---

yaml
---
r: 146409
b: refs/heads/master
c: b5f22a5
h: refs/heads/master
i:
  146407: 67f4813
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3d43321b7015387cfebbe26436d0e9d299162ea1
+refs/heads/master: b5f22a59c0356655a501190959db9f7f5dd07e3f

trunk/security/commoncap.c

@@ -28,6 +28,28 @@
 #include <linux/prctl.h>
 #include <linux/securebits.h>
 
+/*
+ * If a non-root user executes a setuid-root binary in
+ * !secure(SECURE_NOROOT) mode, then we raise capabilities.
+ * However if fE is also set, then the intent is for only
+ * the file capabilities to be applied, and the setuid-root
+ * bit is left on either to change the uid (plausible) or
+ * to get full privilege on a kernel without file capabilities
+ * support.  So in that case we do not raise capabilities.
+ *
+ * Warn if that happens, once per boot.
+ */
+static void warn_setuid_and_fcaps_mixed(char *fname)
+{
+	static int warned;
+	if (!warned) {
+		printk(KERN_INFO "warning: `%s' has both setuid-root and"
+			" effective capabilities. Therefore not raising all"
+			" capabilities.\n", fname);
+		warned = 1;
+	}
+}
+
 int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
 {
 	NETLINK_CB(skb).eff_cap = current_cap();
@@ -463,6 +485,15 @@ int cap_bprm_set_creds(struct linux_binprm *bprm)
 		return ret;
 
 	if (!issecure(SECURE_NOROOT)) {
+		/*
+		 * If the legacy file capability is set, then don't set privs
+		 * for a setuid root binary run by a non-root user.  Do set it
+		 * for a root user just to cause least surprise to an admin.
+		 */
+		if (effective && new->uid != 0 && new->euid == 0) {
+			warn_setuid_and_fcaps_mixed(bprm->filename);
+			goto skip;
+		}
 		/*
 		 * To support inheritance of root-permissions and suid-root
 		 * executables under compatibility mode, we override the
@@ -478,6 +509,7 @@ int cap_bprm_set_creds(struct linux_binprm *bprm)
 		if (new->euid == 0)
 			effective = true;
 	}
+skip:
 
 	/* Don't let someone trace a set[ug]id/setpcap binary with the revised
 	 * credentials unless they have the appropriate permit