Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/shaggy...

[pandora-kernel.git] / security / commoncap.c

diff --git a/security/commoncap.c b/security/commoncap.c
index bf67871..ea61bc7 100644 (file)
--- 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.