Re: [PATCH] net: pre-clear the returned sockaddr_storage variable

From: Eric Dumazet
Date: Tue Apr 09 2013 - 14:10:27 EST


On Tue, 2013-04-09 at 10:50 -0700, Kees Cook wrote:
> To avoid future stack content leaks in the various protocols, pre-clear
> the returned memory.
>
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> Suggested-by: Brad Spengler <spender@xxxxxxxxxxxxxx>
> ---
> net/socket.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/socket.c b/net/socket.c
> index 88f759a..4d2af0d 100644
> --- a/net/socket.c
> +++ b/net/socket.c
> @@ -1838,7 +1838,7 @@ SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, ubuf, size_t, size,
> struct socket *sock;
> struct iovec iov;
> struct msghdr msg;
> - struct sockaddr_storage address;
> + struct sockaddr_storage address = { };
> int err, err2;
> int fput_needed;
>
> @@ -2185,7 +2185,7 @@ static int __sys_recvmsg(struct socket *sock, struct msghdr __user *msg,
> int err, total_len, len;
>
> /* kernel mode address */
> - struct sockaddr_storage addr;
> + struct sockaddr_storage addr = { };
>
> /* user mode address pointers */
> struct sockaddr __user *uaddr;
> --
> 1.7.9.5
>
>

Nack, for obvious performance reasons.



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