Subject: [patch] isdn: fix information leak

From: Dan Carpenter <[email-masked]>
Date: Thu, 5 Aug 2010 11:38:06 +0200

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 <[email-masked]>

diff --git a/drivers/isdn/sc/ioctl.c b/drivers/isdn/sc/ioctl.c
index 1081091..2655e3a 100644
--- a/drivers/isdn/sc/ioctl.c
+++ b/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;