On Wed, Aug 29, 2018 at 04:03:30PM +0200, Arnd Bergmann wrote:
> The ppp_idle structure is defined in terms of __kernel_time_t, which is
> defined as 'long' on all architectures, and this usage is not affected
> by the y2038 problem since it transports a time interval rather than an
> absolute time.
>
> However, the ppp user space defines the same structure as time_t, which
> may be 64-bit wide on new libc versions even on 32-bit architectures.
>
> It's easy enough to just handle both possible structure layouts on
> all architectures, to deal with the possibility that a user space ppp
> implementation comes with its own ppp_idle structure definition, as well
> as to document the fact that the driver is y2038-safe.
>
> Doing this also avoids the need for a special compat mode translation,
> since 32-bit and 64-bit kernels now support the same interfaces.
>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> Documentation/networking/ppp_generic.txt | 2 ++
> drivers/isdn/i4l/isdn_ppp.c | 14 ++++++++---
> drivers/net/ppp/ppp_generic.c | 18 ++++++++++----
> fs/compat_ioctl.c | 31 ------------------------
> include/uapi/linux/ppp-ioctl.h | 2 ++
> include/uapi/linux/ppp_defs.h | 14 +++++++++++
> 6 files changed, 42 insertions(+), 39 deletions(-)
>
> diff --git a/Documentation/networking/ppp_generic.txt b/Documentation/networking/ppp_generic.txt
> index 61daf4b39600..fd563aff5fc9 100644
> --- a/Documentation/networking/ppp_generic.txt
> +++ b/Documentation/networking/ppp_generic.txt
> @@ -378,6 +378,8 @@ an interface unit are:
> CONFIG_PPP_FILTER option is enabled, the set of packets which reset
> the transmit and receive idle timers is restricted to those which
> pass the `active' packet filter.
> + Two versions of this command exist, to deal with user space
> + expecting times as either 32-bit or 64-bit time_t seconds.
>
> * PPPIOCSMAXCID sets the maximum connection-ID parameter (and thus the
> number of connection slots) for the TCP header compressor and
> diff --git a/drivers/isdn/i4l/isdn_ppp.c b/drivers/isdn/i4l/isdn_ppp.c
> index a7b275ea5de1..1f17126c5fa4 100644
> --- a/drivers/isdn/i4l/isdn_ppp.c
> +++ b/drivers/isdn/i4l/isdn_ppp.c
> @@ -543,11 +543,19 @@ isdn_ppp_ioctl(int min, struct file *file, unsigned int cmd, unsigned long arg)
> }
> is->pppcfg = val;
> break;
> - case PPPIOCGIDLE: /* get idle time information */
> + case PPPIOCGIDLE32: /* get idle time information */
> if (lp) {
> - struct ppp_idle pidle;
> + struct ppp_idle32 pidle;
> pidle.xmit_idle = pidle.recv_idle = lp->huptimer;
> - if ((r = set_arg(argp, &pidle, sizeof(struct ppp_idle))))
> + if ((r = set_arg(argp, &pidle, sizeof(struct ppp_idle32))))
> + return r;
> + }
> + break;
> + case PPPIOCGIDLE64: /* get idle time information */
> + if (lp) {
> + struct ppp_idle64 pidle;
> + pidle.xmit_idle = pidle.recv_idle = lp->huptimer;
> + if ((r = set_arg(argp, &pidle, sizeof(struct ppp_idle64))))
> return r;
> }
> break;
> diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
> index 3a7aa2eed415..c8b8aa071140 100644
> --- a/drivers/net/ppp/ppp_generic.c
> +++ b/drivers/net/ppp/ppp_generic.c
> @@ -619,7 +619,8 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> struct ppp_file *pf;
> struct ppp *ppp;
> int err = -EFAULT, val, val2, i;
> - struct ppp_idle idle;
> + struct ppp_idle32 idle32;
> + struct ppp_idle64 idle64;
> struct npioctl npi;
> int unit, cflags;
> struct slcompress *vj;
> @@ -743,10 +744,17 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> err = 0;
> break;
>
> - case PPPIOCGIDLE:
> - idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
> - idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
> - if (copy_to_user(argp, &idle, sizeof(idle)))
> + case PPPIOCGIDLE32:
> + idle32.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
> + idle32.recv_idle = (jiffies - ppp->last_recv) / HZ;
> + if (copy_to_user(argp, &idle32, sizeof(idle32)))
>
Missing 'break;'
> + err = 0;
> + break;
> +
> + case PPPIOCGIDLE64:
> + idle64.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
> + idle64.recv_idle = (jiffies - ppp->last_recv) / HZ;
> + if (copy_to_user(argp, &idle32, sizeof(idle32)))
>
I guess you meant 'idle64' instead of 'idle32'.
