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Message-Id: <20190416202013.4034148-7-arnd@arndb.de>
Date: Tue, 16 Apr 2019 22:19:44 +0200
From: Arnd Bergmann <arnd@...db.de>
To: Alexander Viro <viro@...iv.linux.org.uk>
Cc: linux-fsdevel@...r.kernel.org, y2038@...ts.linaro.org,
linux-kernel@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
"David S. Miller" <davem@...emloft.net>,
Jonathan Corbet <corbet@....net>,
Karsten Keil <isdn@...ux-pingi.de>,
Paul Mackerras <paulus@...ba.org>,
Guillaume Nault <g.nault@...halink.fr>,
Eric Biggers <ebiggers@...gle.com>, netdev@...r.kernel.org,
linux-doc@...r.kernel.org, linux-ppp@...r.kernel.org
Subject: [PATCH v3 06/26] 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.
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
Documentation/networking/ppp_generic.txt | 2 ++
drivers/isdn/i4l/isdn_ppp.c | 14 ++++++++---
drivers/net/ppp/ppp_generic.c | 19 +++++++++++----
fs/compat_ioctl.c | 31 ------------------------
include/uapi/linux/ppp-ioctl.h | 2 ++
include/uapi/linux/ppp_defs.h | 14 +++++++++++
6 files changed, 43 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 b8a867fdd5ad..712fa94650fe 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 +744,18 @@ 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;
diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index d507b7189958..e6dbd956cf66 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -269,36 +269,7 @@ static int sg_grt_trans(struct file *file,
}
return err;
}
-#endif /* CONFIG_BLOCK */
-
-struct ppp_idle32 {
- compat_time_t xmit_idle;
- compat_time_t recv_idle;
-};
-#define PPPIOCGIDLE32 _IOR('t', 63, struct ppp_idle32)
-
-static int ppp_gidle(struct file *file, unsigned int cmd,
- struct ppp_idle32 __user *idle32)
-{
- struct ppp_idle __user *idle;
- __kernel_time_t xmit, recv;
- int err;
-
- idle = compat_alloc_user_space(sizeof(*idle));
- err = do_ioctl(file, PPPIOCGIDLE, (unsigned long) idle);
-
- if (!err) {
- if (get_user(xmit, &idle->xmit_idle) ||
- get_user(recv, &idle->recv_idle) ||
- put_user(xmit, &idle32->xmit_idle) ||
- put_user(recv, &idle32->recv_idle))
- err = -EFAULT;
- }
- return err;
-}
-
-#ifdef CONFIG_BLOCK
struct mtget32 {
compat_long_t mt_type;
compat_long_t mt_resid;
@@ -838,8 +809,6 @@ static long do_ioctl_trans(unsigned int cmd,
void __user *argp = compat_ptr(arg);
switch (cmd) {
- case PPPIOCGIDLE32:
- return ppp_gidle(file, cmd, argp);
#ifdef CONFIG_BLOCK
case SG_IO:
return sg_ioctl_trans(file, cmd, argp);
diff --git a/include/uapi/linux/ppp-ioctl.h b/include/uapi/linux/ppp-ioctl.h
index 88b5f9990320..7bd2a5a75348 100644
--- a/include/uapi/linux/ppp-ioctl.h
+++ b/include/uapi/linux/ppp-ioctl.h
@@ -104,6 +104,8 @@ struct pppol2tp_ioc_stats {
#define PPPIOCGDEBUG _IOR('t', 65, int) /* Read debug level */
#define PPPIOCSDEBUG _IOW('t', 64, int) /* Set debug level */
#define PPPIOCGIDLE _IOR('t', 63, struct ppp_idle) /* get idle time */
+#define PPPIOCGIDLE32 _IOR('t', 63, struct ppp_idle32) /* 32-bit times */
+#define PPPIOCGIDLE64 _IOR('t', 63, struct ppp_idle64) /* 64-bit times */
#define PPPIOCNEWUNIT _IOWR('t', 62, int) /* create new ppp unit */
#define PPPIOCATTACH _IOW('t', 61, int) /* attach to ppp unit */
#define PPPIOCDETACH _IOW('t', 60, int) /* obsolete, do not use */
diff --git a/include/uapi/linux/ppp_defs.h b/include/uapi/linux/ppp_defs.h
index fff51b91b409..0039fa39a358 100644
--- a/include/uapi/linux/ppp_defs.h
+++ b/include/uapi/linux/ppp_defs.h
@@ -142,10 +142,24 @@ struct ppp_comp_stats {
/*
* The following structure records the time in seconds since
* the last NP packet was sent or received.
+ *
+ * Linux implements both 32-bit and 64-bit time_t versions
+ * for compatibility with user space that defines ppp_idle
+ * based on the libc time_t.
*/
struct ppp_idle {
__kernel_time_t xmit_idle; /* time since last NP packet sent */
__kernel_time_t recv_idle; /* time since last NP packet received */
};
+struct ppp_idle32 {
+ __s32 xmit_idle; /* time since last NP packet sent */
+ __s32 recv_idle; /* time since last NP packet received */
+};
+
+struct ppp_idle64 {
+ __s64 xmit_idle; /* time since last NP packet sent */
+ __s64 recv_idle; /* time since last NP packet received */
+};
+
#endif /* _UAPI_PPP_DEFS_H_ */
--
2.20.0
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