From 17c7e7f407085f510a815c0c99b3fd25d5b13110 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 16 Apr 2019 22:19:44 +0200 Subject: compat_ioctl: handle PPPIOCGIDLE for 64-bit time_t 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. The old 32-bit structure is also available on native 64-bit architectures now, but this is harmless. Cc: netdev@vger.kernel.org Cc: linux-ppp@vger.kernel.org Cc: Paul Mackerras Cc: "David S. Miller" Signed-off-by: Arnd Bergmann --- drivers/net/ppp/ppp_generic.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) (limited to 'drivers') diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c index fb8e0ac099b8..ce4dd45c541d 100644 --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -612,7 +612,8 @@ 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; @@ -735,10 +736,18 @@ 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))) + 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, &idle64, sizeof(idle64))) break; err = 0; break; -- cgit v1.2.3