From: Mathias Krause <minipli@googlemail.com>
Date: Sun, 29 Jul 2012 19:45:14 +0000 (+0000)
Subject: net/tun: fix ioctl() based info leaks
X-Git-Tag: firefly_0821_release~3680^2~2286^2~9
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a117dacde0288f3ec60b6e5bcedae8fa37ee0dfc;p=firefly-linux-kernel-4.4.55.git

net/tun: fix ioctl() based info leaks

The tun module leaks up to 36 bytes of memory by not fully initializing
a structure located on the stack that gets copied to user memory by the
TUNGETIFF and SIOCGIFHWADDR ioctl()s.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index c62163e272cd..f55c46222613 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1379,9 +1379,11 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
 	int vnet_hdr_sz;
 	int ret;
 
-	if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
+	if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) {
 		if (copy_from_user(&ifr, argp, ifreq_len))
 			return -EFAULT;
+	} else
+		memset(&ifr, 0, sizeof(ifr));
 
 	if (cmd == TUNGETFEATURES) {
 		/* Currently this just means: "what IFF flags are valid?".