[PATCH] briq_panel: read() and write() get __user pointers, damnit

annotated, fixed a roothole in ->write().  Dereferencing user-supplied pointer
is a Bad Idea(tm)...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/char/briq_panel.c b/drivers/char/briq_panel.c
index caae795..b8c2225 100644 (file)
--- a/drivers/char/briq_panel.c
+++ b/drivers/char/briq_panel.c
@@ -87,7 +87,7 @@ static int briq_panel_release(struct inode *ino, struct file *filep)
        return 0;
 }
 
-static ssize_t briq_panel_read(struct file *file, char *buf, size_t count,
+static ssize_t briq_panel_read(struct file *file, char __user *buf, size_t count,
                         loff_t *ppos)
 {
        unsigned short c;
@@ -135,7 +135,7 @@ static void scroll_vfd( void )
        vfd_cursor = 20;
 }
 
-static ssize_t briq_panel_write(struct file *file, const char *buf, size_t len,
+static ssize_t briq_panel_write(struct file *file, const char __user *buf, size_t len,
                          loff_t *ppos)
 {
        size_t indx = len;
@@ -150,19 +150,22 @@ static ssize_t briq_panel_write(struct file *file, const char *buf, size_t len,
                return -EBUSY;
 
        for (;;) {
+               char c;
                if (!indx)
                        break;
+               if (get_user(c, buf))
+                       return -EFAULT;
                if (esc) {
-                       set_led(*buf);
+                       set_led(c);
                        esc = 0;
-               } else if (*buf == 27) {
+               } else if (c == 27) {
                        esc = 1;
-               } else if (*buf == 12) {
+               } else if (c == 12) {
                        /* do a form feed */
                        for (i=0; i<40; i++)
                                vfd[i] = ' ';
                        vfd_cursor = 0;
-               } else if (*buf == 10) {
+               } else if (c == 10) {
                        if (vfd_cursor < 20)
                                vfd_cursor = 20;
                        else if (vfd_cursor < 40)
@@ -175,7 +178,7 @@ static ssize_t briq_panel_write(struct file *file, const char *buf, size_t len,
                        /* just a character */
                        if (vfd_cursor > 39)
                                scroll_vfd();
-                       vfd[vfd_cursor++] = *buf;
+                       vfd[vfd_cursor++] = c;
                }
                indx--;
                buf++;