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>

diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
index 610b720d3b91789b6f55c618b08535d53edc99c3..59b25e039968596372764e9c5ddd6b92f1a8e045 100644 (file)
--- 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;
 }