diff mbox series

[net-next,v6,8/8] ax.25: x.25: Remove the now superfluous sentinel elements from ctl_table array

Message ID 20240501-jag-sysctl_remset_net-v6-8-370b702b6b4a@samsung.com (mailing list archive)
State Not Applicable
Headers show
Series [net-next,v6,1/8] net: Remove the now superfluous sentinel elements from ctl_table array | expand

Commit Message

Joel Granados via B4 Relay May 1, 2024, 9:29 a.m. UTC 
From: Joel Granados <j.granados@samsung.com>

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which will
reduce the overall build time size of the kernel and run time memory
bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Avoid a buffer overflow when traversing the ctl_table by ensuring that
AX25_MAX_VALUES is the same as the size of ax25_param_table. This is
done with a BUILD_BUG_ON where ax25_param_table is defined and a
CONFIG_AX25_DAMA_SLAVE guard in the unnamed enum definition as well as
in the ax25_dev_device_up and ax25_ds_set_timer functions.

The overflow happened when the sentinel was removed from
ax25_param_table. The sentinel's data element was changed when
CONFIG_AX25_DAMA_SLAVE was undefined. This had no adverse effects as it
still stopped on the sentinel's null procname but needed to be addressed
once the sentinel was removed.

Signed-off-by: Joel Granados <j.granados@samsung.com>
---
 include/net/ax25.h         | 2 ++
 net/ax25/ax25_dev.c        | 3 +++
 net/ax25/ax25_ds_timer.c   | 1 +
 net/ax25/sysctl_net_ax25.c | 3 +--
 net/x25/sysctl_net_x25.c   | 1 -
 5 files changed, 7 insertions(+), 3 deletions(-)

Comments

Sabrina Dubroca May 1, 2024, 1:15 p.m. UTC | #1 
2024-05-01, 11:29:32 +0200, Joel Granados via B4 Relay wrote:
> From: Joel Granados <j.granados@samsung.com>
> 
> This commit comes at the tail end of a greater effort to remove the
> empty elements at the end of the ctl_table arrays (sentinels) which will
> reduce the overall build time size of the kernel and run time memory
> bloat by ~64 bytes per sentinel (further information Link :
> https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)
> 
> Avoid a buffer overflow when traversing the ctl_table by ensuring that
> AX25_MAX_VALUES is the same as the size of ax25_param_table. This is
> done with a BUILD_BUG_ON where ax25_param_table is defined and a
> CONFIG_AX25_DAMA_SLAVE guard in the unnamed enum definition as well as
> in the ax25_dev_device_up and ax25_ds_set_timer functions.
                                ^^
nit:                            not anymore ;)
(but not worth a repost IMO)


> diff --git a/net/ax25/ax25_ds_timer.c b/net/ax25/ax25_ds_timer.c
> index c4f8adbf8144..c50a58d9e368 100644
> --- a/net/ax25/ax25_ds_timer.c
> +++ b/net/ax25/ax25_ds_timer.c
> @@ -55,6 +55,7 @@ void ax25_ds_set_timer(ax25_dev *ax25_dev)
>  	ax25_dev->dama.slave_timeout =
>  		msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10;
>  	mod_timer(&ax25_dev->dama.slave_timer, jiffies + HZ);
> +	return;

nit: return not needed here since we're already at the bottom of the
function, but probably not worth a repost of the series.

>  }
Joel Granados May 3, 2024, 12:18 p.m. UTC | #2 
On Wed, May 01, 2024 at 03:15:54PM +0200, Sabrina Dubroca wrote:
> 2024-05-01, 11:29:32 +0200, Joel Granados via B4 Relay wrote:
> > From: Joel Granados <j.granados@samsung.com>
> > 
> > This commit comes at the tail end of a greater effort to remove the
> > empty elements at the end of the ctl_table arrays (sentinels) which will
> > reduce the overall build time size of the kernel and run time memory
> > bloat by ~64 bytes per sentinel (further information Link :
> > https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)
> > 
> > Avoid a buffer overflow when traversing the ctl_table by ensuring that
> > AX25_MAX_VALUES is the same as the size of ax25_param_table. This is
> > done with a BUILD_BUG_ON where ax25_param_table is defined and a
> > CONFIG_AX25_DAMA_SLAVE guard in the unnamed enum definition as well as
> > in the ax25_dev_device_up and ax25_ds_set_timer functions.
>                                 ^^
> nit:                            not anymore ;)
> (but not worth a repost IMO)
> 
> 
> > diff --git a/net/ax25/ax25_ds_timer.c b/net/ax25/ax25_ds_timer.c
> > index c4f8adbf8144..c50a58d9e368 100644
> > --- a/net/ax25/ax25_ds_timer.c
> > +++ b/net/ax25/ax25_ds_timer.c
> > @@ -55,6 +55,7 @@ void ax25_ds_set_timer(ax25_dev *ax25_dev)
> >  	ax25_dev->dama.slave_timeout =
> >  		msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10;
> >  	mod_timer(&ax25_dev->dama.slave_timer, jiffies + HZ);
> > +	return;
> 
> nit: return not needed here since we're already at the bottom of the
> function, but probably not worth a repost of the series.
> 
Thx. I will not repost, but I have changed them locally so they are
there in case a V7 is required.

Best
Dan Carpenter May 3, 2024, 3:23 p.m. UTC | #3 
On Fri, May 03, 2024 at 02:18:11PM +0200, Joel Granados wrote:
> On Wed, May 01, 2024 at 03:15:54PM +0200, Sabrina Dubroca wrote:
> > 2024-05-01, 11:29:32 +0200, Joel Granados via B4 Relay wrote:
> > > From: Joel Granados <j.granados@samsung.com>
> > > diff --git a/net/ax25/ax25_ds_timer.c b/net/ax25/ax25_ds_timer.c
> > > index c4f8adbf8144..c50a58d9e368 100644
> > > --- a/net/ax25/ax25_ds_timer.c
> > > +++ b/net/ax25/ax25_ds_timer.c
> > > @@ -55,6 +55,7 @@ void ax25_ds_set_timer(ax25_dev *ax25_dev)
> > >  	ax25_dev->dama.slave_timeout =
> > >  		msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10;
> > >  	mod_timer(&ax25_dev->dama.slave_timer, jiffies + HZ);
> > > +	return;
> > 
> > nit: return not needed here since we're already at the bottom of the
> > function, but probably not worth a repost of the series.
> > 
> Thx. I will not repost, but I have changed them locally so they are
> there in case a V7 is required.
> 

It's a checkpatch.pl -f warning so we probably will want to fix it
eventually.

regards,
dan carpenter
Joel Granados May 7, 2024, 8:02 a.m. UTC | #4 
On Fri, May 03, 2024 at 06:23:14PM +0300, Dan Carpenter wrote:
> On Fri, May 03, 2024 at 02:18:11PM +0200, Joel Granados wrote:
> > On Wed, May 01, 2024 at 03:15:54PM +0200, Sabrina Dubroca wrote:
> > > 2024-05-01, 11:29:32 +0200, Joel Granados via B4 Relay wrote:
> > > > From: Joel Granados <j.granados@samsung.com>
> > > > diff --git a/net/ax25/ax25_ds_timer.c b/net/ax25/ax25_ds_timer.c
> > > > index c4f8adbf8144..c50a58d9e368 100644
> > > > --- a/net/ax25/ax25_ds_timer.c
> > > > +++ b/net/ax25/ax25_ds_timer.c
> > > > @@ -55,6 +55,7 @@ void ax25_ds_set_timer(ax25_dev *ax25_dev)
> > > >  	ax25_dev->dama.slave_timeout =
> > > >  		msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10;
> > > >  	mod_timer(&ax25_dev->dama.slave_timer, jiffies + HZ);
> > > > +	return;
> > > 
> > > nit: return not needed here since we're already at the bottom of the
> > > function, but probably not worth a repost of the series.
> > > 
> > Thx. I will not repost, but I have changed them locally so they are
> > there in case a V7 is required.
> > 
> 
> It's a checkpatch.pl -f warning so we probably will want to fix it
> eventually.

According to [1] the patchset has already been applied. So I'll just
send another patch for it to be applied on top.

Thx for pointing this out.


[1] https://patchwork.kernel.org/project/netdevbpf/patch/20240501-jag-sysctl_remset_net-v6-1-370b702b6b4a@samsung.com/
diff mbox series

Patch

diff --git a/include/net/ax25.h b/include/net/ax25.h
index 0d939e5aee4e..eb9cee8252c8 100644
--- a/include/net/ax25.h
+++ b/include/net/ax25.h
@@ -139,7 +139,9 @@  enum {
 	AX25_VALUES_N2,		/* Default N2 value */
 	AX25_VALUES_PACLEN,	/* AX.25 MTU */
 	AX25_VALUES_PROTOCOL,	/* Std AX.25, DAMA Slave, DAMA Master */
+#ifdef CONFIG_AX25_DAMA_SLAVE
 	AX25_VALUES_DS_TIMEOUT,	/* DAMA Slave timeout */
+#endif
 	AX25_MAX_VALUES		/* THIS MUST REMAIN THE LAST ENTRY OF THIS LIST */
 };
 
diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c
index 282ec581c072..0bc682ffae9c 100644
--- a/net/ax25/ax25_dev.c
+++ b/net/ax25/ax25_dev.c
@@ -78,7 +78,10 @@  void ax25_dev_device_up(struct net_device *dev)
 	ax25_dev->values[AX25_VALUES_N2]        = AX25_DEF_N2;
 	ax25_dev->values[AX25_VALUES_PACLEN]	= AX25_DEF_PACLEN;
 	ax25_dev->values[AX25_VALUES_PROTOCOL]  = AX25_DEF_PROTOCOL;
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
 	ax25_dev->values[AX25_VALUES_DS_TIMEOUT]= AX25_DEF_DS_TIMEOUT;
+#endif
 
 #if defined(CONFIG_AX25_DAMA_SLAVE) || defined(CONFIG_AX25_DAMA_MASTER)
 	ax25_ds_setup_timer(ax25_dev);
diff --git a/net/ax25/ax25_ds_timer.c b/net/ax25/ax25_ds_timer.c
index c4f8adbf8144..c50a58d9e368 100644
--- a/net/ax25/ax25_ds_timer.c
+++ b/net/ax25/ax25_ds_timer.c
@@ -55,6 +55,7 @@  void ax25_ds_set_timer(ax25_dev *ax25_dev)
 	ax25_dev->dama.slave_timeout =
 		msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10;
 	mod_timer(&ax25_dev->dama.slave_timer, jiffies + HZ);
+	return;
 }
 
 /*
diff --git a/net/ax25/sysctl_net_ax25.c b/net/ax25/sysctl_net_ax25.c
index e0128dc9def3..68753aa30334 100644
--- a/net/ax25/sysctl_net_ax25.c
+++ b/net/ax25/sysctl_net_ax25.c
@@ -141,8 +141,6 @@  static const struct ctl_table ax25_param_table[] = {
 		.extra2		= &max_ds_timeout
 	},
 #endif
-
-	{ }	/* that's all, folks! */
 };
 
 int ax25_register_dev_sysctl(ax25_dev *ax25_dev)
@@ -155,6 +153,7 @@  int ax25_register_dev_sysctl(ax25_dev *ax25_dev)
 	if (!table)
 		return -ENOMEM;
 
+	BUILD_BUG_ON(ARRAY_SIZE(ax25_param_table) != AX25_MAX_VALUES);
 	for (k = 0; k < AX25_MAX_VALUES; k++)
 		table[k].data = &ax25_dev->values[k];
 
diff --git a/net/x25/sysctl_net_x25.c b/net/x25/sysctl_net_x25.c
index e9802afa43d0..643f50874dfe 100644
--- a/net/x25/sysctl_net_x25.c
+++ b/net/x25/sysctl_net_x25.c
@@ -71,7 +71,6 @@  static struct ctl_table x25_table[] = {
 		.mode = 	0644,
 		.proc_handler = proc_dointvec,
 	},
-	{ },
 };
 
 int __init x25_register_sysctl(void)