Subject: [PATCH] isdnloop: Validate NUL-terminated strings from user.

From: YOSHIFUJI Hideaki <[email-masked]>
Date: Wed, 02 Apr 2014 12:48:42 +0900

Return -EINVAL unless all of user-given strings are correctly
NUL-terminated.

Signed-off-by: YOSHIFUJI Hideaki <[email-masked]>
---
 drivers/isdn/isdnloop/isdnloop.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/isdn/isdnloop/isdnloop.c b/drivers/isdn/isdnloop/isdnloop.c
index 02125e6..e1f8748 100644
--- a/drivers/isdn/isdnloop/isdnloop.c
+++ b/drivers/isdn/isdnloop/isdnloop.c
@@ -1070,6 +1070,12 @@ isdnloop_start(isdnloop_card *card, isdnloop_sdef *sdefp)
 		return -EBUSY;
 	if (copy_from_user((char *) &sdef, (char *) sdefp, sizeof(sdef)))
 		return -EFAULT;
+
+	for (i = 0; i < 3; i++) {
+		if (!memchr(sdef.num[i], 0, sizeof(sdef.num[i])))
+			return -EINVAL;
+	}
+
 	spin_lock_irqsave(&card->isdnloop_lock, flags);
 	switch (sdef.ptype) {
 	case ISDN_PTYPE_EURO:
-- 
1.7.9.5