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 --- Documentation/networking/ppp_generic.txt | 2 ++ 1 file changed, 2 insertions(+) (limited to 'Documentation/networking/ppp_generic.txt') 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 -- cgit