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* [PATCH] net: pre-clear the returned sockaddr_storage variable
@ 2013-04-09 17:50 Kees Cook
  2013-04-09 18:10 ` Eric Dumazet
  2013-04-09 19:05 ` David Miller
  0 siblings, 2 replies; 3+ messages in thread
From: Kees Cook @ 2013-04-09 17:50 UTC (permalink / raw)
  To: linux-kernel; +Cc: David S. Miller, netdev, Mathias Krause, Brad Spengler

To avoid future stack content leaks in the various protocols, pre-clear
the returned memory.

Signed-off-by: Kees Cook <keescook@chromium.org>
Suggested-by: Brad Spengler <spender@grsecurity.net>
---
 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


-- 
Kees Cook
Chrome OS Security

^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH] net: pre-clear the returned sockaddr_storage variable
  2013-04-09 17:50 [PATCH] net: pre-clear the returned sockaddr_storage variable Kees Cook
@ 2013-04-09 18:10 ` Eric Dumazet
  2013-04-09 19:05 ` David Miller
  1 sibling, 0 replies; 3+ messages in thread
From: Eric Dumazet @ 2013-04-09 18:10 UTC (permalink / raw)
  To: Kees Cook
  Cc: linux-kernel, David S. Miller, netdev, Mathias Krause,
	Brad Spengler

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@chromium.org>
> Suggested-by: Brad Spengler <spender@grsecurity.net>
> ---
>  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.

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] net: pre-clear the returned sockaddr_storage variable
  2013-04-09 17:50 [PATCH] net: pre-clear the returned sockaddr_storage variable Kees Cook
  2013-04-09 18:10 ` Eric Dumazet
@ 2013-04-09 19:05 ` David Miller
  1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2013-04-09 19:05 UTC (permalink / raw)
  To: keescook; +Cc: linux-kernel, netdev, minipli, spender

From: Kees Cook <keescook@chromium.org>
Date: Tue, 9 Apr 2013 10:50:24 -0700

> To avoid future stack content leaks in the various protocols, pre-clear
> the returned memory.
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>
> Suggested-by: Brad Spengler <spender@grsecurity.net>

No thanks, clearing 2 full cache lines unnecessarily on every socket
call has real cost.

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2013-04-09 19:05 UTC | newest]

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2013-04-09 17:50 [PATCH] net: pre-clear the returned sockaddr_storage variable Kees Cook
2013-04-09 18:10 ` Eric Dumazet
2013-04-09 19:05 ` David Miller

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