# Re: \[PATCH 10/12\] net: sctp: avoid incorrect time\_t use

- From: Neil Horman \<nhorman@tuxdriver.com\>
- Date: 2015-09-30 13:57:54 
- List: netdev
- Page: https://ratatoskr.run/netdev/2015/09/4587103
- Thread: https://ratatoskr.run/netdev/2015/09/4586972/t.md

```text
On Wed, Sep 30, 2015 at 01:26:40PM +0200, Arnd Bergmann wrote:
> We want to avoid using time_t in the kernel because of the y2038
> overflow problem. The use in sctp is not for storing seconds at
> all, but instead uses microseconds and is passed as 32-bit
> on all machines.
> 
> This patch changes the type to u32, which better fits the use.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Cc: Vlad Yasevich <redacted>
> Cc: Neil Horman <nhorman@tuxdriver.com>
> Cc: <redacted>
> ---
>  net/sctp/sm_make_chunk.c | 2 +-
>  net/sctp/sm_statefuns.c  | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
> index 7954c52e1794..763e06a55155 100644
> --- a/net/sctp/sm_make_chunk.c
> +++ b/net/sctp/sm_make_chunk.c
> @@ -2494,7 +2494,7 @@ static int sctp_process_param(struct sctp_association *asoc,
>  	__u16 sat;
>  	int retval = 1;
>  	sctp_scope_t scope;
> -	time_t stale;
> +	u32 stale;
>  	struct sctp_af *af;
>  	union sctp_addr_param *addr_param;
>  	struct sctp_transport *t;
> diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
> index d7eaa7354cf7..6f46aa16cb76 100644
> --- a/net/sctp/sm_statefuns.c
> +++ b/net/sctp/sm_statefuns.c
> @@ -2306,7 +2306,7 @@ static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net,
>  						 sctp_cmd_seq_t *commands)
>  {
>  	struct sctp_chunk *chunk = arg;
> -	time_t stale;
> +	u32 stale;
>  	sctp_cookie_preserve_param_t bht;
>  	sctp_errhdr_t *err;
>  	struct sctp_chunk *reply;
> -- 
> 2.1.0.rc2
> 
> 

Assignments to this variable use ntohl, won't this change risk overflow?

Neil
```