Re: [PATCH net-next] net: diag: add workaround for inode truncation

[Eric Dumazet <eric.dumazet@gmail.com>]

On 8/31/20 4:59 PM, Jakub Kicinski wrote:
> Dave reports that struct inet_diag_msg::idiag_inode is 32 bit,
> while inode's type is unsigned long. This leads to truncation.
> 
> Since there is nothing we can do about the size of existing
> fields - add a new attribute to carry 64 bit inode numbers.
> 
> Reported-by: Dave Marchevsky <davemarchevsky@fb.com>
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
>  include/linux/inet_diag.h      | 1 +
>  include/uapi/linux/inet_diag.h | 1 +
>  net/ipv4/inet_diag.c           | 7 ++++++-
>  3 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/inet_diag.h b/include/linux/inet_diag.h
> index 0ef2d800fda7..5ea0f965c173 100644
> --- a/include/linux/inet_diag.h
> +++ b/include/linux/inet_diag.h
> @@ -75,6 +75,7 @@ static inline size_t inet_diag_msg_attrs_size(void)
>  #ifdef CONFIG_SOCK_CGROUP_DATA
>  		+ nla_total_size_64bit(sizeof(u64))  /* INET_DIAG_CGROUP_ID */
>  #endif
> +		+ nla_total_size_64bit(sizeof(u64))  /* INET_DIAG_INODE */
>  		;
>  }
>  int inet_diag_msg_attrs_fill(struct sock *sk, struct sk_buff *skb,
> diff --git a/include/uapi/linux/inet_diag.h b/include/uapi/linux/inet_diag.h
> index 5ba122c1949a..0819a473ee9c 100644
> --- a/include/uapi/linux/inet_diag.h
> +++ b/include/uapi/linux/inet_diag.h
> @@ -160,6 +160,7 @@ enum {
>  	INET_DIAG_ULP_INFO,
>  	INET_DIAG_SK_BPF_STORAGES,
>  	INET_DIAG_CGROUP_ID,
> +	INET_DIAG_INODE,
>  	__INET_DIAG_MAX,
>  };
>  
> diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
> index 4a98dd736270..6a52947591fc 100644
> --- a/net/ipv4/inet_diag.c
> +++ b/net/ipv4/inet_diag.c
> @@ -125,6 +125,7 @@ int inet_diag_msg_attrs_fill(struct sock *sk, struct sk_buff *skb,
>  			     bool net_admin)
>  {
>  	const struct inet_sock *inet = inet_sk(sk);
> +	unsigned long ino;
>  
>  	if (nla_put_u8(skb, INET_DIAG_SHUTDOWN, sk->sk_shutdown))
>  		goto errout;
> @@ -177,8 +178,12 @@ int inet_diag_msg_attrs_fill(struct sock *sk, struct sk_buff *skb,
>  		goto errout;
>  #endif
>  
> +	ino = sock_i_ino(sk);
> +	if (nla_put_u64_64bit(skb, INET_DIAG_INODE, ino, INET_DIAG_PAD))
> +		goto errout;
> +
>  	r->idiag_uid = from_kuid_munged(user_ns, sock_i_uid(sk));
> -	r->idiag_inode = sock_i_ino(sk);
> +	r->idiag_inode = ino;
>  
>  	return 0;
>  errout:
> 


Last time I checked socket inode numbers were 32bit ?

Is there a plan changing this ?