From a117dacde0288f3ec60b6e5bcedae8fa37ee0dfc Mon Sep 17 00:00:00 2001 From: Mathias Krause Date: Sun, 29 Jul 2012 19:45:14 +0000 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- drivers/net/tun.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) 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?".