From df4322f2f1310a7269df9841bfcee6274981a19f 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 [ 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 Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/tun.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 66e9ebbcd2bc..e44bfb83a413 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1255,10 +1255,12 @@ 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?". * This is needed because we never checked for invalid flags on -- 2.39.5