Security/SELinux: seperate lsm specific mmap_min_addr

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / security / selinux / hooks.c

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 2081055f6783a64c88ae412b1338f53a50d7777b..5dee88362e71ce02c1e272b54c56f5737995dfaa 100644 (file)
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3034,9 +3034,21 @@ static int selinux_file_mmap(struct file *file, unsigned long reqprot,
        int rc = 0;
        u32 sid = current_sid();
 
-       if (addr < mmap_min_addr)
+       /*
+        * notice that we are intentionally putting the SELinux check before
+        * the secondary cap_file_mmap check.  This is such a likely attempt
+        * at bad behaviour/exploit that we always want to get the AVC, even
+        * if DAC would have also denied the operation.
+        */
+       if (addr < CONFIG_LSM_MMAP_MIN_ADDR) {
                rc = avc_has_perm(sid, sid, SECCLASS_MEMPROTECT,
                                  MEMPROTECT__MMAP_ZERO, NULL);
+               if (rc)
+                       return rc;
+       }
+
+       /* do DAC check on address space usage */
+       rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);
        if (rc || addr_only)
                return rc;
 
@@ -5187,7 +5199,7 @@ static int selinux_setprocattr(struct task_struct *p,
 
                /* Only allow single threaded processes to change context */
                error = -EPERM;
-               if (!is_single_threaded(p)) {
+               if (!current_is_single_threaded()) {
                        error = security_bounded_transition(tsec->sid, sid);
                        if (error)
                                goto abort_change;