vt_ioctl: move perm checks level up

Synchronize with others and check perm directly in vt_k_ioctl.
We do not need to pass perm to do_fontx_ioctl and do_unimap_ioctl then.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200615074910.19267-38-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c
index 224f2a5..91c3017 100644 (file)
--- a/drivers/tty/vt/vt_ioctl.c
+++ b/drivers/tty/vt/vt_ioctl.c
@@ -486,7 +486,7 @@ static int vt_k_ioctl(struct tty_struct *tty, unsigned int cmd,
 }
 
 static inline int do_fontx_ioctl(int cmd,
-               struct consolefontdesc __user *user_cfd, int perm,
+               struct consolefontdesc __user *user_cfd,
                struct console_font_op *op)
 {
        struct consolefontdesc cfdarg;
@@ -497,8 +497,6 @@ static inline int do_fontx_ioctl(int cmd,
 
        switch (cmd) {
        case PIO_FONTX:
-               if (!perm)
-                       return -EPERM;
                op->op = KD_FONT_OP_SET;
                op->flags = KD_FONT_FLAG_OLD;
                op->width = 8;
@@ -552,7 +550,7 @@ static int vt_io_fontreset(struct console_font_op *op)
 }
 
 static inline int do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud,
-               int perm, struct vc_data *vc)
+               struct vc_data *vc)
 {
        struct unimapdesc tmp;
 
@@ -560,11 +558,9 @@ static inline int do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud,
                return -EFAULT;
        switch (cmd) {
        case PIO_UNIMAP:
-               if (!perm)
-                       return -EPERM;
                return con_set_unimap(vc, tmp.entry_ct, tmp.entries);
        case GIO_UNIMAP:
-               if (!perm && fg_console != vc->vc_num)
+               if (fg_console != vc->vc_num)
                        return -EPERM;
                return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct),
                                tmp.entries);
@@ -607,8 +603,12 @@ static int vt_io_ioctl(struct vc_data *vc, unsigned int cmd, void __user *up,
                 return con_get_cmap(up);
 
        case PIO_FONTX:
+               if (!perm)
+                       return -EPERM;
+
+               fallthrough;
        case GIO_FONTX:
-               return do_fontx_ioctl(cmd, up, perm, &op);
+               return do_fontx_ioctl(cmd, up, &op);
 
        case PIO_FONTRESET:
                if (!perm)
@@ -640,7 +640,10 @@ static int vt_io_ioctl(struct vc_data *vc, unsigned int cmd, void __user *up,
 
        case PIO_UNIMAP:
        case GIO_UNIMAP:
-               return do_unimap_ioctl(cmd, up, perm, vc);
+               if (!perm)
+                       return -EPERM;
+
+               return do_unimap_ioctl(cmd, up, vc);
 
        default:
                return -ENOIOCTLCMD;