Commit 78a7b5db authored by Joel Granados's avatar Joel Granados Committed by David S. Miller
Browse files

ax.25: x.25: Remove the now superfluous sentinel elements from ctl_table array 

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: default avatarJoel Granados <j.granados@samsung.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e00e35e2

include/net/ax25.h

+2 −0
Original line number Diff line number Diff line
@@ -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 */

};

net/ax25/ax25_dev.c

+3 −0
Original line number Diff line number Diff line
@@ -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);

net/ax25/ax25_ds_timer.c

+1 −0
Original line number Diff line number Diff line
@@ -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;

}



/*

net/ax25/sysctl_net_ax25.c

+1 −2
Original line number Diff line number Diff line
@@ -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];

net/x25/sysctl_net_x25.c

+0 −1
Original line number Diff line number Diff line
@@ -71,7 +71,6 @@ static struct ctl_table x25_table[] = { 
		.mode = 	0644,

		.proc_handler = proc_dointvec,

	},

	{ },

};



int __init x25_register_sysctl(void)