struct cred *new, const struct cred *old)
 static inline bool __is_setgid(struct cred *new, const struct cred *old)
 { return !gid_eq(new->egid, old->gid); }
 
+/*
+ * Audit candidate if current->cap_effective is set
+ *
+ * We do not bother to audit if 3 things are true:
+ *   1) cap_effective has all caps
+ *   2) we are root
+ *   3) root is supposed to have all caps (SECURE_NOROOT)
+ * Since this is just a normal root execing a process.
+ *
+ * Number 1 above might fail if you don't have a full bset, but I think
+ * that is interesting information to audit.
+ */
+static inline bool nonroot_raised_pE(struct cred *cred, kuid_t root)
+{
+       bool ret = false;
+
+       if (__cap_grew(effective, ambient, cred)) {
+               if (!__cap_full(effective, cred) ||
+                   !__is_eff(root, cred) || !__is_real(root, cred) ||
+                   !root_privileged()) {
+                       ret = true;
+               }
+       }
+       return ret;
+}
+
 /**
  * cap_bprm_set_creds - Set up the proposed credentials for execve().
  * @bprm: The execution parameters, including the proposed creds
@@ -841,26 +867,10 @@ int cap_bprm_set_creds(struct linux_binprm *bprm)
        if (WARN_ON(!cap_ambient_invariant_ok(new)))
                return -EPERM;
 
-       /*
-        * Audit candidate if current->cap_effective is set
-        *
-        * We do not bother to audit if 3 things are true:
-        *   1) cap_effective has all caps
-        *   2) we are root
-        *   3) root is supposed to have all caps (SECURE_NOROOT)
-        * Since this is just a normal root execing a process.
-        *
-        * Number 1 above might fail if you don't have a full bset, but I think
-        * that is interesting information to audit.
-        */
-       if (__cap_grew(effective, ambient, new)) {
-               if (!__cap_full(effective, new) ||
-                   !__is_eff(root_uid, new) || !__is_real(root_uid, new) ||
-                   !root_privileged()) {
-                       ret = audit_log_bprm_fcaps(bprm, new, old);
-                       if (ret < 0)
-                               return ret;
-               }
+       if (nonroot_raised_pE(new, root_uid)) {
+               ret = audit_log_bprm_fcaps(bprm, new, old);
+               if (ret < 0)
+                       return ret;
        }
 
        new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);