Re: [PATCH] fix memory leak in net/ipv4/tcp_probe.c::tcpprobe_read()

[Stephen Hemminger <shemminger@osdl.org>]

Dave, here is my version...
Don't leak memory on interrupted read. And only allocate
as much memory as needed.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>


--- linux-2.6.orig/net/ipv4/tcp_probe.c	2006-08-10 16:32:36.000000000 -0700
+++ linux-2.6/net/ipv4/tcp_probe.c	2006-08-10 16:45:30.000000000 -0700
@@ -114,7 +114,7 @@
 static ssize_t tcpprobe_read(struct file *file, char __user *buf,
 			     size_t len, loff_t *ppos)
 {
-	int error = 0, cnt = 0;
+	int error, cnt;
 	unsigned char *tbuf;
 
 	if (!buf || len < 0)
@@ -123,15 +123,16 @@
 	if (len == 0)
 		return 0;
 
-	tbuf = vmalloc(len);
-	if (!tbuf)
-		return -ENOMEM;
-
 	error = wait_event_interruptible(tcpw.wait,
 					 __kfifo_len(tcpw.fifo) != 0);
 	if (error)
 		return error;
 
+	len = min(len, kfifo_len(tcpw.fifo));
+	tbuf = vmalloc(len);
+	if (!tbuf)
+		return -ENOMEM;
+
 	cnt = kfifo_get(tcpw.fifo, tbuf, len);
 	error = copy_to_user(buf, tbuf, cnt);