From d798b105cee33543b235410d2510219fa887b4d2 Mon Sep 17 00:00:00 2001 From: Mathias Krause Date: Wed, 15 Aug 2012 11:31:53 +0000 Subject: [PATCH] llc: fix info leak via getsockname() commit 3592aaeb80290bda0f2cf0b5456c97bfc638b192 upstream. The LLC code wrongly returns 0, i.e. "success", when the socket is zapped. Together with the uninitialized uaddrlen pointer argument from sys_getsockname this leads to an arbitrary memory leak of up to 128 bytes kernel stack via the getsockname() syscall. Return an error instead when the socket is zapped to prevent the info leak. Also remove the unnecessary memset(0). We don't directly write to the memory pointed by uaddr but memcpy() a local structure at the end of the function that is properly initialized. Signed-off-by: Mathias Krause Cc: Arnaldo Carvalho de Melo Signed-off-by: David S. Miller Signed-off-by: Paul Gortmaker --- net/llc/af_llc.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c index ad4296c852ebc..06010e1e89f9a 100644 --- a/net/llc/af_llc.c +++ b/net/llc/af_llc.c @@ -959,14 +959,13 @@ static int llc_ui_getname(struct socket *sock, struct sockaddr *uaddr, struct sockaddr_llc sllc; struct sock *sk = sock->sk; struct llc_sock *llc = llc_sk(sk); - int rc = 0; + int rc = -EBADF; memset(&sllc, 0, sizeof(sllc)); lock_sock(sk); if (sock_flag(sk, SOCK_ZAPPED)) goto out; *uaddrlen = sizeof(sllc); - memset(uaddr, 0, *uaddrlen); if (peer) { rc = -ENOTCONN; if (sk->sk_state != TCP_ESTABLISHED) -- 2.47.3