tty/vt: don't set font mappings on vc not supporting this

We can call this function for a dummy console that doesn't support
setting the font mapping, which will result in a null ptr BUG. So check
for this case and return error for consoles w/o font mapping support.

Reference: https://bugzilla.kernel.org/show_bug.cgi?id=59321
Signed-off-by: Imre Deak <imre.deak@intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
index 610b720d3b91..59b25e039968 100644
--- a/drivers/tty/vt/consolemap.c
+++ b/drivers/tty/vt/consolemap.c
@@ -539,6 +539,12 @@ int con_set_unimap(struct vc_data *vc, ushort ct, struct unipair __user *list)
 
         /* Save original vc_unipagdir_loc in case we allocate a new one */
         p = *vc->vc_uni_pagedir_loc;
+
+        if (!p) {
+                err = -EINVAL;
+
+                goto out_unlock;
+        }
         
         if (p->refcount > 1) {
                 int j, k;
@@ -623,6 +629,7 @@ int con_set_unimap(struct vc_data *vc, ushort ct, struct unipair __user *list)
                 set_inverse_transl(vc, p, i); /* Update inverse translations */
         set_inverse_trans_unicode(vc, p);
 
+out_unlock:
         console_unlock();
         return err;
 }