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| author | Arnd Bergmann <arnd@arndb.de> | 2019-04-16 22:19:44 +0200 |
|---|---|---|
| committer | Arnd Bergmann <arnd@arndb.de> | 2019-10-23 17:23:47 +0200 |
| commit | 17c7e7f407085f510a815c0c99b3fd25d5b13110 (patch) | |
| tree | aa674e21bcd6b6380049c28333e6b70ab909de34 /drivers/net/ppp | |
| parent | 5b6c02df50fb28d23c733a24df5a06d0a3f28b93 (diff) | |
| download | lwn-17c7e7f407085f510a815c0c99b3fd25d5b13110.tar.gz lwn-17c7e7f407085f510a815c0c99b3fd25d5b13110.zip | |
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 <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'drivers/net/ppp')
| -rw-r--r-- | drivers/net/ppp/ppp_generic.c | 19 |
1 files changed, 14 insertions, 5 deletions
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; |