nfs: new subdir Documentation/filesystems/nfs

[safe/jmp/linux-2.6] / security / commoncap.c

diff --git a/security/commoncap.c b/security/commoncap.c
index 7cd61a5..fe30751 100644 (file)
--- a/security/commoncap.c
+++ b/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();
@@ -79,7 +101,7 @@ int cap_settime(struct timespec *ts, struct timezone *tz)
 }
 
 /**
- * cap_ptrace_may_access - Determine whether the current process may access
+ * cap_ptrace_access_check - Determine whether the current process may access
  *                        another
  * @child: The process to be accessed
  * @mode: The mode of attachment.
@@ -87,7 +109,7 @@ int cap_settime(struct timespec *ts, struct timezone *tz)
  * Determine whether a process may access another, returning 0 if permission
  * granted, -ve if denied.
  */
-int cap_ptrace_may_access(struct task_struct *child, unsigned int mode)
+int cap_ptrace_access_check(struct task_struct *child, unsigned int mode)
 {
        int ret = 0;
 
@@ -464,6 +486,15 @@ int cap_bprm_set_creds(struct linux_binprm *bprm)
 
        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
                 * capability sets for the file.
@@ -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
@@ -916,7 +948,6 @@ changed:
        return commit_creds(new);
 
 no_change:
-       error = 0;
 error:
        abort_creds(new);
        return error;
@@ -953,3 +984,33 @@ int cap_vm_enough_memory(struct mm_struct *mm, long pages)
                cap_sys_admin = 1;
        return __vm_enough_memory(mm, pages, cap_sys_admin);
 }
+
+/*
+ * cap_file_mmap - check if able to map given addr
+ * @file: unused
+ * @reqprot: unused
+ * @prot: unused
+ * @flags: unused
+ * @addr: address attempting to be mapped
+ * @addr_only: unused
+ *
+ * If the process is attempting to map memory below mmap_min_addr they need
+ * CAP_SYS_RAWIO.  The other parameters to this function are unused by the
+ * capability security module.  Returns 0 if this mapping should be allowed
+ * -EPERM if not.
+ */
+int cap_file_mmap(struct file *file, unsigned long reqprot,
+                 unsigned long prot, unsigned long flags,
+                 unsigned long addr, unsigned long addr_only)
+{
+       int ret = 0;
+
+       if (addr < dac_mmap_min_addr) {
+               ret = cap_capable(current, current_cred(), CAP_SYS_RAWIO,
+                                 SECURITY_CAP_AUDIT);
+               /* set PF_SUPERPRIV if it turns out we allow the low mmap */
+               if (ret == 0)
+                       current->flags |= PF_SUPERPRIV;
+       }
+       return ret;
+}