[PATCH] staging: dgrp: dgrp_tty.c: return an -EFAULT if put_user fails

[Kumar Amit Mehta]

This fix adds checks for inspecting the return value of put_user() and return
-EFAULT on error.

Signed-off-by: Kumar Amit Mehta <gmate.amit at gmail.com>
---
 drivers/staging/dgrp/dgrp_tty.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/dgrp/dgrp_tty.c b/drivers/staging/dgrp/dgrp_tty.c
index e125b03..b294197 100644
--- a/drivers/staging/dgrp/dgrp_tty.c
+++ b/drivers/staging/dgrp/dgrp_tty.c
@@ -2265,7 +2265,8 @@ 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);
+	if (put_user(mlast, (unsigned int __user *) value))
+		return -EFAULT;
 
 	return 0;
 }
@@ -2620,7 +2621,8 @@ static int dgrp_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
 			       sizeof(long));
 		if (rc == 0)
 			return -EFAULT;
-		put_user(C_CLOCAL(tty) ? 1 : 0, (unsigned long __user *) arg);
+		if (put_user(C_CLOCAL(tty) ? 1 : 0, (unsigned long __user *) arg))
+			return -EFAULT;
 		return 0;
 
 	case TIOCSSOFTCAR:
@@ -2854,7 +2856,8 @@ static int dgrp_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
 		rc = access_ok(VERIFY_WRITE, (void __user *) arg, sizeof(int));
 		if (rc == 0)
 			return -EFAULT;
-		put_user(ch->ch_custom_speed, (unsigned int __user *) arg);
+		if (put_user(ch->ch_custom_speed, (unsigned int __user *) arg))
+			return -EFAULT;
 		break;
 
 	case DIGI_SETCUSTOMBAUD:
-- 
1.7.9.5