staging: dgrp: dgrp_tty.c: Audit the return values of get/put_user()

fix for missing audits for return values of get_user() and put_user().
Inspecting the return values of get/put_user() would make the access_ok()
redundant, hence removing calls to access_ok() in such scenarios.

Signed-off-by: Kumar Amit Mehta <gmate.amit@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/dgrp/dgrp_tty.c b/drivers/staging/dgrp/dgrp_tty.c
index 5796de8..5647068 100644 (file)
--- a/drivers/staging/dgrp/dgrp_tty.c
+++ b/drivers/staging/dgrp/dgrp_tty.c
@@ -2265,9 +2265,7 @@ static int get_modem_info(struct ch_struct *ch, unsigned int *value)
                | ((mlast & DM_RI)  ? TIOCM_RNG : 0)
                | ((mlast & DM_DSR) ? TIOCM_DSR : 0)
                | ((mlast & DM_CTS) ? TIOCM_CTS : 0);
-       put_user(mlast, (unsigned int __user *) value);
-
-       return 0;
+       return put_user(mlast, (unsigned int __user *) value);
 }
 
 /*
@@ -2285,7 +2283,8 @@ static int set_modem_info(struct ch_struct *ch, unsigned int command,
        if (error == 0)
                return -EFAULT;
 
-       get_user(arg, (unsigned int __user *) value);
+       if (get_user(arg, (unsigned int __user *) value))
+               return -EFAULT;
        mval |= ((arg & TIOCM_RTS) ? DM_RTS : 0)
                | ((arg & TIOCM_DTR) ? DM_DTR : 0);
 
@@ -2616,12 +2615,8 @@ static int dgrp_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
                return 0;
 
        case TIOCGSOFTCAR:
-               rc = access_ok(VERIFY_WRITE, (void __user *) arg,
-                              sizeof(long));
-               if (rc == 0)
-                       return -EFAULT;
-               put_user(C_CLOCAL(tty) ? 1 : 0, (unsigned long __user *) arg);
-               return 0;
+               return put_user(C_CLOCAL(tty) ? 1 : 0,
+                               (unsigned long __user *) arg);
 
        case TIOCMGET:
                rc = access_ok(VERIFY_WRITE, (void __user *) arg,
@@ -2844,17 +2839,16 @@ static int dgrp_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
                break;
 
        case DIGI_GETCUSTOMBAUD:
-               rc = access_ok(VERIFY_WRITE, (void __user *) arg, sizeof(int));
-               if (rc == 0)
+               if (put_user(ch->ch_custom_speed, (unsigned int __user *) arg))
                        return -EFAULT;
-               put_user(ch->ch_custom_speed, (unsigned int __user *) arg);
                break;
 
        case DIGI_SETCUSTOMBAUD:
        {
                int new_rate;
 
-               get_user(new_rate, (unsigned int __user *) arg);
+               if (get_user(new_rate, (unsigned int __user *) arg))
+                       return -EFAULT;
                dgrp_set_custom_speed(ch, new_rate);
 
                break;