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Subject[ 094/109] net/tun: fix ioctl() based info leaks
Date
From: Greg KH <gregkh@linuxfoundation.org>

3.4-stable review patch. If anyone has any objections, please let me know.

------------------


From: Mathias Krause <minipli@googlemail.com>

[ Upstream commits a117dacde0288f3ec60b6e5bcedae8fa37ee0dfc
and 8bbb181308bc348e02bfdbebdedd4e4ec9d452ce ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/tun.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1255,10 +1255,12 @@ static long __tun_chr_ioctl(struct file
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?".
* This is needed because we never checked for invalid flags on



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