From f37107d1e8019aa1e8e8ccc26379e79b5d6abd8d Mon Sep 17 00:00:00 2001 From: Mathias Krause Date: Wed, 15 Aug 2012 11:31:57 +0000 Subject: [PATCH] net: fix info leak in compat dev_ifconf() The implementation of dev_ifconf() for the compat ioctl interface uses an intermediate ifc structure allocated in userland for the duration of the syscall. Though, it fails to initialize the padding bytes inserted for alignment and that for leaks four bytes of kernel stack. Add an explicit memset(0) before filling the structure to avoid the info leak. Signed-off-by: Mathias Krause Signed-off-by: David S. Miller --- net/socket.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/socket.c b/net/socket.c index dfe5b66c97e0b..a5471f804d994 100644 --- a/net/socket.c +++ b/net/socket.c @@ -2657,6 +2657,7 @@ static int dev_ifconf(struct net *net, struct compat_ifconf __user *uifc32) if (copy_from_user(&ifc32, uifc32, sizeof(struct compat_ifconf))) return -EFAULT; + memset(&ifc, 0, sizeof(ifc)); if (ifc32.ifcbuf == 0) { ifc32.ifc_len = 0; ifc.ifc_len = 0; -- 2.39.5