isdn: fix information leak

[ Upstream commit 4b030d42 ]

The main motivation of this patch changing strcpy() to strlcpy().
We strcpy() to copy a 48 byte buffers into a 49 byte buffers.  So at
best the last byte has leaked information, or maybe there is an
overflow?  Anyway, this patch closes the information leaks by zeroing
the memory and the calls to strlcpy() prevent overflows.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/isdn/sc/ioctl.c

@@ -174,7 +174,7 @@ int sc_ioctl(int card, scs_ioctl *data)
 		pr_debug("%s: SCIOGETSPID: ioctl received\n",
 				sc_adapter[card]->devicename);
 
-		spid = kmalloc(SCIOC_SPIDSIZE, GFP_KERNEL);
+		spid = kzalloc(SCIOC_SPIDSIZE, GFP_KERNEL);
 		if (!spid) {
 			kfree(rcvmsg);
 			return -ENOMEM;
@@ -194,7 +194,7 @@ int sc_ioctl(int card, scs_ioctl *data)
 			kfree(rcvmsg);
 			return status;
 		}
-		strcpy(spid, rcvmsg->msg_data.byte_array);
+		strlcpy(spid, rcvmsg->msg_data.byte_array, SCIOC_SPIDSIZE);
 
 		/*
 		 * Package the switch type and send to user space
@@ -272,12 +272,12 @@ int sc_ioctl(int card, scs_ioctl *data)
 			return status;
 		}
 
-		dn = kmalloc(SCIOC_DNSIZE, GFP_KERNEL);
+		dn = kzalloc(SCIOC_DNSIZE, GFP_KERNEL);
 		if (!dn) {
 			kfree(rcvmsg);
 			return -ENOMEM;
 		}
-		strcpy(dn, rcvmsg->msg_data.byte_array);
+		strlcpy(dn, rcvmsg->msg_data.byte_array, SCIOC_DNSIZE);
 		kfree(rcvmsg);
 
 		/*
@@ -348,7 +348,7 @@ int sc_ioctl(int card, scs_ioctl *data)
 		pr_debug("%s: SCIOSTAT: ioctl received\n",
 				sc_adapter[card]->devicename);
 
-		bi = kmalloc (sizeof(boardInfo), GFP_KERNEL);
+		bi = kzalloc(sizeof(boardInfo), GFP_KERNEL);
 		if (!bi) {
 			kfree(rcvmsg);
 			return -ENOMEM;