X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=security%2Fcommoncap.c;h=ea61bc73f6d3c4d1ecfe9d81964342b8cd306d74;hb=36501650ec45b1db308c3b51886044863be2d762;hp=bf67871173efbabbe2ad47a04ba1f24cbc6d3eeb;hpb=6d435365dd49ac5f7fe6f0e757e942875b1d1550;p=linux-2.6-omap-h63xx.git

diff --git a/security/commoncap.c b/security/commoncap.c
index bf67871173e..ea61bc73f6d 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -59,6 +59,12 @@ int cap_netlink_recv(struct sk_buff *skb, int cap)
 
 EXPORT_SYMBOL(cap_netlink_recv);
 
+/*
+ * NOTE WELL: cap_capable() cannot be used like the kernel's capable()
+ * function.  That is, it has the reverse semantics: cap_capable()
+ * returns 0 when a task has a capability, but the kernel's capable()
+ * returns 1 for this case.
+ */
 int cap_capable (struct task_struct *tsk, int cap)
 {
 	/* Derived from include/linux/sched.h:capable. */
@@ -107,10 +113,11 @@ static inline int cap_block_setpcap(struct task_struct *target)
 static inline int cap_inh_is_capped(void)
 {
 	/*
-	 * return 1 if changes to the inheritable set are limited
-	 * to the old permitted set.
+	 * Return 1 if changes to the inheritable set are limited
+	 * to the old permitted set. That is, if the current task
+	 * does *not* possess the CAP_SETPCAP capability.
 	 */
-	return !cap_capable(current, CAP_SETPCAP);
+	return (cap_capable(current, CAP_SETPCAP) != 0);
 }
 
 #else /* ie., ndef CONFIG_SECURITY_FILE_CAPABILITIES */
@@ -526,6 +533,19 @@ int cap_task_kill(struct task_struct *p, struct siginfo *info,
 	if (info != SEND_SIG_NOINFO && (is_si_special(info) || SI_FROMKERNEL(info)))
 		return 0;
 
+	/*
+	 * Running a setuid root program raises your capabilities.
+	 * Killing your own setuid root processes was previously
+	 * allowed.
+	 * We must preserve legacy signal behavior in this case.
+	 */
+	if (p->euid == 0 && p->uid == current->uid)
+		return 0;
+
+	/* sigcont is permitted within same session */
+	if (sig == SIGCONT && (task_session_nr(current) == task_session_nr(p)))
+		return 0;
+
 	if (secid)
 		/*
 		 * Signal sent as a particular user.